drivers/pwm/pwm-pca9685.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Driver for PCA9685 16-channel 12-bit PWM LED controller
  *
  * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
  * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
  *
  * based on the pwm-twl-led.c driver
  */

 #include <linux/acpi.h>
 #include <linux/gpio/driver.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/pm_runtime.h>
 #include <linux/bitmap.h>

 /*
  * Because the PCA9685 has only one prescaler per chip, changing the period of
  * one channel affects the period of all 16 PWM outputs!
  * However, the ratio between each configured duty cycle and the chip-wide
  * period remains constant, because the OFF time is set in proportion to the
  * counter range.
  */

 #define PCA9685_MODE1		0x00
 #define PCA9685_MODE2		0x01
 #define PCA9685_SUBADDR1	0x02
 #define PCA9685_SUBADDR2	0x03
 #define PCA9685_SUBADDR3	0x04
 #define PCA9685_ALLCALLADDR	0x05
 #define PCA9685_LEDX_ON_L	0x06
 #define PCA9685_LEDX_ON_H	0x07
 #define PCA9685_LEDX_OFF_L	0x08
 #define PCA9685_LEDX_OFF_H	0x09

 #define PCA9685_ALL_LED_ON_L	0xFA
 #define PCA9685_ALL_LED_ON_H	0xFB
 #define PCA9685_ALL_LED_OFF_L	0xFC
 #define PCA9685_ALL_LED_OFF_H	0xFD
 #define PCA9685_PRESCALE	0xFE

 #define PCA9685_PRESCALE_MIN	0x03	/* => max. frequency of 1526 Hz */
 #define PCA9685_PRESCALE_MAX	0xFF	/* => min. frequency of 24 Hz */

 #define PCA9685_COUNTER_RANGE	4096
 #define PCA9685_DEFAULT_PERIOD	5000000	/* Default period_ns = 1/200 Hz */
 #define PCA9685_OSC_CLOCK_MHZ	25	/* Internal oscillator with 25 MHz */

 #define PCA9685_NUMREGS		0xFF
 #define PCA9685_MAXCHAN		0x10

 #define LED_FULL		(1 << 4)
 #define MODE1_SLEEP		(1 << 4)
 #define MODE2_INVRT		(1 << 4)
 #define MODE2_OUTDRV		(1 << 2)

 #define LED_N_ON_H(N)	(PCA9685_LEDX_ON_H + (4 * (N)))
 #define LED_N_ON_L(N)	(PCA9685_LEDX_ON_L + (4 * (N)))
 #define LED_N_OFF_H(N)	(PCA9685_LEDX_OFF_H + (4 * (N)))
 #define LED_N_OFF_L(N)	(PCA9685_LEDX_OFF_L + (4 * (N)))

 struct pca9685 {
 	struct pwm_chip chip;
 	struct regmap *regmap;
 	int duty_ns;
 	int period_ns;
 #if IS_ENABLED(CONFIG_GPIOLIB)
 	struct mutex lock;
 	struct gpio_chip gpio;
 	DECLARE_BITMAP(pwms_inuse, PCA9685_MAXCHAN + 1);
 #endif
 };

 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
 {
 	return container_of(chip, struct pca9685, chip);
 }

 #if IS_ENABLED(CONFIG_GPIOLIB)
 static bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca, int pwm_idx)
 {
 	bool is_inuse;

 	mutex_lock(&pca->lock);
 	if (pwm_idx >= PCA9685_MAXCHAN) {
 		/*
 		 * "all LEDs" channel:
 		 * pretend already in use if any of the PWMs are requested
 		 */
 		if (!bitmap_empty(pca->pwms_inuse, PCA9685_MAXCHAN)) {
 			is_inuse = true;
 			goto out;
 		}
 	} else {
 		/*
 		 * regular channel:
 		 * pretend already in use if the "all LEDs" channel is requested
 		 */
 		if (test_bit(PCA9685_MAXCHAN, pca->pwms_inuse)) {
 			is_inuse = true;
 			goto out;
 		}
 	}
 	is_inuse = test_and_set_bit(pwm_idx, pca->pwms_inuse);
 out:
 	mutex_unlock(&pca->lock);
 	return is_inuse;
 }

