From: Troy Mitchell <troymitchell988@gmail.com>
This patch introduces basic I2C support for the SpacemiT K1 SoC,
utilizing interrupts for transfers.
The driver has been tested using i2c-tools on a Bananapi-F3 board,
and basic I2C read/write operations have been confirmed to work.
Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com>
---
drivers/i2c/busses/Kconfig | 19 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 676 insertions(+)
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 6b3ba7e5723a..91630f55667f 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -779,6 +779,25 @@ config I2C_JZ4780
If you don't know what to do here, say N.
+config I2C_K1
+ tristate "Spacemit K1 I2C adapter"
+ depends on ARCH_SPACEMIT || COMPILE_TEST
+ depends on OF
+ help
+ This option enables support for the I2C interface on the Spacemit K1
+ platform.
+
+ If you enable this configuration, the kernel will include support for
+ the I2C adapter specific to the Spacemit K1 platform. This driver ca
+ be used to manage I2C bus transactions, which are necessary for
+ interfacing with I2C peripherals such as sensors, EEPROMs, and other
+ devices.
+
+ This driver can also be compiled as a module. If you choose to build
+ it as a module, the resulting kernel module will be named `i2c-k1`.
+ Loading this module will enable the I2C functionality for the K1
+ platform dynamically, without requiring a rebuild of the kernel.
+
config I2C_KEBA
tristate "KEBA I2C controller support"
depends on HAS_IOMEM
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index ecc07c50f2a0..9744b0e58598 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o
obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o
obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o
+obj-$(CONFIG_I2C_K1) += i2c-k1.o
obj-$(CONFIG_I2C_KEBA) += i2c-keba.o
obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o
diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
new file mode 100644
index 000000000000..12bb71625e0a
--- /dev/null
+++ b/drivers/i2c/busses/i2c-k1.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Troy Mitchell <troymitchell988@gmail.com>
+ */
+
+ #include <linux/clk.h>
+ #include <linux/i2c.h>
+ #include <linux/iopoll.h>
+ #include <linux/module.h>
+ #include <linux/of_address.h>
+ #include <linux/platform_device.h>
+
+/* spacemit i2c registers */
+#define ICR 0x0 /* Control Register */
+#define ISR 0x4 /* Status Register */
+#define ISAR 0x8 /* Slave Address Register */
+#define IDBR 0xc /* Data Buffer Register */
+#define ILCR 0x10 /* Load Count Register */
+#define IWCR 0x14 /* Wait Count Register */
+#define IRST_CYC 0x18 /* Bus reset cycle counter */
+#define IBMR 0x1c /* Bus monitor register */
+#define IWFIFO 0x20 /* Write FIFO Register */
+#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */
+#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */
+#define IRFIFO 0x2c /* Read FIFO Register */
+#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */
+#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */
+
+/* register ICR fields */
+#define CR_START BIT(0) /* start bit */
+#define CR_STOP BIT(1) /* stop bit */
+#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */
+#define CR_TB BIT(3) /* transfer byte bit */
+#define CR_TXBEGIN BIT(4) /* transaction begin */
+#define CR_FIFOEN BIT(5) /* enable FIFO mode */
+#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */
+#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */
+#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */
+#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */
+#define CR_UR BIT(10) /* unit reset */
+#define CR_RSTREQ BIT(11) /* i2c bus reset request */
+#define CR_MA BIT(12) /* master abort */
+#define CR_SCLE BIT(13) /* master clock enable */
+#define CR_IUE BIT(14) /* unit enable */
+#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */
+#define CR_ALDIE BIT(18) /* enable arbitration interrupt */
+#define CR_DTEIE BIT(19) /* enable tx interrupts */
+#define CR_DRFIE BIT(20) /* enable rx interrupts */
+#define CR_GCD BIT(21) /* general call disable */
+#define CR_BEIE BIT(22) /* enable bus error ints */
+#define CR_SADIE BIT(23) /* slave address detected int enable */
+#define CR_SSDIE BIT(24) /* slave STOP detected int enable */
+#define CR_MSDIE BIT(25) /* master STOP detected int enable */
+#define CR_MSDE BIT(26) /* master STOP detected enable */
+#define CR_TXDONEIE BIT(27) /* transaction done int enable */
+#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */
+#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */
+#define CR_RXFIE BIT(30) /* receive FIFO full int enable */
+#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */
+
+/* register ISR fields */
+#define SR_RWM BIT(13) /* read/write mode */
+#define SR_ACKNAK BIT(14) /* ACK/NACK status */
+#define SR_UB BIT(15) /* unit busy */
+#define SR_IBB BIT(16) /* i2c bus busy */
+#define SR_EBB BIT(17) /* early bus busy */
+#define SR_ALD BIT(18) /* arbitration loss detected */
+#define SR_ITE BIT(19) /* tx buffer empty */
+#define SR_IRF BIT(20) /* rx buffer full */
+#define SR_GCAD BIT(21) /* general call address detected */
+#define SR_BED BIT(22) /* bus error no ACK/NAK */
+#define SR_SAD BIT(23) /* slave address detected */
+#define SR_SSD BIT(24) /* slave stop detected */
+#define SR_MSD BIT(26) /* master stop detected */
+#define SR_TXDONE BIT(27) /* transaction done */
+#define SR_TXE BIT(28) /* tx FIFO empty */
+#define SR_RXHF BIT(29) /* rx FIFO half-full */
+#define SR_RXF BIT(30) /* rx FIFO full */
+#define SR_RXOV BIT(31) /* RX FIFO overrun */
+
+/* register ILCR fields */
+#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */
+#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */
+#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */
+#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */
+
+/* register IWCR fields */
+#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */
+#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */
+#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */
+
+/* register IBMR fields */
+#define BMR_SDA BIT(0) /* SDA line level */
+#define BMR_SCL BIT(1) /* SCL line level */
+
+/* register IWFIFO fields */
+#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */
+#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */
+#define WFIFO_CTRL_START BIT(8) /* start bit */
+#define WFIFO_CTRL_STOP BIT(9) /* stop bit */
+#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */
+#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */
+
+/* status register init value */
+#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */
+#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \
+ CR_BEIE | CR_TXDONEIE | CR_TXEIE | \
+ CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \
+ CR_MSDIE)
+
+/* i2c bus recover timeout: us */
+#define I2C_BUS_RECOVER_TIMEOUT (100000)
+
+#define I2C_FAST_MODE_FREQ (400000)
+
+enum spacemit_i2c_state {
+ STATE_IDLE,
+ STATE_START,
+ STATE_READ,
+ STATE_WRITE,
+};
+
+enum spacemit_i2c_dir {
+ DIR_WRITE,
+ DIR_READ
+};
+
+/* i2c-spacemit driver's main struct */
+struct spacemit_i2c_dev {
+ struct device *dev;
+ struct i2c_adapter adapt;
+
+ /* hardware resources */
+ void __iomem *base;
+ int irq;
+
+ struct i2c_msg *msgs;
+ int msg_num;
+ struct i2c_msg *cur_msg;
+
+ /* index of the current message being processed */
+ int msg_idx;
+ u8 *msg_buf;
+ /* the number of unprocessed bytes remaining in each message */
+ size_t unprocessed;
+
+ enum spacemit_i2c_state state;
+ enum spacemit_i2c_dir dir;
+ struct completion complete;
+ u32 status;
+ u32 err;
+};
+
+static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c)
+{
+ u32 val;
+
+ val = readl(i2c->base + ICR);
+ writel(val | CR_IUE, i2c->base + ICR);
+}
+
+static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c)
+{
+ u32 val;
+
+ val = readl(i2c->base + ICR);
+ val &= ~CR_IUE;
+ writel(val, i2c->base + ICR);
+}
+
+static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c)
+{
+ writel(CR_UR, i2c->base + ICR);
+ udelay(5);
+ writel(0, i2c->base + ICR);
+}
+
+static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c);
+
+static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c)
+{
+ u32 status;
+
+ /* if bus is locked, reset unit. 0: locked */
+ status = readl(i2c->base + IBMR);
+ if ((status & BMR_SDA) && (status & BMR_SCL))
+ return;
+
+ spacemit_i2c_reset(i2c);
+ usleep_range(10, 20);
+
+ /* check scl status again */
+ status = readl(i2c->base + IBMR);
+ if (!(status & BMR_SCL))
+ dev_warn_ratelimited(i2c->dev, "unit reset failed\n");
+}
+
+static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c)
+{
+ int ret = 0;
+ u32 val;
+
+ val = readl(i2c->base + ISR);
+ if (likely(!(val & (SR_UB | SR_IBB))))
+ return 0;
+
+ ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)),
+ 1500, I2C_BUS_RECOVER_TIMEOUT);
+ if (unlikely(ret)) {
+ spacemit_i2c_reset(i2c);
+ ret = -EAGAIN;
+ }
+
+ return ret;
+}
+
+static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c)
+{
+ /* in case bus is not released after transfer completes */
+ if (unlikely(readl(i2c->base + ISR) & SR_EBB)) {
+ spacemit_i2c_bus_reset(i2c);
+ usleep_range(90, 150);
+ }
+}
+
+static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c)
+{
+ u32 val = 0;
+
+ /*
+ * Unmask interrupt bits for all xfer mode:
+ * bus error, arbitration loss detected.
