text: /*
   * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
   *
   * Author: Nate Case <ncase@xes-inc.com>
   *
   * This file is subject to the terms and conditions of version 2 of
   * the GNU General Public License.  See the file COPYING in the main
   * directory of this archive for more details.
   *
   * LED driver for various PCA955x I2C LED drivers
   *
   * Supported devices:
   *
   *	Device		Description		7-bit slave address
   *	------		-----------		-------------------
   *	PCA9550		2-bit driver		0x60 .. 0x61
   *	PCA9551		8-bit driver		0x60 .. 0x67
   *	PCA9552		16-bit driver		0x60 .. 0x67
   *	PCA9553/01	4-bit driver		0x62
   *	PCA9553/02	4-bit driver		0x63
   *
   * Philips PCA955x LED driver chips follow a register map as shown below:
   *
   *	Control Register		Description
   *	----------------		-----------
   *	0x0				Input register 0
   *					..
   *	NUM_INPUT_REGS - 1		Last Input register X
   *
   *	NUM_INPUT_REGS			Frequency prescaler 0
   *	NUM_INPUT_REGS + 1		PWM register 0
   *	NUM_INPUT_REGS + 2		Frequency prescaler 1
   *	NUM_INPUT_REGS + 3		PWM register 1
   *
   *	NUM_INPUT_REGS + 4		LED selector 0
   *	NUM_INPUT_REGS + 4
   *	    + NUM_LED_REGS - 1		Last LED selector
   *
   *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
   *  bits the chip supports.
   */
  
  #include <linux/acpi.h>
  #include <linux/ctype.h>
  #include <linux/delay.h>
  #include <linux/err.h>
  #include <linux/gpio.h>
  #include <linux/i2c.h>
  #include <linux/leds.h>
  #include <linux/module.h>
  #include <linux/of_device.h>
  #include <linux/of.h>
  #include <linux/slab.h>
  #include <linux/string.h>
  
  #include <dt-bindings/leds/leds-pca955x.h>
  
  /* LED select registers determine the source that drives LED outputs */
  #define PCA955X_LS_LED_ON	0x0	/* Output LOW */
  #define PCA955X_LS_LED_OFF	0x1	/* Output HI-Z */
  #define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */
  #define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */
  
  #define PCA955X_GPIO_INPUT	LED_OFF
  #define PCA955X_GPIO_HIGH	LED_OFF
  #define PCA955X_GPIO_LOW	LED_FULL
  
  enum pca955x_type {
  	pca9550,
  	pca9551,
  	pca9552,
  	pca9553,
  };
  
  struct pca955x_chipdef {
  	int			bits;
  	u8			slv_addr;	/* 7-bit slave address mask */
  	int			slv_addr_shift;	/* Number of bits to ignore */
  };
  
  static struct pca955x_chipdef pca955x_chipdefs[] = {
  	[pca9550] = {
  		.bits		= 2,
  		.slv_addr	= /* 110000x */ 0x60,
  		.slv_addr_shift	= 1,
  	},
  	[pca9551] = {
  		.bits		= 8,
  		.slv_addr	= /* 1100xxx */ 0x60,
  		.slv_addr_shift	= 3,
  	},
  	[pca9552] = {
  		.bits		= 16,
  		.slv_addr	= /* 1100xxx */ 0x60,
  		.slv_addr_shift	= 3,
  	},
  	[pca9553] = {
  		.bits		= 4,
  		.slv_addr	= /* 110001x */ 0x62,
  		.slv_addr_shift	= 1,
  	},
  };
  
  static const struct i2c_device_id pca955x_id[] = {
  	{ "pca9550", pca9550 },
  	{ "pca9551", pca9551 },
  	{ "pca9552", pca9552 },
  	{ "pca9553", pca9553 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, pca955x_id);
  
  static const struct acpi_device_id pca955x_acpi_ids[] = {
  	{ "PCA9550",  pca9550 },
  	{ "PCA9551",  pca9551 },
  	{ "PCA9552",  pca9552 },
  	{ "PCA9553",  pca9553 },
  	{ }
  };
  MODULE_DEVICE_TABLE(acpi, pca955x_acpi_ids);
  
  struct pca955x {
  	struct mutex lock;
  	struct pca955x_led *leds;
  	struct pca955x_chipdef	*chipdef;
  	struct i2c_client	*client;
  #ifdef CONFIG_LEDS_PCA955X_GPIO
  	struct gpio_chip gpio;
  #endif
  };
  
  struct pca955x_led {
  	struct pca955x	*pca955x;
  	struct led_classdev	led_cdev;
  	int			led_num;	/* 0 .. 15 potentially */
  	char			name[32];
  	u32			type;
  	const char		*default_trigger;
  };
  
  struct pca955x_platform_data {
  	struct pca955x_led	*leds;
  	int			num_leds;
  };
  