 static void pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
 {
 	mutex_lock(&pca->lock);
 	clear_bit(pwm_idx, pca->pwms_inuse);
 	mutex_unlock(&pca->lock);
 }

 static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
 {
 	struct pca9685 *pca = gpiochip_get_data(gpio);

 	if (pca9685_pwm_test_and_set_inuse(pca, offset))
 		return -EBUSY;
 	pm_runtime_get_sync(pca->chip.dev);
 	return 0;
 }

 static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
 {
 	struct pca9685 *pca = gpiochip_get_data(gpio);
 	struct pwm_device *pwm = &pca->chip.pwms[offset];
 	unsigned int value;

 	regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);

 	return value & LED_FULL;
 }

 static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
 				 int value)
 {
 	struct pca9685 *pca = gpiochip_get_data(gpio);
 	struct pwm_device *pwm = &pca->chip.pwms[offset];
 	unsigned int on = value ? LED_FULL : 0;

 	/* Clear both OFF registers */
 	regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
 	regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);

 	/* Set the full ON bit */
 	regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
 }

 static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
 {
 	struct pca9685 *pca = gpiochip_get_data(gpio);

 	pca9685_pwm_gpio_set(gpio, offset, 0);
 	pm_runtime_put(pca->chip.dev);
 	pca9685_pwm_clear_inuse(pca, offset);
 }

 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
 					  unsigned int offset)
 {
 	/* Always out */
 	return 0;
 }

 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
 					    unsigned int offset)
 {
 	return -EINVAL;
 }

 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
 					     unsigned int offset, int value)
 {
 	pca9685_pwm_gpio_set(gpio, offset, value);

 	return 0;
 }

 /*
  * The PCA9685 has a bit for turning the PWM output full off or on. Some
  * boards like Intel Galileo actually uses these as normal GPIOs so we
  * expose a GPIO chip here which can exclusively take over the underlying
  * PWM channel.
  */
 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 {
 	struct device *dev = pca->chip.dev;

 	mutex_init(&pca->lock);

 	pca->gpio.label = dev_name(dev);
 	pca->gpio.parent = dev;
 	pca->gpio.request = pca9685_pwm_gpio_request;
 	pca->gpio.free = pca9685_pwm_gpio_free;
 	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
 	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
 	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
 	pca->gpio.get = pca9685_pwm_gpio_get;
 	pca->gpio.set = pca9685_pwm_gpio_set;
 	pca->gpio.base = -1;
 	pca->gpio.ngpio = PCA9685_MAXCHAN;
 	pca->gpio.can_sleep = true;

 	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
 }
 #else
 static inline bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca,
 						  int pwm_idx)
 {
 	return false;
 }

 static inline void
 pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
 {
 }

 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 {
 	return 0;
 }
 #endif

 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
 {
 	regmap_update_bits(pca->regmap, PCA9685_MODE1,
 			   MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
 	if (!enable) {
 		/* Wait 500us for the oscillator to be back up */
 		udelay(500);
 	}
 }

 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			      int duty_ns, int period_ns)
 {
 	struct pca9685 *pca = to_pca(chip);
 	unsigned long long duty;
 	unsigned int reg;
 	int prescale;

 	if (period_ns != pca->period_ns) {
 		prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
 					     PCA9685_COUNTER_RANGE * 1000) - 1;

 		if (prescale >= PCA9685_PRESCALE_MIN &&
 			prescale <= PCA9685_PRESCALE_MAX) {
 			/*
 			 * putting the chip briefly into SLEEP mode
 			 * at this point won't interfere with the
 			 * pm_runtime framework, because the pm_runtime
 			 * state is guaranteed active here.
 			 */
 			/* Put chip into sleep mode */
 			pca9685_set_sleep_mode(pca, true);

 			/* Change the chip-wide output frequency */
 			regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);

 			/* Wake the chip up */
 			pca9685_set_sleep_mode(pca, false);

 			pca->period_ns = period_ns;
 		} else {
 			dev_err(chip->dev,
 				"prescaler not set: period out of bounds!\n");
 			return -EINVAL;
 		}
 	}

 	pca->duty_ns = duty_ns;

 	if (duty_ns < 1) {
 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
 			reg = PCA9685_ALL_LED_OFF_H;
 		else
 			reg = LED_N_OFF_H(pwm->hwpwm);

 		regmap_write(pca->regmap, reg, LED_FULL);

 		return 0;
 	}

 	if (duty_ns == period_ns) {
 		/* Clear both OFF registers */
 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
 			reg = PCA9685_ALL_LED_OFF_L;
 		else
 			reg = LED_N_OFF_L(pwm->hwpwm);

 		regmap_write(pca->regmap, reg, 0x0);