+ * For transaction complete signal, we use master stop
+ * interrupt, so we don't need to unmask CR_TXDONEIE.
+ */
+ val |= CR_BEIE | CR_ALDIE;
+
+ /*
+ * Unmask interrupt bits for interrupt xfer mode:
+ * DBR rx full.
+ * For tx empty interrupt CR_DTEIE, we only
+ * need to enable when trigger byte transfer to start
+ * data sending.
+ */
+ val |= CR_DRFIE;
+
+ /* set speed bits: default fast mode */
+ val |= CR_MODE_FAST;
+
+ /* disable response to general call */
+ val |= CR_GCD;
+
+ /* enable SCL clock output */
+ val |= CR_SCLE;
+
+ /* enable master stop detected */
+ val |= CR_MSDE | CR_MSDIE;
+
+ writel(val, i2c->base + ICR);
+}
+
+static inline void
+spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask)
+{
+ writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR);
+}
+
+static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)
+{
+ u32 slave_addr_rw, val;
+
+ i2c->dir = i2c->cur_msg->flags & I2C_M_RD;
+ i2c->state = STATE_START;
+
+ if (i2c->cur_msg->flags & I2C_M_RD)
+ slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1;
+ else
+ slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1;
+
+ writel(slave_addr_rw, i2c->base + IDBR);
+
+ val = readl(i2c->base + ICR);
+
+ /* send start pulse */
+ val &= ~CR_STOP;
+ val |= CR_START | CR_TB | CR_DTEIE;
+ writel(val, i2c->base + ICR);
+}
+
+static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c)
+{
+ u32 val;
+
+ val = readl(i2c->base + ICR);
+
+ val |= CR_STOP | CR_ALDIE | CR_TB;
+
+ if (i2c->dir == DIR_READ)
+ val |= CR_ACKNAK;
+
+ writel(val, i2c->base + ICR);
+}
+
+static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
+{
+ unsigned long time_left;
+
+ for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
+ i2c->cur_msg = i2c->msgs + i2c->msg_idx;
+ i2c->msg_buf = i2c->cur_msg->buf;
+ i2c->err = 0;
+ i2c->status = 0;
+ i2c->unprocessed = i2c->cur_msg->len;
+
+ reinit_completion(&i2c->complete);
+
+ spacemit_i2c_start(i2c);
+
+ time_left = wait_for_completion_timeout(&i2c->complete,
+ i2c->adapt.timeout);
+ if (unlikely(time_left == 0)) {
+ dev_alert(i2c->dev, "msg completion timeout\n");
+ spacemit_i2c_bus_reset(i2c);
+ spacemit_i2c_reset(i2c);
+ return -ETIMEDOUT;
+ }
+
+ if (unlikely(i2c->err))
+ return spacemit_i2c_handle_err(i2c);
+ }
+
+ return 0;
+}
+
+static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c)
+{
+ if (i2c->dir == DIR_READ) {
+ if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1)
+ return 1;
+ } else if (i2c->dir == DIR_WRITE) {
+ if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1)
+ return 1;
+ }
+
+ return 0;
+}
+
+static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c)
+{
+ /* if transfer completes, ISR will handle it */
+ if (i2c->status & SR_MSD)
+ return;
+
+ if (i2c->unprocessed) {
+ writel(*i2c->msg_buf++, i2c->base + IDBR);
+ i2c->unprocessed--;
+ return;
+ }
+
+ /* STATE_IDLE avoids trigger next byte */
+ i2c->state = STATE_IDLE;
+ complete(&i2c->complete);
+}
+
+static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c)
+{
+ if (i2c->unprocessed) {
+ *i2c->msg_buf++ = readl(i2c->base + IDBR);
+ i2c->unprocessed--;
+ }
+
+ /* if transfer completes, ISR will handle it */
+ if (i2c->status & (SR_MSD | SR_ACKNAK))
+ return;
+
+ /* it has to append stop bit in icr that read last byte */
+ if (i2c->unprocessed)
+ return;
+
+ /* STATE_IDLE avoids trigger next byte */
+ i2c->state = STATE_IDLE;
+ complete(&i2c->complete);
+}
+
+static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c)
+{
+ if (i2c->dir == DIR_READ) {
+ i2c->state = STATE_READ;
+ return;
+ }
+
+ if (i2c->dir == DIR_WRITE) {
+ i2c->state = STATE_WRITE;
+ spacemit_i2c_handle_write(i2c);
+ }
+}
+
+static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c)
+{
+ if (!i2c->err)
+ return 0;
+
+ dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status);
+
+ if (i2c->err & (SR_BED | SR_ALD))
+ spacemit_i2c_reset(i2c);
+
+ if (i2c->err & (SR_RXOV | SR_ALD))
+ return -EAGAIN;
+
+ return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO;
+}
+
+static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c)
+{
+ u32 val;
+ /*
+ * send transaction complete signal:
+ * error happens, detect master stop
+ */
+ if (likely(i2c->err || (i2c->status & SR_MSD))) {
+ /*
+ * Here the transaction is already done, we don't need any
+ * other interrupt signals from now, in case any interrupt
+ * happens before spacemit_i2c_xfer to disable irq and i2c unit,
+ * we mask all the interrupt signals and clear the interrupt
+ * status.
+ */
+ val = readl(i2c->base + ICR);
+ val &= ~I2C_INT_CTRL_MASK;
+ writel(val, i2c->base + ICR);
+
+ spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK);
+
+ i2c->state = STATE_IDLE;
+ complete(&i2c->complete);
+ }
+}
+
+static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
+{
+ struct spacemit_i2c_dev *i2c = devid;
+ u32 status, val;
+
+ status = readl(i2c->base + ISR);
+ if (!status)
+ return IRQ_HANDLED;
+
+ i2c->status = status;
+
+ i2c->err = status & (SR_BED | SR_RXOV | SR_ALD);
+
+ spacemit_i2c_clear_int_status(i2c, status);
+
+ if (unlikely(i2c->err))
+ goto err_out;
+
+ val = readl(i2c->base + ICR);
+
+ val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START);
+ writel(val, i2c->base + ICR);
+
+ switch (i2c->state) {
+ case STATE_START:
+ spacemit_i2c_handle_start(i2c);
+ break;
+ case STATE_READ:
+ spacemit_i2c_handle_read(i2c);
+ break;
+ case STATE_WRITE:
+ spacemit_i2c_handle_write(i2c);
+ break;
+ default:
+ break;
+ }
+
+ if (i2c->state != STATE_IDLE) {
+ if (spacemit_i2c_is_last_msg(i2c)) {
+ /* trigger next byte with stop */
+ spacemit_i2c_stop(i2c);
+ } else {
+ /* trigger next byte */
+ val |= CR_ALDIE | CR_TB;
+ writel(val, i2c->base + ICR);
+ }
+ }
+
+err_out:
+ spacemit_i2c_err_check(i2c);
+ return IRQ_HANDLED;
+}
+
+static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c)
+{
+ unsigned long timeout;
+ int idx = 0, cnt = 0, freq;
+
+ while (idx < i2c->msg_num) {
+ cnt += (i2c->msgs + idx)->len + 1;
+ idx++;
+ }
+
+ freq = I2C_FAST_MODE_FREQ;
+ /*
+ * multiply by 9 because each byte in I2C transmission requires
+ * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit.
+ */
+ timeout = cnt * 9 * USEC_PER_SEC / freq;
+
+ i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num;
+}
+
+static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c)
+{
+ int ret = 0;
+
+ spacemit_i2c_reset(i2c);
+
+ spacemit_i2c_calc_timeout(i2c);
+
+ spacemit_i2c_init(i2c);
+
+ spacemit_i2c_enable(i2c);
+ enable_irq(i2c->irq);
+
+ /* i2c wait for bus busy */
+ ret = spacemit_i2c_recover_bus_busy(i2c);
+ if (unlikely(ret))
+ return ret;
+
+ ret = spacemit_i2c_xfer_msg(i2c);
+ if (unlikely(ret < 0)) {
+ dev_dbg(i2c->dev, "i2c transfer error\n");
+ /* timeout error should not be overridden, and the transfer
+ * error will be confirmed by err handle function latter,
+ * the reset should be invalid argument error.
