// 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>

  
  /*
   * 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;
  #endif

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

  #if IS_ENABLED(CONFIG_GPIOLIB)
  static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
  {
  	struct pca9685 *pca = gpiochip_get_data(gpio);
  	struct pwm_device *pwm;
  
  	mutex_lock(&pca->lock);
  
  	pwm = &pca->chip.pwms[offset];
  
  	if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
  		mutex_unlock(&pca->lock);
  		return -EBUSY;
  	}
  
  	pwm_set_chip_data(pwm, (void *)1);
  
  	mutex_unlock(&pca->lock);

  	pm_runtime_get_sync(pca->chip.dev);

  	return 0;
  }

  static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
  {
  	bool is_gpio = false;
  
  	mutex_lock(&pca->lock);
  
  	if (pwm->hwpwm >= PCA9685_MAXCHAN) {
  		unsigned int i;
  
  		/*
  		 * Check if any of the GPIOs are requested and in that case
  		 * prevent using the "all LEDs" channel.
  		 */
  		for (i = 0; i < pca->gpio.ngpio; i++)
  			if (gpiochip_is_requested(&pca->gpio, i)) {
  				is_gpio = true;
  				break;
  			}
  	} else if (pwm_get_chip_data(pwm)) {
  		is_gpio = true;
  	}
  
  	mutex_unlock(&pca->lock);
  	return is_gpio;
  }
  
  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);

  }

  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_is_gpio(struct pca9685 *pca,
  				       struct pwm_device *pwm)
  {
  	return false;
  }
  
  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!
  ");
  			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_is_gpio(pca, pwm))
  		return -EBUSY;

  	pm_runtime_get_sync(chip->dev);

  
  	return 0;
  }
  
  static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  {

  	pca9685_pwm_disable(chip, pwm);
  	pm_runtime_put(chip->dev);

  }
  
  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
  ",
  			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");