505 lines
11 KiB
C
505 lines
11 KiB
C
/*
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* TI LP855x Backlight Driver
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*
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* Copyright (C) 2011 Texas Instruments
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/backlight.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/platform_data/lp855x.h>
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#include <linux/pwm.h>
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/* LP8550/1/2/3/6 Registers */
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#define LP855X_BRIGHTNESS_CTRL 0x00
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#define LP855X_DEVICE_CTRL 0x01
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#define LP855X_EEPROM_START 0xA0
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#define LP855X_EEPROM_END 0xA7
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#define LP8556_EPROM_START 0xA0
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#define LP8556_EPROM_END 0xAF
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/* LP8557 Registers */
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#define LP8557_BL_CMD 0x00
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#define LP8557_BL_MASK 0x01
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#define LP8557_BL_ON 0x01
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#define LP8557_BL_OFF 0x00
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#define LP8557_BRIGHTNESS_CTRL 0x04
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#define LP8557_CONFIG 0x10
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#define LP8557_EPROM_START 0x10
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#define LP8557_EPROM_END 0x1E
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#define DEFAULT_BL_NAME "lcd-backlight"
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#define MAX_BRIGHTNESS 255
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enum lp855x_brightness_ctrl_mode {
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PWM_BASED = 1,
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REGISTER_BASED,
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};
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struct lp855x;
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/*
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* struct lp855x_device_config
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* @pre_init_device: init device function call before updating the brightness
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* @reg_brightness: register address for brigthenss control
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* @reg_devicectrl: register address for device control
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* @post_init_device: late init device function call
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*/
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struct lp855x_device_config {
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int (*pre_init_device)(struct lp855x *);
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u8 reg_brightness;
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u8 reg_devicectrl;
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int (*post_init_device)(struct lp855x *);
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};
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struct lp855x {
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const char *chipname;
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enum lp855x_chip_id chip_id;
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enum lp855x_brightness_ctrl_mode mode;
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struct lp855x_device_config *cfg;
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struct i2c_client *client;
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struct backlight_device *bl;
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struct device *dev;
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struct lp855x_platform_data *pdata;
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struct pwm_device *pwm;
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};
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static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
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{
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return i2c_smbus_write_byte_data(lp->client, reg, data);
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}
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static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
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{
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int ret;
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u8 tmp;
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ret = i2c_smbus_read_byte_data(lp->client, reg);
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if (ret < 0) {
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dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
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return ret;
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}
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tmp = (u8)ret;
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tmp &= ~mask;
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tmp |= data & mask;
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return lp855x_write_byte(lp, reg, tmp);
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}
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static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
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{
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u8 start, end;
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switch (lp->chip_id) {
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case LP8550:
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case LP8551:
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case LP8552:
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case LP8553:
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start = LP855X_EEPROM_START;
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end = LP855X_EEPROM_END;
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break;
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case LP8556:
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start = LP8556_EPROM_START;
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end = LP8556_EPROM_END;
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break;
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case LP8557:
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start = LP8557_EPROM_START;
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end = LP8557_EPROM_END;
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break;
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default:
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return false;
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}
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return (addr >= start && addr <= end);
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}
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static int lp8557_bl_off(struct lp855x *lp)
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{
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/* BL_ON = 0 before updating EPROM settings */
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return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
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LP8557_BL_OFF);
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}
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static int lp8557_bl_on(struct lp855x *lp)
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{
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/* BL_ON = 1 after updating EPROM settings */
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return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
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LP8557_BL_ON);
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}
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static struct lp855x_device_config lp855x_dev_cfg = {
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.reg_brightness = LP855X_BRIGHTNESS_CTRL,
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.reg_devicectrl = LP855X_DEVICE_CTRL,
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};
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static struct lp855x_device_config lp8557_dev_cfg = {
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.reg_brightness = LP8557_BRIGHTNESS_CTRL,
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.reg_devicectrl = LP8557_CONFIG,
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.pre_init_device = lp8557_bl_off,
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.post_init_device = lp8557_bl_on,
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};
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/*
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* Device specific configuration flow
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*
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* a) pre_init_device(optional)
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* b) update the brightness register
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* c) update device control register
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* d) update ROM area(optional)
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* e) post_init_device(optional)
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*
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*/
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static int lp855x_configure(struct lp855x *lp)
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{
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u8 val, addr;
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int i, ret;
