Implement the PWM driver for CV1800.
Signed-off-by: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-cv1800.c | 293 +++++++++++++++++++++++++++++++++++++++
3 files changed, 304 insertions(+)
create mode 100644 drivers/pwm/pwm-cv1800.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 1dd7921194f5..3869ca022aeb 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -182,6 +182,16 @@ config PWM_CROS_EC
PWM driver for exposing a PWM attached to the ChromeOS Embedded
Controller.
+config PWM_CV1800
+ tristate "Sophgo CV1800 PWM driver"
+ depends on ARCH_SOPHGO || COMPILE_TEST
+ help
+ Generic PWM framework driver for the Sophgo CV1800 series
+ SoCs.
+
+ To compile this driver as a module, build the dependecies
+ as modules, this will be called pwm-cv1800.
+
config PWM_DWC_CORE
tristate
depends on HAS_IOMEM
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 90913519f11a..6295e2259efc 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_PWM_CLK) += pwm-clk.o
obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
obj-$(CONFIG_PWM_CRC) += pwm-crc.o
obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o
+obj-$(CONFIG_PWM_CV1800) += pwm-cv1800.o
obj-$(CONFIG_PWM_DWC_CORE) += pwm-dwc-core.o
obj-$(CONFIG_PWM_DWC) += pwm-dwc.o
obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
new file mode 100644
index 000000000000..d487af637198
--- /dev/null
+++ b/drivers/pwm/pwm-cv1800.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Sophgo CV1800 PWM driver
+ * Author: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
+ *
+ * Limitations:
+ * - The hardware emits the inactive level when disabled.
+ * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
+ * is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
+ * temporarily stored inside the PWM. If you want to dynamically change the
+ * waveform during PWM output, after writing the new value to HLPERIODn and
+ * PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.
+ * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).
+ * - By setting HLPERIODn to 0, can produce 100% duty cycle.
+ * - This hardware could support inverted polarity. By default, the value of the
+ * POLARITY register is 0x0. This means that HLPERIOD represents the number
+ * of low level beats.
+ * - This hardware supports input mode and output mode, implemented through the
+ * Output-Enable/OE register. However, this driver has not yet implemented
+ * capture callback.
+ */
+
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+
+#define PWM_CV1800_HLPERIOD_BASE 0x00
+#define PWM_CV1800_PERIOD_BASE 0x04
+#define PWM_CV1800_POLARITY 0x40
+#define PWM_CV1800_START 0x44
+#define PWM_CV1800_DONE 0x48
+#define PWM_CV1800_UPDATE 0x4c
+#define PWM_CV1800_OE 0xd0
+
+#define PWM_CV1800_HLPERIOD(n) (PWM_CV1800_HLPERIOD_BASE + ((n)*0x08))
+#define PWM_CV1800_PERIOD(n) (PWM_CV1800_PERIOD_BASE + ((n)*0x08))
+
+#define PWM_CV1800_UPDATE_MASK(n) BIT(n)
+#define PWM_CV1800_OE_MASK(n) BIT(n)
+#define PWM_CV1800_START_MASK(n) BIT(n)
+#define PWM_CV1800_POLARITY_MASK(n) BIT(n)
+
+#define PWM_CV1800_MAXPERIOD 0x3fffffff
+#define PWM_CV1800_MINPERIOD 2
+#define PWM_CV1800_CHANNELS 4
+#define PWM_CV1800_PERIOD_RESET BIT(1)
+#define PWM_CV1800_HLPERIOD_RESET BIT(0)
+#define PWM_CV1800_REG_ENABLE(n) BIT(n)
+
+struct cv1800_pwm {
+ struct regmap *map;
+ struct clk *clk;
+ unsigned long clk_rate;
+};
+
+static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
+{
+ return pwmchip_get_drvdata(chip);
+}
+
+static const struct regmap_config cv1800_pwm_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
+ bool enable)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 pwm_enable, state;
+
+ regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
+ pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
+
+ /*
+ * If the parameters are changed during runtime, Register needs
+ * to be updated to take effect.