 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
 			reg = PCA9685_ALL_LED_OFF_H;
 		else
 			reg = LED_N_OFF_H(pwm->hwpwm);

 		regmap_write(pca->regmap, reg, 0x0);

 		/* Set the full ON bit */
 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
 			reg = PCA9685_ALL_LED_ON_H;
 		else
 			reg = LED_N_ON_H(pwm->hwpwm);

 		regmap_write(pca->regmap, reg, LED_FULL);

 		return 0;
 	}

 	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
 	duty = DIV_ROUND_UP_ULL(duty, period_ns);

 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_OFF_L;
 	else
 		reg = LED_N_OFF_L(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, (int)duty & 0xff);

 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_OFF_H;
 	else
 		reg = LED_N_OFF_H(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);

 	/* Clear the full ON bit, otherwise the set OFF time has no effect */
 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_ON_H;
 	else
 		reg = LED_N_ON_H(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, 0);

 	return 0;
 }

 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct pca9685 *pca = to_pca(chip);
 	unsigned int reg;

 	/*
 	 * The PWM subsystem does not support a pre-delay.
 	 * So, set the ON-timeout to 0
 	 */
 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_ON_L;
 	else
 		reg = LED_N_ON_L(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, 0);

 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_ON_H;
 	else
 		reg = LED_N_ON_H(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, 0);

 	/*
 	 * Clear the full-off bit.
 	 * It has precedence over the others and must be off.
 	 */
 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_OFF_H;
 	else
 		reg = LED_N_OFF_H(pwm->hwpwm);

 	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);

 	return 0;
 }

 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct pca9685 *pca = to_pca(chip);
 	unsigned int reg;

 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_OFF_H;
 	else
 		reg = LED_N_OFF_H(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, LED_FULL);

 	/* Clear the LED_OFF counter. */
 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
 		reg = PCA9685_ALL_LED_OFF_L;
 	else
 		reg = LED_N_OFF_L(pwm->hwpwm);

 	regmap_write(pca->regmap, reg, 0x0);
 }

 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct pca9685 *pca = to_pca(chip);

 	if (pca9685_pwm_test_and_set_inuse(pca, pwm->hwpwm))
 		return -EBUSY;
 	pm_runtime_get_sync(chip->dev);

 	return 0;
 }

 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct pca9685 *pca = to_pca(chip);

 	pca9685_pwm_disable(chip, pwm);
 	pm_runtime_put(chip->dev);
 	pca9685_pwm_clear_inuse(pca, pwm->hwpwm);
 }

 static const struct pwm_ops pca9685_pwm_ops = {
 	.enable = pca9685_pwm_enable,
 	.disable = pca9685_pwm_disable,
 	.config = pca9685_pwm_config,
 	.request = pca9685_pwm_request,
 	.free = pca9685_pwm_free,
 	.owner = THIS_MODULE,
 };

 static const struct regmap_config pca9685_regmap_i2c_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = PCA9685_NUMREGS,
 	.cache_type = REGCACHE_NONE,
 };

 static int pca9685_pwm_probe(struct i2c_client *client,
 				const struct i2c_device_id *id)
 {
 	struct pca9685 *pca;
 	int ret;
 	int mode2;

 	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 	if (!pca)
 		return -ENOMEM;

 	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 	if (IS_ERR(pca->regmap)) {
 		ret = PTR_ERR(pca->regmap);
 		dev_err(&client->dev, "Failed to initialize register map: %d\n",
 			ret);
 		return ret;
 	}
 	pca->duty_ns = 0;
 	pca->period_ns = PCA9685_DEFAULT_PERIOD;

 	i2c_set_clientdata(client, pca);

 	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);

 	if (device_property_read_bool(&client->dev, "invert"))
 		mode2 |= MODE2_INVRT;
 	else
 		mode2 &= ~MODE2_INVRT;

 	if (device_property_read_bool(&client->dev, "open-drain"))
 		mode2 &= ~MODE2_OUTDRV;
 	else
 		mode2 |= MODE2_OUTDRV;

 	regmap_write(pca->regmap, PCA9685_MODE2, mode2);

