diff options
Diffstat (limited to 'drivers/video/backlight/lp855x_bl.c')
| -rw-r--r-- | drivers/video/backlight/lp855x_bl.c | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c new file mode 100644 index 0000000..bbedab5 --- /dev/null +++ b/drivers/video/backlight/lp855x_bl.c @@ -0,0 +1,466 @@ +/* + * TI LP855x Backlight Driver + * + * Copyright (C) 2011 Texas Instruments + * + * 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/module.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/backlight.h> +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/gpio.h> +#include <linux/platform_data/lp855x.h> +#ifdef CONFIG_HAS_EARLYSUSPEND +#include <linux/earlysuspend.h> +#endif + +/* Registers */ +#define BRIGHTNESS_CTRL 0x00 +#define DEVICE_CTRL 0x01 +#define EEPROM_START 0xA0 +#define EEPROM_END 0xA7 +#define EPROM_START 0xA0 +#define EPROM_END 0xAF + +#if defined(CONFIG_MACH_KONA) +#define EEPROM_CFG3 0xA3 +#define EEPROM_CFG5 0xA5 +#endif + +#define BUF_SIZE 20 +#define DEFAULT_BL_NAME "lcd-backlight" +#define MAX_BRIGHTNESS 255 + +struct lp855x { + const char *chipname; + enum lp855x_chip_id chip_id; + struct i2c_client *client; + struct backlight_device *bl; + struct device *dev; + struct mutex xfer_lock; + struct lp855x_platform_data *pdata; + int enabled; +#ifdef CONFIG_HAS_EARLYSUSPEND + struct early_suspend early_suspend; +#endif +}; + +static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data) +{ + int ret; + + mutex_lock(&lp->xfer_lock); + ret = i2c_smbus_read_byte_data(lp->client, reg); + if (ret < 0) { + mutex_unlock(&lp->xfer_lock); + dev_err(lp->dev, "failed to read 0x%.2x\n", reg); + return ret; + } + mutex_unlock(&lp->xfer_lock); + + *data = (u8)ret; + return 0; +} + +static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) +{ + int ret; + + mutex_lock(&lp->xfer_lock); + ret = i2c_smbus_write_byte_data(lp->client, reg, data); + mutex_unlock(&lp->xfer_lock); + + return ret; +} + +static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) +{ + u8 start, end; + + switch (lp->chip_id) { + case LP8550: + case LP8551: + case LP8552: + case LP8553: + start = EEPROM_START; + end = EEPROM_END; + break; + case LP8556: + start = EPROM_START; + end = EPROM_END; + break; + default: + return false; + } + + return (addr >= start && addr <= end); +} + +static int lp855x_init_registers(struct lp855x *lp) +{ + u8 val, addr, mask; + int i, ret; + struct lp855x_platform_data *pd = lp->pdata; + + val = pd->initial_brightness; + ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); + if (ret) + return ret; + + val = pd->device_control; + ret = lp855x_write_byte(lp, DEVICE_CTRL, val); + if (ret) + return ret; + + if (pd->load_new_rom_data && pd->size_program) { + for (i = 0; i < pd->size_program; i++) { + addr = pd->rom_data[i].addr; + val = pd->rom_data[i].val; + mask = pd->rom_data[i].mask; + if (!lp855x_is_valid_rom_area(lp, addr)) + continue; + + if (mask) { + u8 reg_val; + + ret = lp855x_read_byte(lp, addr, ®_val); + if (ret) + return ret; + val = (val & ~mask) | (reg_val & mask); + } + + ret = lp855x_write_byte(lp, addr, val); + if (ret) + return ret; + } + } + + return ret; +} + +static int lp855x_bl_update_status(struct backlight_device *bl) +{ + struct lp855x *lp = bl_get_data(bl); + enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; + int ret; + + if (bl->props.state & BL_CORE_SUSPENDED) + bl->props.brightness = 0; + + if (mode == PWM_BASED) { + struct lp855x_pwm_data *pd = &lp->pdata->pwm_data; + int