+ */
+ if (pwm_enable && enable) {
+ regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
+ PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+ regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
+ PWM_CV1800_UPDATE_MASK(pwm->hwpwm), 0);
+ } else if (!pwm_enable && enable) {
+ regmap_update_bits(priv->map, PWM_CV1800_START,
+ PWM_CV1800_START_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+ } else if (pwm_enable && !enable) {
+ regmap_update_bits(priv->map, PWM_CV1800_START,
+ PWM_CV1800_START_MASK(pwm->hwpwm), 0);
+ }
+
+ /* check and set OE/Output-Enable mode */
+ regmap_read(priv->map, PWM_CV1800_OE, &state);
+
+ if ((state & BIT(pwm->hwpwm)) && enable)
+ regmap_update_bits(priv->map, PWM_CV1800_OE,
+ PWM_CV1800_OE_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+
+ return 0;
+}
+
+static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 config_polarity = 0;
+
+ if (pwm->state.enabled)
+ cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);
+
+ if (polarity == PWM_POLARITY_NORMAL)
+ config_polarity = PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
+
+ regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
+ PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
+ config_polarity);
+}
+
+static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 period_val, hlperiod_val;
+ u64 ticks;
+
+ if (state->polarity != pwm->state.polarity)
+ cv1800_pwm_set_polarity(chip, pwm, state->polarity);
+
+ /*
+ * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
+ *
+ * The meaning of PERIOD is how many clock cycles (from the clock source)
+ * are used to represent PWM waves.
+ * PERIOD = rate(MHz) / target(MHz)
+ * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
+ */
+ ticks = mul_u64_u64_div_u64(state->period, priv->clk_rate,
+ NSEC_PER_SEC);
+ if (ticks < PWM_CV1800_MINPERIOD)
+ return -EINVAL;
+
+ if (ticks > PWM_CV1800_MAXPERIOD)
+ ticks = PWM_CV1800_MAXPERIOD;
+ period_val = (u32)ticks;
+
+ /*
+ * After mapping, hlperiod represents the same polarity as duty.
+ * HLPERIOD = rate(MHz) / duty(MHz)
+ * HLPERIOD = duty(ns) * rate(Hz) / NSEC_PER_SEC
+ */
+ ticks = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
+ NSEC_PER_SEC);
+ if (ticks > period_val)
+ ticks = period_val;
+ hlperiod_val = (u32)ticks;
+
+ regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
+ regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
+
+ cv1800_pwm_enable(chip, pwm, state->enabled);
+
+ return 0;
+}
+
+static int cv1800_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 period_val, hlperiod_val;
+ u64 period_ns = 0, duty_ns = 0;
+ u32 enable = 0, polarity = 0;
+
+ regmap_read(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), &period_val);
+ regmap_read(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), &hlperiod_val);
+
+ if (period_val != PWM_CV1800_PERIOD_RESET ||
+ hlperiod_val != PWM_CV1800_HLPERIOD_RESET) {
+ period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,
+ priv->clk_rate);
+ duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * NSEC_PER_SEC,
+ priv->clk_rate);
+
+ regmap_read(priv->map, PWM_CV1800_START, &enable);
+ enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
+
+ regmap_read(priv->map, PWM_CV1800_POLARITY, &polarity);
+ polarity &= PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
+ }
+
+ state->period = period_ns;
+ state->duty_cycle = duty_ns;
+ state->enabled = enable;
+
+ /*
+ * To ensure that duty and hlperiod represent the same polarity
+ * the following mapping needs to be completed.
