/*
   * Copyright (C) 2011 ST-Ericsson SA.
   * Copyright (C) 2009 Motorola, Inc.
   *
   * License Terms: GNU General Public License v2
   *
   * Simple driver for National Semiconductor LM3530 Backlight driver chip
   *
   * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
   * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com>
   */
  
  #include <linux/i2c.h>
  #include <linux/leds.h>
  #include <linux/slab.h>
  #include <linux/platform_device.h>
  #include <linux/input.h>
  #include <linux/led-lm3530.h>
  #include <linux/types.h>
  #include <linux/regulator/consumer.h>
  #include <linux/module.h>
  
  #define LM3530_LED_DEV "lcd-backlight"
  #define LM3530_NAME "lm3530-led"
  
  #define LM3530_GEN_CONFIG		0x10
  #define LM3530_ALS_CONFIG		0x20
  #define LM3530_BRT_RAMP_RATE		0x30
  #define LM3530_ALS_IMP_SELECT		0x41
  #define LM3530_BRT_CTRL_REG		0xA0
  #define LM3530_ALS_ZB0_REG		0x60
  #define LM3530_ALS_ZB1_REG		0x61
  #define LM3530_ALS_ZB2_REG		0x62
  #define LM3530_ALS_ZB3_REG		0x63
  #define LM3530_ALS_Z0T_REG		0x70
  #define LM3530_ALS_Z1T_REG		0x71
  #define LM3530_ALS_Z2T_REG		0x72
  #define LM3530_ALS_Z3T_REG		0x73
  #define LM3530_ALS_Z4T_REG		0x74
  #define LM3530_REG_MAX			14
  
  /* General Control Register */
  #define LM3530_EN_I2C_SHIFT		(0)
  #define LM3530_RAMP_LAW_SHIFT		(1)
  #define LM3530_MAX_CURR_SHIFT		(2)
  #define LM3530_EN_PWM_SHIFT		(5)
  #define LM3530_PWM_POL_SHIFT		(6)
  #define LM3530_EN_PWM_SIMPLE_SHIFT	(7)
  
  #define LM3530_ENABLE_I2C		(1 << LM3530_EN_I2C_SHIFT)
  #define LM3530_ENABLE_PWM		(1 << LM3530_EN_PWM_SHIFT)
  #define LM3530_POL_LOW			(1 << LM3530_PWM_POL_SHIFT)
  #define LM3530_ENABLE_PWM_SIMPLE	(1 << LM3530_EN_PWM_SIMPLE_SHIFT)
  
  /* ALS Config Register Options */
  #define LM3530_ALS_AVG_TIME_SHIFT	(0)
  #define LM3530_EN_ALS_SHIFT		(3)
  #define LM3530_ALS_SEL_SHIFT		(5)
  
  #define LM3530_ENABLE_ALS		(3 << LM3530_EN_ALS_SHIFT)
  
  /* Brightness Ramp Rate Register */
  #define LM3530_BRT_RAMP_FALL_SHIFT	(0)
  #define LM3530_BRT_RAMP_RISE_SHIFT	(3)
  
  /* ALS Resistor Select */
  #define LM3530_ALS1_IMP_SHIFT		(0)
  #define LM3530_ALS2_IMP_SHIFT		(4)
  
  /* Zone Boundary Register defaults */
  #define LM3530_ALS_ZB_MAX		(4)
  #define LM3530_ALS_WINDOW_mV		(1000)
  #define LM3530_ALS_OFFSET_mV		(4)
  
  /* Zone Target Register defaults */
  #define LM3530_DEF_ZT_0			(0x7F)
  #define LM3530_DEF_ZT_1			(0x66)
  #define LM3530_DEF_ZT_2			(0x4C)
  #define LM3530_DEF_ZT_3			(0x33)
  #define LM3530_DEF_ZT_4			(0x19)
  
  /* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */
  #define MAX_BRIGHTNESS			(127)
  
  struct lm3530_mode_map {
  	const char *mode;
  	enum lm3530_mode mode_val;
  };
  
  static struct lm3530_mode_map mode_map[] = {
  	{ "man", LM3530_BL_MODE_MANUAL },
  	{ "als", LM3530_BL_MODE_ALS },
  	{ "pwm", LM3530_BL_MODE_PWM },
  };
  
