drivers/leds/leds-lm3530.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2011 ST-Ericsson SA.
  * Copyright (C) 2009 Motorola, Inc.
  *
  * 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
  * @brightness: 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\n", 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\n",
 			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\n", 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\n", 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 mode_show(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, "\n");

 	return len;
 }

 static ssize_t mode_store(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\n");
 		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\n", buf, err);
 		return err;
 	}

 	return sizeof(drvdata->mode);
 }
 static DEVICE_ATTR_RW(mode);

 static struct attribute *lm3530_attrs[] = {
 	&dev_attr_mode.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(lm3530);

 static int lm3530_probe(struct i2c_client *client)
 {
 	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\n");
 		return -ENODEV;
 	}

 	/* BL mode */
 	if (pdata->mode > LM3530_BL_MODE_PWM) {
 		dev_err(&client->dev, "Illegal Mode request\n");
 		return -EINVAL;
 	}

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
 		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\n");
 		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\n", err);
 			return err;
 		}
 	}
 	err = led_classdev_register(&client->dev, &drvdata->led_dev);
 	if (err < 0) {
 		dev_err(&client->dev, "Register led class failed: %d\n", err);
 		return err;
 	}

 	return 0;
 }

 static void lm3530_remove(struct i2c_client *client)
 {
 	struct lm3530_data *drvdata = i2c_get_clientdata(client);

 	lm3530_led_disable(drvdata);
 	led_classdev_unregister(&drvdata->led_dev);
 }

 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_new = 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>");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2011 ST-Ericsson SA.
	* Copyright (C) 2009 Motorola, Inc.
	*
	* 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
	* @brightness: 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\n", 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\n",
	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\n", 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\n", 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 mode_show(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, "\n");

	return len;
	}

	static ssize_t mode_store(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\n");
	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\n", buf, err);
	return err;
	}

	return sizeof(drvdata->mode);
	}
	static DEVICE_ATTR_RW(mode);

	static struct attribute *lm3530_attrs[] = {
	&dev_attr_mode.attr,
	NULL
	};
	ATTRIBUTE_GROUPS(lm3530);

	static int lm3530_probe(struct i2c_client *client)
	{
	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\n");
	return -ENODEV;
	}

	/* BL mode */
	if (pdata->mode > LM3530_BL_MODE_PWM) {
	dev_err(&client->dev, "Illegal Mode request\n");
	return -EINVAL;
	}

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
	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\n");
	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\n", err);
	return err;
	}
	}
	err = led_classdev_register(&client->dev, &drvdata->led_dev);
	if (err < 0) {
	dev_err(&client->dev, "Register led class failed: %d\n", err);
	return err;
	}

	return 0;
	}

	static void lm3530_remove(struct i2c_client *client)
	{
	struct lm3530_data *drvdata = i2c_get_clientdata(client);

	lm3530_led_disable(drvdata);
	led_classdev_unregister(&drvdata->led_dev);
	}

	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_new = 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>");