/*
  * Simple driver for Texas Instruments LM3642 LED Flash driver chip
  * Copyright (C) 2012 Texas Instruments
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  */
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/i2c.h>
  #include <linux/leds.h>
  #include <linux/slab.h>
  #include <linux/platform_device.h>
  #include <linux/fs.h>
  #include <linux/regmap.h>
  #include <linux/workqueue.h>
  #include <linux/platform_data/leds-lm3642.h>
  
  #define	REG_FILT_TIME			(0x0)
  #define	REG_IVFM_MODE			(0x1)
  #define	REG_TORCH_TIME			(0x6)
  #define	REG_FLASH			(0x8)
  #define	REG_I_CTRL			(0x9)
  #define	REG_ENABLE			(0xA)
  #define	REG_FLAG			(0xB)
  #define	REG_MAX				(0xB)
  
  #define	UVLO_EN_SHIFT			(7)
  #define	IVM_D_TH_SHIFT			(2)
  #define	TORCH_RAMP_UP_TIME_SHIFT	(3)
  #define	TORCH_RAMP_DN_TIME_SHIFT	(0)
  #define	INDUCTOR_I_LIMIT_SHIFT		(6)
  #define	FLASH_RAMP_TIME_SHIFT		(3)
  #define	FLASH_TOUT_TIME_SHIFT		(0)
  #define	TORCH_I_SHIFT			(4)
  #define	FLASH_I_SHIFT			(0)
  #define	IVFM_SHIFT			(7)
  #define	TX_PIN_EN_SHIFT			(6)
  #define	STROBE_PIN_EN_SHIFT		(5)
  #define	TORCH_PIN_EN_SHIFT		(4)
  #define	MODE_BITS_SHIFT			(0)
  
  #define	UVLO_EN_MASK			(0x1)
  #define	IVM_D_TH_MASK			(0x7)
  #define	TORCH_RAMP_UP_TIME_MASK		(0x7)
  #define	TORCH_RAMP_DN_TIME_MASK		(0x7)
  #define	INDUCTOR_I_LIMIT_MASK		(0x1)
  #define	FLASH_RAMP_TIME_MASK		(0x7)
  #define	FLASH_TOUT_TIME_MASK		(0x7)
  #define	TORCH_I_MASK			(0x7)
  #define	FLASH_I_MASK			(0xF)
  #define	IVFM_MASK			(0x1)
  #define	TX_PIN_EN_MASK			(0x1)
  #define	STROBE_PIN_EN_MASK		(0x1)
  #define	TORCH_PIN_EN_MASK		(0x1)
  #define	MODE_BITS_MASK			(0x73)
  #define EX_PIN_CONTROL_MASK		(0x71)
  #define EX_PIN_ENABLE_MASK		(0x70)
  
  enum lm3642_mode {
  	MODES_STASNDBY = 0,
  	MODES_INDIC,
  	MODES_TORCH,
  	MODES_FLASH
  };
  
  struct lm3642_chip_data {
  	struct device *dev;
  
  	struct led_classdev cdev_flash;
  	struct led_classdev cdev_torch;
  	struct led_classdev cdev_indicator;
  
  	struct work_struct work_flash;
  	struct work_struct work_torch;
  	struct work_struct work_indicator;
  
  	u8 br_flash;
  	u8 br_torch;
  	u8 br_indicator;
  
  	enum lm3642_torch_pin_enable torch_pin;
  	enum lm3642_strobe_pin_enable strobe_pin;
  	enum lm3642_tx_pin_enable tx_pin;
  
  	struct lm3642_platform_data *pdata;
  	struct regmap *regmap;
  	struct mutex lock;
  
  	unsigned int last_flag;
  };
  
  /* chip initialize */
  static int lm3642_chip_init(struct lm3642_chip_data *chip)
  {
  	int ret;
  	struct lm3642_platform_data *pdata = chip->pdata;
  
  	/* set enable register */
  	ret = regmap_update_bits(chip->regmap, REG_ENABLE, EX_PIN_ENABLE_MASK,
  				 pdata->tx_pin);
  	if (ret < 0)
  		dev_err(chip->dev, "Failed to update REG_ENABLE Register
  ");
  	return ret;
  }
  