 	/* clear all "full off" bits */
 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);

 	pca->chip.ops = &pca9685_pwm_ops;
 	/* add an extra channel for ALL_LED */
 	pca->chip.npwm = PCA9685_MAXCHAN + 1;

 	pca->chip.dev = &client->dev;
 	pca->chip.base = -1;

 	ret = pwmchip_add(&pca->chip);
 	if (ret < 0)
 		return ret;

 	ret = pca9685_pwm_gpio_probe(pca);
 	if (ret < 0) {
 		pwmchip_remove(&pca->chip);
 		return ret;
 	}

 	/* the chip comes out of power-up in the active state */
 	pm_runtime_set_active(&client->dev);
 	/*
 	 * enable will put the chip into suspend, which is what we
 	 * want as all outputs are disabled at this point
 	 */
 	pm_runtime_enable(&client->dev);

 	return 0;
 }

 static int pca9685_pwm_remove(struct i2c_client *client)
 {
 	struct pca9685 *pca = i2c_get_clientdata(client);
 	int ret;

 	ret = pwmchip_remove(&pca->chip);
 	if (ret)
 		return ret;
 	pm_runtime_disable(&client->dev);
 	return 0;
 }

 #ifdef CONFIG_PM
 static int pca9685_pwm_runtime_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct pca9685 *pca = i2c_get_clientdata(client);

 	pca9685_set_sleep_mode(pca, true);
 	return 0;
 }

 static int pca9685_pwm_runtime_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct pca9685 *pca = i2c_get_clientdata(client);

 	pca9685_set_sleep_mode(pca, false);
 	return 0;
 }
 #endif

 static const struct i2c_device_id pca9685_id[] = {
 	{ "pca9685", 0 },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(i2c, pca9685_id);

 #ifdef CONFIG_ACPI
 static const struct acpi_device_id pca9685_acpi_ids[] = {
 	{ "INT3492", 0 },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
 #endif

 #ifdef CONFIG_OF
 static const struct of_device_id pca9685_dt_ids[] = {
 	{ .compatible = "nxp,pca9685-pwm", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 #endif

 static const struct dev_pm_ops pca9685_pwm_pm = {
 	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
 			   pca9685_pwm_runtime_resume, NULL)
 };

 static struct i2c_driver pca9685_i2c_driver = {
 	.driver = {
 		.name = "pca9685-pwm",
 		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
 		.of_match_table = of_match_ptr(pca9685_dt_ids),
 		.pm = &pca9685_pwm_pm,
 	},
 	.probe = pca9685_pwm_probe,
 	.remove = pca9685_pwm_remove,
 	.id_table = pca9685_id,
 };

 module_i2c_driver(pca9685_i2c_driver);

 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
 MODULE_DESCRIPTION("PWM driver for PCA9685");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Driver for PCA9685 16-channel 12-bit PWM LED controller
	*
	* Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
	* Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
	*
	* based on the pwm-twl-led.c driver
	*/

	#include <linux/acpi.h>
	#include <linux/gpio/driver.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/platform_device.h>
	#include <linux/property.h>
	#include <linux/pwm.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>
	#include <linux/delay.h>
	#include <linux/pm_runtime.h>
	#include <linux/bitmap.h>

	/*
	* Because the PCA9685 has only one prescaler per chip, changing the period of
	* one channel affects the period of all 16 PWM outputs!
	* However, the ratio between each configured duty cycle and the chip-wide
	* period remains constant, because the OFF time is set in proportion to the
	* counter range.
	*/

	#define PCA9685_MODE1 0x00
	#define PCA9685_MODE2 0x01
	#define PCA9685_SUBADDR1 0x02
	#define PCA9685_SUBADDR2 0x03
	#define PCA9685_SUBADDR3 0x04
	#define PCA9685_ALLCALLADDR 0x05
	#define PCA9685_LEDX_ON_L 0x06
	#define PCA9685_LEDX_ON_H 0x07
	#define PCA9685_LEDX_OFF_L 0x08
	#define PCA9685_LEDX_OFF_H 0x09