+ */
+ if (ret != -ETIMEDOUT)
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int
+spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num)
+{
+ struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt);
+ int ret;
+
+ i2c->msgs = msgs;
+ i2c->msg_num = num;
+
+ ret = spacemit_i2c_xfer_core(i2c);
+ if (likely(!ret))
+ spacemit_i2c_check_bus_release(i2c);
+
+ disable_irq(i2c->irq);
+
+ spacemit_i2c_disable(i2c);
+
+ if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN)))
+ dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err);
+
+ return ret < 0 ? ret : num;
+}
+
+static u32 spacemit_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static const struct i2c_algorithm spacemit_i2c_algo = {
+ .xfer = spacemit_i2c_xfer,
+ .functionality = spacemit_i2c_func,
+};
+
+static int spacemit_i2c_probe(struct platform_device *pdev)
+{
+ struct spacemit_i2c_dev *i2c;
+ struct device_node *of_node = pdev->dev.of_node;
+ struct clk *clk;
+ int ret = 0;
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ i2c->dev = &pdev->dev;
+
+ i2c->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(i2c->base))
+ return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap");
+
+ i2c->irq = platform_get_irq(pdev, 0);
+ if (i2c->irq < 0)
+ return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource");
+
+ ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
+ IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "failed to request irq");
+
+ disable_irq(i2c->irq);
+
+ clk = devm_clk_get_enabled(&pdev->dev, NULL);
+ if (IS_ERR(clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock");
+
+ i2c_set_adapdata(&i2c->adapt, i2c);
+ i2c->adapt.owner = THIS_MODULE;
+ i2c->adapt.algo = &spacemit_i2c_algo;
+ i2c->adapt.dev.parent = i2c->dev;
+ i2c->adapt.nr = pdev->id;
+
+ i2c->adapt.dev.of_node = of_node;
+ i2c->adapt.algo_data = i2c;
+
+ strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
+
+ init_completion(&i2c->complete);
+
+ ret = i2c_add_numbered_adapter(&i2c->adapt);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
+
+ platform_set_drvdata(pdev, i2c);
+
+ return 0;
+}
+
+static void spacemit_i2c_remove(struct platform_device *pdev)
+{
+ struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c->adapt);
+}
+
+static const struct of_device_id spacemit_i2c_of_match[] = {
+ { .compatible = "spacemit,k1-i2c", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
+
+static struct platform_driver spacemit_i2c_driver = {
+ .probe = spacemit_i2c_probe,
+ .remove = spacemit_i2c_remove,
+ .driver = {
+ .name = "i2c-k1",
+ .of_match_table = spacemit_i2c_of_match,
+ },
+};
+module_platform_driver(spacemit_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");
--
2.34.1On 11:07 Tue 12 Nov , Troy Mitchell wrote:
> From: Troy Mitchell <troymitchell988@gmail.com>
>
> This patch introduces basic I2C support for the SpacemiT K1 SoC,
> utilizing interrupts for transfers.
>
> The driver has been tested using i2c-tools on a Bananapi-F3 board,
> and basic I2C read/write operations have been confirmed to work.
>
> Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com>
> ---
> drivers/i2c/busses/Kconfig | 19 ++
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 676 insertions(+)
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 6b3ba7e5723a..91630f55667f 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -779,6 +779,25 @@ config I2C_JZ4780
>
> If you don't know what to do here, say N.
>
> +config I2C_K1
> + tristate "Spacemit K1 I2C adapter"
> + depends on ARCH_SPACEMIT || COMPILE_TEST
> + depends on OF
> + help
> + This option enables support for the I2C interface on the Spacemit K1
> + platform.
> +
> + If you enable this configuration, the kernel will include support for
> + the I2C adapter specific to the Spacemit K1 platform. This driver ca
> + be used to manage I2C bus transactions, which are necessary for
> + interfacing with I2C peripherals such as sensors, EEPROMs, and other
> + devices.
> +
> + This driver can also be compiled as a module. If you choose to build
> + it as a module, the resulting kernel module will be named `i2c-k1`.
> + Loading this module will enable the I2C functionality for the K1
> + platform dynamically, without requiring a rebuild of the kernel.
> +
> config I2C_KEBA
> tristate "KEBA I2C controller support"
> depends on HAS_IOMEM
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index ecc07c50f2a0..9744b0e58598 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o
> obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o
> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
> obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o
> +obj-$(CONFIG_I2C_K1) += i2c-k1.o
> obj-$(CONFIG_I2C_KEBA) += i2c-keba.o
> obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
> obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o
> diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
> new file mode 100644
> index 000000000000..12bb71625e0a
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-k1.c
> @@ -0,0 +1,656 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2024 Troy Mitchell <troymitchell988@gmail.com>
> + */
> +
> + #include <linux/clk.h>
> + #include <linux/i2c.h>
> + #include <linux/iopoll.h>
> + #include <linux/module.h>
> + #include <linux/of_address.h>
> + #include <linux/platform_device.h>
> +
> +/* spacemit i2c registers */
> +#define ICR 0x0 /* Control Register */
> +#define ISR 0x4 /* Status Register */
> +#define ISAR 0x8 /* Slave Address Register */
> +#define IDBR 0xc /* Data Buffer Register */
> +#define ILCR 0x10 /* Load Count Register */
> +#define IWCR 0x14 /* Wait Count Register */
> +#define IRST_CYC 0x18 /* Bus reset cycle counter */
> +#define IBMR 0x1c /* Bus monitor register */
> +#define IWFIFO 0x20 /* Write FIFO Register */
> +#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */
> +#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */
> +#define IRFIFO 0x2c /* Read FIFO Register */
> +#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */
> +#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */
> +
> +/* register ICR fields */
> +#define CR_START BIT(0) /* start bit */
> +#define CR_STOP BIT(1) /* stop bit */
> +#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */
> +#define CR_TB BIT(3) /* transfer byte bit */
> +#define CR_TXBEGIN BIT(4) /* transaction begin */
> +#define CR_FIFOEN BIT(5) /* enable FIFO mode */
> +#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */
> +#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */
> +#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */
> +#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */
> +#define CR_UR BIT(10) /* unit reset */
> +#define CR_RSTREQ BIT(11) /* i2c bus reset request */
> +#define CR_MA BIT(12) /* master abort */
> +#define CR_SCLE BIT(13) /* master clock enable */
> +#define CR_IUE BIT(14) /* unit enable */
> +#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */
> +#define CR_ALDIE BIT(18) /* enable arbitration interrupt */
> +#define CR_DTEIE BIT(19) /* enable tx interrupts */
> +#define CR_DRFIE BIT(20) /* enable rx interrupts */
> +#define CR_GCD BIT(21) /* general call disable */
> +#define CR_BEIE BIT(22) /* enable bus error ints */
> +#define CR_SADIE BIT(23) /* slave address detected int enable */
> +#define CR_SSDIE BIT(24) /* slave STOP detected int enable */
> +#define CR_MSDIE BIT(25) /* master STOP detected int enable */
> +#define CR_MSDE BIT(26) /* master STOP detected enable */
> +#define CR_TXDONEIE BIT(27) /* transaction done int enable */
> +#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */
> +#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */
> +#define CR_RXFIE BIT(30) /* receive FIFO full int enable */
> +#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */
> +
> +/* register ISR fields */
> +#define SR_RWM BIT(13) /* read/write mode */
> +#define SR_ACKNAK BIT(14) /* ACK/NACK status */
> +#define SR_UB BIT(15) /* unit busy */
> +#define SR_IBB BIT(16) /* i2c bus busy */
> +#define SR_EBB BIT(17) /* early bus busy */
> +#define SR_ALD BIT(18) /* arbitration loss detected */
> +#define SR_ITE BIT(19) /* tx buffer empty */
> +#define SR_IRF BIT(20) /* rx buffer full */
> +#define SR_GCAD BIT(21) /* general call address detected */
> +#define SR_BED BIT(22) /* bus error no ACK/NAK */
> +#define SR_SAD BIT(23) /* slave address detected */
> +#define SR_SSD BIT(24) /* slave stop detected */
> +#define SR_MSD BIT(26) /* master stop detected */
> +#define SR_TXDONE BIT(27) /* transaction done */
> +#define SR_TXE BIT(28) /* tx FIFO empty */
> +#define SR_RXHF BIT(29) /* rx FIFO half-full */
> +#define SR_RXF BIT(30) /* rx FIFO full */
> +#define SR_RXOV BIT(31) /* RX FIFO overrun */
> +
> +/* register ILCR fields */
