diff mbox series

[4/8] pwm: max7360: Add MAX7360 PWM support

Message ID 20241219-mdb-max7360-support-v1-4-8e8317584121@bootlin.com (mailing list archive)
State New
Headers show
Series Add support for MAX7360 multifunction device | expand

Commit Message

Mathieu Dubois-Briand Dec. 19, 2024, 4:21 p.m. UTC 
From: Kamel Bouhara <kamel.bouhara@bootlin.com>

Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
8 independent PWM outputs.

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
 drivers/pwm/Kconfig       |  11 +++
 drivers/pwm/Makefile      |   1 +
 drivers/pwm/pwm-max7360.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 185 insertions(+)

Comments

Uwe Kleine-König Dec. 19, 2024, 9:53 p.m. UTC | #1 
Hello,

On Thu, Dec 19, 2024 at 05:21:21PM +0100, mathieu.dubois-briand@bootlin.com wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
> 8 independent PWM outputs.
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
> ---
>  drivers/pwm/Kconfig       |  11 +++
>  drivers/pwm/Makefile      |   1 +
>  drivers/pwm/pwm-max7360.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 185 insertions(+)
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 0915c1e7df16..399dc3f76e92 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -745,4 +745,15 @@ config PWM_XILINX
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called pwm-xilinx.
>  
> +config PWM_MAX7360
> +	tristate "MAX7360 PWMs"
> +	depends on MFD_MAX7360
> +	depends on OF_GPIO
> +	help
> +	  PWM driver for Maxim Integrated MAX7360 multifunction device, with
> +	  support for up to 8 PWM outputs.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called pwm-max7360.
> +
>  endif
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 9081e0c0e9e0..ae8908ffc892 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_PWM_LPC32XX)	+= pwm-lpc32xx.o
>  obj-$(CONFIG_PWM_LPSS)		+= pwm-lpss.o
>  obj-$(CONFIG_PWM_LPSS_PCI)	+= pwm-lpss-pci.o
>  obj-$(CONFIG_PWM_LPSS_PLATFORM)	+= pwm-lpss-platform.o
> +obj-$(CONFIG_PWM_MAX7360)	+= pwm-max7360.o
>  obj-$(CONFIG_PWM_MESON)		+= pwm-meson.o
>  obj-$(CONFIG_PWM_MEDIATEK)	+= pwm-mediatek.o
>  obj-$(CONFIG_PWM_MICROCHIP_CORE)	+= pwm-microchip-core.o
> diff --git a/drivers/pwm/pwm-max7360.c b/drivers/pwm/pwm-max7360.c
> new file mode 100644
> index 000000000000..b1cde3e86864
> --- /dev/null
> +++ b/drivers/pwm/pwm-max7360.c
> @@ -0,0 +1,173 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2024 Bootlin
> + *
> + * Author: Kamel BOUHARA <kamel.bouhara@bootlin.com>
> + */
> +#include <linux/math.h>
> +#include <linux/mfd/max7360.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
> +
> +#define MAX7360_NUM_PWMS			8
> +#define MAX7360_PWM_MAX_RES			256
> +#define MAX7360_PWM_PERIOD_NS			2000000 /* 500 Hz */
> +#define MAX7360_PWM_COMMON_PWN			BIT(5)
> +#define MAX7360_PWM_CTRL_ENABLE(n)		BIT(n)
> +#define MAX7360_PWM_PORT(n)			BIT(n)
> +
> +struct max7360_pwm {
> +	struct device *dev;
> +	struct regmap *regmap;
> +};
> +
> +static inline struct max7360_pwm *to_max7360_pwm(struct pwm_chip *chip)
> +{
> +	return pwmchip_get_drvdata(chip);
> +}
> +
> +static int max7360_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	struct max7360_pwm *max7360_pwm;
> +	int ret;
> +
> +	max7360_pwm = to_max7360_pwm(chip);
> +	ret = max7360_port_pin_request(max7360_pwm->dev->parent, pwm->hwpwm,
> +				       true);
> +	if (ret) {
> +		dev_err(&chip->dev, "failed to request pwm-%d\n", pwm->hwpwm);

Please no error messages after probe.