  /**
   * struct lm3530_data
   * @led_dev: led class device
   * @client: i2c client
   * @pdata: LM3530 platform data
   * @mode: mode of operation - manual, ALS, PWM
   * @regulator: regulator
   * @brighness: previous brightness value
   * @enable: regulator is enabled
   */
  struct lm3530_data {
  	struct led_classdev led_dev;
  	struct i2c_client *client;
  	struct lm3530_platform_data *pdata;
  	enum lm3530_mode mode;
  	struct regulator *regulator;
  	enum led_brightness brightness;
  	bool enable;
  };
  
  /*
   * struct lm3530_als_data
   * @config  : value of ALS configuration register
   * @imp_sel : value of ALS resistor select register
   * @zone    : values of ALS ZB(Zone Boundary) registers
   */
  struct lm3530_als_data {
  	u8 config;
  	u8 imp_sel;
  	u8 zones[LM3530_ALS_ZB_MAX];
  };
  
  static const u8 lm3530_reg[LM3530_REG_MAX] = {
  	LM3530_GEN_CONFIG,
  	LM3530_ALS_CONFIG,
  	LM3530_BRT_RAMP_RATE,
  	LM3530_ALS_IMP_SELECT,
  	LM3530_BRT_CTRL_REG,
  	LM3530_ALS_ZB0_REG,
  	LM3530_ALS_ZB1_REG,
  	LM3530_ALS_ZB2_REG,
  	LM3530_ALS_ZB3_REG,
  	LM3530_ALS_Z0T_REG,
  	LM3530_ALS_Z1T_REG,
  	LM3530_ALS_Z2T_REG,
  	LM3530_ALS_Z3T_REG,
  	LM3530_ALS_Z4T_REG,
  };
  
  static int lm3530_get_mode_from_str(const char *str)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
  		if (sysfs_streq(str, mode_map[i].mode))
  			return mode_map[i].mode_val;
  
  	return -EINVAL;
  }
  
  static void lm3530_als_configure(struct lm3530_platform_data *pdata,
  				struct lm3530_als_data *als)
  {
  	int i;
  	u32 als_vmin, als_vmax, als_vstep;
  
  	if (pdata->als_vmax == 0) {
  		pdata->als_vmin = 0;
  		pdata->als_vmax = LM3530_ALS_WINDOW_mV;
  	}
  
  	als_vmin = pdata->als_vmin;
  	als_vmax = pdata->als_vmax;
  
  	if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
  		pdata->als_vmax = als_vmax = als_vmin + LM3530_ALS_WINDOW_mV;
  
  	/* n zone boundary makes n+1 zones */
  	als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
  
  	for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
  		als->zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
  			als_vstep + (i * als_vstep)) * LED_FULL) / 1000;
  
  	als->config =
  		(pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
  		(LM3530_ENABLE_ALS) |
  		(pdata->als_input_mode << LM3530_ALS_SEL_SHIFT);
  
  	als->imp_sel =
  		(pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
  		(pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
  }
  
  static int lm3530_led_enable(struct lm3530_data *drvdata)
  {
  	int ret;
  
  	if (drvdata->enable)
  		return 0;
  
  	ret = regulator_enable(drvdata->regulator);
  	if (ret) {
  		dev_err(drvdata->led_dev.dev, "Failed to enable vin:%d
  ", ret);
  		return ret;
  	}
  
  	drvdata->enable = true;
  	return 0;
  }
  
  static void lm3530_led_disable(struct lm3530_data *drvdata)
  {
  	int ret;
  
  	if (!drvdata->enable)
  		return;
  
  	ret = regulator_disable(drvdata->regulator);
  	if (ret) {
  		dev_err(drvdata->led_dev.dev, "Failed to disable vin:%d
  ",
  			ret);
  		return;
  	}
  
  	drvdata->enable = false;
  }
  
  static int lm3530_init_registers(struct lm3530_data *drvdata)
  {
  	int ret = 0;
  	int i;
  	u8 gen_config;
  	u8 brt_ramp;
  	u8 brightness;
  	u8 reg_val[LM3530_REG_MAX];
  	struct lm3530_platform_data *pdata = drvdata->pdata;
  	struct i2c_client *client = drvdata->client;
  	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
  	struct lm3530_als_data als;
  
  	memset(&als, 0, sizeof(struct lm3530_als_data));
  
  	gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
  			((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT);
  