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struct lp855x_platform_data *pd = lp->pdata;
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switch (lp->chip_id) {
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case LP8550 ... LP8556:
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lp->cfg = &lp855x_dev_cfg;
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break;
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case LP8557:
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lp->cfg = &lp8557_dev_cfg;
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break;
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default:
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return -EINVAL;
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}
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if (lp->cfg->pre_init_device) {
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ret = lp->cfg->pre_init_device(lp);
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if (ret) {
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dev_err(lp->dev, "pre init device err: %d\n", ret);
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goto err;
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}
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}
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val = pd->initial_brightness;
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ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
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if (ret)
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goto err;
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val = pd->device_control;
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ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
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if (ret)
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goto err;
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if (pd->size_program > 0) {
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for (i = 0; i < pd->size_program; i++) {
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addr = pd->rom_data[i].addr;
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val = pd->rom_data[i].val;
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if (!lp855x_is_valid_rom_area(lp, addr))
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continue;
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ret = lp855x_write_byte(lp, addr, val);
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if (ret)
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goto err;
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}
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}
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if (lp->cfg->post_init_device) {
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ret = lp->cfg->post_init_device(lp);
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if (ret) {
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dev_err(lp->dev, "post init device err: %d\n", ret);
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goto err;
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}
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}
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return 0;
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err:
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return ret;
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}
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static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
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{
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unsigned int period = lp->pdata->period_ns;
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unsigned int duty = br * period / max_br;
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struct pwm_device *pwm;
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/* request pwm device with the consumer name */
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if (!lp->pwm) {
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pwm = devm_pwm_get(lp->dev, lp->chipname);
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if (IS_ERR(pwm))
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return;
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lp->pwm = pwm;
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}
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pwm_config(lp->pwm, duty, period);
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if (duty)
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pwm_enable(lp->pwm);
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else
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pwm_disable(lp->pwm);
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}
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static int lp855x_bl_update_status(struct backlight_device *bl)
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{
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struct lp855x *lp = bl_get_data(bl);
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if (bl->props.state & BL_CORE_SUSPENDED)
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bl->props.brightness = 0;
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if (lp->mode == PWM_BASED) {
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int br = bl->props.brightness;
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int max_br = bl->props.max_brightness;
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lp855x_pwm_ctrl(lp, br, max_br);
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} else if (lp->mode == REGISTER_BASED) {
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u8 val = bl->props.brightness;
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lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
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}
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return 0;
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}
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static int lp855x_bl_get_brightness(struct backlight_device *bl)
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{
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return bl->props.brightness;
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}
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static const struct backlight_ops lp855x_bl_ops = {
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.options = BL_CORE_SUSPENDRESUME,
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.update_status = lp855x_bl_update_status,
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.get_brightness = lp855x_bl_get_brightness,
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};
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static int lp855x_backlight_register(struct lp855x *lp)
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{
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struct backlight_device *bl;
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struct backlight_properties props;
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struct lp855x_platform_data *pdata = lp->pdata;
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const char *name = pdata->name ? : DEFAULT_BL_NAME;
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props.type = BACKLIGHT_PLATFORM;
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props.max_brightness = MAX_BRIGHTNESS;
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if (pdata->initial_brightness > props.max_brightness)
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pdata->initial_brightness = props.max_brightness;
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props.brightness = pdata->initial_brightness;
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bl = backlight_device_register(name, lp->dev, lp,
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&lp855x_bl_ops, &props);
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if (IS_ERR(bl))
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return PTR_ERR(bl);
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lp->bl = bl;
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return 0;
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}
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static void lp855x_backlight_unregister(struct lp855x *lp)
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{
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if (lp->bl)
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backlight_device_unregister(lp->bl);
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}
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static ssize_t lp855x_get_chip_id(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct lp855x *lp = dev_get_drvdata(dev);
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return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
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}
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static ssize_t lp855x_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 lp855x *lp = dev_get_drvdata(dev);
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char *strmode = NULL;
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if (lp->mode == PWM_BASED)
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strmode = "pwm based";
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else if (lp->mode == REGISTER_BASED)
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strmode = "register based";
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return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
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}
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static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
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static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
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static struct attribute *lp855x_attributes[] = {
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&dev_attr_chip_id.attr,