  /* 8 bits per input register */
  static inline int pca95xx_num_input_regs(int bits)
  {
  	return (bits + 7) / 8;
  }
  
  /* 4 bits per LED selector register */
  static inline int pca95xx_num_led_regs(int bits)
  {
  	return (bits + 3)  / 4;
  }
  
  /*
   * Return an LED selector register value based on an existing one, with
   * the appropriate 2-bit state value set for the given LED number (0-3).
   */
  static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
  {
  	return (oldval & (~(0x3 << (led_num << 1)))) |
  		((state & 0x3) << (led_num << 1));
  }
  
  /*
   * Write to frequency prescaler register, used to program the
   * period of the PWM output.  period = (PSCx + 1) / 38
   */
  static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
  {
  	struct pca955x *pca955x = i2c_get_clientdata(client);
  	int ret;
  
  	ret = i2c_smbus_write_byte_data(client,
  		pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
  		val);
  	if (ret < 0)
  		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
  			__func__, n, val, ret);
  	return ret;
  }
  
  /*
   * Write to PWM register, which determines the duty cycle of the
   * output.  LED is OFF when the count is less than the value of this
   * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
   *
   * Duty cycle is (256 - PWMx) / 256
   */
  static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
  {
  	struct pca955x *pca955x = i2c_get_clientdata(client);
  	int ret;
  
  	ret = i2c_smbus_write_byte_data(client,
  		pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
  		val);
  	if (ret < 0)
  		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
  			__func__, n, val, ret);
  	return ret;
  }
  
  /*
   * Write to LED selector register, which determines the source that
   * drives the LED output.
   */
  static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
  {
  	struct pca955x *pca955x = i2c_get_clientdata(client);
  	int ret;
  
  	ret = i2c_smbus_write_byte_data(client,
  		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
  		val);
  	if (ret < 0)
  		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
  			__func__, n, val, ret);
  	return ret;
  }
  
  /*
   * Read the LED selector register, which determines the source that
   * drives the LED output.
   */
  static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
  {
  	struct pca955x *pca955x = i2c_get_clientdata(client);
  	int ret;
  
  	ret = i2c_smbus_read_byte_data(client,
  		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
  	if (ret < 0) {
  		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
  			__func__, n, ret);
  		return ret;
  	}
  	*val = (u8)ret;
  	return 0;
  }
  
  static int pca955x_led_set(struct led_classdev *led_cdev,
  			    enum led_brightness value)
  {
  	struct pca955x_led *pca955x_led;
  	struct pca955x *pca955x;
  	u8 ls;
  	int chip_ls;	/* which LSx to use (0-3 potentially) */
  	int ls_led;	/* which set of bits within LSx to use (0-3) */
  	int ret;
  
  	pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
  	pca955x = pca955x_led->pca955x;
  
  	chip_ls = pca955x_led->led_num / 4;
  	ls_led = pca955x_led->led_num % 4;
  
  	mutex_lock(&pca955x->lock);
  
  	ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
  	if (ret)
  		goto out;
  
  	switch (value) {
  	case LED_FULL:
  		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
  		break;
  	case LED_OFF:
  		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
  		break;
  	case LED_HALF:
  		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
  		break;
  	default:
  		/*
  		 * Use PWM1 for all other values.  This has the unwanted
  		 * side effect of making all LEDs on the chip share the
  		 * same brightness level if set to a value other than
  		 * OFF, HALF, or FULL.  But, this is probably better than
  		 * just turning off for all other values.
  		 */
  		ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
  		if (ret)
  			goto out;
  		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
  		break;
  	}
  
  	ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
  
  out:
  	mutex_unlock(&pca955x->lock);
  
  	return ret;
  }
  
  #ifdef CONFIG_LEDS_PCA955X_GPIO
  /*
   * Read the INPUT register, which contains the state of LEDs.
   */
  static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
  {
  	int ret = i2c_smbus_read_byte_data(client, n);
  
  	if (ret < 0) {
  		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
  			__func__, n, ret);
  		return ret;
  	}
  	*val = (u8)ret;
  	return 0;
  