+ *
+ * |----------|------------|------------|-----------|
+ * | Linux | register | duty | register |
+ * | polarity | polarity | | hlperiod |
+ * |----------|------------|------------|-----------|
+ * | 1 | 0 | low level | low level |
+ * |----------|------------|------------|-----------|
+ * | 0 | 1 | high level | high level|
+ * |----------|------------|------------|-----------|
+ */
+ state->polarity = polarity ? PWM_POLARITY_NORMAL :
+ PWM_POLARITY_INVERSED;
+
+ return 0;
+}
+
+static const struct pwm_ops cv1800_pwm_ops = {
+ .apply = cv1800_pwm_apply,
+ .get_state = cv1800_pwm_get_state,
+};
+
+static int cv1800_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cv1800_pwm *priv;
+ struct pwm_chip *chip;
+ void __iomem *base;
+ int ret;
+
+ chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));
+ if (!chip)
+ return PTR_ERR(chip);
+ priv = to_cv1800_pwm_dev(chip);
+
+ base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ priv->map = devm_regmap_init_mmio(&pdev->dev, base,
+ &cv1800_pwm_regmap_config);
+ if (IS_ERR(priv->map)) {
+ dev_err(dev, "Couldn't create PWM regmap\n");
+ return PTR_ERR(priv->map);
+ }
+
+ priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+ if (IS_ERR(priv->clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
+ "clk not found\n");
+
+ ret = devm_clk_rate_exclusive_get(dev, priv->clk);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to get exclusive rate\n");
+
+ priv->clk_rate = clk_get_rate(priv->clk);
+ if (!priv->clk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL,
+ "Invalid clock rate: %lu\n",
+ priv->clk_rate);
+
+ chip->ops = &cv1800_pwm_ops;
+
+ ret = devm_pwmchip_add(dev, chip);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
+
+ return 0;
+}
+
+static const struct of_device_id cv1800_pwm_dt_ids[] = {
+ { .compatible = "sophgo,cv1800-pwm" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cv1800_pwm_dt_ids);
+
+static struct platform_driver cv1800_pwm_driver = {
+ .probe = cv1800_pwm_probe,
+ .driver = {
+ .name = "cv1800-pwm",
+ .of_match_table = cv1800_pwm_dt_ids,
+ },
+};
+module_platform_driver(cv1800_pwm_driver);
+
+MODULE_AUTHOR("Jingbao Qiu");
+MODULE_DESCRIPTION("Sophgo cv1800 PWM Driver");
+MODULE_LICENSE("GPL");
--
2.25.1Hello,
On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
> [...]
> diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
> new file mode 100644
> index 000000000000..d487af637198
> --- /dev/null
> +++ b/drivers/pwm/pwm-cv1800.c
> @@ -0,0 +1,293 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Sophgo CV1800 PWM driver
> + * Author: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
> + *
> + * Limitations:
> + * - The hardware emits the inactive level when disabled.
> + * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
> + * is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
> + * temporarily stored inside the PWM. If you want to dynamically change the
> + * waveform during PWM output, after writing the new value to HLPERIODn and
> + * PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.
To change polarity, the hardware has to be stopped though.
> + * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).
Rate = input clock rate?
> + * - By setting HLPERIODn to 0, can produce 100% duty cycle.
> + * - This hardware could support inverted polarity. By default, the value of the
> + * POLARITY register is 0x0. This means that HLPERIOD represents the number
> + * of low level beats.
> + * - This hardware supports input mode and output mode, implemented through the
> + * Output-Enable/OE register. However, this driver has not yet implemented
> + * capture callback.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
> +
> +#define PWM_CV1800_HLPERIOD_BASE 0x00
> +#define PWM_CV1800_PERIOD_BASE 0x04
> +#define PWM_CV1800_POLARITY 0x40
> +#define PWM_CV1800_START 0x44
> +#define PWM_CV1800_DONE 0x48
> +#define PWM_CV1800_UPDATE 0x4c
> +#define PWM_CV1800_OE 0xd0
> +
> +#define PWM_CV1800_HLPERIOD(n) (PWM_CV1800_HLPERIOD_BASE + ((n)*0x08))
> +#define PWM_CV1800_PERIOD(n) (PWM_CV1800_PERIOD_BASE + ((n)*0x08))
I suggest to drop the ..._BASE defines and hardcode the 0 and 4
respectively in the definition of PWM_CV1800_HLPERIOD and
PWM_CV1800_PERIOD. Also please use spaces around the multiplication *.
> +#define PWM_CV1800_UPDATE_MASK(n) BIT(n)
> +#define PWM_CV1800_OE_MASK(n) BIT(n)
> +#define PWM_CV1800_START_MASK(n) BIT(n)
> +#define PWM_CV1800_POLARITY_MASK(n) BIT(n)
> +
> +#define PWM_CV1800_MAXPERIOD 0x3fffffff
> +#define PWM_CV1800_MINPERIOD 2
> +#define PWM_CV1800_CHANNELS 4
> +#define PWM_CV1800_PERIOD_RESET BIT(1)
This is strange, the PWM_CV1800_PERIOD can be programmed with values >=
PWM_CV1800_MINPERIOD; if you program 2, you use period ==
PWM_CV1800_PERIOD_RESET.