  	switch (drvdata->mode) {
  	case LM3530_BL_MODE_MANUAL:
  		gen_config |= LM3530_ENABLE_I2C;
  		break;
  	case LM3530_BL_MODE_ALS:
  		gen_config |= LM3530_ENABLE_I2C;
  		lm3530_als_configure(pdata, &als);
  		break;
  	case LM3530_BL_MODE_PWM:
  		gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE |
  			      (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT);
  		break;
  	}
  
  	brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
  			(pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
  
  	if (drvdata->brightness)
  		brightness = drvdata->brightness;
  	else
  		brightness = drvdata->brightness = pdata->brt_val;
  
  	if (brightness > drvdata->led_dev.max_brightness)
  		brightness = drvdata->led_dev.max_brightness;
  
  	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
  	reg_val[1] = als.config;	/* LM3530_ALS_CONFIG */
  	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
  	reg_val[3] = als.imp_sel;	/* LM3530_ALS_IMP_SELECT */
  	reg_val[4] = brightness;	/* LM3530_BRT_CTRL_REG */
  	reg_val[5] = als.zones[0];	/* LM3530_ALS_ZB0_REG */
  	reg_val[6] = als.zones[1];	/* LM3530_ALS_ZB1_REG */
  	reg_val[7] = als.zones[2];	/* LM3530_ALS_ZB2_REG */
  	reg_val[8] = als.zones[3];	/* LM3530_ALS_ZB3_REG */
  	reg_val[9] = LM3530_DEF_ZT_0;	/* LM3530_ALS_Z0T_REG */
  	reg_val[10] = LM3530_DEF_ZT_1;	/* LM3530_ALS_Z1T_REG */
  	reg_val[11] = LM3530_DEF_ZT_2;	/* LM3530_ALS_Z2T_REG */
  	reg_val[12] = LM3530_DEF_ZT_3;	/* LM3530_ALS_Z3T_REG */
  	reg_val[13] = LM3530_DEF_ZT_4;	/* LM3530_ALS_Z4T_REG */
  
  	ret = lm3530_led_enable(drvdata);
  	if (ret)
  		return ret;
  
  	for (i = 0; i < LM3530_REG_MAX; i++) {
  		/* do not update brightness register when pwm mode */
  		if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
  		    drvdata->mode == LM3530_BL_MODE_PWM) {
  			if (pwm->pwm_set_intensity)
  				pwm->pwm_set_intensity(reg_val[i],
  					drvdata->led_dev.max_brightness);
  			continue;
  		}
  
  		ret = i2c_smbus_write_byte_data(client,
  				lm3530_reg[i], reg_val[i]);
  		if (ret)
  			break;
  	}
  
  	return ret;
  }
  
  static void lm3530_brightness_set(struct led_classdev *led_cdev,
  				     enum led_brightness brt_val)
  {
  	int err;
  	struct lm3530_data *drvdata =
  	    container_of(led_cdev, struct lm3530_data, led_dev);
  	struct lm3530_platform_data *pdata = drvdata->pdata;
  	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
  	u8 max_brightness = led_cdev->max_brightness;
  
  	switch (drvdata->mode) {
  	case LM3530_BL_MODE_MANUAL:
  
  		if (!drvdata->enable) {
  			err = lm3530_init_registers(drvdata);
  			if (err) {
  				dev_err(&drvdata->client->dev,
  					"Register Init failed: %d
  ", err);
  				break;
  			}
  		}
  
  		/* set the brightness in brightness control register*/
  		err = i2c_smbus_write_byte_data(drvdata->client,
  				LM3530_BRT_CTRL_REG, brt_val);
  		if (err)
  			dev_err(&drvdata->client->dev,
  				"Unable to set brightness: %d
  ", err);
  		else
  			drvdata->brightness = brt_val;
  
  		if (brt_val == 0)
  			lm3530_led_disable(drvdata);
  		break;
  	case LM3530_BL_MODE_ALS:
  		break;
  	case LM3530_BL_MODE_PWM:
  		if (pwm->pwm_set_intensity)
  			pwm->pwm_set_intensity(brt_val, max_brightness);
  		break;
  	default:
  		break;
  	}
  }
  
  static ssize_t lm3530_mode_get(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lm3530_data *drvdata;
  	int i, len = 0;
  