	#define PCA9685_ALL_LED_ON_L 0xFA
	#define PCA9685_ALL_LED_ON_H 0xFB
	#define PCA9685_ALL_LED_OFF_L 0xFC
	#define PCA9685_ALL_LED_OFF_H 0xFD
	#define PCA9685_PRESCALE 0xFE

	#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
	#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */

	#define PCA9685_COUNTER_RANGE 4096
	#define PCA9685_DEFAULT_PERIOD 5000000 /* Default period_ns = 1/200 Hz */
	#define PCA9685_OSC_CLOCK_MHZ 25 /* Internal oscillator with 25 MHz */

	#define PCA9685_NUMREGS 0xFF
	#define PCA9685_MAXCHAN 0x10

	#define LED_FULL (1 << 4)
	#define MODE1_SLEEP (1 << 4)
	#define MODE2_INVRT (1 << 4)
	#define MODE2_OUTDRV (1 << 2)

	#define LED_N_ON_H(N) (PCA9685_LEDX_ON_H + (4 * (N)))
	#define LED_N_ON_L(N) (PCA9685_LEDX_ON_L + (4 * (N)))
	#define LED_N_OFF_H(N) (PCA9685_LEDX_OFF_H + (4 * (N)))
	#define LED_N_OFF_L(N) (PCA9685_LEDX_OFF_L + (4 * (N)))

	struct pca9685 {
	struct pwm_chip chip;
	struct regmap *regmap;
	int duty_ns;
	int period_ns;
	#if IS_ENABLED(CONFIG_GPIOLIB)
	struct mutex lock;
	struct gpio_chip gpio;
	DECLARE_BITMAP(pwms_inuse, PCA9685_MAXCHAN + 1);
	#endif
	};

	static inline struct pca9685 to_pca(struct pwm_chip chip)
	{
	return container_of(chip, struct pca9685, chip);
	}

	#if IS_ENABLED(CONFIG_GPIOLIB)
	static bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca, int pwm_idx)
	{
	bool is_inuse;

	mutex_lock(&pca->lock);
	if (pwm_idx >= PCA9685_MAXCHAN) {
	/*
	* "all LEDs" channel:
	* pretend already in use if any of the PWMs are requested
	*/
	if (!bitmap_empty(pca->pwms_inuse, PCA9685_MAXCHAN)) {
	is_inuse = true;
	goto out;
	}
	} else {
	/*
	* regular channel:
	* pretend already in use if the "all LEDs" channel is requested
	*/
	if (test_bit(PCA9685_MAXCHAN, pca->pwms_inuse)) {
	is_inuse = true;
	goto out;
	}
	}
	is_inuse = test_and_set_bit(pwm_idx, pca->pwms_inuse);
	out:
	mutex_unlock(&pca->lock);
	return is_inuse;
	}

	static void pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
	{
	mutex_lock(&pca->lock);
	clear_bit(pwm_idx, pca->pwms_inuse);
	mutex_unlock(&pca->lock);
	}

	static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
	{
	struct pca9685 *pca = gpiochip_get_data(gpio);

	if (pca9685_pwm_test_and_set_inuse(pca, offset))
	return -EBUSY;
	pm_runtime_get_sync(pca->chip.dev);
	return 0;
	}

	static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
	{
	struct pca9685 *pca = gpiochip_get_data(gpio);
	struct pwm_device *pwm = &pca->chip.pwms[offset];
	unsigned int value;

	regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);

	return value & LED_FULL;
	}

	static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
	int value)
	{
	struct pca9685 *pca = gpiochip_get_data(gpio);
	struct pwm_device *pwm = &pca->chip.pwms[offset];
	unsigned int on = value ? LED_FULL : 0;

	/* Clear both OFF registers */
	regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
	regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);