> +#define PWM_CV1800_HLPERIOD_RESET BIT(0)
> +#define PWM_CV1800_REG_ENABLE(n) BIT(n)
> +
> +struct cv1800_pwm {
> + struct regmap *map;
> + struct clk *clk;
> + unsigned long clk_rate;
> +};
> +
> +static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
> +{
> + return pwmchip_get_drvdata(chip);
> +}
> +
> +static const struct regmap_config cv1800_pwm_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> +};
> +
> +static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
> + bool enable)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 pwm_enable, state;
> +
> + regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
> + pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
This value tells if the HW is enabled, right. Maybe rename the variable
to pwm_enabled (or pwm_is_enabled).
> + /*
> + * If the parameters are changed during runtime, Register needs
> + * to be updated to take effect.
> + */
> + if (pwm_enable && enable) {
> + regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> + PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
I would consider
regmap_set_bits(priv->map, PWM_CV1800_UPDATE, BIT(pwm->hwpwm));
more readable.
> + regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> + PWM_CV1800_UPDATE_MASK(pwm->hwpwm), 0);
Maybe add a comment about why you modify the same bit here twice.
> + } else if (!pwm_enable && enable) {
> + regmap_update_bits(priv->map, PWM_CV1800_START,
> + PWM_CV1800_START_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> + } else if (pwm_enable && !enable) {
> + regmap_update_bits(priv->map, PWM_CV1800_START,
> + PWM_CV1800_START_MASK(pwm->hwpwm), 0);
> + }
The previous construct can be (IMO) simplified by doing:
if (!enable) {
if (pwm_enabled)
regmap_clear_bits(...);
return 0;
}
if (pwm_enabled) {
...
} else {
...
}
(This slightly changes semantics, but that's fine.)
> +
> + /* check and set OE/Output-Enable mode */
> + regmap_read(priv->map, PWM_CV1800_OE, &state);
> +
> + if ((state & BIT(pwm->hwpwm)) && enable)
> + regmap_update_bits(priv->map, PWM_CV1800_OE,
> + PWM_CV1800_OE_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
This looks strange. If BIT(hwpwm) is already set, set it again?!
Also if you used the caching implemented in regmap, you don't need to
make this conditional.
> + return 0;
> +}
> +
> +static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + enum pwm_polarity polarity)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 config_polarity = 0;
> +
> + if (pwm->state.enabled)
> + cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);
Using false instead of !pwm->state.enabled would be more straight
forward.
> + if (polarity == PWM_POLARITY_NORMAL)
> + config_polarity = PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
> +
> + regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> + PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> + config_polarity);
> +}
> +
> +static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + const struct pwm_state *state)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 period_val, hlperiod_val;
> + u64 ticks;
> +
> + if (state->polarity != pwm->state.polarity)
> + cv1800_pwm_set_polarity(chip, pwm, state->polarity);
> +
> + /*
> + * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
> + *
> + * The meaning of PERIOD is how many clock cycles (from the clock source)
> + * are used to represent PWM waves.
> + * PERIOD = rate(MHz) / target(MHz)
> + * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
> + */
> + ticks = mul_u64_u64_div_u64(state->period, priv->clk_rate,
> + NSEC_PER_SEC);
> + if (ticks < PWM_CV1800_MINPERIOD)
> + return -EINVAL;
If you check this before configuring the period, it won't happen that
the hw state is modified before you notice you cannot fulfill the
requested state.
> + if (ticks > PWM_CV1800_MAXPERIOD)
> + ticks = PWM_CV1800_MAXPERIOD;
> + period_val = (u32)ticks;
Maybe use period_ticks instead of period_val to have a consistent
naming.
> +
> + /*
> + * After mapping, hlperiod represents the same polarity as duty.
> + * HLPERIOD = rate(MHz) / duty(MHz)
> + * HLPERIOD = duty(ns) * rate(Hz) / NSEC_PER_SEC
> + */
I don't understand that comment.
> + ticks = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
> + NSEC_PER_SEC);
> + if (ticks > period_val)
> + ticks = period_val;
> + hlperiod_val = (u32)ticks;
> +
> + regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
> + regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
> +
> + cv1800_pwm_enable(chip, pwm, state->enabled);
> +
> + return 0;
> +}
> +
> [...]
