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326 lines
7.5 KiB
326 lines
7.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* TI LP8788 MFD - backlight driver |
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* |
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* Copyright 2012 Texas Instruments |
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* |
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* Author: Milo(Woogyom) Kim <[email protected]> |
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*/ |
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#include <linux/backlight.h> |
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#include <linux/err.h> |
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#include <linux/mfd/lp8788.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/pwm.h> |
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#include <linux/slab.h> |
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/* Register address */ |
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#define LP8788_BL_CONFIG 0x96 |
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#define LP8788_BL_EN BIT(0) |
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#define LP8788_BL_PWM_INPUT_EN BIT(5) |
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#define LP8788_BL_FULLSCALE_SHIFT 2 |
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#define LP8788_BL_DIM_MODE_SHIFT 1 |
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#define LP8788_BL_PWM_POLARITY_SHIFT 6 |
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#define LP8788_BL_BRIGHTNESS 0x97 |
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#define LP8788_BL_RAMP 0x98 |
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#define LP8788_BL_RAMP_RISE_SHIFT 4 |
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#define MAX_BRIGHTNESS 127 |
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#define DEFAULT_BL_NAME "lcd-backlight" |
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struct lp8788_bl_config { |
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enum lp8788_bl_ctrl_mode bl_mode; |
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enum lp8788_bl_dim_mode dim_mode; |
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enum lp8788_bl_full_scale_current full_scale; |
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enum lp8788_bl_ramp_step rise_time; |
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enum lp8788_bl_ramp_step fall_time; |
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enum pwm_polarity pwm_pol; |
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}; |
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struct lp8788_bl { |
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struct lp8788 *lp; |
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struct backlight_device *bl_dev; |
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struct lp8788_backlight_platform_data *pdata; |
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enum lp8788_bl_ctrl_mode mode; |
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struct pwm_device *pwm; |
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}; |
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static struct lp8788_bl_config default_bl_config = { |
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.bl_mode = LP8788_BL_REGISTER_ONLY, |
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.dim_mode = LP8788_DIM_EXPONENTIAL, |
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.full_scale = LP8788_FULLSCALE_1900uA, |
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.rise_time = LP8788_RAMP_8192us, |
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.fall_time = LP8788_RAMP_8192us, |
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.pwm_pol = PWM_POLARITY_NORMAL, |
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}; |
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static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode) |
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{ |
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return mode == LP8788_BL_COMB_PWM_BASED; |
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} |
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static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode) |
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{ |
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return mode == LP8788_BL_REGISTER_ONLY || |
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mode == LP8788_BL_COMB_REGISTER_BASED; |
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} |
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static int lp8788_backlight_configure(struct lp8788_bl *bl) |
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{ |
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struct lp8788_backlight_platform_data *pdata = bl->pdata; |
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struct lp8788_bl_config *cfg = &default_bl_config; |
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int ret; |
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u8 val; |
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/* |
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* Update chip configuration if platform data exists, |
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* otherwise use the default settings. |
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*/ |
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if (pdata) { |
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cfg->bl_mode = pdata->bl_mode; |
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cfg->dim_mode = pdata->dim_mode; |
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cfg->full_scale = pdata->full_scale; |
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cfg->rise_time = pdata->rise_time; |
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cfg->fall_time = pdata->fall_time; |
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cfg->pwm_pol = pdata->pwm_pol; |
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} |
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/* Brightness ramp up/down */ |
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val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time; |
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ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val); |
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if (ret) |
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return ret; |
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/* Fullscale current setting */ |
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val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) | |
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(cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT); |
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/* Brightness control mode */ |
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switch (cfg->bl_mode) { |
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case LP8788_BL_REGISTER_ONLY: |
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val |= LP8788_BL_EN; |
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break; |
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case LP8788_BL_COMB_PWM_BASED: |
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case LP8788_BL_COMB_REGISTER_BASED: |
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val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN | |
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(cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT); |
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break; |
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default: |
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dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode); |
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return -EINVAL; |
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} |
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bl->mode = cfg->bl_mode; |
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return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val); |
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} |
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static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br) |
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{ |
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unsigned int period; |
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unsigned int duty; |
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struct device *dev; |
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struct pwm_device *pwm; |
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if (!bl->pdata) |
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return; |
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period = bl->pdata->period_ns; |
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duty = br * period / max_br; |
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dev = bl->lp->dev; |
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/* request PWM device with the consumer name */ |
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if (!bl->pwm) { |
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pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT); |
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if (IS_ERR(pwm)) { |
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dev_err(dev, "can not get PWM device\n"); |
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return; |
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} |
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bl->pwm = pwm; |
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/* |
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* FIXME: pwm_apply_args() should be removed when switching to |
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* the atomic PWM API. |
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*/ |
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pwm_apply_args(pwm); |
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} |
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pwm_config(bl->pwm, duty, period); |
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if (duty) |
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pwm_enable(bl->pwm); |
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else |
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pwm_disable(bl->pwm); |
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} |