	/* Set the full ON bit */
	regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
	}

	static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
	{
	struct pca9685 *pca = gpiochip_get_data(gpio);

	pca9685_pwm_gpio_set(gpio, offset, 0);
	pm_runtime_put(pca->chip.dev);
	pca9685_pwm_clear_inuse(pca, offset);
	}

	static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
	unsigned int offset)
	{
	/* Always out */
	return 0;
	}

	static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
	unsigned int offset)
	{
	return -EINVAL;
	}

	static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
	unsigned int offset, int value)
	{
	pca9685_pwm_gpio_set(gpio, offset, value);

	return 0;
	}

	/*
	* The PCA9685 has a bit for turning the PWM output full off or on. Some
	* boards like Intel Galileo actually uses these as normal GPIOs so we
	* expose a GPIO chip here which can exclusively take over the underlying
	* PWM channel.
	*/
	static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
	{
	struct device *dev = pca->chip.dev;

	mutex_init(&pca->lock);

	pca->gpio.label = dev_name(dev);
	pca->gpio.parent = dev;
	pca->gpio.request = pca9685_pwm_gpio_request;
	pca->gpio.free = pca9685_pwm_gpio_free;
	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
	pca->gpio.get = pca9685_pwm_gpio_get;
	pca->gpio.set = pca9685_pwm_gpio_set;
	pca->gpio.base = -1;
	pca->gpio.ngpio = PCA9685_MAXCHAN;
	pca->gpio.can_sleep = true;

	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
	}
	#else
	static inline bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca,
	int pwm_idx)
	{
	return false;
	}

	static inline void
	pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
	{
	}

	static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
	{
	return 0;
	}
	#endif

	static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
	{
	regmap_update_bits(pca->regmap, PCA9685_MODE1,
	MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
	if (!enable) {
	/* Wait 500us for the oscillator to be back up */
	udelay(500);
	}
	}

	static int pca9685_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
	int duty_ns, int period_ns)
	{
	struct pca9685 *pca = to_pca(chip);
	unsigned long long duty;
	unsigned int reg;
	int prescale;

	if (period_ns != pca->period_ns) {
	prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
	PCA9685_COUNTER_RANGE * 1000) - 1;

	if (prescale >= PCA9685_PRESCALE_MIN &&
	prescale <= PCA9685_PRESCALE_MAX) {
	/*
	* putting the chip briefly into SLEEP mode
	* at this point won't interfere with the
	* pm_runtime framework, because the pm_runtime
	* state is guaranteed active here.
	*/
	/* Put chip into sleep mode */
	pca9685_set_sleep_mode(pca, true);

	/* Change the chip-wide output frequency */
	regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);

	/* Wake the chip up */
	pca9685_set_sleep_mode(pca, false);

	pca->period_ns = period_ns;
	} else {
	dev_err(chip->dev,
	"prescaler not set: period out of bounds!\n");
	return -EINVAL;
	}
	}

	pca->duty_ns = duty_ns;

	if (duty_ns < 1) {
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_H;
	else
	reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, LED_FULL);

	return 0;
	}

	if (duty_ns == period_ns) {
	/* Clear both OFF registers */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_L;
	else
	reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0x0);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_H;
	else
	reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0x0);

	/* Set the full ON bit */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_ON_H;
	else
	reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, LED_FULL);

	return 0;
	}

	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
	duty = DIV_ROUND_UP_ULL(duty, period_ns);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_L;
	else
	reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, (int)duty & 0xff);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_H;
	else
	reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);

	/* Clear the full ON bit, otherwise the set OFF time has no effect */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_ON_H;
	else
	reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	return 0;
	}

	static int pca9685_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct pca9685 *pca = to_pca(chip);
	unsigned int reg;

	/*
	* The PWM subsystem does not support a pre-delay.
	* So, set the ON-timeout to 0
	*/
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_ON_L;
	else
	reg = LED_N_ON_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_ON_H;
	else
	reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	/*
	* Clear the full-off bit.
	* It has precedence over the others and must be off.
	*/
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_H;
	else
	reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);

	return 0;
	}

	static void pca9685_pwm_disable(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct pca9685 *pca = to_pca(chip);
	unsigned int reg;

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_H;
	else
	reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, LED_FULL);

