diff options
Diffstat (limited to 'drivers/video/backlight/lp855x_bl.c')
| -rw-r--r-- | drivers/video/backlight/lp855x_bl.c | 557 |
1 files changed, 557 insertions, 0 deletions
diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c new file mode 100644 index 000000000..e94932c69 --- /dev/null +++ b/drivers/video/backlight/lp855x_bl.c @@ -0,0 +1,557 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * TI LP855x Backlight Driver + * + * Copyright (C) 2011 Texas Instruments + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/backlight.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/platform_data/lp855x.h> +#include <linux/pwm.h> +#include <linux/regulator/consumer.h> + +/* LP8550/1/2/3/6 Registers */ +#define LP855X_BRIGHTNESS_CTRL 0x00 +#define LP855X_DEVICE_CTRL 0x01 +#define LP855X_EEPROM_START 0xA0 +#define LP855X_EEPROM_END 0xA7 +#define LP8556_EPROM_START 0xA0 +#define LP8556_EPROM_END 0xAF + +/* LP8555/7 Registers */ +#define LP8557_BL_CMD 0x00 +#define LP8557_BL_MASK 0x01 +#define LP8557_BL_ON 0x01 +#define LP8557_BL_OFF 0x00 +#define LP8557_BRIGHTNESS_CTRL 0x04 +#define LP8557_CONFIG 0x10 +#define LP8555_EPROM_START 0x10 +#define LP8555_EPROM_END 0x7A +#define LP8557_EPROM_START 0x10 +#define LP8557_EPROM_END 0x1E + +#define DEFAULT_BL_NAME "lcd-backlight" +#define MAX_BRIGHTNESS 255 + +enum lp855x_brightness_ctrl_mode { + PWM_BASED = 1, + REGISTER_BASED, +}; + +struct lp855x; + +/* + * struct lp855x_device_config + * @pre_init_device: init device function call before updating the brightness + * @reg_brightness: register address for brigthenss control + * @reg_devicectrl: register address for device control + * @post_init_device: late init device function call + */ +struct lp855x_device_config { + int (*pre_init_device)(struct lp855x *); + u8 reg_brightness; + u8 reg_devicectrl; + int (*post_init_device)(struct lp855x *); +}; + +struct lp855x { + const char *chipname; + enum lp855x_chip_id chip_id; + enum lp855x_brightness_ctrl_mode mode; + struct lp855x_device_config *cfg; + struct i2c_client *client; + struct backlight_device *bl; + struct device *dev; + struct lp855x_platform_data *pdata; + struct pwm_device *pwm; + struct regulator *supply; /* regulator for VDD input */ + struct regulator *enable; /* regulator for EN/VDDIO input */ +}; + +static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) +{ + return i2c_smbus_write_byte_data(lp->client, reg, data); +} + +static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data) +{ + int ret; + u8 tmp; + + ret = i2c_smbus_read_byte_data(lp->client, reg); + if (ret < 0) { + dev_err(lp->dev, "failed to read 0x%.2x\n", reg); + return ret; + } + + tmp = (u8)ret; + tmp &= ~mask; + tmp |= data & mask; + + return lp855x_write_byte(lp, reg, tmp); +} + +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 = LP855X_EEPROM_START; + end = LP855X_EEPROM_END; + break; + case LP8556: + start = LP8556_EPROM_START; + end = LP8556_EPROM_END; + break; + case LP8555: + start = LP8555_EPROM_START; + end = LP8555_EPROM_END; + break; + case LP8557: + start = LP8557_EPROM_START; + end = LP8557_EPROM_END; + break; + default: + return false; + } + + return addr >= start && addr <= end; +} + +static int lp8557_bl_off(struct lp855x *lp) +{ + /* BL_ON = 0 before updating EPROM settings */ + return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, + LP8557_BL_OFF); +} + +static int lp8557_bl_on(struct lp855x *lp) +{ + /* BL_ON = 1 after updating EPROM settings */ + return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, + LP8557_BL_ON); +} + +static struct lp855x_device_config lp855x_dev_cfg = { + .reg_brightness = LP855X_BRIGHTNESS_CTRL, + .reg_devicectrl = LP855X_DEVICE_CTRL, +}; + +static struct lp855x_device_config lp8557_dev_cfg = { + .reg_brightness = LP8557_BRIGHTNESS_CTRL, + .reg_devicectrl = LP8557_CONFIG, + .pre_init_device = lp8557_bl_off, + .post_init_device = lp8557_bl_on, +}; + +/* + * Device specific configuration flow + * + * a) pre_init_device(optional) + * b) update the brightness register + * c) update device control register + * d) update ROM area(optional) + * e) post_init_device(optional) + * + */ +static int lp855x_configure(struct lp855x *lp) +{ + u8 val, addr; + int i, ret; + struct lp855x_platform_data *pd = lp->pdata; + + switch (lp->chip_id) { + case LP8550: + case LP8551: + case LP8552: + case LP8553: + case LP8556: + lp->cfg = &lp855x_dev_cfg; + break; + case LP8555: + case LP8557: + lp->cfg = &lp8557_dev_cfg; + break; + default: + return -EINVAL; + } + + if (lp->cfg->pre_init_device) { + ret = lp->cfg->pre_init_device(lp); + if (ret) { + dev_err(lp->dev, "pre init device err: %d\n", ret); + goto err; + } + } + + val = pd->initial_brightness; + ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val); + if (ret) + goto err; + + val = pd->device_control; + ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val); + if (ret) + goto err; + + if (pd->size_program > 0) { + for (i = 0; i < pd->size_program; i++) { + addr = pd->rom_data[i].addr; + val = pd->rom_data[i].val; + if (!lp855x_is_valid_rom_area(lp, addr)) + continue; + + ret = lp855x_write_byte(lp, addr, val); + if (ret) + goto err; + } + } + + if (lp->cfg->post_init_device) { + ret = lp->cfg->post_init_device(lp); + if (ret) { + dev_err(lp->dev, "post init device err: %d\n", ret); + goto err; + } + } + + return 0; + +err: + return ret; +} + +static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) +{ + unsigned int period = lp->pdata->period_ns; + unsigned int duty = br * period / max_br; + struct pwm_device *pwm; + + /* request pwm device with the consumer name */ + if (!lp->pwm) { + pwm = devm_pwm_get(lp->dev, lp->chipname); + if (IS_ERR(pwm)) + return; + + lp->pwm = pwm; + + /* + * FIXME: pwm_apply_args() should be removed when switching to + * the atomic PWM API. + */ + pwm_apply_args(pwm); + } + + pwm_config(lp->pwm, duty, period); + if (duty) + pwm_enable(lp->pwm); + else + pwm_disable(lp->pwm); +} + +static int lp855x_bl_update_status(struct backlight_device *bl) +{ + struct lp855x *lp = bl_get_data(bl); + int brightness = bl->props.brightness; + + if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) + brightness = 0; + + if (lp->mode == PWM_BASED) + lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness); + else if (lp->mode == REGISTER_BASED) + lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness); + + return 0; +} + +static const struct backlight_ops lp855x_bl_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = lp855x_bl_update_status, +}; + +static int lp855x_backlight_register(struct lp855x *lp) +{ + struct backlight_device *bl; + struct backlight_properties props; + struct lp855x_platform_data *pdata = lp->pdata; + const char *name = pdata->name ? : DEFAULT_BL_NAME; + + memset(&props, 0, sizeof(props)); + 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 = devm_backlight_device_register(lp->dev, name, lp->dev, lp, + &lp855x_bl_ops, &props); + if (IS_ERR(bl)) + return PTR_ERR(bl); + + lp->bl = bl; + + return 0; +} + +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, PAGE_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); + char *strmode = NULL; + + if (lp->mode == PWM_BASED) + strmode = "pwm based"; + else if (lp->mode == REGISTER_BASED) + strmode = "register based"; + + return scnprintf(buf, PAGE_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, +}; + +#ifdef CONFIG_OF +static int lp855x_parse_dt(struct lp855x *lp) +{ + struct device *dev = lp->dev; + struct device_node *node = dev->of_node; + struct lp855x_platform_data *pdata; + int rom_length; + + if (!node) { + dev_err(dev, "no platform data\n"); + return -EINVAL; + } + + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + of_property_read_string(node, "bl-name", &pdata->name); + of_property_read_u8(node, "dev-ctrl", &pdata->device_control); + of_property_read_u8(node, "init-brt", &pdata->initial_brightness); + of_property_read_u32(node, "pwm-period", &pdata->period_ns); + + /* Fill