> +#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */
> +#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */
> +#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */
> +#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */
> +
> +/* register IWCR fields */
> +#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */
> +#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */
> +#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */
> +
> +/* register IBMR fields */
> +#define BMR_SDA BIT(0) /* SDA line level */
> +#define BMR_SCL BIT(1) /* SCL line level */
> +
> +/* register IWFIFO fields */
> +#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */
> +#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */
> +#define WFIFO_CTRL_START BIT(8) /* start bit */
> +#define WFIFO_CTRL_STOP BIT(9) /* stop bit */
> +#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */
> +#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */
> +
> +/* status register init value */
> +#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */
> +#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \
> + CR_BEIE | CR_TXDONEIE | CR_TXEIE | \
> + CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \
> + CR_MSDIE)
> +
> +/* i2c bus recover timeout: us */
> +#define I2C_BUS_RECOVER_TIMEOUT (100000)
> +
> +#define I2C_FAST_MODE_FREQ (400000)
> +
> +enum spacemit_i2c_state {
> + STATE_IDLE,
> + STATE_START,
> + STATE_READ,
> + STATE_WRITE,
> +};
> +
> +enum spacemit_i2c_dir {
> + DIR_WRITE,
> + DIR_READ
> +};
> +
> +/* i2c-spacemit driver's main struct */
> +struct spacemit_i2c_dev {
> + struct device *dev;
> + struct i2c_adapter adapt;
> +
> + /* hardware resources */
> + void __iomem *base;
> + int irq;
> +
> + struct i2c_msg *msgs;
> + int msg_num;
> + struct i2c_msg *cur_msg;
> +
> + /* index of the current message being processed */
> + int msg_idx;
> + u8 *msg_buf;
> + /* the number of unprocessed bytes remaining in each message */
> + size_t unprocessed;
> +
> + enum spacemit_i2c_state state;
> + enum spacemit_i2c_dir dir;
> + struct completion complete;
> + u32 status;
> + u32 err;
> +};
> +
> +static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> +
> + val = readl(i2c->base + ICR);
> + writel(val | CR_IUE, i2c->base + ICR);
> +}
> +
> +static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> +
> + val = readl(i2c->base + ICR);
> + val &= ~CR_IUE;
> + writel(val, i2c->base + ICR);
> +}
> +
> +static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c)
> +{
> + writel(CR_UR, i2c->base + ICR);
> + udelay(5);
> + writel(0, i2c->base + ICR);
> +}
> +
> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c);
> +
> +static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c)
> +{
> + u32 status;
> +
> + /* if bus is locked, reset unit. 0: locked */
> + status = readl(i2c->base + IBMR);
> + if ((status & BMR_SDA) && (status & BMR_SCL))
> + return;
> +
> + spacemit_i2c_reset(i2c);
> + usleep_range(10, 20);
> +
> + /* check scl status again */
> + status = readl(i2c->base + IBMR);
> + if (!(status & BMR_SCL))
> + dev_warn_ratelimited(i2c->dev, "unit reset failed\n");
> +}
> +
> +static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c)
> +{
> + int ret = 0;
> + u32 val;
> +
> + val = readl(i2c->base + ISR);
> + if (likely(!(val & (SR_UB | SR_IBB))))
> + return 0;
> +
> + ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)),
> + 1500, I2C_BUS_RECOVER_TIMEOUT);
> + if (unlikely(ret)) {
> + spacemit_i2c_reset(i2c);
> + ret = -EAGAIN;
> + }
> +
> + return ret;
> +}
> +
> +static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c)
> +{
> + /* in case bus is not released after transfer completes */
> + if (unlikely(readl(i2c->base + ISR) & SR_EBB)) {
> + spacemit_i2c_bus_reset(i2c);
> + usleep_range(90, 150);
> + }
> +}
> +
> +static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val = 0;
> +
> + /*
> + * Unmask interrupt bits for all xfer mode:
> + * bus error, arbitration loss detected.
> + * For transaction complete signal, we use master stop
> + * interrupt, so we don't need to unmask CR_TXDONEIE.
> + */
> + val |= CR_BEIE | CR_ALDIE;
> +
> + /*
> + * Unmask interrupt bits for interrupt xfer mode:
> + * DBR rx full.
> + * For tx empty interrupt CR_DTEIE, we only
> + * need to enable when trigger byte transfer to start
> + * data sending.
> + */
> + val |= CR_DRFIE;
> +
> + /* set speed bits: default fast mode */
> + val |= CR_MODE_FAST;
> +
> + /* disable response to general call */
> + val |= CR_GCD;
> +
> + /* enable SCL clock output */
> + val |= CR_SCLE;
> +
> + /* enable master stop detected */
> + val |= CR_MSDE | CR_MSDIE;
> +
> + writel(val, i2c->base + ICR);
> +}
> +
> +static inline void
> +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask)
> +{
> + writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR);
> +}
> +
> +static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)
> +{
> + u32 slave_addr_rw, val;
> +
> + i2c->dir = i2c->cur_msg->flags & I2C_M_RD;
> + i2c->state = STATE_START;
> +
> + if (i2c->cur_msg->flags & I2C_M_RD)
> + slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1;
> + else
> + slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1;
> +
> + writel(slave_addr_rw, i2c->base + IDBR);
> +
> + val = readl(i2c->base + ICR);
> +
> + /* send start pulse */
> + val &= ~CR_STOP;
> + val |= CR_START | CR_TB | CR_DTEIE;
> + writel(val, i2c->base + ICR);
> +}
> +
> +static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> +
> + val = readl(i2c->base + ICR);
> +
> + val |= CR_STOP | CR_ALDIE | CR_TB;
> +
> + if (i2c->dir == DIR_READ)
> + val |= CR_ACKNAK;
> +
> + writel(val, i2c->base + ICR);
> +}
> +
> +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
> +{
> + unsigned long time_left;
> +
> + for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
> + i2c->cur_msg = i2c->msgs + i2c->msg_idx;
> + i2c->msg_buf = i2c->cur_msg->buf;
> + i2c->err = 0;
> + i2c->status = 0;
> + i2c->unprocessed = i2c->cur_msg->len;
> +
> + reinit_completion(&i2c->complete);
> +
> + spacemit_i2c_start(i2c);
> +
> + time_left = wait_for_completion_timeout(&i2c->complete,
> + i2c->adapt.timeout);
> + if (unlikely(time_left == 0)) {
> + dev_alert(i2c->dev, "msg completion timeout\n");
> + spacemit_i2c_bus_reset(i2c);
> + spacemit_i2c_reset(i2c);
> + return -ETIMEDOUT;
> + }
> +
> + if (unlikely(i2c->err))
> + return spacemit_i2c_handle_err(i2c);
> + }
> +
> + return 0;
> +}
> +
> +static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c)
> +{
> + if (i2c->dir == DIR_READ) {
> + if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1)
> + return 1;
> + } else if (i2c->dir == DIR_WRITE) {
> + if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1)
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c)
> +{
> + /* if transfer completes, ISR will handle it */
> + if (i2c->status & SR_MSD)
> + return;
> +
> + if (i2c->unprocessed) {
> + writel(*i2c->msg_buf++, i2c->base + IDBR);
> + i2c->unprocessed--;
> + return;
> + }
> +
> + /* STATE_IDLE avoids trigger next byte */
> + i2c->state = STATE_IDLE;
> + complete(&i2c->complete);
> +}
> +
> +static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c)
> +{
> + if (i2c->unprocessed) {
> + *i2c->msg_buf++ = readl(i2c->base + IDBR);
> + i2c->unprocessed--;
> + }
> +
> + /* if transfer completes, ISR will handle it */
> + if (i2c->status & (SR_MSD | SR_ACKNAK))
> + return;
> +
> + /* it has to append stop bit in icr that read last byte */
> + if (i2c->unprocessed)
> + return;
> +
> + /* STATE_IDLE avoids trigger next byte */
> + i2c->state = STATE_IDLE;
> + complete(&i2c->complete);
> +}
> +
> +static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c)
> +{
> + if (i2c->dir == DIR_READ) {
> + i2c->state = STATE_READ;
> + return;
> + }
> +
> + if (i2c->dir == DIR_WRITE) {
> + i2c->state = STATE_WRITE;
> + spacemit_i2c_handle_write(i2c);
> + }
> +}
> +
> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c)
> +{
> + if (!i2c->err)
> + return 0;
> +
> + dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status);
> +
> + if (i2c->err & (SR_BED | SR_ALD))
> + spacemit_i2c_reset(i2c);
> +
> + if (i2c->err & (SR_RXOV | SR_ALD))
> + return -EAGAIN;
> +
> + return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO;
> +}
> +
> +static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> + /*
> + * send transaction complete signal:
> + * error happens, detect master stop
> + */
> + if (likely(i2c->err || (i2c->status & SR_MSD))) {
> + /*
> + * Here the transaction is already done, we don't need any
> + * other interrupt signals from now, in case any interrupt
> + * happens before spacemit_i2c_xfer to disable irq and i2c unit,
> + * we mask all the interrupt signals and clear the interrupt
> + * status.