  }
  
  static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
  {
  	struct pca955x *pca955x = gpiochip_get_data(gc);
  	struct pca955x_led *led = &pca955x->leds[offset];
  
  	if (led->type == PCA955X_TYPE_GPIO)
  		return 0;
  
  	return -EBUSY;
  }
  
  static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
  			     int val)
  {
  	struct pca955x *pca955x = gpiochip_get_data(gc);
  	struct pca955x_led *led = &pca955x->leds[offset];
  
  	if (val)
  		return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
  
  	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
  }
  
  static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
  				   int val)
  {
  	pca955x_set_value(gc, offset, val);
  }
  
  static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
  {
  	struct pca955x *pca955x = gpiochip_get_data(gc);
  	struct pca955x_led *led = &pca955x->leds[offset];
  	u8 reg = 0;
  
  	/* There is nothing we can do about errors */
  	pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
  
  	return !!(reg & (1 << (led->led_num % 8)));
  }
  
  static int pca955x_gpio_direction_input(struct gpio_chip *gc,
  					unsigned int offset)
  {
  	struct pca955x *pca955x = gpiochip_get_data(gc);
  	struct pca955x_led *led = &pca955x->leds[offset];
  
  	/* To use as input ensure pin is not driven. */
  	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
  }
  
  static int pca955x_gpio_direction_output(struct gpio_chip *gc,
  					 unsigned int offset, int val)
  {
  	return pca955x_set_value(gc, offset, val);
  }
  #endif /* CONFIG_LEDS_PCA955X_GPIO */
  
  #if IS_ENABLED(CONFIG_OF)
  static struct pca955x_platform_data *
  pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
  {
  	struct device_node *np = client->dev.of_node;
  	struct device_node *child;
  	struct pca955x_platform_data *pdata;
  	int count;
  
  	count = of_get_child_count(np);
  	if (!count || count > chip->bits)
  		return ERR_PTR(-ENODEV);
  
  	pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return ERR_PTR(-ENOMEM);
  
  	pdata->leds = devm_kzalloc(&client->dev,
  				   sizeof(struct pca955x_led) * chip->bits,
  				   GFP_KERNEL);
  	if (!pdata->leds)
  		return ERR_PTR(-ENOMEM);
  
  	for_each_child_of_node(np, child) {
  		const char *name;
  		u32 reg;
  		int res;
  
  		res = of_property_read_u32(child, "reg", &reg);
  		if ((res != 0) || (reg >= chip->bits))
  			continue;
  
  		if (of_property_read_string(child, "label", &name))
  			name = child->name;
  
  		snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
  			 "%s", name);
  
  		pdata->leds[reg].type = PCA955X_TYPE_LED;
  		of_property_read_u32(child, "type", &pdata->leds[reg].type);
  		of_property_read_string(child, "linux,default-trigger",
  					&pdata->leds[reg].default_trigger);
  	}
  
  	pdata->num_leds = chip->bits;
  
  	return pdata;
  }
  
  static const struct of_device_id of_pca955x_match[] = {
  	{ .compatible = "nxp,pca9550", .data = (void *)pca9550 },
  	{ .compatible = "nxp,pca9551", .data = (void *)pca9551 },
  	{ .compatible = "nxp,pca9552", .data = (void *)pca9552 },
  	{ .compatible = "nxp,pca9553", .data = (void *)pca9553 },
  	{},
  };
  
  MODULE_DEVICE_TABLE(of, of_pca955x_match);
  #else
  static struct pca955x_platform_data *
  pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
  {
  	return ERR_PTR(-ENODEV);
  }
  #endif
  
  static int pca955x_probe(struct i2c_client *client,
  					const struct i2c_device_id *id)
  {
  	struct pca955x *pca955x;
  	struct pca955x_led *pca955x_led;
  	struct pca955x_chipdef *chip;
  	struct i2c_adapter *adapter;
  	int i, err;
  	struct pca955x_platform_data *pdata;
  	int ngpios = 0;
  
  	if (id) {
  		chip = &pca955x_chipdefs[id->driver_data];
  	} else {
  		const struct acpi_device_id *acpi_id;
  
  		acpi_id = acpi_match_device(pca955x_acpi_ids, &client->dev);
  		if (!acpi_id)
  			return -ENODEV;
  		chip = &pca955x_chipdefs[acpi_id->driver_data];
  	}
  	adapter = to_i2c_adapter(client->dev.parent);
  	pdata = dev_get_platdata(&client->dev);
  	if (!pdata) {
  		pdata =	pca955x_pdata_of_init(client, chip);
  		if (IS_ERR(pdata))
  			return PTR_ERR(pdata);
  	}
  
