drivers/video/backlight/lp8788_bl.c - kernel/quantenna - Git at Google

 /*
  * TI LP8788 MFD - backlight driver
  *
  * Copyright 2012 Texas Instruments
  *
  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
  *
  * 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/backlight.h>
 #include <linux/err.h>
 #include <linux/mfd/lp8788.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>

 /* Register address */
 #define LP8788_BL_CONFIG		0x96
 #define LP8788_BL_EN			BIT(0)
 #define LP8788_BL_PWM_INPUT_EN		BIT(5)
 #define LP8788_BL_FULLSCALE_SHIFT	2
 #define LP8788_BL_DIM_MODE_SHIFT	1
 #define LP8788_BL_PWM_POLARITY_SHIFT	6

 #define LP8788_BL_BRIGHTNESS		0x97

 #define LP8788_BL_RAMP			0x98
 #define LP8788_BL_RAMP_RISE_SHIFT	4

 #define MAX_BRIGHTNESS			127
 #define DEFAULT_BL_NAME			"lcd-backlight"

 struct lp8788_bl_config {
 	enum lp8788_bl_ctrl_mode bl_mode;
 	enum lp8788_bl_dim_mode dim_mode;
 	enum lp8788_bl_full_scale_current full_scale;
 	enum lp8788_bl_ramp_step rise_time;
 	enum lp8788_bl_ramp_step fall_time;
 	enum pwm_polarity pwm_pol;
 };

 struct lp8788_bl {
 	struct lp8788 *lp;
 	struct backlight_device *bl_dev;
 	struct lp8788_backlight_platform_data *pdata;
 	enum lp8788_bl_ctrl_mode mode;
 	struct pwm_device *pwm;
 };

 static struct lp8788_bl_config default_bl_config = {
 	.bl_mode    = LP8788_BL_REGISTER_ONLY,
 	.dim_mode   = LP8788_DIM_EXPONENTIAL,
 	.full_scale = LP8788_FULLSCALE_1900uA,
 	.rise_time  = LP8788_RAMP_8192us,
 	.fall_time  = LP8788_RAMP_8192us,
 	.pwm_pol    = PWM_POLARITY_NORMAL,
 };

 static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode)
 {
 	return mode == LP8788_BL_COMB_PWM_BASED;
 }

 static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode)
 {
 	return mode == LP8788_BL_REGISTER_ONLY ||
 		mode == LP8788_BL_COMB_REGISTER_BASED;
 }

 static int lp8788_backlight_configure(struct lp8788_bl *bl)
 {
 	struct lp8788_backlight_platform_data *pdata = bl->pdata;
 	struct lp8788_bl_config *cfg = &default_bl_config;
 	int ret;
 	u8 val;

 	/*
 	 * Update chip configuration if platform data exists,
 	 * otherwise use the default settings.
 	 */
 	if (pdata) {
 		cfg->bl_mode    = pdata->bl_mode;
 		cfg->dim_mode   = pdata->dim_mode;
 		cfg->full_scale = pdata->full_scale;
 		cfg->rise_time  = pdata->rise_time;
 		cfg->fall_time  = pdata->fall_time;
 		cfg->pwm_pol    = pdata->pwm_pol;
 	}

 	/* Brightness ramp up/down */
 	val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time;
 	ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val);
 	if (ret)
 		return ret;

 	/* Fullscale current setting */
 	val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) |
 		(cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT);

 	/* Brightness control mode */
 	switch (cfg->bl_mode) {
 	case LP8788_BL_REGISTER_ONLY:
 		val |= LP8788_BL_EN;
 		break;
 	case LP8788_BL_COMB_PWM_BASED:
 	case LP8788_BL_COMB_REGISTER_BASED:
 		val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN |
 			(cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT);
 		break;
 	default:
 		dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode);
 		return -EINVAL;
 	}

 	bl->mode = cfg->bl_mode;

 	return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val);
 }

 static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br)
 {
 	unsigned int period;
 	unsigned int duty;
 	struct device *dev;
 	struct pwm_device *pwm;

 	if (!bl->pdata)
 		return;

 	period = bl->pdata->period_ns;
 	duty = br * period / max_br;
 	dev = bl->lp->dev;

 	/* request PWM device with the consumer name */
 	if (!bl->pwm) {
 		pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT);
 		if (IS_ERR(pwm)) {
 			dev_err(dev, "can not get PWM device\n");
 			return;
 		}

 		bl->pwm = pwm;

