From: Alexander Sverdlin <[email protected]> Move the TI LP8864/LP8866 driver from drivers/leds/ to drivers/video/backlight/ and convert it to register a backlight class device as its primary interface.
The motivation is a use case on a hot-pluggable segment of an I2C bus. The generic led-backlight driver (drivers/video/backlight/led_bl.c) is a platform driver and as such inherently non-hotpluggable. It cannot react to dynamic appearance/disappearance of the underlying I2C device. By making the LP8864 driver directly register a backlight class device, it becomes a native I2C driver that properly supports hot-plug/unplug events on the I2C bus. Key changes: - Register a backlight class device using devm_backlight_device_register() as the primary interface - Implement backlight_ops (update_status, get_brightness) - The hardware 16-bit brightness register (0x0000-0xFFFF) is directly exposed as the backlight brightness range - Support DT properties "default-brightness" and "max-brightness" from the backlight common binding - Include BL_CORE_SUSPENDRESUME for proper power management integration - Preserve backward-compatible LED class device registration: if the "led" child node is present in the DT, an LED class device is also registered (same as the original driver behavior) - Preserve the CONFIG_LEDS_LP8864 Kconfig symbol name so that existing kernel configurations are not affected - Update MAINTAINERS to reflect the new file location This will be noticeable for applications which already used the LP8864 as a backend for the generic led-backlight platform driver, as a backlight device will now appear directly in addition to the LED class device. However, no in-tree device-trees reference this driver, so there is no mainline impact. Signed-off-by: Alexander Sverdlin <[email protected]> --- MAINTAINERS | 2 +- drivers/leds/Kconfig | 12 -- drivers/leds/Makefile | 1 - drivers/video/backlight/Kconfig | 15 +++ drivers/video/backlight/Makefile | 1 + .../backlight/lp8864_bl.c} | 111 ++++++++++++++---- 6 files changed, 106 insertions(+), 36 deletions(-) rename drivers/{leds/leds-lp8864.c => video/backlight/lp8864_bl.c} (70%) diff --git a/MAINTAINERS b/MAINTAINERS index dbd4552236e64..250e8b1ed4bb5 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -26481,7 +26481,7 @@ M: Alexander Sverdlin <[email protected]> L: [email protected] S: Maintained F: Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml -F: drivers/leds/leds-lp8864.c +F: drivers/video/backlight/lp8864_bl.c TEXAS INSTRUMENTS' SYSTEM CONTROL INTERFACE (TISCI) PROTOCOL DRIVER M: Nishanth Menon <[email protected]> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index f4a0a3c8c8705..990cb9ef18c1e 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -529,18 +529,6 @@ config LEDS_LP8860 on the LP8860 4 channel LED driver using the I2C communication bus. -config LEDS_LP8864 - tristate "LED support for the TI LP8864/LP8866 4/6 channel LED drivers" - depends on LEDS_CLASS && I2C && OF - select REGMAP_I2C - help - If you say yes here you get support for the TI LP8864-Q1, - LP8864S-Q1, LP8866-Q1, LP8866S-Q1 4/6 channel LED backlight - drivers with I2C interface. - - To compile this driver as a module, choose M here: the - module will be called leds-lp8864. - config LEDS_CLEVO_MAIL tristate "Mail LED on Clevo notebook" depends on LEDS_CLASS && BROKEN diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index 8fdb45d5b4393..5e624a48aa2a5 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -59,7 +59,6 @@ obj-$(CONFIG_LEDS_LP55XX_COMMON) += leds-lp55xx-common.o obj-$(CONFIG_LEDS_LP8501) += leds-lp8501.o obj-$(CONFIG_LEDS_LP8788) += leds-lp8788.o obj-$(CONFIG_LEDS_LP8860) += leds-lp8860.o -obj-$(CONFIG_LEDS_LP8864) += leds-lp8864.o obj-$(CONFIG_LEDS_LT3593) += leds-lt3593.o obj-$(CONFIG_LEDS_MAX5970) += leds-max5970.o obj-$(CONFIG_LEDS_MAX77650) += leds-max77650.o diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index a7a3fbaf7c29e..82ecd7e46236d 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -514,6 +514,21 @@ config BACKLIGHT_LED If you have a LCD backlight adjustable by LED class driver, say Y to enable this driver. +config LEDS_LP8864 + tristate "Backlight driver for TI LP8864/LP8866 4/6 channel LED drivers" + depends on I2C && OF + select REGMAP_I2C + select NEW_LEDS + select LEDS_CLASS + help + If you say yes here you get support for the TI LP8864-Q1, + LP8864S-Q1, LP8866-Q1, LP8866S-Q1 4/6 channel LED backlight + drivers with I2C interface. The driver registers a backlight + class device and optionally an LED class device. + + To compile this driver as a module, choose M here: the + module will be called lp8864_bl. + endif # BACKLIGHT_CLASS_DEVICE endmenu diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 794820a98ed49..6a7287d01d81b 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -62,3 +62,4 @@ obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o obj-$(CONFIG_BACKLIGHT_LED) += led_bl.o +obj-$(CONFIG_LEDS_LP8864) += lp8864_bl.o diff --git a/drivers/leds/leds-lp8864.c b/drivers/video/backlight/lp8864_bl.c similarity index 70% rename from drivers/leds/leds-lp8864.c rename to drivers/video/backlight/lp8864_bl.c index d05211b970c94..67b28f7daedd2 100644 --- a/drivers/leds/leds-lp8864.c +++ b/drivers/video/backlight/lp8864_bl.c @@ -1,12 +1,13 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * TI LP8864/LP8866 4/6 Channel LED Driver + * TI LP8864/LP8866 4/6 Channel LED Backlight Driver * - * Copyright (C) 2024 Siemens AG + * Copyright (C) 2024-2026 Siemens AG * * Based on LP8860 driver by Dan Murphy <[email protected]> */ +#include <linux/backlight.h> #include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/init.h> @@ -27,6 +28,8 @@ #define LP8864_LED_STATUS 0x12 #define LP8864_LED_STATUS_WR_MASK GENMASK(14, 9) /* Writeable bits in the LED_STATUS reg */ +#define LP8864_MAX_BRIGHTNESS 0xffff + /* Textual meaning for status bits, starting from bit 1 */ static const char *const lp8864_supply_status_msg[] = { "Vin under-voltage fault", @@ -71,13 +74,15 @@ static const char *const lp8864_led_status_msg[] = { /** * struct lp8864 * @client: Pointer to the I2C client - * @led_dev: led class device pointer + * @led_dev: optional led class device pointer + * @bl: backlight device pointer * @regmap: Devices register map * @led_status_mask: Helps to report LED fault only once */ struct lp8864 { struct i2c_client *client; - struct led_classdev led_dev; + struct led_classdev *led_dev; + struct backlight_device *bl; struct regmap *regmap; u16 led_status_mask; }; @@ -157,28 +162,59 @@ static int lp8864_fault_check(struct lp8864 *priv) return ret; } -static int lp8864_brightness_set(struct led_classdev *led_cdev, - enum led_brightness brt_val) +static int lp8864_brightness_set(struct lp8864 *priv, unsigned int brightness) { - struct lp8864 *priv = container_of(led_cdev, struct lp8864, led_dev); - /* Scale 0..LED_FULL into 16-bit HW brightness */ - unsigned int val = brt_val * 0xffff / LED_FULL; int ret; ret = lp8864_fault_check(priv); if (ret) return ret; - ret = regmap_write(priv->regmap, LP8864_BRT_CONTROL, val); + ret = regmap_write(priv->regmap, LP8864_BRT_CONTROL, brightness); if (ret) dev_err(&priv->client->dev, "Failed to write brightness value\n"); return ret; } -static enum led_brightness lp8864_brightness_get(struct led_classdev *led_cdev) +static int lp8864_backlight_update_status(struct backlight_device *bl) +{ + return lp8864_brightness_set(bl_get_data(bl), backlight_get_brightness(bl)); +} + +static int lp8864_backlight_get_brightness(struct backlight_device *bl) { - struct lp8864 *priv = container_of(led_cdev, struct lp8864, led_dev); + struct lp8864 *priv = bl_get_data(bl); + unsigned int val; + int