backlight: new backlight driver for LP855x devices
THis driver supports TI LP8550/LP8551/LP8552/LP8553/LP8556 backlight devices. The brightness can be controlled by the I2C or PWM input. The lp855x driver provides both modes. For the PWM control, pwm-specific functions can be defined in the platform data. And some information can be read via the sysfs(lp855x device attributes). For details, please refer to Documentation/backlight/lp855x-driver.txt. [axel.lin@gmail.com: add missing mutex_unlock in lp855x_read_byte() error path] [axel.lin@gmail.com: check platform data in lp855x_probe()] [axel.lin@gmail.com: small cleanups] [dan.carpenter@oracle.com: silence a compiler warning] [axel.lin@gmail.com: use id->driver_data to differentiate lp855x chips] [akpm@linux-foundation.org: simplify boolean return expression] Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com> Signed-off-by: Axel Lin <axel.lin@gmail.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kim, Milo
committed by
Linus Torvalds
Linus Torvalds
parent
050ea48bbf
commit
7be865ab86
331
drivers/video/backlight/lp855x_bl.c
Normal file
331
drivers/video/backlight/lp855x_bl.c
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/*
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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/lp855x.h>
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/* Registers */
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#define BRIGHTNESS_CTRL (0x00)
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#define DEVICE_CTRL (0x01)
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#define BUF_SIZE 20
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#define DEFAULT_BL_NAME "lcd-backlight"
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#define MAX_BRIGHTNESS 255
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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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struct i2c_client *client;
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struct backlight_device *bl;
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struct device *dev;
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struct mutex xfer_lock;
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struct lp855x_platform_data *pdata;
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};
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static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data)
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{
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int ret;
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mutex_lock(&lp->xfer_lock);
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ret = i2c_smbus_read_byte_data(lp->client, reg);
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if (ret < 0) {
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mutex_unlock(&lp->xfer_lock);
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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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mutex_unlock(&lp->xfer_lock);
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*data = (u8)ret;
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return 0;
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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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int ret;
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mutex_lock(&lp->xfer_lock);
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ret = i2c_smbus_write_byte_data(lp->client, reg, data);
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mutex_unlock(&lp->xfer_lock);
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return ret;
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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 = EEPROM_START;
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end = EEPROM_END;
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break;
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case LP8556:
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start = EPROM_START;
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end = 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 lp855x_init_registers(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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val = pd->initial_brightness;
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ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
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if (ret)
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return ret;
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val = pd->device_control;
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ret = lp855x_write_byte(lp, DEVICE_CTRL, val);
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if (ret)
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return ret;
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if (pd->load_new_rom_data && pd->size_program) {
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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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return ret;
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}
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}
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return ret;
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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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enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
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if (bl->props.state & BL_CORE_SUSPENDED)
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bl->props.brightness = 0;
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if (mode == PWM_BASED) {
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struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
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int br = bl->props.brightness;
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int max_br = bl->props.max_brightness;
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if (pd->pwm_set_intensity)
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pd->pwm_set_intensity(br, max_br);
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} else if (mode == REGISTER_BASED) {
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u8 val = bl->props.brightness;
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lp855x_write_byte(lp, BRIGHTNESS_CTRL, 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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struct lp855x *lp = bl_get_data(bl);
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enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
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if (mode == PWM_BASED) {
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struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
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int max_br = bl->props.max_brightness;
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if (pd->pwm_get_intensity)
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bl->props.brightness = pd->pwm_get_intensity(max_br);
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} else if (mode == REGISTER_BASED) {
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u8 val = 0;
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lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);
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bl->props.brightness = val;
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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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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, BUF_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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enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
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char *strmode = NULL;
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if (mode == PWM_BASED)
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strmode = "pwm based";
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else if (mode == REGISTER_BASED)
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strmode = "register based";
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return scnprintf(buf, BUF_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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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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enum lp855x_brightness_ctrl_mode mode;
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int ret;
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if (!pdata) {
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dev_err(&cl->dev, "no platform data supplied\n");
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return -EINVAL;
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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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mode = pdata->mode;
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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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mutex_init(&lp->xfer_lock);
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ret = lp855x_init_registers(lp);
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if (ret) {
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dev_err(lp->dev, "i2c communication err: %d", ret);
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if (mode == REGISTER_BASED)
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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 __devexit 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 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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{ }
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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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},
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.probe = lp855x_probe,
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.remove = __devexit_p(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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