> +static int cv1800_pwm_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct cv1800_pwm *priv;
> + struct pwm_chip *chip;
> + void __iomem *base;
> + int ret;
> +
> + chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));
PWM_CV1800_CHANNELS is only used here. I'd prefer a plain 4 here. This
also makes this value easier to grep for.
> + if (!chip)
> + return PTR_ERR(chip);
> + priv = to_cv1800_pwm_dev(chip);
> +
> + base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + priv->map = devm_regmap_init_mmio(&pdev->dev, base,
> + &cv1800_pwm_regmap_config);
> + if (IS_ERR(priv->map)) {
> + dev_err(dev, "Couldn't create PWM regmap\n");
> + return PTR_ERR(priv->map);
Use dev_err_probe please.
> + }
> +
> + priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
> + if (IS_ERR(priv->clk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
> + "clk not found\n");
> +
> + ret = devm_clk_rate_exclusive_get(dev, priv->clk);
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret,
> + "failed to get exclusive rate\n");
> +
> + priv->clk_rate = clk_get_rate(priv->clk);
> + if (!priv->clk_rate)
> + return dev_err_probe(&pdev->dev, -EINVAL,
> + "Invalid clock rate: %lu\n",
> + priv->clk_rate);
Please also error out if clk_rate > NSEC_PER_SEC, because otherwise you
might get overflows for the calculations in .apply().
> +
> + chip->ops = &cv1800_pwm_ops;
> +
> + ret = devm_pwmchip_add(dev, chip);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
> +
> + return 0;
> +}
> [...]
Best regards
Uwe
Hello,
On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
> On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
>> [...]
>> + if ((state & BIT(pwm->hwpwm)) && enable)
>> + regmap_update_bits(priv->map, PWM_CV1800_OE,
>> + PWM_CV1800_OE_MASK(pwm->hwpwm),
>> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
>
> This looks strange. If BIT(hwpwm) is already set, set it again?!
> Also if you used the caching implemented in regmap, you don't need to
> make this conditional.
>
I was testing the series and noticed indeed an issue in this driver at
those lines. If PWM_CV1800_OE isn't set by something else than the
kernel it will never be set and so, there will never be a PWM outputted.
Using :
if (!(state & BIT(pwm->hwpwm)) && enable)
Solved the issue but as Uwe said you can probably rely on regmap caching
to avoid this condition.
>
> ...
>
Do you plan on sending a new iteration some day ? I may have some time
to continue the upstreaming process if you need to.
Thank you for this series !
Thomas
On Sun, Apr 06, 2025 at 02:16:41AM +0200, Thomas Bonnefille wrote: > Hello, > > On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote: > > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote: > >> [...] > >> + if ((state & BIT(pwm->hwpwm)) && enable) > >> + regmap_update_bits(priv->map, PWM_CV1800_OE, > >> + PWM_CV1800_OE_MASK(pwm->hwpwm), > >> + PWM_CV1800_REG_ENABLE(pwm->hwpwm)); > > > > This looks strange. If BIT(hwpwm) is already set, set it again?! > > Also if you used the caching implemented in regmap, you don't need to > > make this conditional. > > > > I was testing the series and noticed indeed an issue in this driver at > those lines. If PWM_CV1800_OE isn't set by something else than the > kernel it will never be set and so, there will never be a PWM outputted. > > Using : > if (!(state & BIT(pwm->hwpwm)) && enable) > Solved the issue but as Uwe said you can probably rely on regmap caching > to avoid this condition. > > > > > ... > > > > Do you plan on sending a new iteration some day ? I may have some time > to continue the upstreaming process if you need to. > > Thank you for this series ! > Thomas I suggest checking existing spi-sg2044-nor driver, which may reduce your work for upstreaming. Regards, Inochi