  /* chip control */
  static int lm3642_control(struct lm3642_chip_data *chip,
  			  u8 brightness, enum lm3642_mode opmode)
  {
  	int ret;
  
  	ret = regmap_read(chip->regmap, REG_FLAG, &chip->last_flag);
  	if (ret < 0) {
  		dev_err(chip->dev, "Failed to read REG_FLAG Register
  ");
  		goto out;
  	}
  
  	if (chip->last_flag)
  		dev_info(chip->dev, "Last FLAG is 0x%x
  ", chip->last_flag);
  
  	/* brightness 0 means off-state */
  	if (!brightness)
  		opmode = MODES_STASNDBY;
  
  	switch (opmode) {
  	case MODES_TORCH:
  		ret = regmap_update_bits(chip->regmap, REG_I_CTRL,
  					 TORCH_I_MASK << TORCH_I_SHIFT,
  					 (brightness - 1) << TORCH_I_SHIFT);
  
  		if (chip->torch_pin)
  			opmode |= (TORCH_PIN_EN_MASK << TORCH_PIN_EN_SHIFT);
  		break;
  
  	case MODES_FLASH:
  		ret = regmap_update_bits(chip->regmap, REG_I_CTRL,
  					 FLASH_I_MASK << FLASH_I_SHIFT,
  					 (brightness - 1) << FLASH_I_SHIFT);
  
  		if (chip->strobe_pin)
  			opmode |= (STROBE_PIN_EN_MASK << STROBE_PIN_EN_SHIFT);
  		break;
  
  	case MODES_INDIC:
  		ret = regmap_update_bits(chip->regmap, REG_I_CTRL,
  					 TORCH_I_MASK << TORCH_I_SHIFT,
  					 (brightness - 1) << TORCH_I_SHIFT);
  		break;
  
  	case MODES_STASNDBY:
  
  		break;
  
  	default:
  		return ret;
  	}
  	if (ret < 0) {
  		dev_err(chip->dev, "Failed to write REG_I_CTRL Register
  ");
  		goto out;
  	}
  
  	if (chip->tx_pin)
  		opmode |= (TX_PIN_EN_MASK << TX_PIN_EN_SHIFT);
  
  	ret = regmap_update_bits(chip->regmap, REG_ENABLE,
  				 MODE_BITS_MASK << MODE_BITS_SHIFT,
  				 opmode << MODE_BITS_SHIFT);
  out:
  	return ret;
  }
  
  /* torch */
  
  /* torch pin config for lm3642*/
  static ssize_t lm3642_torch_pin_store(struct device *dev,
  				      struct device_attribute *attr,
  				      const char *buf, size_t size)
  {
  	ssize_t ret;
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lm3642_chip_data *chip =
  	    container_of(led_cdev, struct lm3642_chip_data, cdev_indicator);
  	unsigned int state;
  
  	ret = kstrtouint(buf, 10, &state);
  	if (ret)
  		goto out_strtoint;
  	if (state != 0)
  		state = 0x01 << TORCH_PIN_EN_SHIFT;
  
  	chip->torch_pin = state;
  	ret = regmap_update_bits(chip->regmap, REG_ENABLE,
  				 TORCH_PIN_EN_MASK << TORCH_PIN_EN_SHIFT,
  				 state);
  	if (ret < 0)
  		goto out;
  
  	return size;
  out:
  	dev_err(chip->dev, "%s:i2c access fail to register
  ", __func__);
  	return ret;
  out_strtoint:
  	dev_err(chip->dev, "%s: fail to change str to int
  ", __func__);
  	return ret;
  }
  
  static DEVICE_ATTR(torch_pin, S_IWUSR, NULL, lm3642_torch_pin_store);
  
  static void lm3642_deferred_torch_brightness_set(struct work_struct *work)
  {
  	struct lm3642_chip_data *chip =
  	    container_of(work, struct lm3642_chip_data, work_torch);
  
  	mutex_lock(&chip->lock);
  	lm3642_control(chip, chip->br_torch, MODES_TORCH);
  	mutex_unlock(&chip->lock);
  }
  
  static void lm3642_torch_brightness_set(struct led_classdev *cdev,
  					enum led_brightness brightness)
  {
  	struct lm3642_chip_data *chip =
  	    container_of(cdev, struct lm3642_chip_data, cdev_torch);
  
