--- /dev/null
+/*
+ * 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>
+#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;
+};
+
+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;
+ }
+
+ 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_CORE_FBBLANK))
+ 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 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;
+
+ 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_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];
+ }
+
+ pdata->supply = devm_regulator_get(dev, "power");
+ if (IS_ERR(pdata->supply)) {
+ if (PTR_ERR(pdata->supply) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ pdata->supply = NULL;
+ }
+
+ 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;
+
+ if (lp->pdata->supply) {
+ ret = regulator_enable(lp->pdata->supply);
+ if (ret < 0) {
+ dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
+ return ret;
+ }
+ }
+
+ i2c_set_clientdata(cl, lp);
+
+ ret = lp855x_configure(lp);
+ if (ret) {
+ dev_err(lp->dev, "device config err: %d", ret);
+ return ret;
+ }
+
+ ret = lp855x_backlight_register(lp);
+ if (ret) {
+ dev_err(lp->dev,
+ "failed to register backlight. err: %d\n", ret);
+ return ret;
+ }
+
+ ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
+ if (ret) {
+ dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
+ return ret;
+ }
+
+ backlight_update_status(lp->bl);
+ return 0;
+}
+
+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->pdata->supply)
+ regulator_disable(lp->pdata->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");
Code Review / kvmfornfv.git / blobdiff