> +		return ret;
> +	}
> +
> +	ret = regmap_write_bits(max7360_pwm->regmap,
> +				MAX7360_REG_PWMCFG + pwm->hwpwm,
> +				MAX7360_PWM_COMMON_PWN,
> +				0);
> +	if (ret) {
> +		dev_err(&chip->dev, "failed to write pwm-%d cfg register, error %d\n",
> +			pwm->hwpwm, ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_PORTS,
> +				MAX7360_PWM_PORT(pwm->hwpwm),
> +				MAX7360_PWM_PORT(pwm->hwpwm));
> +	if (ret) {
> +		dev_err(&chip->dev, "failed to write pwm-%d ports register, error %d\n",
> +			pwm->hwpwm, ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void max7360_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	struct max7360_pwm *max7360_pwm;
> +	int ret;
> +
> +	max7360_pwm = to_max7360_pwm(chip);
> +	ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
> +				MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm),
> +				0);
> +	if (ret)
> +		dev_err(&chip->dev, "failed to enable pwm-%d , error %d\n",
> +			pwm->hwpwm, ret);
> +
> +	max7360_port_pin_request(max7360_pwm->dev->parent, pwm->hwpwm,
> +				 false);
> +}
> +
> +static int max7360_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> +			     const struct pwm_state *state)
> +{
> +	struct max7360_pwm *max7360_pwm;
> +	u64 duty_steps = state->duty_cycle * MAX7360_PWM_MAX_RES;

This might overflow.

> +	int ret;
> +
> +	if (state->polarity != PWM_POLARITY_NORMAL)
> +		return -EINVAL;
> +
> +	max7360_pwm = to_max7360_pwm(chip);
> +	ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
> +				MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm),
> +				MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm));
> +	if (ret) {
> +		dev_err(&chip->dev, "failed to enable pwm-%d , error %d\n",
> +			pwm->hwpwm, ret);
> +		return ret;
> +	}
> +
> +	do_div(duty_steps, MAX7360_PWM_PERIOD_NS);
> +
> +	ret = regmap_write(max7360_pwm->regmap, MAX7360_REG_PWMBASE + pwm->hwpwm,
> +			   duty_steps >= 255 ? 255 : duty_steps);
> +	if (ret) {
> +		dev_err(&chip->dev,
> +			"failed to apply pwm duty_cycle %llu on pwm-%d, error %d\n",
> +			duty_steps, pwm->hwpwm, ret);
> +		return ret;
> +	}

Huh, state->period isn't used at all. That is wrong for sure.

> +
> +	return 0;
> +}
> +
> +static const struct pwm_ops max7360_pwm_ops = {
> +	.request = max7360_pwm_request,
> +	.free = max7360_pwm_free,
> +	.apply = max7360_pwm_apply,

Please implement .get_state() (or the new waveform callbacks)

> +};
> +
> +static int max7360_pwm_probe(struct platform_device *pdev)
> +{
> +	struct max7360_pwm *max7360_pwm;
> +	struct pwm_chip *chip;
> +
> +	if (!pdev->dev.parent) {
> +		dev_err(&pdev->dev, "no parent device\n");
> +		return -ENODEV;

return dev_err_probe(...);

> +	}
> +
> +	chip = devm_pwmchip_alloc(&pdev->dev, MAX7360_NUM_PWMS,
> +				  sizeof(*max7360_pwm));
> +	if (IS_ERR(chip))
> +		return PTR_ERR(chip);
> +	chip->ops = &max7360_pwm_ops;
> +
> +	max7360_pwm = to_max7360_pwm(chip);
> +	max7360_pwm->dev = &pdev->dev;

This is only ever used to get max7360_pwm->dev->parent; so better store
the parent directly in max7360_pwm.

> +
> +	max7360_pwm->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!max7360_pwm->regmap) {
> +		dev_err(&pdev->dev, "could not get parent regmap\n");
> +		return -ENODEV;
> +	}
> +
> +	return devm_pwmchip_add(&pdev->dev, chip);

error message please

> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id max7360_pwm_of_match[] = {
> +	{ .compatible = "maxim,max7360-pwm", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, max7360_pwm_of_match);
> +#endif

Please drop the CONFIG_OF guard.