  	chip->br_torch = brightness;
  	schedule_work(&chip->work_torch);
  }
  
  /* flash */
  
  /* strobe pin config for lm3642*/
  static ssize_t lm3642_strobe_pin_store(struct device *dev,
  				       struct device_attribute *attr,
  				       const char *buf, size_t size)
  {
  	ssize_t ret;
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lm3642_chip_data *chip =
  	    container_of(led_cdev, struct lm3642_chip_data, cdev_indicator);
  	unsigned int state;
  
  	ret = kstrtouint(buf, 10, &state);
  	if (ret)
  		goto out_strtoint;
  	if (state != 0)
  		state = 0x01 << STROBE_PIN_EN_SHIFT;
  
  	chip->strobe_pin = state;
  	ret = regmap_update_bits(chip->regmap, REG_ENABLE,
  				 STROBE_PIN_EN_MASK << STROBE_PIN_EN_SHIFT,
  				 state);
  	if (ret < 0)
  		goto out;
  
  	return size;
  out:
  	dev_err(chip->dev, "%s:i2c access fail to register
  ", __func__);
  	return ret;
  out_strtoint:
  	dev_err(chip->dev, "%s: fail to change str to int
  ", __func__);
  	return ret;
  }
  
  static DEVICE_ATTR(strobe_pin, S_IWUSR, NULL, lm3642_strobe_pin_store);
  
  static void lm3642_deferred_strobe_brightness_set(struct work_struct *work)
  {
  	struct lm3642_chip_data *chip =
  	    container_of(work, struct lm3642_chip_data, work_flash);
  
  	mutex_lock(&chip->lock);
  	lm3642_control(chip, chip->br_flash, MODES_FLASH);
  	mutex_unlock(&chip->lock);
  }
  
  static void lm3642_strobe_brightness_set(struct led_classdev *cdev,
  					 enum led_brightness brightness)
  {
  	struct lm3642_chip_data *chip =
  	    container_of(cdev, struct lm3642_chip_data, cdev_flash);
  
  	chip->br_flash = brightness;
  	schedule_work(&chip->work_flash);
  }
  
  /* indicator */
  static void lm3642_deferred_indicator_brightness_set(struct work_struct *work)
  {
  	struct lm3642_chip_data *chip =
  	    container_of(work, struct lm3642_chip_data, work_indicator);
  
  	mutex_lock(&chip->lock);
  	lm3642_control(chip, chip->br_indicator, MODES_INDIC);
  	mutex_unlock(&chip->lock);
  }
  
  static void lm3642_indicator_brightness_set(struct led_classdev *cdev,
  					    enum led_brightness brightness)
  {
  	struct lm3642_chip_data *chip =
  	    container_of(cdev, struct lm3642_chip_data, cdev_indicator);
  
  	chip->br_indicator = brightness;
  	schedule_work(&chip->work_indicator);
  }
  
  static const struct regmap_config lm3642_regmap = {
  	.reg_bits = 8,
  	.val_bits = 8,
  	.max_register = REG_MAX,
  };
  
  static struct attribute *lm3642_flash_attrs[] = {
  	&dev_attr_strobe_pin.attr,
  	NULL
  };
  ATTRIBUTE_GROUPS(lm3642_flash);
  
  static struct attribute *lm3642_torch_attrs[] = {
  	&dev_attr_torch_pin.attr,
  	NULL
  };
  ATTRIBUTE_GROUPS(lm3642_torch);
  
  static int lm3642_probe(struct i2c_client *client,
  				  const struct i2c_device_id *id)
  {
  	struct lm3642_platform_data *pdata = dev_get_platdata(&client->dev);
  	struct lm3642_chip_data *chip;
  
  	int err;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  		dev_err(&client->dev, "i2c functionality check fail.
  ");
  		return -EOPNOTSUPP;
  	}
  
  	if (pdata == NULL) {
  		dev_err(&client->dev, "needs Platform Data.
  ");
  		return -ENODATA;
  	}
  
  	chip = devm_kzalloc(&client->dev,
  			    sizeof(struct lm3642_chip_data), GFP_KERNEL);
  	if (!chip)
  		return -ENOMEM;
  
  	chip->dev = &client->dev;
  	chip->pdata = pdata;
  
  	chip->tx_pin = pdata->tx_pin;
  	chip->torch_pin = pdata->torch_pin;
  	chip->strobe_pin = pdata->strobe_pin;
  
  	chip->regmap = devm_regmap_init_i2c(client, &lm3642_regmap);
  	if (IS_ERR(chip->regmap)) {
  		err = PTR_ERR(chip->regmap);
  		dev_err(&client->dev, "Failed to allocate register map: %d
  ",
  			err);
  		return err;
  	}
  
  	mutex_init(&chip->lock);
  	i2c_set_clientdata(client, chip);
  
  	err = lm3642_chip_init(chip);
  	if (err < 0)
  		goto err_out;
  
