From: Gerhard Engleder <eg@keba.com>

KEBA CP500 devices use the LAN9252 controller for EtherCAT
communication. For a stable Ethernet link the PHY registers of the
controller need to be configured correctly. This driver configures these
PHY registers as required.

Signed-off-by: Gerhard Engleder <eg@keba.com>
---
 drivers/misc/keba/Kconfig   |  11 ++
 drivers/misc/keba/Makefile  |   1 +
 drivers/misc/keba/lan9252.c | 359 ++++++++++++++++++++++++++++++++++++
 3 files changed, 371 insertions(+)
 create mode 100644 drivers/misc/keba/lan9252.c

diff --git a/drivers/misc/keba/Kconfig b/drivers/misc/keba/Kconfig
index 5fbcbc2252ac..dc27b902f34e 100644
--- a/drivers/misc/keba/Kconfig
+++ b/drivers/misc/keba/Kconfig
@@ -11,3 +11,14 @@ config KEBA_CP500
 
 	  This driver can also be built as a module. If so, the module will be
 	  called cp500.
+
+config KEBA_LAN9252
+	tristate "KEBA CP500 LAN9252 configuration"
+	depends on SPI
+	depends on KEBA_CP500 || COMPILE_TEST
+	help
+	  This driver is used for updating the configuration of the LAN9252
+	  controller on KEBA CP500 devices.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called lan9252.
diff --git a/drivers/misc/keba/Makefile b/drivers/misc/keba/Makefile
index 0a8b846cda7d..05e9efcad54f 100644
--- a/drivers/misc/keba/Makefile
+++ b/drivers/misc/keba/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_KEBA_CP500)	+= cp500.o
+obj-$(CONFIG_KEBA_LAN9252)	+= lan9252.o
diff --git a/drivers/misc/keba/lan9252.c b/drivers/misc/keba/lan9252.c
new file mode 100644
index 000000000000..d2e734239b70
--- /dev/null
+++ b/drivers/misc/keba/lan9252.c
@@ -0,0 +1,359 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) KEBA Industrial Automation Gmbh 2024
+ *
+ * Driver for LAN9252 on KEBA CP500 devices
+ *
+ * This driver is used for updating the configuration of the LAN9252 controller
+ * on KEBA CP500 devices. The LAN9252 is connected over SPI, which is also named
+ * PDI.
+ */
+
+#include <linux/spi/spi.h>
+#include <linux/mii.h>
+
+/* SPI commands */
+#define LAN9252_SPI_READ	0x3
+#define LAN9252_SPI_WRITE	0x2
+
+struct lan9252_read_cmd {
+	u8 cmd;
+	u8 addr_0;
+	u8 addr_1;
+} __packed;
+
+struct lan9252_write_cmd {
+	u8 cmd;
+	u8 addr_0;
+	u8 addr_1;
+	u32 data;
+} __packed;
+
+/* byte test register */
+#define LAN9252_BYTE_TEST		0x64
+#define   LAN9252_BYTE_TEST_VALUE	0x87654321
+
+/* hardware configuration register */
+#define LAN9252_HW_CFG		0x74
+#define   LAN9252_HW_CFG_READY	0x08000000
+
+/* EtherCAT CSR interface data register */
+#define LAN9252_ECAT_CSR_DATA	0x300
+
+/* EtherCAT CSR interface command register */
+#define LAN9252_ECAT_CSR_CMD	0x304
+#define   LAN9252_ECAT_CSR_BUSY	0x80000000
+#define   LAN9252_ECAT_CSR_READ	0x40000000
+
+/* EtherCAT slave controller MII register */
+#define LAN9252_ESC_MII			0x510
+#define   LAN9252_ESC_MII_BUSY		0x8000
+#define   LAN9252_ESC_MII_CMD_ERR	0x4000
+#define   LAN9252_ESC_MII_READ_ERR	0x2000
+#define   LAN9252_ESC_MII_ERR_MASK	(LAN9252_ESC_MII_CMD_ERR | \
+					 LAN9252_ESC_MII_READ_ERR)
+#define   LAN9252_ESC_MII_WRITE		0x0200
+#define   LAN9252_ESC_MII_READ		0x0100
+
+/* EtherCAT slave controller PHY address register */
+#define LAN9252_ESC_PHY_ADDR		0x512
+
+/* EtherCAT slave controller PHY register address register */
+#define LAN9252_ESC_PHY_REG_ADDR	0x513
+
+/* EtherCAT slave controller PHY data register */