> +
> +static struct platform_driver max7360_pwm_driver = {
> +	.driver = {
> +		.name = "max7360-pwm",
> +		.of_match_table = of_match_ptr(max7360_pwm_of_match),
> +	},
> +	.probe = max7360_pwm_probe,
> +};
> +module_platform_driver(max7360_pwm_driver);
> +
> +MODULE_DESCRIPTION("MAX7360 PWM driver");
> +MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");
> +MODULE_ALIAS("platform:max7360-pwm");
> +MODULE_LICENSE("GPL");
Uwe Kleine-König Dec. 20, 2024, 5:51 a.m. UTC | #2 
Hello again,

On Thu, Dec 19, 2024 at 05:21:21PM +0100, mathieu.dubois-briand@bootlin.com wrote:
> diff --git a/drivers/pwm/pwm-max7360.c b/drivers/pwm/pwm-max7360.c
> new file mode 100644
> index 000000000000..b1cde3e86864
> --- /dev/null
> +++ b/drivers/pwm/pwm-max7360.c
> @@ -0,0 +1,173 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2024 Bootlin
> + *

I forgot: Please also add a paragraph here describing the relevant
features here in the format that several other drivers use. Such that

	sed -rn '/Limitations:/,/\*\/?$/p' drivers/pwm/*.c

emits it. Relevant are at least:

 - Only supports normal polarity

 - How does it behave on disable? (Constant low? Freeze at the level
   where it just happens to be? High-Z?)

 - How does it behave on reconfiguration? (counter reset? Mixed output
   possible?

Best regards
Uwe
diff mbox series

Patch

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 0915c1e7df16..399dc3f76e92 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -745,4 +745,15 @@  config PWM_XILINX
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-xilinx.
 