> + */
> + val = readl(i2c->base + ICR);
> + val &= ~I2C_INT_CTRL_MASK;
> + writel(val, i2c->base + ICR);
> +
> + spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK);
> +
> + i2c->state = STATE_IDLE;
> + complete(&i2c->complete);
> + }
> +}
> +
> +static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
> +{
> + struct spacemit_i2c_dev *i2c = devid;
> + u32 status, val;
> +
> + status = readl(i2c->base + ISR);
> + if (!status)
> + return IRQ_HANDLED;
> +
> + i2c->status = status;
> +
> + i2c->err = status & (SR_BED | SR_RXOV | SR_ALD);
> +
> + spacemit_i2c_clear_int_status(i2c, status);
> +
> + if (unlikely(i2c->err))
> + goto err_out;
> +
> + val = readl(i2c->base + ICR);
> +
> + val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START);
> + writel(val, i2c->base + ICR);
> +
> + switch (i2c->state) {
> + case STATE_START:
> + spacemit_i2c_handle_start(i2c);
> + break;
> + case STATE_READ:
> + spacemit_i2c_handle_read(i2c);
> + break;
> + case STATE_WRITE:
> + spacemit_i2c_handle_write(i2c);
> + break;
> + default:
> + break;
> + }
> +
> + if (i2c->state != STATE_IDLE) {
> + if (spacemit_i2c_is_last_msg(i2c)) {
> + /* trigger next byte with stop */
> + spacemit_i2c_stop(i2c);
> + } else {
> + /* trigger next byte */
> + val |= CR_ALDIE | CR_TB;
> + writel(val, i2c->base + ICR);
> + }
> + }
> +
> +err_out:
> + spacemit_i2c_err_check(i2c);
> + return IRQ_HANDLED;
> +}
> +
> +static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c)
> +{
> + unsigned long timeout;
> + int idx = 0, cnt = 0, freq;
> +
> + while (idx < i2c->msg_num) {
> + cnt += (i2c->msgs + idx)->len + 1;
> + idx++;
> + }
> +
> + freq = I2C_FAST_MODE_FREQ;
so this will set frequency to fast mode (400K), this contradict with PATCH[1/2] which
says default clock-frequency is 100000, either you need to change the code? or
update the dt-binding?
> + /*
> + * multiply by 9 because each byte in I2C transmission requires
> + * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit.
> + */
> + timeout = cnt * 9 * USEC_PER_SEC / freq;
> +
> + i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num;
> +}
> +
> +static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c)
drop inline? IMO, it isn't worth here for long function
> +{
> + int ret = 0;
no need to initilize to 0
> +
> + spacemit_i2c_reset(i2c);
> +
> + spacemit_i2c_calc_timeout(i2c);
> +
> + spacemit_i2c_init(i2c);
> +
> + spacemit_i2c_enable(i2c);
> + enable_irq(i2c->irq);
> +
> + /* i2c wait for bus busy */
> + ret = spacemit_i2c_recover_bus_busy(i2c);
> + if (unlikely(ret))
> + return ret;
> +
> + ret = spacemit_i2c_xfer_msg(i2c);
> + if (unlikely(ret < 0)) {
> + dev_dbg(i2c->dev, "i2c transfer error\n");
> + /* timeout error should not be overridden, and the transfer
> + * error will be confirmed by err handle function latter,
> + * the reset should be invalid argument error.
> + */
> + if (ret != -ETIMEDOUT)
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static int
> +spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num)
no need to wrap the line, it makes the code a little bit weird..
current policy increase to 100characters, the old 80-column is not enforced
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdc48fa11e46f867ea4d75fa59ee87a7f48be144
> +{
> + struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt);
> + int ret;
> +
> + i2c->msgs = msgs;
> + i2c->msg_num = num;
> +
> + ret = spacemit_i2c_xfer_core(i2c);
> + if (likely(!ret))
> + spacemit_i2c_check_bus_release(i2c);
> +
> + disable_irq(i2c->irq);
> +
> + spacemit_i2c_disable(i2c);
> +
> + if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN)))
> + dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err);
> +
> + return ret < 0 ? ret : num;
> +}
> +
> +static u32 spacemit_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
> +}
> +
> +static const struct i2c_algorithm spacemit_i2c_algo = {
> + .xfer = spacemit_i2c_xfer,
> + .functionality = spacemit_i2c_func,
> +};
> +
> +static int spacemit_i2c_probe(struct platform_device *pdev)
> +{
> + struct spacemit_i2c_dev *i2c;
> + struct device_node *of_node = pdev->dev.of_node;
> + struct clk *clk;
> + int ret = 0;
> +
> + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
> + if (!i2c)
> + return -ENOMEM;
> +
> + i2c->dev = &pdev->dev;
> +
> + i2c->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(i2c->base))
> + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap");
> +
> + i2c->irq = platform_get_irq(pdev, 0);
> + if (i2c->irq < 0)
> + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource");
> +
> + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
> + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret, "failed to request irq");
> +
> + disable_irq(i2c->irq);
> +
> + clk = devm_clk_get_enabled(&pdev->dev, NULL);
> + if (IS_ERR(clk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock");
> +
I'd suggest also to handle pin request here, since pinctrl driver is merged
https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/
> + i2c_set_adapdata(&i2c->adapt, i2c);
> + i2c->adapt.owner = THIS_MODULE;
> + i2c->adapt.algo = &spacemit_i2c_algo;
> + i2c->adapt.dev.parent = i2c->dev;
> + i2c->adapt.nr = pdev->id;
> +
> + i2c->adapt.dev.of_node = of_node;
> + i2c->adapt.algo_data = i2c;
> +
> + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
> +
> + init_completion(&i2c->complete);
> +
> + ret = i2c_add_numbered_adapter(&i2c->adapt);
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
> +
> + platform_set_drvdata(pdev, i2c);
> +
> + return 0;
> +}
> +
> +static void spacemit_i2c_remove(struct platform_device *pdev)
> +{
> + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
> +
> + i2c_del_adapter(&i2c->adapt);
> +}
> +
> +static const struct of_device_id spacemit_i2c_of_match[] = {
> + { .compatible = "spacemit,k1-i2c", },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
> +
> +static struct platform_driver spacemit_i2c_driver = {
> + .probe = spacemit_i2c_probe,
> + .remove = spacemit_i2c_remove,
> + .driver = {
> + .name = "i2c-k1",
> + .of_match_table = spacemit_i2c_of_match,
> + },
> +};
> +module_platform_driver(spacemit_i2c_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");
>
> --
> 2.34.1
>
--
Yixun Lan (dlan)
Gentoo Linux Developer
GPG Key ID AABEFD55
Hi, Yixun. thanks for ur review.
On 2024/11/14 14:49, Yixun Lan wrote:
> On 11:07 Tue 12 Nov , Troy Mitchell wrote:
>> From: Troy Mitchell <troymitchell988@gmail.com>
>>
>> This patch introduces basic I2C support for the SpacemiT K1 SoC,
>> utilizing interrupts for transfers.
>>
>> The driver has been tested using i2c-tools on a Bananapi-F3 board,
>> and basic I2C read/write operations have been confirmed to work.
>>
>> Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com>
>> ---
>> drivers/i2c/busses/Kconfig | 19 ++
>> drivers/i2c/busses/Makefile | 1 +
>> drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 676 insertions(+)
>>
>> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
>> index 6b3ba7e5723a..91630f55667f 100644
>> --- a/drivers/i2c/busses/Kconfig
>> +++ b/drivers/i2c/busses/Kconfig
>> @@ -779,6 +779,25 @@ config I2C_JZ4780
>>
>> If you don't know what to do here, say N.
>>
>> +config I2C_K1
>> + tristate "Spacemit K1 I2C adapter"
>> + depends on ARCH_SPACEMIT || COMPILE_TEST
>> + depends on OF
>> + help
>> + This option enables support for the I2C interface on the Spacemit K1
>> + platform.
>> +
>> + If you enable this configuration, the kernel will include support for
>> + the I2C adapter specific to the Spacemit K1 platform. This driver ca
>> + be used to manage I2C bus transactions, which are necessary for
>> + interfacing with I2C peripherals such as sensors, EEPROMs, and other
>> + devices.
>> +
>> + This driver can also be compiled as a module. If you choose to build
>> + it as a module, the resulting kernel module will be named `i2c-k1`.
>> + Loading this module will enable the I2C functionality for the K1
>> + platform dynamically, without requiring a rebuild of the kernel.