 		/*
 		 * FIXME: pwm_apply_args() should be removed when switching to
 		 * the atomic PWM API.
 		 */
 		pwm_apply_args(pwm);
 	}

 	pwm_config(bl->pwm, duty, period);
 	if (duty)
 		pwm_enable(bl->pwm);
 	else
 		pwm_disable(bl->pwm);
 }

 static int lp8788_bl_update_status(struct backlight_device *bl_dev)
 {
 	struct lp8788_bl *bl = bl_get_data(bl_dev);
 	enum lp8788_bl_ctrl_mode mode = bl->mode;

 	if (bl_dev->props.state & BL_CORE_SUSPENDED)
 		bl_dev->props.brightness = 0;

 	if (is_brightness_ctrl_by_pwm(mode)) {
 		int brt = bl_dev->props.brightness;
 		int max = bl_dev->props.max_brightness;

 		lp8788_pwm_ctrl(bl, brt, max);
 	} else if (is_brightness_ctrl_by_register(mode)) {
 		u8 brt = bl_dev->props.brightness;

 		lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt);
 	}

 	return 0;
 }

 static const struct backlight_ops lp8788_bl_ops = {
 	.options = BL_CORE_SUSPENDRESUME,
 	.update_status = lp8788_bl_update_status,
 };

 static int lp8788_backlight_register(struct lp8788_bl *bl)
 {
 	struct backlight_device *bl_dev;
 	struct backlight_properties props;
 	struct lp8788_backlight_platform_data *pdata = bl->pdata;
 	int init_brt;
 	char *name;

 	props.type = BACKLIGHT_PLATFORM;
 	props.max_brightness = MAX_BRIGHTNESS;

 	/* Initial brightness */
 	if (pdata)
 		init_brt = min_t(int, pdata->initial_brightness,
 				props.max_brightness);
 	else
 		init_brt = 0;

 	props.brightness = init_brt;

 	/* Backlight device name */
 	if (!pdata || !pdata->name)
 		name = DEFAULT_BL_NAME;
 	else
 		name = pdata->name;

 	bl_dev = backlight_device_register(name, bl->lp->dev, bl,
 				       &lp8788_bl_ops, &props);
 	if (IS_ERR(bl_dev))
 		return PTR_ERR(bl_dev);

 	bl->bl_dev = bl_dev;

 	return 0;
 }

 static void lp8788_backlight_unregister(struct lp8788_bl *bl)
 {
 	struct backlight_device *bl_dev = bl->bl_dev;

 	backlight_device_unregister(bl_dev);
 }

 static ssize_t lp8788_get_bl_ctl_mode(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
 	struct lp8788_bl *bl = dev_get_drvdata(dev);
 	enum lp8788_bl_ctrl_mode mode = bl->mode;
 	char *strmode;

 	if (is_brightness_ctrl_by_pwm(mode))
 		strmode = "PWM based";
 	else if (is_brightness_ctrl_by_register(mode))
 		strmode = "Register based";
 	else
 		strmode = "Invalid mode";

 	return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
 }

 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL);

 static struct attribute *lp8788_attributes[] = {
 	&dev_attr_bl_ctl_mode.attr,
 	NULL,
 };

 static const struct attribute_group lp8788_attr_group = {
 	.attrs = lp8788_attributes,
 };

 static int lp8788_backlight_probe(struct platform_device *pdev)
 {
 	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
 	struct lp8788_bl *bl;
 	int ret;

 	bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL);
 	if (!bl)
 		return -ENOMEM;

 	bl->lp = lp;
 	if (lp->pdata)
 		bl->pdata = lp->pdata->bl_pdata;

 	platform_set_drvdata(pdev, bl);

 	ret = lp8788_backlight_configure(bl);
 	if (ret) {
 		dev_err(lp->dev, "backlight config err: %d\n", ret);
 		goto err_dev;
 	}

 	ret = lp8788_backlight_register(bl);
 	if (ret) {
 		dev_err(lp->dev, "register backlight err: %d\n", ret);
 		goto err_dev;
 	}

 	ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group);
 	if (ret) {
 		dev_err(lp->dev, "register sysfs err: %d\n", ret);
 		goto err_sysfs;
 	}

 	backlight_update_status(bl->bl_dev);

 	return 0;

 err_sysfs:
 	lp8788_backlight_unregister(bl);
 err_dev:
 	return ret;
 }

 static int lp8788_backlight_remove(struct platform_device *pdev)
 {
 	struct lp8788_bl *bl = platform_get_drvdata(pdev);
 	struct backlight_device *bl_dev = bl->bl_dev;

 	bl_dev->props.brightness = 0;
 	backlight_update_status(bl_dev);
 	sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group);
 	lp8788_backlight_unregister(bl);

 	return 0;
 }

 static struct platform_driver lp8788_bl_driver = {
 	.probe = lp8788_backlight_probe,
 	.remove = lp8788_backlight_remove,
 	.driver = {
 		.name = LP8788_DEV_BACKLIGHT,
 	},
 };
 module_platform_driver(lp8788_bl_driver);

 MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver");
 MODULE_AUTHOR("Milo Kim");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:lp8788-backlight");
	/*
	* TI LP8788 MFD - backlight driver
	*
	* Copyright 2012 Texas Instruments
	*
	* Author: Milo(Woogyom) Kim <milo.kim@ti.com>
	*
	* 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/backlight.h>
	#include <linux/err.h>
	#include <linux/mfd/lp8788.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/slab.h>

	/* Register address */
	#define LP8788_BL_CONFIG 0x96
	#define LP8788_BL_EN BIT(0)
	#define LP8788_BL_PWM_INPUT_EN BIT(5)
	#define LP8788_BL_FULLSCALE_SHIFT 2
	#define LP8788_BL_DIM_MODE_SHIFT 1
	#define LP8788_BL_PWM_POLARITY_SHIFT 6

	#define LP8788_BL_BRIGHTNESS 0x97

	#define LP8788_BL_RAMP 0x98
	#define LP8788_BL_RAMP_RISE_SHIFT 4

	#define MAX_BRIGHTNESS 127
	#define DEFAULT_BL_NAME "lcd-backlight"

	struct lp8788_bl_config {
	enum lp8788_bl_ctrl_mode bl_mode;
	enum lp8788_bl_dim_mode dim_mode;
	enum lp8788_bl_full_scale_current full_scale;
	enum lp8788_bl_ramp_step rise_time;
	enum lp8788_bl_ramp_step fall_time;
	enum pwm_polarity pwm_pol;
	};

	struct lp8788_bl {
	struct lp8788 *lp;
	struct backlight_device *bl_dev;
	struct lp8788_backlight_platform_data *pdata;
	enum lp8788_bl_ctrl_mode mode;
	struct pwm_device *pwm;
	};

	static struct lp8788_bl_config default_bl_config = {
	.bl_mode = LP8788_BL_REGISTER_ONLY,
	.dim_mode = LP8788_DIM_EXPONENTIAL,
	.full_scale = LP8788_FULLSCALE_1900uA,
	.rise_time = LP8788_RAMP_8192us,
	.fall_time = LP8788_RAMP_8192us,
	.pwm_pol = PWM_POLARITY_NORMAL,
	};

	static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode)
	{
	return mode == LP8788_BL_COMB_PWM_BASED;
	}

	static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode)
	{
	return mode == LP8788_BL_REGISTER_ONLY \|\|
	mode == LP8788_BL_COMB_REGISTER_BASED;
	}

	static int lp8788_backlight_configure(struct lp8788_bl *bl)
	{
	struct lp8788_backlight_platform_data *pdata = bl->pdata;
	struct lp8788_bl_config *cfg = &default_bl_config;
	int ret;
	u8 val;

	/*
	* Update chip configuration if platform data exists,
	* otherwise use the default settings.
	*/
	if (pdata) {
	cfg->bl_mode = pdata->bl_mode;
	cfg->dim_mode = pdata->dim_mode;
	cfg->full_scale = pdata->full_scale;
	cfg->rise_time = pdata->rise_time;
	cfg->fall_time = pdata->fall_time;
	cfg->pwm_pol = pdata->pwm_pol;
	}

	/* Brightness ramp up/down */
	val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) \| cfg->fall_time;
	ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val);
	if (ret)
	return ret;

	/* Fullscale current setting */
	val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) \|
	(cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT);

	/* Brightness control mode */
	switch (cfg->bl_mode) {
	case LP8788_BL_REGISTER_ONLY:
	val \|= LP8788_BL_EN;
	break;
	case LP8788_BL_COMB_PWM_BASED:
	case LP8788_BL_COMB_REGISTER_BASED:
	val \|= LP8788_BL_EN \| LP8788_BL_PWM_INPUT_EN \|
	(cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT);
	break;
	default:
	dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode);
	return -EINVAL;
	}

	bl->mode = cfg->bl_mode;

	return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val);
	}

	static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br)
	{
	unsigned int period;
	unsigned int duty;
	struct device *dev;
	struct pwm_device *pwm;

	if (!bl->pdata)
	return;

	period = bl->pdata->period_ns;
	duty = br * period / max_br;
	dev = bl->lp->dev;

	/* request PWM device with the consumer name */
	if (!bl->pwm) {
	pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT);
	if (IS_ERR(pwm)) {
	dev_err(dev, "can not get PWM device\n");
	return;
	}

	bl->pwm = pwm;

