/*
* 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/of.h>
#include <linux/platform_data/lp855x.h>
#include <linux/pwm.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
/* LP8557 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 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;
};
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 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 ... LP8556:
lp->cfg = &lp855x_dev_cfg;
break;
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;
}
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);
if (bl->props.state & BL_CORE_SUSPENDED)
bl->props.brightness = 0;
if (lp->mode == PWM_BASED) {
int br = bl->props.brightness;
int max_br = bl->props.max_brightness;
lp855x_pwm_ctrl(lp, br, max_br);
} else if (lp->mode == REGISTER_BASED) {
u8 val = bl->props.brightness;
lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
}
return 0;
}
static int lp855x_bl_get_brightness(struct backlight_device *bl)
{
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;
const 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, 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 device *dev, struct device_node *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_kzalloc(dev, sizeof(*rom) * rom_length, 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];
}
dev->platform_data = pdata;
return 0;
}
#else
static int lp855x_parse_dt(struct device *dev, struct device_node *node)
{
return -EINVAL;
}
#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;
struct device_node *node = cl->dev.of_node;
int ret;
if (!pdata) {
ret = lp855x_parse_dt(&cl->dev, node);
if (ret < 0)
return ret;
pdata = cl->dev.platform_data;
}
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;
if (pdata->period_ns > 0)
lp->mode = PWM_BASED;
else
lp->mode = REGISTER_BASED;
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);
ret = lp855x_configure(lp);
if (ret) {
dev_err(lp->dev, "device config err: %d", ret);
goto err_dev;
}
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);
return 0;
err_sysfs:
lp855x_backlight_unregister(lp);
err_dev:
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);
sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
lp855x_backlight_unregister(lp);
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,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},
{"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");