+config PWM_MAX7360
+	tristate "MAX7360 PWMs"
+	depends on MFD_MAX7360
+	depends on OF_GPIO
+	help
+	  PWM driver for Maxim Integrated MAX7360 multifunction device, with
+	  support for up to 8 PWM outputs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-max7360.
+
 endif
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 9081e0c0e9e0..ae8908ffc892 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -36,6 +36,7 @@  obj-$(CONFIG_PWM_LPC32XX)	+= pwm-lpc32xx.o
 obj-$(CONFIG_PWM_LPSS)		+= pwm-lpss.o
 obj-$(CONFIG_PWM_LPSS_PCI)	+= pwm-lpss-pci.o
 obj-$(CONFIG_PWM_LPSS_PLATFORM)	+= pwm-lpss-platform.o
+obj-$(CONFIG_PWM_MAX7360)	+= pwm-max7360.o
 obj-$(CONFIG_PWM_MESON)		+= pwm-meson.o
 obj-$(CONFIG_PWM_MEDIATEK)	+= pwm-mediatek.o
 obj-$(CONFIG_PWM_MICROCHIP_CORE)	+= pwm-microchip-core.o
diff --git a/drivers/pwm/pwm-max7360.c b/drivers/pwm/pwm-max7360.c
new file mode 100644
index 000000000000..b1cde3e86864
--- /dev/null
+++ b/drivers/pwm/pwm-max7360.c
@@ -0,0 +1,173 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024 Bootlin
+ *
+ * Author: Kamel BOUHARA <kamel.bouhara@bootlin.com>
+ */
+#include <linux/math.h>
+#include <linux/mfd/max7360.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+
+#define MAX7360_NUM_PWMS			8
+#define MAX7360_PWM_MAX_RES			256
+#define MAX7360_PWM_PERIOD_NS			2000000 /* 500 Hz */
+#define MAX7360_PWM_COMMON_PWN			BIT(5)
+#define MAX7360_PWM_CTRL_ENABLE(n)		BIT(n)
+#define MAX7360_PWM_PORT(n)			BIT(n)
+
+struct max7360_pwm {
+	struct device *dev;
+	struct regmap *regmap;
+};
+
+static inline struct max7360_pwm *to_max7360_pwm(struct pwm_chip *chip)
+{
+	return pwmchip_get_drvdata(chip);
+}
+
+static int max7360_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct max7360_pwm *max7360_pwm;
+	int ret;
+
+	max7360_pwm = to_max7360_pwm(chip);
+	ret = max7360_port_pin_request(max7360_pwm->dev->parent, pwm->hwpwm,
+				       true);
+	if (ret) {
+		dev_err(&chip->dev, "failed to request pwm-%d\n", pwm->hwpwm);
+		return ret;
+	}
+
+	ret = regmap_write_bits(max7360_pwm->regmap,
+				MAX7360_REG_PWMCFG + pwm->hwpwm,
+				MAX7360_PWM_COMMON_PWN,
+				0);
+	if (ret) {
+		dev_err(&chip->dev, "failed to write pwm-%d cfg register, error %d\n",
+			pwm->hwpwm, ret);
+		return ret;
+	}
+
+	ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_PORTS,
+				MAX7360_PWM_PORT(pwm->hwpwm),
+				MAX7360_PWM_PORT(pwm->hwpwm));
+	if (ret) {
+		dev_err(&chip->dev, "failed to write pwm-%d ports register, error %d\n",
+			pwm->hwpwm, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void max7360_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct max7360_pwm *max7360_pwm;
+	int ret;
+
+	max7360_pwm = to_max7360_pwm(chip);
+	ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
+				MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm),
+				0);
+	if (ret)
+		dev_err(&chip->dev, "failed to enable pwm-%d , error %d\n",
+			pwm->hwpwm, ret);
+
+	max7360_port_pin_request(max7360_pwm->dev->parent, pwm->hwpwm,
+				 false);
+}
+
+static int max7360_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			     const struct pwm_state *state)
+{
+	struct max7360_pwm *max7360_pwm;
+	u64 duty_steps = state->duty_cycle * MAX7360_PWM_MAX_RES;
+	int ret;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	max7360_pwm = to_max7360_pwm(chip);
+	ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
+				MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm),
+				MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm));
+	if (ret) {
+		dev_err(&chip->dev, "failed to enable pwm-%d , error %d\n",
+			pwm->hwpwm, ret);
+		return ret;
+	}
+
+	do_div(duty_steps, MAX7360_PWM_PERIOD_NS);
+
+	ret = regmap_write(max7360_pwm->regmap, MAX7360_REG_PWMBASE + pwm->hwpwm,
+			   duty_steps >= 255 ? 255 : duty_steps);
+	if (ret) {
+		dev_err(&chip->dev,
+			"failed to apply pwm duty_cycle %llu on pwm-%d, error %d\n",
+			duty_steps, pwm->hwpwm, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct pwm_ops max7360_pwm_ops = {
+	.request = max7360_pwm_request,
+	.free = max7360_pwm_free,
+	.apply = max7360_pwm_apply,
+};
+
+static int max7360_pwm_probe(struct platform_device *pdev)
+{
+	struct max7360_pwm *max7360_pwm;
+	struct pwm_chip *chip;
+
+	if (!pdev->dev.parent) {
+		dev_err(&pdev->dev, "no parent device\n");
+		return -ENODEV;
+	}
+
+	chip = devm_pwmchip_alloc(&pdev->dev, MAX7360_NUM_PWMS,
+				  sizeof(*max7360_pwm));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	chip->ops = &max7360_pwm_ops;
+
+	max7360_pwm = to_max7360_pwm(chip);
+	max7360_pwm->dev = &pdev->dev;
+
+	max7360_pwm->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!max7360_pwm->regmap) {
+		dev_err(&pdev->dev, "could not get parent regmap\n");
+		return -ENODEV;
+	}
+
+	return devm_pwmchip_add(&pdev->dev, chip);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id max7360_pwm_of_match[] = {
+	{ .compatible = "maxim,max7360-pwm", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max7360_pwm_of_match);
+#endif
+
+static struct platform_driver max7360_pwm_driver = {
+	.driver = {
+		.name = "max7360-pwm",
+		.of_match_table = of_match_ptr(max7360_pwm_of_match),
+	},
+	.probe = max7360_pwm_probe,
+};
+module_platform_driver(max7360_pwm_driver);
+
+MODULE_DESCRIPTION("MAX7360 PWM driver");
+MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");
+MODULE_ALIAS("platform:max7360-pwm");
+MODULE_LICENSE("GPL");