  	/* flash */
  	INIT_WORK(&chip->work_flash, lm3642_deferred_strobe_brightness_set);
  	chip->cdev_flash.name = "flash";
  	chip->cdev_flash.max_brightness = 16;
  	chip->cdev_flash.brightness_set = lm3642_strobe_brightness_set;
  	chip->cdev_flash.default_trigger = "flash";
  	chip->cdev_flash.groups = lm3642_flash_groups,
  	err = led_classdev_register((struct device *)
  				    &client->dev, &chip->cdev_flash);
  	if (err < 0) {
  		dev_err(chip->dev, "failed to register flash
  ");
  		goto err_out;
  	}
  
  	/* torch */
  	INIT_WORK(&chip->work_torch, lm3642_deferred_torch_brightness_set);
  	chip->cdev_torch.name = "torch";
  	chip->cdev_torch.max_brightness = 8;
  	chip->cdev_torch.brightness_set = lm3642_torch_brightness_set;
  	chip->cdev_torch.default_trigger = "torch";
  	chip->cdev_torch.groups = lm3642_torch_groups,
  	err = led_classdev_register((struct device *)
  				    &client->dev, &chip->cdev_torch);
  	if (err < 0) {
  		dev_err(chip->dev, "failed to register torch
  ");
  		goto err_create_torch_file;
  	}
  
  	/* indicator */
  	INIT_WORK(&chip->work_indicator,
  		  lm3642_deferred_indicator_brightness_set);
  	chip->cdev_indicator.name = "indicator";
  	chip->cdev_indicator.max_brightness = 8;
  	chip->cdev_indicator.brightness_set = lm3642_indicator_brightness_set;
  	err = led_classdev_register((struct device *)
  				    &client->dev, &chip->cdev_indicator);
  	if (err < 0) {
  		dev_err(chip->dev, "failed to register indicator
  ");
  		goto err_create_indicator_file;
  	}
  
  	dev_info(&client->dev, "LM3642 is initialized
  ");
  	return 0;
  
  err_create_indicator_file:
  	led_classdev_unregister(&chip->cdev_torch);
  err_create_torch_file:
  	led_classdev_unregister(&chip->cdev_flash);
  err_out:
  	return err;
  }
  
  static int lm3642_remove(struct i2c_client *client)
  {
  	struct lm3642_chip_data *chip = i2c_get_clientdata(client);
  
  	led_classdev_unregister(&chip->cdev_indicator);
  	flush_work(&chip->work_indicator);
  	led_classdev_unregister(&chip->cdev_torch);
  	flush_work(&chip->work_torch);
  	led_classdev_unregister(&chip->cdev_flash);
  	flush_work(&chip->work_flash);
  	regmap_write(chip->regmap, REG_ENABLE, 0);
  	return 0;
  }
  
  static const struct i2c_device_id lm3642_id[] = {
  	{LM3642_NAME, 0},
  	{}
  };
  
  MODULE_DEVICE_TABLE(i2c, lm3642_id);
  
  static struct i2c_driver lm3642_i2c_driver = {
  	.driver = {
  		   .name = LM3642_NAME,
  		   .pm = NULL,
  		   },
  	.probe = lm3642_probe,
  	.remove = lm3642_remove,
  	.id_table = lm3642_id,
  };
  
  module_i2c_driver(lm3642_i2c_driver);
  
  MODULE_DESCRIPTION("Texas Instruments Flash Lighting driver for LM3642");
  MODULE_AUTHOR("Daniel Jeong <daniel.jeong@ti.com>");
  MODULE_AUTHOR("G.Shark Jeong <gshark.jeong@gmail.com>");
  MODULE_LICENSE("GPL v2");