ret; + + ret = regmap_read(priv->regmap, LP8864_BRT_CONTROL, &val); + if (ret) { + dev_err(&priv->client->dev, "Failed to read brightness value\n"); + return ret; + } + + return val; +} + +static const struct backlight_ops lp8864_backlight_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = lp8864_backlight_update_status, + .get_brightness = lp8864_backlight_get_brightness, +}; + +static int lp8864_led_brightness_set(struct led_classdev *led_cdev, + enum led_brightness brt_val) +{ + struct lp8864 *priv = dev_get_drvdata(led_cdev->dev->parent); + + /* Scale 0..LED_FULL into 16-bit HW brightness */ + return lp8864_brightness_set(priv, brt_val * 0xffff / LED_FULL); +} + +static enum led_brightness lp8864_led_brightness_get(struct led_classdev *led_cdev) +{ + struct lp8864 *priv = dev_get_drvdata(led_cdev->dev->parent); unsigned int val; int ret; @@ -212,18 +248,15 @@ static int lp8864_probe(struct i2c_client *client) struct device_node *np = dev_of_node(&client->dev); struct device_node *child_node; struct led_init_data init_data = {}; + struct backlight_device *bl; + struct backlight_properties props; struct gpio_desc *enable_gpio; + u32 val; priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; - child_node = of_get_next_available_child(np, NULL); - if (!child_node) { - dev_err(&client->dev, "No LED function defined\n"); - return -EINVAL; - } - ret = devm_regulator_get_enable_optional(&client->dev, "vled"); if (ret && ret != -ENODEV) return dev_err_probe(&client->dev, ret, "Failed to enable vled regulator\n"); @@ -238,8 +271,7 @@ static int lp8864_probe(struct i2c_client *client) return ret; priv->client = client; - priv->led_dev.brightness_set_blocking = lp8864_brightness_set; - priv->led_dev.brightness_get = lp8864_brightness_get; + i2c_set_clientdata(client, priv); priv->regmap = devm_regmap_init_i2c(client, &lp8864_regmap_config); if (IS_ERR(priv->regmap)) @@ -258,11 +290,46 @@ static int lp8864_probe(struct i2c_client *client) if (ret) return ret; + /* Register backlight class device */ + memset(&props, 0, sizeof(props)); + props.type = BACKLIGHT_RAW; + props.max_brightness = LP8864_MAX_BRIGHTNESS; + props.brightness = LP8864_MAX_BRIGHTNESS; + props.scale = BACKLIGHT_SCALE_LINEAR; + + if (!device_property_read_u32(&client->dev, "max-brightness", &val)) + props.max_brightness = val; + + if (!device_property_read_u32(&client->dev, "default-brightness", &val)) + props.brightness = val; + + bl = devm_backlight_device_register(&client->dev, "lp8864-backlight", + &client->dev, priv, + &lp8864_backlight_ops, &props); + if (IS_ERR(bl)) + return dev_err_probe(&client->dev, PTR_ERR(bl), + "Failed to register backlight device\n"); + + priv->bl = bl; + backlight_update_status(bl); + + /* Register LED class device if "led" child node is present */ + child_node = of_get_available_child_by_name(np, "led"); + if (!child_node) + return 0; + + priv->led_dev = devm_kzalloc(&client->dev, sizeof(*priv->led_dev), GFP_KERNEL); + if (!priv->led_dev) + return -ENOMEM; + + priv->led_dev->brightness_set_blocking = lp8864_led_brightness_set; + priv->led_dev->brightness_get = lp8864_led_brightness_get; + init_data.fwnode = of_fwnode_handle(child_node); init_data.devicename = "lp8864"; init_data.default_label = ":display_cluster"; - ret = devm_led_classdev_register_ext(&client->dev, &priv->led_dev, &init_data); + ret = devm_led_classdev_register_ext(&client->dev, priv->led_dev, &init_data); if (ret) dev_err(&client->dev, "Failed to register LED device (%pe)\n", ERR_PTR(ret)); @@ -291,6 +358,6 @@ static struct i2c_driver lp8864_driver = { }; module_i2c_driver(lp8864_driver); -MODULE_DESCRIPTION("Texas Instruments LP8864/LP8866 LED driver"); +MODULE_DESCRIPTION("Texas Instruments LP8864/LP8866 LED Backlight driver"); MODULE_AUTHOR("Alexander Sverdlin <[email protected]>"); MODULE_LICENSE("GPL"); -- 2.54.0