+#define LAN9252_ESC_PHY_DATA		0x514
+
+/* EtherCAT slave controller PDI access state register */
+#define LAN9252_ESC_MII_PDI		0x517
+#define   LAN9252_ESC_MII_ACCESS_PDI	0x01
+#define   LAN9252_ESC_MII_ACCESS_ECAT	0x00
+
+/* PHY address */
+#define PHY_ADDRESS	2
+
+#define SPI_RETRY_COUNT		10
+#define SPI_WAIT_US		100
+#define SPI_CSR_WAIT_US		500
+
+static int lan9252_spi_read(struct spi_device *spi, u16 addr, u32 *data)
+{
+	struct lan9252_read_cmd cmd;
+
+	cmd.cmd = LAN9252_SPI_READ;
+	cmd.addr_0 = (addr >> 8) & 0xFF;
+	cmd.addr_1 = addr & 0xFF;
+
+	return spi_write_then_read(spi, (u8 *)&cmd,
+				   sizeof(struct lan9252_read_cmd),
+				   (u8 *)data, sizeof(u32));
+}
+
+static int lan9252_spi_write(struct spi_device *spi, u16 addr, u32 data)
+{
+	struct lan9252_write_cmd cmd;
+
+	cmd.cmd = LAN9252_SPI_WRITE;
+	cmd.addr_0 = (addr >> 8) & 0xFF;
+	cmd.addr_1 = addr & 0xFF;
+	cmd.data = data;
+
+	return spi_write(spi, (u8 *)&cmd, sizeof(struct lan9252_write_cmd));
+}
+
+static bool lan9252_init(struct spi_device *spi)
+{
+	u32 data;
+	int ret;
+
+	ret = lan9252_spi_read(spi, LAN9252_BYTE_TEST, &data);
+	if (ret || data != LAN9252_BYTE_TEST_VALUE)
+		return false;
+
+	ret = lan9252_spi_read(spi, LAN9252_HW_CFG, &data);
+	if (ret || !(data & LAN9252_HW_CFG_READY))
+		return false;
+
+	return true;
+}
+
+static u8 lan9252_esc_get_size(u16 addr)
+{
+	if (addr == LAN9252_ESC_MII || addr == LAN9252_ESC_PHY_DATA)
+		return 2;
+
+	return 1;
+}
+
+static int lan9252_esc_wait(struct spi_device *spi)
+{
+	ktime_t timeout = ktime_add_us(ktime_get(), SPI_WAIT_US);
+	u32 data;
+	int ret;
+
+	/* wait while CSR command is busy */
+	for (;;) {
+		ret = lan9252_spi_read(spi, LAN9252_ECAT_CSR_CMD, &data);
+		if (ret)
+			return ret;
+		if (!(data & LAN9252_ECAT_CSR_BUSY))
+			return 0;
+
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			ret = lan9252_spi_read(spi, LAN9252_ECAT_CSR_CMD, &data);
+			if (ret)
+				return ret;
+			break;
+		}
+	}
+
+	return (!(data & LAN9252_ECAT_CSR_BUSY)) ? 0 : -ETIMEDOUT;
+}
+
+static int lan9252_esc_read(struct spi_device *spi, u16 addr, u32 *data)
+{
+	u32 csr_cmd;
+	u8 size;
+	int ret;
+
+	size = lan9252_esc_get_size(addr);
+	csr_cmd = LAN9252_ECAT_CSR_BUSY | LAN9252_ECAT_CSR_READ;
+	csr_cmd |= (size << 16) | addr;
+	ret = lan9252_spi_write(spi, LAN9252_ECAT_CSR_CMD, csr_cmd);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_wait(spi);
+	if (ret)
+		return ret;
+
+	ret = lan9252_spi_read(spi, LAN9252_ECAT_CSR_DATA, data);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int lan9252_esc_write(struct spi_device *spi, u16 addr, u32 data)
+{
+	u32 csr_cmd;
+	u8 size;
+	int ret;
+
+	ret = lan9252_spi_write(spi, LAN9252_ECAT_CSR_DATA, data);
+	if (ret)
+		return ret;
+
+	size = lan9252_esc_get_size(addr);
+	csr_cmd = LAN9252_ECAT_CSR_BUSY;
+	csr_cmd |= (size << 16) | addr;
+	ret = lan9252_spi_write(spi, LAN9252_ECAT_CSR_CMD, csr_cmd);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_wait(spi);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int lan9252_access_mii(struct spi_device *spi, bool access)
+{
+	u32 data;
+
+	if (access)
+		data = LAN9252_ESC_MII_ACCESS_PDI;
+	else
+		data = LAN9252_ESC_MII_ACCESS_ECAT;
+
+	return lan9252_esc_write(spi, LAN9252_ESC_MII_PDI, data);
+}
+
+static int lan9252_mii_wait(struct spi_device *spi)
+{
+	ktime_t timeout = ktime_add_us(ktime_get(), SPI_CSR_WAIT_US);