  	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
  	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
  		if (drvdata->mode == mode_map[i].mode_val)
  			len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
  		else
  			len += sprintf(buf + len, "%s ", mode_map[i].mode);
  
  	len += sprintf(buf + len, "
  ");
  
  	return len;
  }
  
  static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
  				   *attr, const char *buf, size_t size)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lm3530_data *drvdata;
  	struct lm3530_pwm_data *pwm;
  	u8 max_brightness;
  	int mode, err;
  
  	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
  	pwm = &drvdata->pdata->pwm_data;
  	max_brightness = led_cdev->max_brightness;
  	mode = lm3530_get_mode_from_str(buf);
  	if (mode < 0) {
  		dev_err(dev, "Invalid mode
  ");
  		return mode;
  	}
  
  	drvdata->mode = mode;
  
  	/* set pwm to low if unnecessary */
  	if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
  		pwm->pwm_set_intensity(0, max_brightness);
  
  	err = lm3530_init_registers(drvdata);
  	if (err) {
  		dev_err(dev, "Setting %s Mode failed :%d
  ", buf, err);
  		return err;
  	}
  
  	return sizeof(drvdata->mode);
  }
  static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
  
  static struct attribute *lm3530_attrs[] = {
  	&dev_attr_mode.attr,
  	NULL
  };
  ATTRIBUTE_GROUPS(lm3530);
  
  static int lm3530_probe(struct i2c_client *client,
  			   const struct i2c_device_id *id)
  {
  	struct lm3530_platform_data *pdata = dev_get_platdata(&client->dev);
  	struct lm3530_data *drvdata;
  	int err = 0;
  
  	if (pdata == NULL) {
  		dev_err(&client->dev, "platform data required
  ");
  		return -ENODEV;
  	}
  
  	/* BL mode */
  	if (pdata->mode > LM3530_BL_MODE_PWM) {
  		dev_err(&client->dev, "Illegal Mode request
  ");
  		return -EINVAL;
  	}
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  		dev_err(&client->dev, "I2C_FUNC_I2C not supported
  ");
  		return -EIO;
  	}
  
  	drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
  				GFP_KERNEL);
  	if (drvdata == NULL)
  		return -ENOMEM;
  
  	drvdata->mode = pdata->mode;
  	drvdata->client = client;
  	drvdata->pdata = pdata;
  	drvdata->brightness = LED_OFF;
  	drvdata->enable = false;
  	drvdata->led_dev.name = LM3530_LED_DEV;
  	drvdata->led_dev.brightness_set = lm3530_brightness_set;
  	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
  	drvdata->led_dev.groups = lm3530_groups;
  
  	i2c_set_clientdata(client, drvdata);
  
  	drvdata->regulator = devm_regulator_get(&client->dev, "vin");
  	if (IS_ERR(drvdata->regulator)) {
  		dev_err(&client->dev, "regulator get failed
  ");
  		err = PTR_ERR(drvdata->regulator);
  		drvdata->regulator = NULL;
  		return err;
  	}
  
  	if (drvdata->pdata->brt_val) {
  		err = lm3530_init_registers(drvdata);
  		if (err < 0) {
  			dev_err(&client->dev,
  				"Register Init failed: %d
  ", err);
  			return err;
  		}
  	}
  	err = led_classdev_register(&client->dev, &drvdata->led_dev);
  	if (err < 0) {
  		dev_err(&client->dev, "Register led class failed: %d
  ", err);
  		return err;
  	}
  
  	return 0;
  }
  
  static int lm3530_remove(struct i2c_client *client)
  {
  	struct lm3530_data *drvdata = i2c_get_clientdata(client);
  
  	lm3530_led_disable(drvdata);
  	led_classdev_unregister(&drvdata->led_dev);
  	return 0;
  }
  
  static const struct i2c_device_id lm3530_id[] = {
  	{LM3530_NAME, 0},
  	{}
  };
  MODULE_DEVICE_TABLE(i2c, lm3530_id);
  
  static struct i2c_driver lm3530_i2c_driver = {
  	.probe = lm3530_probe,
  	.remove = lm3530_remove,
  	.id_table = lm3530_id,
  	.driver = {
  		.name = LM3530_NAME,
  	},
  };
  
  module_i2c_driver(lm3530_i2c_driver);
  
  MODULE_DESCRIPTION("Back Light driver for LM3530");
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");