	/* Clear the LED_OFF counter. */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
	reg = PCA9685_ALL_LED_OFF_L;
	else
	reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0x0);
	}

	static int pca9685_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct pca9685 *pca = to_pca(chip);

	if (pca9685_pwm_test_and_set_inuse(pca, pwm->hwpwm))
	return -EBUSY;
	pm_runtime_get_sync(chip->dev);

	return 0;
	}

	static void pca9685_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct pca9685 *pca = to_pca(chip);

	pca9685_pwm_disable(chip, pwm);
	pm_runtime_put(chip->dev);
	pca9685_pwm_clear_inuse(pca, pwm->hwpwm);
	}

	static const struct pwm_ops pca9685_pwm_ops = {
	.enable = pca9685_pwm_enable,
	.disable = pca9685_pwm_disable,
	.config = pca9685_pwm_config,
	.request = pca9685_pwm_request,
	.free = pca9685_pwm_free,
	.owner = THIS_MODULE,
	};

	static const struct regmap_config pca9685_regmap_i2c_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = PCA9685_NUMREGS,
	.cache_type = REGCACHE_NONE,
	};

	static int pca9685_pwm_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct pca9685 *pca;
	int ret;
	int mode2;

	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
	if (!pca)
	return -ENOMEM;

	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
	if (IS_ERR(pca->regmap)) {
	ret = PTR_ERR(pca->regmap);
	dev_err(&client->dev, "Failed to initialize register map: %d\n",
	ret);
	return ret;
	}
	pca->duty_ns = 0;
	pca->period_ns = PCA9685_DEFAULT_PERIOD;

	i2c_set_clientdata(client, pca);

	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);

	if (device_property_read_bool(&client->dev, "invert"))
	mode2 \|= MODE2_INVRT;
	else
	mode2 &= ~MODE2_INVRT;

	if (device_property_read_bool(&client->dev, "open-drain"))
	mode2 &= ~MODE2_OUTDRV;
	else
	mode2 \|= MODE2_OUTDRV;

	regmap_write(pca->regmap, PCA9685_MODE2, mode2);

	/* clear all "full off" bits */
	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);

	pca->chip.ops = &pca9685_pwm_ops;
	/* add an extra channel for ALL_LED */
	pca->chip.npwm = PCA9685_MAXCHAN + 1;

	pca->chip.dev = &client->dev;
	pca->chip.base = -1;

	ret = pwmchip_add(&pca->chip);
	if (ret < 0)
	return ret;

	ret = pca9685_pwm_gpio_probe(pca);
	if (ret < 0) {
	pwmchip_remove(&pca->chip);
	return ret;
	}

	/* the chip comes out of power-up in the active state */
	pm_runtime_set_active(&client->dev);
	/*
	* enable will put the chip into suspend, which is what we
	* want as all outputs are disabled at this point
	*/
	pm_runtime_enable(&client->dev);

	return 0;
	}

	static int pca9685_pwm_remove(struct i2c_client *client)
	{
	struct pca9685 *pca = i2c_get_clientdata(client);
	int ret;

	ret = pwmchip_remove(&pca->chip);
	if (ret)
	return ret;
	pm_runtime_disable(&client->dev);
	return 0;
	}

	#ifdef CONFIG_PM
	static int pca9685_pwm_runtime_suspend(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct pca9685 *pca = i2c_get_clientdata(client);

	pca9685_set_sleep_mode(pca, true);
	return 0;
	}

	static int pca9685_pwm_runtime_resume(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct pca9685 *pca = i2c_get_clientdata(client);

	pca9685_set_sleep_mode(pca, false);
	return 0;
	}
	#endif

	static const struct i2c_device_id pca9685_id[] = {
	{ "pca9685", 0 },
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(i2c, pca9685_id);

	#ifdef CONFIG_ACPI
	static const struct acpi_device_id pca9685_acpi_ids[] = {
	{ "INT3492", 0 },
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
	#endif

	#ifdef CONFIG_OF
	static const struct of_device_id pca9685_dt_ids[] = {
	{ .compatible = "nxp,pca9685-pwm", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
	#endif

	static const struct dev_pm_ops pca9685_pwm_pm = {
	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
	pca9685_pwm_runtime_resume, NULL)
	};

	static struct i2c_driver pca9685_i2c_driver = {
	.driver = {
	.name = "pca9685-pwm",
	.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
	.of_match_table = of_match_ptr(pca9685_dt_ids),
	.pm = &pca9685_pwm_pm,
	},
	.probe = pca9685_pwm_probe,
	.remove = pca9685_pwm_remove,
	.id_table = pca9685_id,
	};

	module_i2c_driver(pca9685_i2c_driver);

	MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
	MODULE_DESCRIPTION("PWM driver for PCA9685");
	MODULE_LICENSE("GPL");