Commit d93a75d9 authored by Kamel Bouhara's avatar Kamel Bouhara Committed by Lee Jones
Browse files

pwm: max7360: Add MAX7360 PWM support 



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

Signed-off-by: default avatarKamel Bouhara <kamel.bouhara@bootlin.com>
Co-developed-by: default avatarMathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: default avatarMathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarUwe Kleine-König <ukleinek@kernel.org>
Link: https://lore.kernel.org/r/20250824-mdb-max7360-support-v14-4-435cfda2b1ea@bootlin.com


Signed-off-by: default avatarLee Jones <lee@kernel.org>
parent b4b993c0

drivers/pwm/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -432,6 +432,16 @@ config PWM_LPSS_PLATFORM 
	  To compile this driver as a module, choose M here: the module

	  will be called pwm-lpss-platform.



config PWM_MAX7360

	tristate "MAX7360 PWMs"

	depends on MFD_MAX7360

	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.



config PWM_MC33XS2410

	tristate "MC33XS2410 PWM support"

	depends on OF

drivers/pwm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 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_MC33XS2410)	+= pwm-mc33xs2410.o

obj-$(CONFIG_PWM_MEDIATEK)	+= pwm-mediatek.o

obj-$(CONFIG_PWM_MESON)		+= pwm-meson.o

drivers/pwm/pwm-max7360.c

0 → 100644
+209 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright 2025 Bootlin

 *

 * Author: Kamel BOUHARA <kamel.bouhara@bootlin.com>

 * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>

 *

 * PWM functionality of the MAX7360 multi-function device.

 * https://www.analog.com/media/en/technical-documentation/data-sheets/MAX7360.pdf

 *

 * Limitations:

 * - Only supports normal polarity.

 * - The period is fixed to 2 ms.

 * - Only the duty cycle can be changed, new values are applied at the beginning

 *   of the next cycle.

 * - When disabled, the output is put in Hi-Z immediately.

 */

#include <linux/bits.h>

#include <linux/dev_printk.h>

#include <linux/err.h>

#include <linux/math64.h>

#include <linux/mfd/max7360.h>

#include <linux/minmax.h>

#include <linux/mod_devicetable.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/pwm.h>

#include <linux/regmap.h>

#include <linux/time.h>

#include <linux/types.h>



#define MAX7360_NUM_PWMS			8

#define MAX7360_PWM_MAX				255

#define MAX7360_PWM_STEPS			256

#define MAX7360_PWM_PERIOD_NS			(2 * NSEC_PER_MSEC)



struct max7360_pwm_waveform {

	u8 duty_steps;

	bool enabled;

};



static int max7360_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct regmap *regmap = pwmchip_get_drvdata(chip);



	/*

	 * Make sure we use the individual PWM configuration register and not

	 * the global one.

	 * We never need to use the global one, so there is no need to revert

	 * that in the .free() callback.

	 */

	return regmap_write_bits(regmap, MAX7360_REG_PWMCFG(pwm->hwpwm),

				 MAX7360_PORT_CFG_COMMON_PWM, 0);

}



static int max7360_pwm_round_waveform_tohw(struct pwm_chip *chip,

					   struct pwm_device *pwm,

					   const struct pwm_waveform *wf,

					   void *_wfhw)

{

	struct max7360_pwm_waveform *wfhw = _wfhw;

	u64 duty_steps;



	/*

	 * Ignore user provided values for period_length_ns and duty_offset_ns:

	 * we only support fixed period of MAX7360_PWM_PERIOD_NS and offset of 0.

	 * Values from 0 to 254 as duty_steps will provide duty cycles of 0/256

	 * to 254/256, while value 255 will provide a duty cycle of 100%.

