Add support for National Semiconductor/TI LP8550/1/2/3/5/6/7
LED Backlight. Driver is based on Linux version but is
reworked and optimised for U-Boot DM framework. Currently
only register driven backlight control is supported, PWM
driver backlight control may be added later if needed.
Signed-off-by: Svyatoslav Ryhel <clamo...@gmail.com>
---
drivers/video/Kconfig | 10 +
drivers/video/Makefile | 1 +
drivers/video/lp855x_backlight.c | 302 +++++++++++++++++++++++++++++++
3 files changed, 313 insertions(+)
create mode 100644 drivers/video/lp855x_backlight.c
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 3c3cebaacd0..926dafe7a5a 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -743,6 +743,16 @@ config BACKLIGHT_LM3533
LM3533 Lighting Power chip. Only Bank A is supported as for now.
Supported backlight level range is from 2 to 255 with step of 1.
+config BACKLIGHT_LP855x
+ bool "Backlight Driver for LP855x"
+ depends on BACKLIGHT
+ select DM_I2C
+ help
+ Say Y to enable the backlight driver for National Semiconductor / TI
+ LP8550/1/2/3/5/6/7 LED Backlight Driver. Only register driven mode is
+ supported for now, PWM mode can be added if there will be any need in
+ it. Supported backlight level range is from 0 to 255 with step of 1.
+
source "drivers/video/ti/Kconfig"
source "drivers/video/exynos/Kconfig"
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 5a00438ce06..391ef8397bc 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_$(PHASE_)BMP) += bmp.o
endif
obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_backlight.o
+obj-$(CONFIG_BACKLIGHT_LP855x) += lp855x_backlight.o
obj-${CONFIG_EXYNOS_FB} += exynos/
obj-${CONFIG_VIDEO_ROCKCHIP} += rockchip/
obj-${CONFIG_VIDEO_STM32} += stm32/
diff --git a/drivers/video/lp855x_backlight.c b/drivers/video/lp855x_backlight.c
new file mode 100644
index 00000000000..5debc0aa453
--- /dev/null
+++ b/drivers/video/lp855x_backlight.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2011 Texas Instruments
+ * Copyright (c) 2024 Svyatoslav Ryhel <clamo...@gmail.com>
+ */
+
+#define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT
+
+#include <malloc.h>
+#include <backlight.h>
+#include <dm.h>
+#include <dm/devres.h>
+#include <i2c.h>
+#include <log.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <asm/gpio.h>
+#include <power/regulator.h>
+
+#define LP855x_MIN_BRIGHTNESS 0x00
+#define LP855x_MAX_BRIGHTNESS 0xff
+
+/* 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 0x98
+#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
+
+struct lp855x_rom_data {
+ u8 addr;
+ u8 val;
+};
+
+struct lp855x_backlight_priv;
+
+/*
+ * 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 udevice *dev);
+ u8 reg_brightness;
+ u8 reg_devicectrl;
+ u8 reg_eepromstart;
+ u8 reg_eepromend;
+ int (*post_init_device)(struct udevice *dev);
+};
+
+struct lp855x_backlight_priv {
+ struct udevice *supply; /* regulator for VDD input */
+ struct udevice *enable; /* regulator for EN/VDDIO input */
+
+ u8 device_control;
+ u8 initial_brightness;
+
+ int size_program;
+ struct lp855x_rom_data *rom_data;
+ struct lp855x_device_config *cfg;
+};
+
+static int lp855x_backlight_enable(struct udevice *dev)
+{
+ struct lp855x_backlight_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = regulator_set_enable_if_allowed(priv->supply, 1);
+ if (ret) {
+ log_debug("%s: enabling power-supply failed (%d)\n",
+ __func__, ret);
+ return ret;
+ }
+
+ ret = regulator_set_enable_if_allowed(priv->enable, 1);
+ if (ret) {
+ log_debug("%s: enabling enable-supply failed (%d)\n",
+ __func__, ret);
+ return ret;
+ }
+ mdelay(2);
+
+ if (priv->cfg->pre_init_device) {
+ ret = priv->cfg->pre_init_device(dev);
+ if (ret) {
+ log_debug("%s: pre init device err: %d\n",
+ __func__, ret);
+ return ret;
+ }
+ }
+
+ ret = dm_i2c_reg_write(dev, priv->cfg->reg_brightness,
+ priv->initial_brightness);
+ if (ret)
+ return ret;
+
+ ret = dm_i2c_reg_write(dev, priv->cfg->reg_devicectrl,
+ priv->device_control);
+ if (ret)
+ return ret;
+
+ if (priv->size_program > 0) {
+ int i;
+ u8 val, addr;
+
+ for (i = 0; i < priv->size_program; i++) {
+ addr = priv->rom_data[i].addr;
+ val = priv->rom_data[i].val;
+
+ if (addr < priv->cfg->reg_eepromstart &&
+ addr > priv->cfg->reg_eepromend)
+ continue;
+
+ ret = dm_i2c_reg_write(dev, addr, val);
+ if (ret)
+ return ret;
+ }
+ }
+
+ if (priv->cfg->post_init_device) {
+ ret = priv->cfg->post_init_device(dev);
+ if (ret) {