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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 lp855x_attr_group = {
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.attrs = lp855x_attributes,
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};
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#ifdef CONFIG_OF
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static int lp855x_parse_dt(struct device *dev, struct device_node *node)
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{
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struct lp855x_platform_data *pdata;
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int rom_length;
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if (!node) {
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dev_err(dev, "no platform data\n");
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return -EINVAL;
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}
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pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata)
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return -ENOMEM;
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of_property_read_string(node, "bl-name", &pdata->name);
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of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
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of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
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of_property_read_u32(node, "pwm-period", &pdata->period_ns);
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/* Fill ROM platform data if defined */
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rom_length = of_get_child_count(node);
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if (rom_length > 0) {
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struct lp855x_rom_data *rom;
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struct device_node *child;
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int i = 0;
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rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
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if (!rom)
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return -ENOMEM;
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for_each_child_of_node(node, child) {
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of_property_read_u8(child, "rom-addr", &rom[i].addr);
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of_property_read_u8(child, "rom-val", &rom[i].val);
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i++;
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}
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pdata->size_program = rom_length;
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pdata->rom_data = &rom[0];
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}
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dev->platform_data = pdata;
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return 0;
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}
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#else
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static int lp855x_parse_dt(struct device *dev, struct device_node *node)
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{
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return -EINVAL;
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}
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#endif
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static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
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{
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struct lp855x *lp;
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struct lp855x_platform_data *pdata = cl->dev.platform_data;
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struct device_node *node = cl->dev.of_node;
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int ret;
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if (!pdata) {
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ret = lp855x_parse_dt(&cl->dev, node);
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if (ret < 0)
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return ret;
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pdata = cl->dev.platform_data;
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}
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if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
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return -EIO;
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lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
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if (!lp)
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return -ENOMEM;
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if (pdata->period_ns > 0)
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lp->mode = PWM_BASED;
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else
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lp->mode = REGISTER_BASED;
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lp->client = cl;
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lp->dev = &cl->dev;
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lp->pdata = pdata;
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lp->chipname = id->name;
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lp->chip_id = id->driver_data;
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i2c_set_clientdata(cl, lp);
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ret = lp855x_configure(lp);
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if (ret) {
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dev_err(lp->dev, "device config err: %d", ret);
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goto err_dev;
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}
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ret = lp855x_backlight_register(lp);
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if (ret) {
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dev_err(lp->dev,
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"failed to 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(&lp->dev->kobj, &lp855x_attr_group);
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if (ret) {
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dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
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goto err_sysfs;
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}
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backlight_update_status(lp->bl);
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return 0;
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err_sysfs:
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lp855x_backlight_unregister(lp);
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err_dev:
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return ret;
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}
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static int lp855x_remove(struct i2c_client *cl)
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{
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struct lp855x *lp = i2c_get_clientdata(cl);
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lp->bl->props.brightness = 0;
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backlight_update_status(lp->bl);
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sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
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lp855x_backlight_unregister(lp);
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return 0;
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}
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static const struct of_device_id lp855x_dt_ids[] = {
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{ .compatible = "ti,lp8550", },
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{ .compatible = "ti,lp8551", },
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{ .compatible = "ti,lp8552", },
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{ .compatible = "ti,lp8553", },
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{ .compatible = "ti,lp8556", },
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{ .compatible = "ti,lp8557", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
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static const struct i2c_device_id lp855x_ids[] = {
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{"lp8550", LP8550},
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{"lp8551", LP8551},
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{"lp8552", LP8552},
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{"lp8553", LP8553},
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{"lp8556", LP8556},
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{"lp8557", LP8557},
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, lp855x_ids);
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static struct i2c_driver lp855x_driver = {
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.driver = {
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.name = "lp855x",
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.of_match_table = of_match_ptr(lp855x_dt_ids),
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},
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.probe = lp855x_probe,
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.remove = lp855x_remove,
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.id_table = lp855x_ids,
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};
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module_i2c_driver(lp855x_driver);
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MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
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MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
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MODULE_LICENSE("GPL");
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