br = bl->props.brightness; + int max_br = bl->props.max_brightness; + + if (pd->pwm_set_intensity) + pd->pwm_set_intensity(br, max_br); + + } else if (mode == REGISTER_BASED) { + u8 val = bl->props.brightness; + ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); + if (ret) + return ret; + } + + return 0; +} + +static int lp855x_bl_get_brightness(struct backlight_device *bl) +{ + struct lp855x *lp = bl_get_data(bl); + enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; + + if (mode == PWM_BASED) { + struct lp855x_pwm_data *pd = &lp->pdata->pwm_data; + int max_br = bl->props.max_brightness; + + if (pd->pwm_get_intensity) + bl->props.brightness = pd->pwm_get_intensity(max_br); + + } else if (mode == REGISTER_BASED) { + u8 val = 0; + + lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val); + bl->props.brightness = val; + } + + return bl->props.brightness; +} + +static const struct backlight_ops lp855x_bl_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = lp855x_bl_update_status, + .get_brightness = lp855x_bl_get_brightness, +}; + +static int lp855x_backlight_register(struct lp855x *lp) +{ + struct backlight_device *bl; + struct backlight_properties props; + struct lp855x_platform_data *pdata = lp->pdata; + char *name = pdata->name ? : DEFAULT_BL_NAME; + + props.type = BACKLIGHT_PLATFORM; + props.max_brightness = MAX_BRIGHTNESS; + + if (pdata->initial_brightness > props.max_brightness) + pdata->initial_brightness = props.max_brightness; + + props.brightness = pdata->initial_brightness; + + bl = backlight_device_register(name, lp->dev, lp, + &lp855x_bl_ops, &props); + if (IS_ERR(bl)) + return PTR_ERR(bl); + + lp->bl = bl; + + return 0; +} + +static void lp855x_backlight_unregister(struct lp855x *lp) +{ + if (lp->bl) + backlight_device_unregister(lp->bl); +} + +static ssize_t lp855x_get_chip_id(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct lp855x *lp = dev_get_drvdata(dev); + return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname); +} + +static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct lp855x *lp = dev_get_drvdata(dev); + enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; + char *strmode = NULL; + + if (mode == PWM_BASED) + strmode = "pwm based"; + else if (mode == REGISTER_BASED) + strmode = "register based"; + + return scnprintf(buf, BUF_SIZE, "%s\n", strmode); +} + +static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); +static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); + +static struct attribute *lp855x_attributes[] = { + &dev_attr_chip_id.attr, + &dev_attr_bl_ctl_mode.attr, + NULL, +}; + +static const struct attribute_group lp855x_attr_group = { + .attrs = lp855x_attributes, +}; + +static int lp855x_set_power(struct lp855x *lp, int on) +{ + unsigned long on_udelay = lp->pdata->power_on_udelay; + + pr_info("%s : %d\n", __func__, on); + + if (on) { + int ret = 0; + + gpio_set_value(lp->pdata->gpio_en, GPIO_LEVEL_HIGH); + usleep_range(on_udelay, on_udelay); + + ret = lp855x_init_registers(lp); + if (ret) + return ret; + } else { + gpio_set_value(lp->pdata->gpio_en, GPIO_LEVEL_LOW); + } + + lp->enabled = on; + + return 0; +} + +#if defined(CONFIG_MACH_KONA) +static int lp855x_config(struct lp855x *lp) +{ + u8 val; + int ret; + + /* DEVICE CONTROL: No FAST bit to prevent LP8556 register reset */ + ret = lp855x_write_byte(lp, DEVICE_CTRL, 0x81); + if (ret) + return ret; + + /* CFG3: SCURVE_EN is linear transitions, SLOPE = 200ms, + * FILTER = heavy