From: Tomi Valkeinen <tomi.valkeinen@xxxxxx> This patch adds a led-backlight driver (led_bl), which is mostly similar to pwm_bl except the driver uses a LED class driver to adjust the brightness in the HW. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxx> --- drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/led_bl.c | 217 +++++++++++++++++++++++++++++++ 3 files changed, 225 insertions(+) create mode 100644 drivers/video/backlight/led_bl.c diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 8b081d61773e..585a1787618c 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -458,6 +458,13 @@ config BACKLIGHT_RAVE_SP help Support for backlight control on RAVE SP device. +config BACKLIGHT_LED + tristate "Generic LED based Backlight Driver" + depends on LEDS_CLASS && OF + help + If you have a LCD backlight adjustable by LED class driver, say Y + to enable this driver. + endif # BACKLIGHT_CLASS_DEVICE endmenu diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 63c507c07437..2a67642966a5 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -57,3 +57,4 @@ obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o obj-$(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 diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c new file mode 100644 index 000000000000..e699924cc2bc --- /dev/null +++ b/drivers/video/backlight/led_bl.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2018 Texas Instruments Incorporated - http://www.ti.com/ + * Author: Tomi Valkeinen <tomi.valkeinen@xxxxxx> + * + * Based on pwm_bl.c + */ + +#include <linux/backlight.h> +#include <linux/gpio/consumer.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> + +struct led_bl_data { + struct device *dev; + struct backlight_device *bl_dev; + + unsigned int *levels; + bool enabled; + struct regulator *power_supply; + struct gpio_desc *enable_gpio; + + struct led_classdev *led_cdev; + + unsigned int max_brightness; + unsigned int default_brightness; +}; + +static void led_bl_set_brightness(struct led_bl_data *priv, int brightness) +{ + int err; + + if (!priv->enabled) { + err = regulator_enable(priv->power_supply); + if (err < 0) + dev_err(priv->dev, "failed to enable power supply\n"); + + if (priv->enable_gpio) + gpiod_set_value_cansleep(priv->enable_gpio, 1); + } + + led_set_brightness(priv->led_cdev, priv->levels[brightness]); + + priv->enabled = true; +} + +static void led_bl_power_off(struct led_bl_data *priv) +{ + if (!priv->enabled) + return; + + led_set_brightness(priv->led_cdev, LED_OFF); + + if (priv->enable_gpio) + gpiod_set_value_cansleep(priv->enable_gpio, 0); + + regulator_disable(priv->power_supply); + + priv->enabled = false; +} + +static int led_bl_update_status(struct backlight_device *bl) +{ + struct led_bl_data *priv = bl_get_data(bl); + int brightness = bl->props.brightness; + + if (bl->props.power != FB_BLANK_UNBLANK || + bl->props.fb_blank != FB_BLANK_UNBLANK || + bl->props.state & BL_CORE_FBBLANK) + brightness = 0; + + if (brightness > 0) + led_bl_set_brightness(priv, brightness); + else + led_bl_power_off(priv); + + return 0; +} + +static const struct backlight_ops led_bl_ops = { + .update_status = led_bl_update_status, +}; + +static int led_bl_parse_dt(struct device *dev, + struct led_bl_data *priv) +{ + struct device_node *node = dev->of_node; + int num_levels; + u32 *levels; + u32 value; + int ret; + + if (!node) + return -ENODEV; + + num_levels = of_property_count_u32_elems(node, "brightness-levels"); + if (num_levels < 0) + return num_levels; + + levels = devm_kzalloc(dev, sizeof(u32) * num_levels, GFP_KERNEL); + if (!levels) + return -ENOMEM; + + ret = of_property_read_u32_array(node, "brightness-levels", + levels, + num_levels); + if (ret < 0) + return ret; + + ret = of_property_read_u32(node, "default-brightness-level", &value); + if (ret < 0) + return ret; + + if (value >= num_levels) { + dev_err(dev, "invalid default-brightness-level\n"); + return -EINVAL; + } + + priv->levels = levels; + priv->max_brightness = num_levels - 1; + priv->default_brightness = value; + + return 0; +} + +static int led_bl_probe(struct platform_device *pdev) +{ + struct backlight_properties props; + struct led_bl_data *priv; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + platform_set_drvdata(pdev, priv); + + priv->dev = &pdev->dev; + priv->led_cdev = to_led_classdev(pdev->dev.parent); + + ret = led_bl_parse_dt(&pdev->dev, priv); + if (ret < 0) { + if (ret != -EPROBE_DEFER) + dev_err(&pdev->dev, "failed to parse DT data\n"); + return ret; + } + + priv->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", + GPIOD_OUT_LOW); + if (IS_ERR(priv->enable_gpio)) { + ret = PTR_ERR(priv->enable_gpio); + goto err; + } + + priv->power_supply = devm_regulator_get(&pdev->dev, "power"); + if (IS_ERR(priv->power_supply)) { + ret = PTR_ERR(priv->power_supply); + goto err; + } + + memset(&props, 0, sizeof(struct backlight_properties)); + props.type = BACKLIGHT_RAW; + props.max_brightness = priv->max_brightness; + priv->bl_dev = backlight_device_register(dev_name(&pdev->dev), + &pdev->dev, priv, &led_bl_ops, &props); + if (IS_ERR(priv->bl_dev)) { + dev_err(&pdev->dev, "failed to register backlight\n"); + ret = PTR_ERR(priv->bl_dev); + goto err; + } + + priv->bl_dev->props.brightness = priv->default_brightness; + backlight_update_status(priv->bl_dev); + + return 0; + +err: + + return ret; +} + +static int led_bl_remove(struct platform_device *pdev) +{ + struct led_bl_data *priv = platform_get_drvdata(pdev); + struct backlight_device *bl = priv->bl_dev; + + backlight_device_unregister(bl); + + led_bl_power_off(priv); + + return 0; +} + +static const struct of_device_id led_bl_of_match[] = { + { .compatible = "led-backlight" }, + { } +}; + +MODULE_DEVICE_TABLE(of, led_bl_of_match); + +static struct platform_driver led_bl_driver = { + .driver = { + .name = "led-backlight", + .of_match_table = of_match_ptr(led_bl_of_match), + }, + .probe = led_bl_probe, + .remove = led_bl_remove, +}; + +module_platform_driver(led_bl_driver); + +MODULE_DESCRIPTION("LED based Backlight Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:led-backlight"); -- 2.17.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