>> +
>> config I2C_KEBA
>> tristate "KEBA I2C controller support"
>> depends on HAS_IOMEM
>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>> index ecc07c50f2a0..9744b0e58598 100644
>> --- a/drivers/i2c/busses/Makefile
>> +++ b/drivers/i2c/busses/Makefile
>> @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o
>> obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o
>> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
>> obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o
>> +obj-$(CONFIG_I2C_K1) += i2c-k1.o
>> obj-$(CONFIG_I2C_KEBA) += i2c-keba.o
>> obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
>> obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o
>> diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
>> new file mode 100644
>> index 000000000000..12bb71625e0a
>> --- /dev/null
>> +++ b/drivers/i2c/busses/i2c-k1.c
>> @@ -0,0 +1,656 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2024 Troy Mitchell <troymitchell988@gmail.com>
>> + */
>> +
>> + #include <linux/clk.h>
>> + #include <linux/i2c.h>
>> + #include <linux/iopoll.h>
>> + #include <linux/module.h>
>> + #include <linux/of_address.h>
>> + #include <linux/platform_device.h>
>> +
>> +/* spacemit i2c registers */
>> +#define ICR 0x0 /* Control Register */
>> +#define ISR 0x4 /* Status Register */
>> +#define ISAR 0x8 /* Slave Address Register */
>> +#define IDBR 0xc /* Data Buffer Register */
>> +#define ILCR 0x10 /* Load Count Register */
>> +#define IWCR 0x14 /* Wait Count Register */
>> +#define IRST_CYC 0x18 /* Bus reset cycle counter */
>> +#define IBMR 0x1c /* Bus monitor register */
>> +#define IWFIFO 0x20 /* Write FIFO Register */
>> +#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */
>> +#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */
>> +#define IRFIFO 0x2c /* Read FIFO Register */
>> +#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */
>> +#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */
>> +
>> +/* register ICR fields */
>> +#define CR_START BIT(0) /* start bit */
>> +#define CR_STOP BIT(1) /* stop bit */
>> +#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */
>> +#define CR_TB BIT(3) /* transfer byte bit */
>> +#define CR_TXBEGIN BIT(4) /* transaction begin */
>> +#define CR_FIFOEN BIT(5) /* enable FIFO mode */
>> +#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */
>> +#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */
>> +#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */
>> +#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */
>> +#define CR_UR BIT(10) /* unit reset */
>> +#define CR_RSTREQ BIT(11) /* i2c bus reset request */
>> +#define CR_MA BIT(12) /* master abort */
>> +#define CR_SCLE BIT(13) /* master clock enable */
>> +#define CR_IUE BIT(14) /* unit enable */
>> +#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */
>> +#define CR_ALDIE BIT(18) /* enable arbitration interrupt */
>> +#define CR_DTEIE BIT(19) /* enable tx interrupts */
>> +#define CR_DRFIE BIT(20) /* enable rx interrupts */
>> +#define CR_GCD BIT(21) /* general call disable */
>> +#define CR_BEIE BIT(22) /* enable bus error ints */
>> +#define CR_SADIE BIT(23) /* slave address detected int enable */
>> +#define CR_SSDIE BIT(24) /* slave STOP detected int enable */
>> +#define CR_MSDIE BIT(25) /* master STOP detected int enable */
>> +#define CR_MSDE BIT(26) /* master STOP detected enable */
>> +#define CR_TXDONEIE BIT(27) /* transaction done int enable */
>> +#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */
>> +#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */
>> +#define CR_RXFIE BIT(30) /* receive FIFO full int enable */
>> +#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */
>> +
>> +/* register ISR fields */
>> +#define SR_RWM BIT(13) /* read/write mode */
>> +#define SR_ACKNAK BIT(14) /* ACK/NACK status */
>> +#define SR_UB BIT(15) /* unit busy */
>> +#define SR_IBB BIT(16) /* i2c bus busy */
>> +#define SR_EBB BIT(17) /* early bus busy */
>> +#define SR_ALD BIT(18) /* arbitration loss detected */
>> +#define SR_ITE BIT(19) /* tx buffer empty */
>> +#define SR_IRF BIT(20) /* rx buffer full */
>> +#define SR_GCAD BIT(21) /* general call address detected */
>> +#define SR_BED BIT(22) /* bus error no ACK/NAK */
>> +#define SR_SAD BIT(23) /* slave address detected */
>> +#define SR_SSD BIT(24) /* slave stop detected */
>> +#define SR_MSD BIT(26) /* master stop detected */
>> +#define SR_TXDONE BIT(27) /* transaction done */
>> +#define SR_TXE BIT(28) /* tx FIFO empty */
>> +#define SR_RXHF BIT(29) /* rx FIFO half-full */
>> +#define SR_RXF BIT(30) /* rx FIFO full */
>> +#define SR_RXOV BIT(31) /* RX FIFO overrun */
>> +
>> +/* register ILCR fields */
>> +#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */
>> +#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */
>> +#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */
>> +#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */
>> +
>> +/* register IWCR fields */
>> +#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */
>> +#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */
>> +#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */
>> +
>> +/* register IBMR fields */
>> +#define BMR_SDA BIT(0) /* SDA line level */
>> +#define BMR_SCL BIT(1) /* SCL line level */
>> +
>> +/* register IWFIFO fields */
>> +#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */
>> +#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */
>> +#define WFIFO_CTRL_START BIT(8) /* start bit */
>> +#define WFIFO_CTRL_STOP BIT(9) /* stop bit */
>> +#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */
>> +#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */
>> +
>> +/* status register init value */
>> +#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */
>> +#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \
>> + CR_BEIE | CR_TXDONEIE | CR_TXEIE | \
>> + CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \
>> + CR_MSDIE)
>> +
>> +/* i2c bus recover timeout: us */
>> +#define I2C_BUS_RECOVER_TIMEOUT (100000)
>> +
>> +#define I2C_FAST_MODE_FREQ (400000)
>> +
>> +enum spacemit_i2c_state {
>> + STATE_IDLE,
>> + STATE_START,
>> + STATE_READ,
>> + STATE_WRITE,
>> +};
>> +
>> +enum spacemit_i2c_dir {
>> + DIR_WRITE,
>> + DIR_READ
>> +};
>> +
>> +/* i2c-spacemit driver's main struct */
>> +struct spacemit_i2c_dev {
>> + struct device *dev;
>> + struct i2c_adapter adapt;
>> +
>> + /* hardware resources */
>> + void __iomem *base;
>> + int irq;
>> +
>> + struct i2c_msg *msgs;
>> + int msg_num;
>> + struct i2c_msg *cur_msg;
>> +
>> + /* index of the current message being processed */
>> + int msg_idx;
>> + u8 *msg_buf;
>> + /* the number of unprocessed bytes remaining in each message */
>> + size_t unprocessed;
>> +
>> + enum spacemit_i2c_state state;
>> + enum spacemit_i2c_dir dir;
>> + struct completion complete;
>> + u32 status;
>> + u32 err;
>> +};
>> +
>> +static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 val;
>> +
>> + val = readl(i2c->base + ICR);
>> + writel(val | CR_IUE, i2c->base + ICR);
>> +}
>> +
>> +static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 val;
>> +
>> + val = readl(i2c->base + ICR);
>> + val &= ~CR_IUE;
>> + writel(val, i2c->base + ICR);
>> +}
>> +
>> +static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c)
>> +{
>> + writel(CR_UR, i2c->base + ICR);
>> + udelay(5);
>> + writel(0, i2c->base + ICR);
>> +}
>> +
>> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c);
>> +
>> +static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 status;
>> +
>> + /* if bus is locked, reset unit. 0: locked */
>> + status = readl(i2c->base + IBMR);
>> + if ((status & BMR_SDA) && (status & BMR_SCL))
>> + return;
>> +
>> + spacemit_i2c_reset(i2c);
>> + usleep_range(10, 20);
>> +
>> + /* check scl status again */
>> + status = readl(i2c->base + IBMR);
>> + if (!(status & BMR_SCL))
>> + dev_warn_ratelimited(i2c->dev, "unit reset failed\n");
>> +}
>> +
>> +static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c)
>> +{
>> + int ret = 0;
>> + u32 val;
>> +
>> + val = readl(i2c->base + ISR);
>> + if (likely(!(val & (SR_UB | SR_IBB))))
>> + return 0;
>> +
>> + ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)),
>> + 1500, I2C_BUS_RECOVER_TIMEOUT);
>> + if (unlikely(ret)) {
>> + spacemit_i2c_reset(i2c);
>> + ret = -EAGAIN;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c)
>> +{
>> + /* in case bus is not released after transfer completes */
>> + if (unlikely(readl(i2c->base + ISR) & SR_EBB)) {
>> + spacemit_i2c_bus_reset(i2c);
>> + usleep_range(90, 150);
>> + }
>> +}
>> +
>> +static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 val = 0;
>> +
>> + /*
>> + * Unmask interrupt bits for all xfer mode:
>> + * bus error, arbitration loss detected.
