1 files changed, 608 insertions, 0 deletions

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
new file mode 100644
index 0000000000..da1f124db6
--- /dev/null
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -0,0 +1,608 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * TI LP855x Backlight Driver
+ *
+ *			Copyright (C) 2011 Texas Instruments
+ */
+
+#include <linux/acpi.h>
+#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;
+	bool needs_pwm_init;
+	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;
+
+	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 int lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
+{
+	struct pwm_state state;
+
+	if (lp->needs_pwm_init) {
+		pwm_init_state(lp->pwm, &state);
+		/* Legacy platform data compatibility */
+		if (lp->pdata->period_ns > 0)
+			state.period = lp->pdata->period_ns;
+		lp->needs_pwm_init = false;
+	} else {
+		pwm_get_state(lp->pwm, &state);
+	}
+
+	state.duty_cycle = div_u64(br * state.period, max_br);
+	state.enabled = state.duty_cycle;
+
+	return pwm_apply_state(lp->pwm, &state);
+}
+
+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)
+		return lp855x_pwm_ctrl(lp, brightness,
+				      bl->props.max_brightness);
+	else if (lp->mode == REGISTER_BASED)
+		return lp855x_write_byte(lp, lp->cfg->reg_brightness,
+					(u8)brightness);
+	return -EINVAL;
+}
+
+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 = lp->pdata;
+	int rom_length;
+
+	if (!node) {
+		dev_err(dev, "no platform data\n");
+		return -EINVAL;
+	}
+
+	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);
+	/* Deprecated, specify period in pwms property instead */
+	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];
+	}
+
+	return 0;
+}
+#else
+static int lp855x_parse_dt(struct lp855x *lp)
+{
+	return -EINVAL;
+}
+#endif
+
+static int lp855x_parse_acpi(struct lp855x *lp)
+{
+	int ret;
+
+	/*
+	 * On ACPI the device has already been initialized by the firmware
+	 * and is in register mode, so we can read back the settings from
+	 * the registers.
+	 */
+	ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_brightness);
+	if (ret < 0)
+		return ret;
+
+	lp->pdata->initial_brightness = ret;
+
+	ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_devicectrl);
+	if (ret < 0)
+		return ret;
+
+	lp->pdata->device_control = ret;
+	return 0;
+}
+
+static int lp855x_probe(struct i2c_client *cl)
+{
+	const struct i2c_device_id *id = i2c_client_get_device_id(cl);
+	const struct acpi_device_id *acpi_id = NULL;
+	struct device *dev = &cl->dev;
+	struct lp855x *lp;
+	int ret;
+
+	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
+		return -EIO;
+
+	lp = devm_kzalloc(dev, sizeof(struct lp855x), GFP_KERNEL);
+	if (!lp)
+		return -ENOMEM;
+
+	lp->client = cl;
+	lp->dev = dev;
+	lp->pdata = dev_get_platdata(dev);
+
+	if (id) {
+		lp->chipname = id->name;
+		lp->chip_id = id->driver_data;
+	} else {
+		acpi_id = acpi_match_device(dev->driver->acpi_match_table, dev);
+		if (!acpi_id)
+			return -ENODEV;
+
+		lp->chipname = acpi_id->id;
+		lp->chip_id = acpi_id->driver_data;
+	}
+
+	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->pdata) {
+		lp->pdata = devm_kzalloc(dev, sizeof(*lp->pdata), GFP_KERNEL);
+		if (!lp->pdata)
+			return -ENOMEM;
+
+		if (id) {
+			ret = lp855x_parse_dt(lp);
+			if (ret < 0)
+				return ret;
+		} else {
+			ret = lp855x_parse_acpi(lp);
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	lp->supply = devm_regulator_get(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(dev, "enable");
+	if (IS_ERR(lp->enable)) {
+		ret = PTR_ERR(lp->enable);
+		if (ret == -ENODEV)
+			lp->enable = NULL;
+		else
+			return dev_err_probe(dev, ret, "getting enable regulator\n");
+	}
+
+	lp->pwm = devm_pwm_get(lp->dev, lp->chipname);
+	if (IS_ERR(lp->pwm)) {
+		ret = PTR_ERR(lp->pwm);
+		if (ret == -ENODEV || ret == -EINVAL)
+			lp->pwm = NULL;
+		else
+			return dev_err_probe(dev, ret, "getting PWM\n");
+
+		lp->needs_pwm_init = false;
+		lp->mode = REGISTER_BASED;
+		dev_dbg(dev, "mode: register based\n");
+	} else {
+		lp->needs_pwm_init = true;
+		lp->mode = PWM_BASED;
+		dev_dbg(dev, "mode: PWM based\n");
+	}
+
+	if (lp->supply) {
+		ret = regulator_enable(lp->supply);
+		if (ret < 0) {
+			dev_err(dev, "failed to enable supply: %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (lp->enable) {
+		ret = regulator_enable(lp->enable);
+		if (ret < 0) {
+			dev_err(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(dev, "device config err: %d", ret);
+		goto disable_vddio;
+	}
+
+	ret = lp855x_backlight_register(lp);
+	if (ret) {
+		dev_err(dev, "failed to register backlight. err: %d\n", ret);
+		goto disable_vddio;
+	}
+
+	ret = sysfs_create_group(&dev->kobj, &lp855x_attr_group);
+	if (ret) {
+		dev_err(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 void 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);
+}
+
+static const struct of_device_id lp855x_dt_ids[] __maybe_unused = {
+	{ .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);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id lp855x_acpi_match[] = {
+	/* Xiaomi specific HID used for the LP8556 on the Mi Pad 2 */
+	{ "XMCC0001", LP8556 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, lp855x_acpi_match);
+#endif
+
+static struct i2c_driver lp855x_driver = {
+	.driver = {
+		   .name = "lp855x",
+		   .of_match_table = of_match_ptr(lp855x_dt_ids),
+		   .acpi_match_table = ACPI_PTR(lp855x_acpi_match),
+		   },
+	.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");