ROM platform data if defined */ + rom_length = of_get_child_count(node); + if (rom_length > 0) { + struct lp855x_rom_data *rom; + struct device_node *child; + int i = 0; + + rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL); + if (!rom) + return -ENOMEM; + + for_each_child_of_node(node, child) { + of_property_read_u8(child, "rom-addr", &rom[i].addr); + of_property_read_u8(child, "rom-val", &rom[i].val); + i++; + } + + pdata->size_program = rom_length; + pdata->rom_data = &rom[0]; + } + + lp->pdata = pdata; + + return 0; +} +#else +static int lp855x_parse_dt(struct lp855x *lp) +{ + return -EINVAL; +} +#endif + +static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) +{ + struct lp855x *lp; + int ret; + + 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; + + lp->client = cl; + lp->dev = &cl->dev; + lp->chipname = id->name; + lp->chip_id = id->driver_data; + lp->pdata = dev_get_platdata(&cl->dev); + + if (!lp->pdata) { + ret = lp855x_parse_dt(lp); + if (ret < 0) + return ret; + } + + if (lp->pdata->period_ns > 0) + lp->mode = PWM_BASED; + else + lp->mode = REGISTER_BASED; + + lp->supply = devm_regulator_get(lp->dev, "power"); + if (IS_ERR(lp->supply)) { + if (PTR_ERR(lp->supply) == -EPROBE_DEFER) + return -EPROBE_DEFER; + lp->supply = NULL; + } + + lp->enable = devm_regulator_get_optional(lp->dev, "enable"); + if (IS_ERR(lp->enable)) { + ret = PTR_ERR(lp->enable); + if (ret == -ENODEV) { + lp->enable = NULL; + } else { + if (ret != -EPROBE_DEFER) + dev_err(lp->dev, "error getting enable regulator: %d\n", + ret); + return ret; + } + } + + if (lp->supply) { + ret = regulator_enable(lp->supply); + if (ret < 0) { + dev_err(&cl->dev, "failed to enable supply: %d\n", ret); + return ret; + } + } + + if (lp->enable) { + ret = regulator_enable(lp->enable); + if (ret < 0) { + dev_err(lp->dev, "failed to enable vddio: %d\n", ret); + goto disable_supply; + } + + /* + * LP8555 datasheet says t_RESPONSE (time between VDDIO and + * I2C) is 1ms. + */ + usleep_range(1000, 2000); + } + + i2c_set_clientdata(cl, lp); + + ret = lp855x_configure(lp); + if (ret) { + dev_err(lp->dev, "device config err: %d", ret); + goto disable_vddio; + } + + ret = lp855x_backlight_register(lp); + if (ret) { + dev_err(lp->dev, + "failed to register backlight. err: %d\n", ret); + goto disable_vddio; + } + + 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 disable_vddio; + } + + backlight_update_status(lp->bl); + + return 0; + +disable_vddio: + if (lp->enable) + regulator_disable(lp->enable); +disable_supply: + if (lp->supply) + regulator_disable(lp->supply); + + return ret; +} + +static int lp855x_remove(struct i2c_client *cl) +{ + struct lp855x *lp = i2c_get_clientdata(cl); + + lp->bl->props.brightness = 0; + backlight_update_status(lp->bl); + if (lp->enable) + regulator_disable(lp->enable); + if (lp->supply) + regulator_disable(lp->supply); + sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); + + return 0; +} + +static const struct of_device_id lp855x_dt_ids[] = { + { .compatible = "ti,lp8550", }, + { .compatible = "ti,lp8551", }, + { .compatible = "ti,lp8552", }, + { .compatible = "ti,lp8553", }, + { .compatible = "ti,lp8555", }, + { .compatible = "ti,lp8556", }, + { .compatible = "ti,lp8557", }, + { } +}; +MODULE_DEVICE_TABLE(of, lp855x_dt_ids); + +static const struct i2c_device_id lp855x_ids[] = { + {"lp8550", LP8550}, + {"lp8551", LP8551}, + {"lp8552", LP8552}, + {"lp8553", LP8553}, + {"lp8555", LP8555}, + {"lp8556", LP8556}, + {"lp8557", LP8557}, + { } +}; +MODULE_DEVICE_TABLE(i2c, lp855x_ids); + +static struct i2c_driver lp855x_driver = { + .driver = { + .name = "lp855x", + .of_match_table = of_match_ptr(lp855x_dt_ids), + }, + .probe = lp855x_probe, + .remove = lp855x_remove, + .id_table = lp855x_ids, +}; + +module_i2c_driver(lp855x_driver); + +MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); +MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); +MODULE_LICENSE("GPL"); |