>> + * For transaction complete signal, we use master stop
>> + * interrupt, so we don't need to unmask CR_TXDONEIE.
>> + */
>> + val |= CR_BEIE | CR_ALDIE;
>> +
>> + /*
>> + * Unmask interrupt bits for interrupt xfer mode:
>> + * DBR rx full.
>> + * For tx empty interrupt CR_DTEIE, we only
>> + * need to enable when trigger byte transfer to start
>> + * data sending.
>> + */
>> + val |= CR_DRFIE;
>> +
>> + /* set speed bits: default fast mode */
>> + val |= CR_MODE_FAST;
>> +
>> + /* disable response to general call */
>> + val |= CR_GCD;
>> +
>> + /* enable SCL clock output */
>> + val |= CR_SCLE;
>> +
>> + /* enable master stop detected */
>> + val |= CR_MSDE | CR_MSDIE;
>> +
>> + writel(val, i2c->base + ICR);
>> +}
>> +
>> +static inline void
>> +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask)
>> +{
>> + writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR);
>> +}
>> +
>> +static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 slave_addr_rw, val;
>> +
>> + i2c->dir = i2c->cur_msg->flags & I2C_M_RD;
>> + i2c->state = STATE_START;
>> +
>> + if (i2c->cur_msg->flags & I2C_M_RD)
>> + slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1;
>> + else
>> + slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1;
>> +
>> + writel(slave_addr_rw, i2c->base + IDBR);
>> +
>> + val = readl(i2c->base + ICR);
>> +
>> + /* send start pulse */
>> + val &= ~CR_STOP;
>> + val |= CR_START | CR_TB | CR_DTEIE;
>> + writel(val, i2c->base + ICR);
>> +}
>> +
>> +static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 val;
>> +
>> + val = readl(i2c->base + ICR);
>> +
>> + val |= CR_STOP | CR_ALDIE | CR_TB;
>> +
>> + if (i2c->dir == DIR_READ)
>> + val |= CR_ACKNAK;
>> +
>> + writel(val, i2c->base + ICR);
>> +}
>> +
>> +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
>> +{
>> + unsigned long time_left;
>> +
>> + for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
>> + i2c->cur_msg = i2c->msgs + i2c->msg_idx;
>> + i2c->msg_buf = i2c->cur_msg->buf;
>> + i2c->err = 0;
>> + i2c->status = 0;
>> + i2c->unprocessed = i2c->cur_msg->len;
>> +
>> + reinit_completion(&i2c->complete);
>> +
>> + spacemit_i2c_start(i2c);
>> +
>> + time_left = wait_for_completion_timeout(&i2c->complete,
>> + i2c->adapt.timeout);
>> + if (unlikely(time_left == 0)) {
>> + dev_alert(i2c->dev, "msg completion timeout\n");
>> + spacemit_i2c_bus_reset(i2c);
>> + spacemit_i2c_reset(i2c);
>> + return -ETIMEDOUT;
>> + }
>> +
>> + if (unlikely(i2c->err))
>> + return spacemit_i2c_handle_err(i2c);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c)
>> +{
>> + if (i2c->dir == DIR_READ) {
>> + if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1)
>> + return 1;
>> + } else if (i2c->dir == DIR_WRITE) {
>> + if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1)
>> + return 1;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c)
>> +{
>> + /* if transfer completes, ISR will handle it */
>> + if (i2c->status & SR_MSD)
>> + return;
>> +
>> + if (i2c->unprocessed) {
>> + writel(*i2c->msg_buf++, i2c->base + IDBR);
>> + i2c->unprocessed--;
>> + return;
>> + }
>> +
>> + /* STATE_IDLE avoids trigger next byte */
>> + i2c->state = STATE_IDLE;
>> + complete(&i2c->complete);
>> +}
>> +
>> +static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c)
>> +{
>> + if (i2c->unprocessed) {
>> + *i2c->msg_buf++ = readl(i2c->base + IDBR);
>> + i2c->unprocessed--;
>> + }
>> +
>> + /* if transfer completes, ISR will handle it */
>> + if (i2c->status & (SR_MSD | SR_ACKNAK))
>> + return;
>> +
>> + /* it has to append stop bit in icr that read last byte */
>> + if (i2c->unprocessed)
>> + return;
>> +
>> + /* STATE_IDLE avoids trigger next byte */
>> + i2c->state = STATE_IDLE;
>> + complete(&i2c->complete);
>> +}
>> +
>> +static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c)
>> +{
>> + if (i2c->dir == DIR_READ) {
>> + i2c->state = STATE_READ;
>> + return;
>> + }
>> +
>> + if (i2c->dir == DIR_WRITE) {
>> + i2c->state = STATE_WRITE;
>> + spacemit_i2c_handle_write(i2c);
>> + }
>> +}
>> +
>> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c)
>> +{
>> + if (!i2c->err)
>> + return 0;
>> +
>> + dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status);
>> +
>> + if (i2c->err & (SR_BED | SR_ALD))
>> + spacemit_i2c_reset(i2c);
>> +
>> + if (i2c->err & (SR_RXOV | SR_ALD))
>> + return -EAGAIN;
>> +
>> + return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO;
>> +}
>> +
>> +static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c)
>> +{
>> + u32 val;
>> + /*
>> + * send transaction complete signal:
>> + * error happens, detect master stop
>> + */
>> + if (likely(i2c->err || (i2c->status & SR_MSD))) {
>> + /*
>> + * Here the transaction is already done, we don't need any
>> + * other interrupt signals from now, in case any interrupt
>> + * happens before spacemit_i2c_xfer to disable irq and i2c unit,
>> + * we mask all the interrupt signals and clear the interrupt
>> + * status.
>> + */
>> + val = readl(i2c->base + ICR);
>> + val &= ~I2C_INT_CTRL_MASK;
>> + writel(val, i2c->base + ICR);
>> +
>> + spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK);
>> +
>> + i2c->state = STATE_IDLE;
>> + complete(&i2c->complete);
>> + }
>> +}
>> +
>> +static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
>> +{
>> + struct spacemit_i2c_dev *i2c = devid;
>> + u32 status, val;
>> +
>> + status = readl(i2c->base + ISR);
>> + if (!status)
>> + return IRQ_HANDLED;
>> +
>> + i2c->status = status;
>> +
>> + i2c->err = status & (SR_BED | SR_RXOV | SR_ALD);
>> +
>> + spacemit_i2c_clear_int_status(i2c, status);
>> +
>> + if (unlikely(i2c->err))
>> + goto err_out;
>> +
>> + val = readl(i2c->base + ICR);
>> +
>> + val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START);
>> + writel(val, i2c->base + ICR);
>> +
>> + switch (i2c->state) {
>> + case STATE_START:
>> + spacemit_i2c_handle_start(i2c);
>> + break;
>> + case STATE_READ:
>> + spacemit_i2c_handle_read(i2c);
>> + break;
>> + case STATE_WRITE:
>> + spacemit_i2c_handle_write(i2c);
>> + break;
>> + default:
>> + break;
>> + }
>> +
>> + if (i2c->state != STATE_IDLE) {
>> + if (spacemit_i2c_is_last_msg(i2c)) {
>> + /* trigger next byte with stop */
>> + spacemit_i2c_stop(i2c);
>> + } else {
>> + /* trigger next byte */
>> + val |= CR_ALDIE | CR_TB;
>> + writel(val, i2c->base + ICR);
>> + }
>> + }
>> +
>> +err_out:
>> + spacemit_i2c_err_check(i2c);
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c)
>> +{
>> + unsigned long timeout;
>> + int idx = 0, cnt = 0, freq;
>> +
>> + while (idx < i2c->msg_num) {
>> + cnt += (i2c->msgs + idx)->len + 1;
>> + idx++;
>> + }
>> +
>> + freq = I2C_FAST_MODE_FREQ;
> so this will set frequency to fast mode (400K), this contradict with PATCH[1/2] which
> says default clock-frequency is 100000, either you need to change the code? or
> update the dt-binding?
I will update the dt-binding in next version.
>
>> + /*
>> + * multiply by 9 because each byte in I2C transmission requires
>> + * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit.
>> + */
>> + timeout = cnt * 9 * USEC_PER_SEC / freq;
>> +
>> + i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num;
>> +}
>> +
>> +static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c)
> drop inline? IMO, it isn't worth here for long function
okay
>
>> +{
>> + int ret = 0;
> no need to initilize to 0
ok
>> +
>> + spacemit_i2c_reset(i2c);
>> +
>> + spacemit_i2c_calc_timeout(i2c);
>> +
>> + spacemit_i2c_init(i2c);
>> +
>> + spacemit_i2c_enable(i2c);
>> + enable_irq(i2c->irq);
>> +
>> + /* i2c wait for bus busy */
>> + ret = spacemit_i2c_recover_bus_busy(i2c);
>> + if (unlikely(ret))
>> + return ret;
>> +
>> + ret = spacemit_i2c_xfer_msg(i2c);
>> + if (unlikely(ret < 0)) {
>> + dev_dbg(i2c->dev, "i2c transfer error\n");
>> + /* timeout error should not be overridden, and the transfer
>> + * error will be confirmed by err handle function latter,
>> + * the reset should be invalid argument error.
>> + */
>> + if (ret != -ETIMEDOUT)
>> + ret = -EINVAL;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int
>> +spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num)
> no need to wrap the line, it makes the code a little bit weird..
>
> current policy increase to 100characters, the old 80-column is not enforced
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdc48fa11e46f867ea4d75fa59ee87a7f48be144
ok
>
>> +{
>> + struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt);
>> + int ret;
>> +
>> + i2c->msgs = msgs;
>> + i2c->msg_num = num;
>> +
>> + ret = spacemit_i2c_xfer_core(i2c);
>> + if (likely(!ret))
>> + spacemit_i2c_check_bus_release(i2c);
>> +
>> + disable_irq(i2c->irq);
>> +
>> + spacemit_i2c_disable(i2c);
>> +
>> + if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN)))
>> + dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err);
>> +
>> + return ret < 0 ? ret : num;
>> +}
>> +
>> +static u32 spacemit_i2c_func(struct i2c_adapter *adap)
>> +{
>> + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
>> +}
>> +
>> +static const struct i2c_algorithm spacemit_i2c_algo = {
>> + .xfer = spacemit_i2c_xfer,
>> + .functionality = spacemit_i2c_func,
>> +};
>> +
>> +static int spacemit_i2c_probe(struct platform_device *pdev)
>> +{
>> + struct spacemit_i2c_dev *i2c;
>> + struct device_node *of_node = pdev->dev.of_node;
>> + struct clk *clk;
>> + int ret = 0;
>> +
>> + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
>> + if (!i2c)
>> + return -ENOMEM;
>> +
>> + i2c->dev = &pdev->dev;
>> +
>> + i2c->base = devm_platform_ioremap_resource(pdev, 0);
>> + if (IS_ERR(i2c->base))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap");
>> +
>> + i2c->irq = platform_get_irq(pdev, 0);
>> + if (i2c->irq < 0)
>> + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource");
>> +
>> + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
>> + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
>> + if (ret)
>> + return dev_err_probe(&pdev->dev, ret, "failed to request irq");
>> +
>> + disable_irq(i2c->irq);
>> +
>> + clk = devm_clk_get_enabled(&pdev->dev, NULL);
>> + if (IS_ERR(clk))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock");
>> +
> I'd suggest also to handle pin request here, since pinctrl driver is merged
>
> https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/
sry, I don't understand what pin I need to request?
>
>> + i2c_set_adapdata(&i2c->adapt, i2c);
>> + i2c->adapt.owner = THIS_MODULE;
>> + i2c->adapt.algo = &spacemit_i2c_algo;
>> + i2c->adapt.dev.parent = i2c->dev;
>> + i2c->adapt.nr = pdev->id;
>> +
>> + i2c->adapt.dev.of_node = of_node;
>> + i2c->adapt.algo_data = i2c;
>> +
>> + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
>> +
>> + init_completion(&i2c->complete);
>> +
>> + ret = i2c_add_numbered_adapter(&i2c->adapt);
>> + if (ret)
>> + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
>> +
>> + platform_set_drvdata(pdev, i2c);
>> +
>> + return 0;
>> +}
>> +
>> +static void spacemit_i2c_remove(struct platform_device *pdev)
>> +{
>> + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
>> +
>> + i2c_del_adapter(&i2c->adapt);
>> +}
>> +
>> +static const struct of_device_id spacemit_i2c_of_match[] = {
>> + { .compatible = "spacemit,k1-i2c", },
>> + { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
>> +
>> +static struct platform_driver spacemit_i2c_driver = {
>> + .probe = spacemit_i2c_probe,
>> + .remove = spacemit_i2c_remove,
>> + .driver = {
>> + .name = "i2c-k1",
>> + .of_match_table = spacemit_i2c_of_match,
>> + },
>> +};
>> +module_platform_driver(spacemit_i2c_driver);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");
>>
>> --
>> 2.34.1
>>
>
--
Troy Mitchell
Hi Troy:
On 12:11 Thu 21 Nov , Troy Mitchell wrote:
> Hi, Yixun. thanks for ur review.
>
> On 2024/11/14 14:49, Yixun Lan wrote:
> > On 11:07 Tue 12 Nov , Troy Mitchell wrote:
> >> From: Troy Mitchell <troymitchell988@gmail.com>
> >>
> >> This patch introduces basic I2C support for the SpacemiT K1 SoC,
> >> utilizing interrupts for transfers.
> >>
> >> The driver has been tested using i2c-tools on a Bananapi-F3 board,
> >> and basic I2C read/write operations have been confirmed to work.
> >>
> >> Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com>
> >> ---
> >> drivers/i2c/busses/Kconfig | 19 ++
> >> drivers/i2c/busses/Makefile | 1 +
> >> drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++
> >> 3 files changed, 676 insertions(+)
> >>
...
> >> +
> >> +static int spacemit_i2c_probe(struct platform_device *pdev)
> >> +{
> >> + struct spacemit_i2c_dev *i2c;
> >> + struct device_node *of_node = pdev->dev.of_node;
> >> + struct clk *clk;
> >> + int ret = 0;
> >> +
> >> + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
> >> + if (!i2c)
> >> + return -ENOMEM;
> >> +
> >> + i2c->dev = &pdev->dev;
> >> +
> >> + i2c->base = devm_platform_ioremap_resource(pdev, 0);
> >> + if (IS_ERR(i2c->base))
> >> + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap");
> >> +
> >> + i2c->irq = platform_get_irq(pdev, 0);
> >> + if (i2c->irq < 0)
> >> + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource");
> >> +
> >> + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
> >> + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
> >> + if (ret)
> >> + return dev_err_probe(&pdev->dev, ret, "failed to request irq");
> >> +
> >> + disable_irq(i2c->irq);
> >> +
> >> + clk = devm_clk_get_enabled(&pdev->dev, NULL);
> >> + if (IS_ERR(clk))
> >> + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock");
> >> +
> > I'd suggest also to handle pin request here, since pinctrl driver is merged
> >
> > https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/
> sry, I don't understand what pin I need to request?
> >
I was suggesting to add devm_pinctrl_get(), but after checking,
this is not needed anymore since it's already handled by device core,
so no need to change here..
check drivers/core/pinctrl.c -> pinctrl_bind_pins()
> >> + i2c_set_adapdata(&i2c->adapt, i2c);
> >> + i2c->adapt.owner = THIS_MODULE;
> >> + i2c->adapt.algo = &spacemit_i2c_algo;
> >> + i2c->adapt.dev.parent = i2c->dev;
> >> + i2c->adapt.nr = pdev->id;
> >> +
> >> + i2c->adapt.dev.of_node = of_node;
> >> + i2c->adapt.algo_data = i2c;
> >> +
> >> + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
> >> +
> >> + init_completion(&i2c->complete);
> >> +
> >> + ret = i2c_add_numbered_adapter(&i2c->adapt);
> >> + if (ret)
> >> + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
> >> +
> >> + platform_set_drvdata(pdev, i2c);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static void spacemit_i2c_remove(struct platform_device *pdev)
> >> +{
> >> + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
> >> +
> >> + i2c_del_adapter(&i2c->adapt);
> >> +}
> >> +
> >> +static const struct of_device_id spacemit_i2c_of_match[] = {
> >> + { .compatible = "spacemit,k1-i2c", },
> >> + { /* sentinel */ }
> >> +};
> >> +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
> >> +
> >> +static struct platform_driver spacemit_i2c_driver = {
> >> + .probe = spacemit_i2c_probe,
> >> + .remove = spacemit_i2c_remove,
> >> + .driver = {
> >> + .name = "i2c-k1",
> >> + .of_match_table = spacemit_i2c_of_match,
> >> + },
> >> +};
> >> +module_platform_driver(spacemit_i2c_driver);
> >> +
> >> +MODULE_LICENSE("GPL");
> >> +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");
> >>
> >> --
> >> 2.34.1
> >>
> >
>
> --
> Troy Mitchell
--
Yixun Lan (dlan)
Gentoo Linux Developer
GPG Key ID AABEFD55
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