  	/* Make sure the slave address / chip type combo given is possible */
  	if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
  	    chip->slv_addr) {
  		dev_err(&client->dev, "invalid slave address %02x\n",
  				client->addr);
  		return -ENODEV;
  	}
  
  	dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
  			"slave address 0x%02x\n",
  			client->name, chip->bits, client->addr);
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -EIO;
  
  	if (pdata->num_leds != chip->bits) {
  		dev_err(&client->dev,
  			"board info claims %d LEDs on a %d-bit chip\n",
  			pdata->num_leds, chip->bits);
  		return -ENODEV;
  	}
  
  	pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
  	if (!pca955x)
  		return -ENOMEM;
  
  	pca955x->leds = devm_kzalloc(&client->dev,
  			sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
  	if (!pca955x->leds)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, pca955x);
  
  	mutex_init(&pca955x->lock);
  	pca955x->client = client;
  	pca955x->chipdef = chip;
  
  	for (i = 0; i < chip->bits; i++) {
  		pca955x_led = &pca955x->leds[i];
  		pca955x_led->led_num = i;
  		pca955x_led->pca955x = pca955x;
  		pca955x_led->type = pdata->leds[i].type;
  
  		switch (pca955x_led->type) {
  		case PCA955X_TYPE_NONE:
  			break;
  		case PCA955X_TYPE_GPIO:
  			ngpios++;
  			break;
  		case PCA955X_TYPE_LED:
  			/*
  			 * Platform data can specify LED names and
  			 * default triggers
  			 */
  			if (pdata->leds[i].name[0] == '\0')
  				snprintf(pdata->leds[i].name,
  					sizeof(pdata->leds[i].name), "%d", i);
  
  			snprintf(pca955x_led->name,
  				sizeof(pca955x_led->name), "pca955x:%s",
  				pdata->leds[i].name);
  
  			if (pdata->leds[i].default_trigger)
  				pca955x_led->led_cdev.default_trigger =
  					pdata->leds[i].default_trigger;
  
  			pca955x_led->led_cdev.name = pca955x_led->name;
  			pca955x_led->led_cdev.brightness_set_blocking =
  				pca955x_led_set;
  
  			err = devm_led_classdev_register(&client->dev,
  							&pca955x_led->led_cdev);
  			if (err)
  				return err;
  
  			/* Turn off LED */
  			err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
  			if (err)
  				return err;
  		}
  	}
  
  	/* PWM0 is used for half brightness or 50% duty cycle */
  	err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
  	if (err)
  		return err;
  
  	/* PWM1 is used for variable brightness, default to OFF */
  	err = pca955x_write_pwm(client, 1, 0);
  	if (err)
  		return err;
  
  	/* Set to fast frequency so we do not see flashing */
  	err = pca955x_write_psc(client, 0, 0);
  	if (err)
  		return err;
  	err = pca955x_write_psc(client, 1, 0);
  	if (err)
  		return err;
  
  #ifdef CONFIG_LEDS_PCA955X_GPIO
  	if (ngpios) {
  		pca955x->gpio.label = "gpio-pca955x";
  		pca955x->gpio.direction_input = pca955x_gpio_direction_input;
  		pca955x->gpio.direction_output = pca955x_gpio_direction_output;
  		pca955x->gpio.set = pca955x_gpio_set_value;
  		pca955x->gpio.get = pca955x_gpio_get_value;
  		pca955x->gpio.request = pca955x_gpio_request_pin;
  		pca955x->gpio.can_sleep = 1;
  		pca955x->gpio.base = -1;
  		pca955x->gpio.ngpio = ngpios;
  		pca955x->gpio.parent = &client->dev;
  		pca955x->gpio.owner = THIS_MODULE;
  
  		err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
  					     pca955x);
  		if (err) {
  			/* Use data->gpio.dev as a flag for freeing gpiochip */
  			pca955x->gpio.parent = NULL;
  			dev_warn(&client->dev, "could not add gpiochip\n");
  			return err;
  		}
  		dev_info(&client->dev, "gpios %i...%i\n",
  			 pca955x->gpio.base, pca955x->gpio.base +
  			 pca955x->gpio.ngpio - 1);
  	}
  #endif
  
  	return 0;
  }
  
  static struct i2c_driver pca955x_driver = {
  	.driver = {
  		.name	= "leds-pca955x",
  		.acpi_match_table = ACPI_PTR(pca955x_acpi_ids),
  		.of_match_table = of_match_ptr(of_pca955x_match),
  	},
  	.probe	= pca955x_probe,
  	.id_table = pca955x_id,
  };
  
  module_i2c_driver(pca955x_driver);
  
  MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
  MODULE_DESCRIPTION("PCA955x LED driver");
  MODULE_LICENSE("GPL v2");
  