smoothing, + * PWM_INPUT_HYSTERESIS = 1-bit hysteresis with 12-bit resolution + */ + ret = lp855x_write_byte(lp, EEPROM_CFG3, 0x5E); + if (ret) + return ret; + + /* CFG5: No PWM_DIRECT, PS_MODE from platform data, PWM_FREQ = 9616Hz */ + val = 0x2 << 4 | 0x04; + ret = lp855x_write_byte(lp, EEPROM_CFG5, val); + + if (ret) + return ret; + + return 0; + +} +#endif + +#ifdef CONFIG_HAS_EARLYSUSPEND +static void lp855x_early_suspend(struct early_suspend *h) +{ + struct lp855x *lp = + container_of(h, struct lp855x, early_suspend); + + lp855x_set_power(lp, 0); +} + +static void lp855x_late_resume(struct early_suspend *h) +{ + struct lp855x *lp = + container_of(h, struct lp855x, early_suspend); + + lp855x_set_power(lp, 1); + backlight_update_status(lp->bl); +#if defined(CONFIG_MACH_KONA) + lp855x_config(lp); +#endif + +} +#endif + +static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) +{ + struct lp855x *lp; + struct lp855x_platform_data *pdata = cl->dev.platform_data; + enum lp855x_brightness_ctrl_mode mode; + int ret; + + if (!pdata) { + dev_err(&cl->dev, "no platform data supplied\n"); + return -EINVAL; + } + + if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) + return -EIO; + + lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); + if (!lp) + return -ENOMEM; + + mode = pdata->mode; + lp->client = cl; + lp->dev = &cl->dev; + lp->pdata = pdata; + lp->chipname = id->name; + lp->chip_id = id->driver_data; + i2c_set_clientdata(cl, lp); + + mutex_init(&lp->xfer_lock); + + ret = lp855x_init_registers(lp); + if (ret) { + dev_err(lp->dev, "i2c communication err: %d", ret); + if (mode == REGISTER_BASED) + goto err_dev; + } + + lp->enabled = 1; +#ifdef CONFIG_HAS_EARLYSUSPEND + if (lp->pdata->use_gpio_en) { + lp->early_suspend.level = EARLY_SUSPEND_LEVEL_DISABLE_FB - 2; + lp->early_suspend.suspend = lp855x_early_suspend; + lp->early_suspend.resume = lp855x_late_resume; + register_early_suspend(&lp->early_suspend); + } +#endif + + ret = lp855x_backlight_register(lp); + if (ret) { + dev_err(lp->dev, + "failed to register backlight. err: %d\n", ret); + goto err_dev; + } + + ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); + if (ret) { + dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); + goto err_sysfs; + } + + backlight_update_status(lp->bl); + +#if defined(CONFIG_MACH_KONA) + lp855x_config(lp); +#endif + + return 0; + +err_sysfs: + lp855x_backlight_unregister(lp); +err_dev: + return ret; +} + +static int __devexit lp855x_remove(struct i2c_client *cl) +{ + struct lp855x *lp = i2c_get_clientdata(cl); + + lp->bl->props.brightness = 0; + backlight_update_status(lp->bl); + sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); + lp855x_backlight_unregister(lp); + + return 0; +} + +static const struct i2c_device_id lp855x_ids[] = { + {"lp8550", LP8550}, + {"lp8551", LP8551}, + {"lp8552", LP8552}, + {"lp8553", LP8553}, + {"lp8556", LP8556}, + { } +}; +MODULE_DEVICE_TABLE(i2c, lp855x_ids); + +static struct i2c_driver lp855x_driver = { + .driver = { + .name = "lp855x", + }, + .probe = lp855x_probe, + .remove = __devexit_p(lp855x_remove), + .id_table = lp855x_ids, +}; + +static int __init lp855x_init(void) +{ + return i2c_add_driver(&lp855x_driver); +} + +static void __exit lp855x_exit(void) +{ + i2c_del_driver(&lp855x_driver); +} + +module_init(lp855x_init); +module_exit(lp855x_exit); + +MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); +MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); +MODULE_LICENSE("GPL"); |