	/*
	* FIXME: pwm_apply_args() should be removed when switching to
	* the atomic PWM API.
	*/
	pwm_apply_args(pwm);
	}

	pwm_config(bl->pwm, duty, period);
	if (duty)
	pwm_enable(bl->pwm);
	else
	pwm_disable(bl->pwm);
	}

	static int lp8788_bl_update_status(struct backlight_device *bl_dev)
	{
	struct lp8788_bl *bl = bl_get_data(bl_dev);
	enum lp8788_bl_ctrl_mode mode = bl->mode;

	if (bl_dev->props.state & BL_CORE_SUSPENDED)
	bl_dev->props.brightness = 0;

	if (is_brightness_ctrl_by_pwm(mode)) {
	int brt = bl_dev->props.brightness;
	int max = bl_dev->props.max_brightness;

	lp8788_pwm_ctrl(bl, brt, max);
	} else if (is_brightness_ctrl_by_register(mode)) {
	u8 brt = bl_dev->props.brightness;

	lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt);
	}

	return 0;
	}

	static const struct backlight_ops lp8788_bl_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = lp8788_bl_update_status,
	};

	static int lp8788_backlight_register(struct lp8788_bl *bl)
	{
	struct backlight_device *bl_dev;
	struct backlight_properties props;
	struct lp8788_backlight_platform_data *pdata = bl->pdata;
	int init_brt;
	char *name;

	props.type = BACKLIGHT_PLATFORM;
	props.max_brightness = MAX_BRIGHTNESS;

	/* Initial brightness */
	if (pdata)
	init_brt = min_t(int, pdata->initial_brightness,
	props.max_brightness);
	else
	init_brt = 0;

	props.brightness = init_brt;

	/* Backlight device name */
	if (!pdata \|\| !pdata->name)
	name = DEFAULT_BL_NAME;
	else
	name = pdata->name;

	bl_dev = backlight_device_register(name, bl->lp->dev, bl,
	&lp8788_bl_ops, &props);
	if (IS_ERR(bl_dev))
	return PTR_ERR(bl_dev);

	bl->bl_dev = bl_dev;

	return 0;
	}

	static void lp8788_backlight_unregister(struct lp8788_bl *bl)
	{
	struct backlight_device *bl_dev = bl->bl_dev;

	backlight_device_unregister(bl_dev);
	}

	static ssize_t lp8788_get_bl_ctl_mode(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct lp8788_bl *bl = dev_get_drvdata(dev);
	enum lp8788_bl_ctrl_mode mode = bl->mode;
	char *strmode;

	if (is_brightness_ctrl_by_pwm(mode))
	strmode = "PWM based";
	else if (is_brightness_ctrl_by_register(mode))
	strmode = "Register based";
	else
	strmode = "Invalid mode";

	return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
	}

	static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL);

	static struct attribute *lp8788_attributes[] = {
	&dev_attr_bl_ctl_mode.attr,
	NULL,
	};

	static const struct attribute_group lp8788_attr_group = {
	.attrs = lp8788_attributes,
	};

	static int lp8788_backlight_probe(struct platform_device *pdev)
	{
	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
	struct lp8788_bl *bl;
	int ret;

	bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL);
	if (!bl)
	return -ENOMEM;

	bl->lp = lp;
	if (lp->pdata)
	bl->pdata = lp->pdata->bl_pdata;

	platform_set_drvdata(pdev, bl);

	ret = lp8788_backlight_configure(bl);
	if (ret) {
	dev_err(lp->dev, "backlight config err: %d\n", ret);
	goto err_dev;
	}

	ret = lp8788_backlight_register(bl);
	if (ret) {
	dev_err(lp->dev, "register backlight err: %d\n", ret);
	goto err_dev;
	}

	ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group);
	if (ret) {
	dev_err(lp->dev, "register sysfs err: %d\n", ret);
	goto err_sysfs;
	}

	backlight_update_status(bl->bl_dev);

	return 0;

	err_sysfs:
	lp8788_backlight_unregister(bl);
	err_dev:
	return ret;
	}

	static int lp8788_backlight_remove(struct platform_device *pdev)
	{
	struct lp8788_bl *bl = platform_get_drvdata(pdev);
	struct backlight_device *bl_dev = bl->bl_dev;

	bl_dev->props.brightness = 0;
	backlight_update_status(bl_dev);
	sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group);
	lp8788_backlight_unregister(bl);

	return 0;
	}

	static struct platform_driver lp8788_bl_driver = {
	.probe = lp8788_backlight_probe,
	.remove = lp8788_backlight_remove,
	.driver = {
	.name = LP8788_DEV_BACKLIGHT,
	},
	};
	module_platform_driver(lp8788_bl_driver);

	MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver");
	MODULE_AUTHOR("Milo Kim");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:lp8788-backlight");