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static int lp8788_bl_update_status(struct backlight_device *bl_dev) |
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{ |
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struct lp8788_bl *bl = bl_get_data(bl_dev); |
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enum lp8788_bl_ctrl_mode mode = bl->mode; |
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if (bl_dev->props.state & BL_CORE_SUSPENDED) |
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bl_dev->props.brightness = 0; |
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if (is_brightness_ctrl_by_pwm(mode)) { |
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int brt = bl_dev->props.brightness; |
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int max = bl_dev->props.max_brightness; |
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lp8788_pwm_ctrl(bl, brt, max); |
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} else if (is_brightness_ctrl_by_register(mode)) { |
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u8 brt = bl_dev->props.brightness; |
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lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt); |
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} |
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return 0; |
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} |
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static const struct backlight_ops lp8788_bl_ops = { |
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.options = BL_CORE_SUSPENDRESUME, |
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.update_status = lp8788_bl_update_status, |
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}; |
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static int lp8788_backlight_register(struct lp8788_bl *bl) |
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{ |
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struct backlight_device *bl_dev; |
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struct backlight_properties props; |
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struct lp8788_backlight_platform_data *pdata = bl->pdata; |
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int init_brt; |
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char *name; |
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props.type = BACKLIGHT_PLATFORM; |
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props.max_brightness = MAX_BRIGHTNESS; |
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/* Initial brightness */ |
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if (pdata) |
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init_brt = min_t(int, pdata->initial_brightness, |
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props.max_brightness); |
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else |
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init_brt = 0; |
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props.brightness = init_brt; |
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/* Backlight device name */ |
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if (!pdata || !pdata->name) |
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name = DEFAULT_BL_NAME; |
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else |
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name = pdata->name; |
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bl_dev = backlight_device_register(name, bl->lp->dev, bl, |
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&lp8788_bl_ops, &props); |
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if (IS_ERR(bl_dev)) |
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return PTR_ERR(bl_dev); |
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bl->bl_dev = bl_dev; |
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return 0; |
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} |
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static void lp8788_backlight_unregister(struct lp8788_bl *bl) |
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{ |
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struct backlight_device *bl_dev = bl->bl_dev; |
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backlight_device_unregister(bl_dev); |
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} |
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static ssize_t lp8788_get_bl_ctl_mode(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct lp8788_bl *bl = dev_get_drvdata(dev); |
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enum lp8788_bl_ctrl_mode mode = bl->mode; |
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char *strmode; |
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if (is_brightness_ctrl_by_pwm(mode)) |
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strmode = "PWM based"; |
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else if (is_brightness_ctrl_by_register(mode)) |
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strmode = "Register based"; |
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else |
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strmode = "Invalid mode"; |
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return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); |
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} |
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static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL); |
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static struct attribute *lp8788_attributes[] = { |
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&dev_attr_bl_ctl_mode.attr, |
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NULL, |
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}; |
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static const struct attribute_group lp8788_attr_group = { |
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.attrs = lp8788_attributes, |
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}; |
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static int lp8788_backlight_probe(struct platform_device *pdev) |
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{ |
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struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent); |
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struct lp8788_bl *bl; |
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int ret; |
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bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL); |
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if (!bl) |
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return -ENOMEM; |
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bl->lp = lp; |
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if (lp->pdata) |
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bl->pdata = lp->pdata->bl_pdata; |
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platform_set_drvdata(pdev, bl); |
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ret = lp8788_backlight_configure(bl); |
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if (ret) { |
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dev_err(lp->dev, "backlight config err: %d\n", ret); |
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goto err_dev; |
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} |
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ret = lp8788_backlight_register(bl); |
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if (ret) { |
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dev_err(lp->dev, "register backlight err: %d\n", ret); |
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goto err_dev; |
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} |
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ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group); |
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if (ret) { |
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dev_err(lp->dev, "register sysfs err: %d\n", ret); |
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goto err_sysfs; |
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} |
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backlight_update_status(bl->bl_dev); |
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return 0; |
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err_sysfs: |
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lp8788_backlight_unregister(bl); |
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err_dev: |
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return ret; |
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} |
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static int lp8788_backlight_remove(struct platform_device *pdev) |
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{ |
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struct lp8788_bl *bl = platform_get_drvdata(pdev); |
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struct backlight_device *bl_dev = bl->bl_dev; |
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bl_dev->props.brightness = 0; |
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backlight_update_status(bl_dev); |
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sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group); |
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lp8788_backlight_unregister(bl); |
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return 0; |
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} |
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static struct platform_driver lp8788_bl_driver = { |
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.probe = lp8788_backlight_probe, |
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.remove = lp8788_backlight_remove, |
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.driver = { |
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.name = LP8788_DEV_BACKLIGHT, |
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}, |
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}; |
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module_platform_driver(lp8788_bl_driver); |
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MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver"); |
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MODULE_AUTHOR("Milo Kim"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:lp8788-backlight");
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