+ log_debug("%s: post init device err: %d\n",
+ __func__, ret);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int lp855x_backlight_set_brightness(struct udevice *dev, int percent)
+{
+ struct lp855x_backlight_priv *priv = dev_get_priv(dev);
+
+ if (percent == BACKLIGHT_DEFAULT)
+ percent = priv->initial_brightness;
+
+ if (percent < LP855x_MIN_BRIGHTNESS)
+ percent = LP855x_MIN_BRIGHTNESS;
+
+ if (percent > LP855x_MAX_BRIGHTNESS)
+ percent = LP855x_MAX_BRIGHTNESS;
+
+ /* Set brightness level */
+ return dm_i2c_reg_write(dev, priv->cfg->reg_brightness,
+ percent);
+}
+
+static int lp855x_backlight_probe(struct udevice *dev)
+{
+ struct lp855x_backlight_priv *priv = dev_get_priv(dev);
+ int rom_length, ret;
+
+ if (device_get_uclass_id(dev->parent) != UCLASS_I2C)
+ return -EPROTONOSUPPORT;
+
+ priv->cfg = (struct lp855x_device_config *)dev_get_driver_data(dev);
+
+ dev_read_u8(dev, "dev-ctrl", &priv->device_control);
+ dev_read_u8(dev, "init-brt", &priv->initial_brightness);
+
+ /* Fill ROM platform data if defined */
+ rom_length = dev_get_child_count(dev);
+ if (rom_length > 0) {
+ struct lp855x_rom_data *rom;
+ ofnode child;
+ int i = 0;
+
+ rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
+ if (!rom)
+ return -ENOMEM;
+
+ dev_for_each_subnode(child, dev) {
+ ofnode_read_u8(child, "rom-addr", &rom[i].addr);
+ ofnode_read_u8(child, "rom-val", &rom[i].val);
+ i++;
+ }
+
+ priv->size_program = rom_length;
+ priv->rom_data = &rom[0];
+ }
+
+ ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
+ "power-supply", &priv->supply);
+ if (ret) {
+ log_err("%s: cannot get power-supply: ret = %d\n", __func__,
ret);
+ return ret;
+ }
+
+ ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
+ "enable-supply", &priv->enable);
+ if (ret) {
+ log_err("%s: cannot get enable-supply: ret = %d\n", __func__,
ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct backlight_ops lp855x_backlight_ops = {
+ .enable = lp855x_backlight_enable,
+ .set_brightness = lp855x_backlight_set_brightness,
+};
+
+static int lp8556_bl_rst(struct udevice *dev)
+{
+ int ret;
+
+ /* Reset backlight after updating EPROM settings */
+ ret = dm_i2c_reg_clrset(dev, LP855X_DEVICE_CTRL, LP8557_BL_MASK,
+ LP8557_BL_OFF);
+ if (ret)
+ return ret;
+
+ mdelay(10);
+
+ return dm_i2c_reg_clrset(dev, LP855X_DEVICE_CTRL, LP8557_BL_MASK,
+ LP8557_BL_ON);
+}
+
+static int lp8557_bl_off(struct udevice *dev)
+{
+ /* BL_ON = 0 before updating EPROM settings */
+ return dm_i2c_reg_clrset(dev, LP8557_BL_CMD, LP8557_BL_MASK,
+ LP8557_BL_OFF);
+}
+
+static int lp8557_bl_on(struct udevice *dev)
+{
+ /* BL_ON = 1 after updating EPROM settings */
+ return dm_i2c_reg_clrset(dev, 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,
+ .reg_eepromstart = LP855X_EEPROM_START,
+ .reg_eepromend = LP855X_EEPROM_END,
+};
+
+static struct lp855x_device_config lp8555_dev_cfg = {
+ .reg_brightness = LP8557_BRIGHTNESS_CTRL,
+ .reg_devicectrl = LP8557_CONFIG,
+ .reg_eepromstart = LP8555_EPROM_START,
+ .reg_eepromend = LP8555_EPROM_END,
+ .pre_init_device = lp8557_bl_off,
+ .post_init_device = lp8557_bl_on,
+};
+
+static struct lp855x_device_config lp8556_dev_cfg = {
+ .reg_brightness = LP855X_BRIGHTNESS_CTRL,
+ .reg_devicectrl = LP855X_DEVICE_CTRL,
+ .reg_eepromstart = LP8556_EPROM_START,
+ .reg_eepromend = LP8556_EPROM_END,
+ .post_init_device = lp8556_bl_rst,
+};
+
+static struct lp855x_device_config lp8557_dev_cfg = {
+ .reg_brightness = LP8557_BRIGHTNESS_CTRL,
+ .reg_devicectrl = LP8557_CONFIG,
+ .reg_eepromstart = LP8557_EPROM_START,
+ .reg_eepromend = LP8557_EPROM_END,
+ .pre_init_device = lp8557_bl_off,
+ .post_init_device = lp8557_bl_on,
+};
+
+static const struct udevice_id lp855x_backlight_ids[] = {
+ { .compatible = "ti,lp8550", .data = (ulong)&lp855x_dev_cfg },
+ { .compatible = "ti,lp8551", .data = (ulong)&lp855x_dev_cfg },
+ { .compatible = "ti,lp8552", .data = (ulong)&lp855x_dev_cfg },
+ { .compatible = "ti,lp8553", .data = (ulong)&lp855x_dev_cfg },
+ { .compatible = "ti,lp8555", .data = (ulong)&lp8555_dev_cfg },
+ { .compatible = "ti,lp8556", .data = (ulong)&lp8556_dev_cfg },
+ { .compatible = "ti,lp8557", .data = (ulong)&lp8557_dev_cfg },
+ { }
+};
+
+U_BOOT_DRIVER(lp855x_backlight) = {
+ .name = "lp855x_backlight",
+ .id = UCLASS_PANEL_BACKLIGHT,
+ .of_match = lp855x_backlight_ids,
+ .probe = lp855x_backlight_probe,
+ .ops = &lp855x_backlight_ops,
+ .priv_auto = sizeof(struct lp855x_backlight_priv),
+};
--
2.43.0