On Mon Apr 7, 2025 at 9:21 AM CEST, Inochi Amaoto wrote: > On Sun, Apr 06, 2025 at 02:16:41AM +0200, Thomas Bonnefille wrote: >> Hello, >> >> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote: >> > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote: >> >> [...] >> >> + if ((state & BIT(pwm->hwpwm)) && enable) >> >> + regmap_update_bits(priv->map, PWM_CV1800_OE, >> >> + PWM_CV1800_OE_MASK(pwm->hwpwm), >> >> + PWM_CV1800_REG_ENABLE(pwm->hwpwm)); >> > >> > This looks strange. If BIT(hwpwm) is already set, set it again?! >> > Also if you used the caching implemented in regmap, you don't need to >> > make this conditional. >> > >> >> I was testing the series and noticed indeed an issue in this driver at >> those lines. If PWM_CV1800_OE isn't set by something else than the >> kernel it will never be set and so, there will never be a PWM outputted. >> >> Using : >> if (!(state & BIT(pwm->hwpwm)) && enable) >> Solved the issue but as Uwe said you can probably rely on regmap caching >> to avoid this condition. >> >> > >> > ... >> > >> >> Do you plan on sending a new iteration some day ? I may have some time >> to continue the upstreaming process if you need to. >> >> Thank you for this series ! >> Thomas > > I suggest checking existing spi-sg2044-nor driver, which may reduce your > work for upstreaming. > > Regards, > Inochi Hello Inochi, Thank you very much, however even after reading it I can't see the link between the SPI NOR controller driver of the SG2044 and the PWM driver for the CV18XX series ? Regards, Thomas
On Tue, Apr 08, 2025 at 09:54:27AM +0200, Thomas Bonnefille wrote: > On Mon Apr 7, 2025 at 9:21 AM CEST, Inochi Amaoto wrote: > > On Sun, Apr 06, 2025 at 02:16:41AM +0200, Thomas Bonnefille wrote: > >> Hello, > >> > >> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote: > >> > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote: > >> >> [...] > >> >> + if ((state & BIT(pwm->hwpwm)) && enable) > >> >> + regmap_update_bits(priv->map, PWM_CV1800_OE, > >> >> + PWM_CV1800_OE_MASK(pwm->hwpwm), > >> >> + PWM_CV1800_REG_ENABLE(pwm->hwpwm)); > >> > > >> > This looks strange. If BIT(hwpwm) is already set, set it again?! > >> > Also if you used the caching implemented in regmap, you don't need to > >> > make this conditional. > >> > > >> > >> I was testing the series and noticed indeed an issue in this driver at > >> those lines. If PWM_CV1800_OE isn't set by something else than the > >> kernel it will never be set and so, there will never be a PWM outputted. > >> > >> Using : > >> if (!(state & BIT(pwm->hwpwm)) && enable) > >> Solved the issue but as Uwe said you can probably rely on regmap caching > >> to avoid this condition. > >> > >> > > >> > ... > >> > > >> > >> Do you plan on sending a new iteration some day ? I may have some time > >> to continue the upstreaming process if you need to. > >> > >> Thank you for this series ! > >> Thomas > > > > I suggest checking existing spi-sg2044-nor driver, which may reduce your > > work for upstreaming. > > > > Regards, > > Inochi > > Hello Inochi, > > Thank you very much, however even after reading it I can't see the link > between the SPI NOR controller driver of the SG2044 and the PWM driver > for the CV18XX series ? > > Regards, > Thomas I am sorry, I mistake this as the spi-nor one. You may want to check the SG2044 pwm driver, which should be similiar. You could find it at https://lore.kernel.org/all/20250407072056.8629-1-looong.bin@gmail.com/ Regards, Inochi
On Sun, Apr 6, 2025 at 8:16 AM Thomas Bonnefille <thomas.bonnefille@bootlin.com> wrote: > > Hello, > > On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote: > > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote: > >> [...] > >> + if ((state & BIT(pwm->hwpwm)) && enable) > >> + regmap_update_bits(priv->map, PWM_CV1800_OE, > >> + PWM_CV1800_OE_MASK(pwm->hwpwm), > >> + PWM_CV1800_REG_ENABLE(pwm->hwpwm)); > > > > This looks strange. If BIT(hwpwm) is already set, set it again?! > > Also if you used the caching implemented in regmap, you don't need to > > make this conditional. > > > > I was testing the series and noticed indeed an issue in this driver at > those lines. If PWM_CV1800_OE isn't set by something else than the > kernel it will never be set and so, there will never be a PWM outputted. > > Using : > if (!(state & BIT(pwm->hwpwm)) && enable) > Solved the issue but as Uwe said you can probably rely on regmap caching > to avoid this condition. > > > > > ... > > > > Do you plan on sending a new iteration some day ? I may have some time > to continue the upstreaming process if you need to. > I am so happy you can continue finish this patch. Best regards Jingbao Qiu
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