+	u32 data;
+	int ret;
+
+	/* wait while MII control state machine is busy */
+	for (;;) {
+		ret = lan9252_esc_read(spi, LAN9252_ESC_MII, &data);
+		if (ret)
+			return ret;
+		if (data & LAN9252_ESC_MII_ERR_MASK)
+			return -EIO;
+		if (!(data & LAN9252_ESC_MII_BUSY))
+			return 0;
+
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			ret = lan9252_esc_read(spi, LAN9252_ESC_MII, &data);
+			if (ret)
+				return ret;
+			if (data & LAN9252_ESC_MII_ERR_MASK)
+				return -EIO;
+			break;
+		}
+	}
+
+	return (!(data & LAN9252_ESC_MII_BUSY)) ? 0 : -ETIMEDOUT;
+}
+
+static int lan9252_mii_read(struct spi_device *spi, u8 phy_addr, u8 reg_addr,
+			    u32 *data)
+{
+	int ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_ADDR, phy_addr);
+	if (ret)
+		return ret;
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_REG_ADDR, reg_addr);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_MII, LAN9252_ESC_MII_READ);
+	if (ret)
+		return ret;
+
+	ret = lan9252_mii_wait(spi);
+	if (ret)
+		return ret;
+
+	return lan9252_esc_read(spi, LAN9252_ESC_PHY_DATA, data);
+}
+
+static int lan9252_mii_write(struct spi_device *spi, u8 phy_addr, u8 reg_addr,
+			     u32 data)
+{
+	int ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_ADDR, phy_addr);
+	if (ret)
+		return ret;
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_REG_ADDR, reg_addr);
+	if (ret)
+		return ret;
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_DATA, data);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_MII, LAN9252_ESC_MII_WRITE);
+	if (ret)
+		return ret;
+
+	return lan9252_mii_wait(spi);
+}
+
+static int lan9252_probe(struct spi_device *spi)
+{
+	u32 data;
+	int retry = SPI_RETRY_COUNT;
+	int ret;
+
+	/* execute specified initialization sequence */
+	while (retry && !lan9252_init(spi))
+		retry--;
+	if (retry == 0) {
+		dev_err(&spi->dev,
+			"Can't initialize LAN9252 SPI communication!");
+		return ret;
+	}
+
+	/* enable access to MII management for PDI */
+	ret = lan9252_access_mii(spi, true);
+	if (ret) {
+		dev_err(&spi->dev, "Can't enable access to MII management!");
+		return ret;
+	}
+
+	/*
+	 * check PHY configuration and configure if necessary
+	 *	- full duplex
+	 *	- auto negotiation disabled
+	 *	- 100 Mbps
+	 */
+	ret = lan9252_mii_read(spi, PHY_ADDRESS, MII_BMCR, &data);
+	if (ret) {
+		dev_err(&spi->dev, "Can't read LAN9252 configuration!");
+		goto out;
+	}
+	if (!(data & BMCR_FULLDPLX) || (data & BMCR_ANENABLE) ||
+	    !(data & BMCR_SPEED100)) {
+		/*
+		 */
+		data &= ~(BMCR_ANENABLE);
+		data |= (BMCR_FULLDPLX | BMCR_SPEED100);
+		ret = lan9252_mii_write(spi, PHY_ADDRESS, MII_BMCR, data);
+		if (ret)
+			dev_err(&spi->dev,
+				"Can't write LAN9252 configuration!");
+	}
+
+	dev_info(&spi->dev, "LAN9252 PHY configuration");
+
+out:
+	/* disable access to MII management for PDI */
+	lan9252_access_mii(spi, false);
+
+	return ret;
+}
+
+static const struct spi_device_id lan9252_id[] = {
+	{"lan9252"},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, lan9252_id);
+
+static struct spi_driver lan9252_driver = {
+	.driver = {
+		.name	= "lan9252",
+	},
+	.probe		= lan9252_probe,
+	.id_table	= lan9252_id,
+};
+module_spi_driver(lan9252_driver);
+
+MODULE_AUTHOR("Petar Bojanic <boja@keba.com>");
+MODULE_AUTHOR("Gerhard Engleder <eg@keba.com>");
+MODULE_DESCRIPTION("KEBA LAN9252 driver");
+MODULE_LICENSE("GPL");
-- 
2.39.2