	 */

	if (wf->duty_length_ns >= MAX7360_PWM_PERIOD_NS) {

		duty_steps = MAX7360_PWM_MAX;

	} else {

		duty_steps = (u32)wf->duty_length_ns * MAX7360_PWM_STEPS / MAX7360_PWM_PERIOD_NS;

		if (duty_steps == MAX7360_PWM_MAX)

			duty_steps = MAX7360_PWM_MAX - 1;

	}



	wfhw->duty_steps = min(MAX7360_PWM_MAX, duty_steps);

	wfhw->enabled = !!wf->period_length_ns;



	if (wf->period_length_ns && wf->period_length_ns < MAX7360_PWM_PERIOD_NS)

		return 1;

	else

		return 0;

}



static int max7360_pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,

					     const void *_wfhw, struct pwm_waveform *wf)

{

	const struct max7360_pwm_waveform *wfhw = _wfhw;



	wf->period_length_ns = wfhw->enabled ? MAX7360_PWM_PERIOD_NS : 0;

	wf->duty_offset_ns = 0;



	if (wfhw->enabled) {

		if (wfhw->duty_steps == MAX7360_PWM_MAX)

			wf->duty_length_ns = MAX7360_PWM_PERIOD_NS;

		else

			wf->duty_length_ns = DIV_ROUND_UP(wfhw->duty_steps * MAX7360_PWM_PERIOD_NS,

							  MAX7360_PWM_STEPS);

	} else {

		wf->duty_length_ns = 0;

	}



	return 0;

}



static int max7360_pwm_write_waveform(struct pwm_chip *chip,

				      struct pwm_device *pwm,

				      const void *_wfhw)

{

	struct regmap *regmap = pwmchip_get_drvdata(chip);

	const struct max7360_pwm_waveform *wfhw = _wfhw;

	unsigned int val;

	int ret;



	if (wfhw->enabled) {

		ret = regmap_write(regmap, MAX7360_REG_PWM(pwm->hwpwm), wfhw->duty_steps);

		if (ret)

			return ret;

	}



	val = wfhw->enabled ? BIT(pwm->hwpwm) : 0;

	return regmap_write_bits(regmap, MAX7360_REG_GPIOCTRL, BIT(pwm->hwpwm), val);

}



static int max7360_pwm_read_waveform(struct pwm_chip *chip,

				     struct pwm_device *pwm,

				     void *_wfhw)

{

	struct regmap *regmap = pwmchip_get_drvdata(chip);

	struct max7360_pwm_waveform *wfhw = _wfhw;

	unsigned int val;

	int ret;



	ret = regmap_read(regmap, MAX7360_REG_GPIOCTRL, &val);

	if (ret)

		return ret;



	if (val & BIT(pwm->hwpwm)) {

		wfhw->enabled = true;

		ret = regmap_read(regmap, MAX7360_REG_PWM(pwm->hwpwm), &val);

		if (ret)

			return ret;



		wfhw->duty_steps = val;

	} else {

		wfhw->enabled = false;

		wfhw->duty_steps = 0;

	}



	return 0;

}



static const struct pwm_ops max7360_pwm_ops = {

	.request = max7360_pwm_request,

	.round_waveform_tohw = max7360_pwm_round_waveform_tohw,

	.round_waveform_fromhw = max7360_pwm_round_waveform_fromhw,

	.read_waveform = max7360_pwm_read_waveform,

	.write_waveform = max7360_pwm_write_waveform,

};



static int max7360_pwm_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct pwm_chip *chip;

	struct regmap *regmap;

	int ret;



	regmap = dev_get_regmap(dev->parent, NULL);

	if (!regmap)

		return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");



	/*

	 * This MFD sub-device does not have any associated device tree node:

	 * properties are stored in the device node of the parent (MFD) device

	 * and this same node is used in phandles of client devices.

	 * Reuse this device tree node here, as otherwise the PWM subsystem

	 * would be confused by this topology.

	 */

	device_set_of_node_from_dev(dev, dev->parent);



	chip = devm_pwmchip_alloc(dev, MAX7360_NUM_PWMS, 0);

	if (IS_ERR(chip))

		return PTR_ERR(chip);

	chip->ops = &max7360_pwm_ops;



	pwmchip_set_drvdata(chip, regmap);



	ret = devm_pwmchip_add(dev, chip);

	if (ret)

		return dev_err_probe(dev, ret, "Failed to add PWM chip\n");



	return 0;

}



static struct platform_driver max7360_pwm_driver = {

	.driver = {

		.name = "max7360-pwm",

		.probe_type = PROBE_PREFER_ASYNCHRONOUS,

	},

	.probe = max7360_pwm_probe,

};

module_platform_driver(max7360_pwm_driver);



MODULE_DESCRIPTION("MAX7360 PWM driver");

MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");

MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");

MODULE_LICENSE("GPL");