Hi Gerhard,

kernel test robot noticed the following build warnings:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on char-misc/char-misc-next char-misc/char-misc-linus linus/master v6.12-rc2 next-20241010]
[cannot apply to soc/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Gerhard-Engleder/misc-keba-Add-SPI-controller-device/20241010-051016
base:   char-misc/char-misc-testing
patch link:    https://lore.kernel.org/r/20241009202949.20164-3-gerhard%40engleder-embedded.com
patch subject: [PATCH 2/6] misc: keba: Add LAN9252 driver
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20241011/202410111611.EMSfFrYK-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241011/202410111611.EMSfFrYK-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410111611.EMSfFrYK-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/misc/keba/lan9252.c:299:10: warning: variable 'ret' is uninitialized when used here [-Wuninitialized]
     299 |                 return ret;
         |                        ^~~
   drivers/misc/keba/lan9252.c:291:9: note: initialize the variable 'ret' to silence this warning
     291 |         int ret;
         |                ^
         |                 = 0
   1 warning generated.


vim +/ret +299 drivers/misc/keba/lan9252.c

   286	
   287	static int lan9252_probe(struct spi_device *spi)
   288	{
   289		u32 data;
   290		int retry = SPI_RETRY_COUNT;
   291		int ret;
   292	
   293		/* execute specified initialization sequence */
   294		while (retry && !lan9252_init(spi))
   295			retry--;
   296		if (retry == 0) {
   297			dev_err(&spi->dev,
   298				"Can't initialize LAN9252 SPI communication!");
 > 299			return ret;
   300		}
   301	
   302		/* enable access to MII management for PDI */
   303		ret = lan9252_access_mii(spi, true);
   304		if (ret) {
   305			dev_err(&spi->dev, "Can't enable access to MII management!");
   306			return ret;
   307		}
   308	
   309		/*
   310		 * check PHY configuration and configure if necessary
   311		 *	- full duplex
   312		 *	- auto negotiation disabled
   313		 *	- 100 Mbps
   314		 */
   315		ret = lan9252_mii_read(spi, PHY_ADDRESS, MII_BMCR, &data);
   316		if (ret) {
   317			dev_err(&spi->dev, "Can't read LAN9252 configuration!");
   318			goto out;
   319		}
   320		if (!(data & BMCR_FULLDPLX) || (data & BMCR_ANENABLE) ||
   321		    !(data & BMCR_SPEED100)) {
   322			/*
   323			 */
   324			data &= ~(BMCR_ANENABLE);
   325			data |= (BMCR_FULLDPLX | BMCR_SPEED100);
   326			ret = lan9252_mii_write(spi, PHY_ADDRESS, MII_BMCR, data);
   327			if (ret)
   328				dev_err(&spi->dev,
   329					"Can't write LAN9252 configuration!");
   330		}
   331	
   332		dev_info(&spi->dev, "LAN9252 PHY configuration");
   333	
   334	out:
   335		/* disable access to MII management for PDI */
   336		lan9252_access_mii(spi, false);
   337	
   338		return ret;
   339	}
   340	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki