Jingoo? On Wed, 30 Sep 2015, Tomi Valkeinen wrote: > This patch adds a led-backlight driver (led_bl), which is similar to > pwm_bl except the driver uses a LED class driver to adjust the > brightness in the HW. > > Signed-off-by: Tomi Valkeinen <[email protected]> > --- > drivers/video/backlight/Kconfig | 7 ++ > drivers/video/backlight/Makefile | 1 + > drivers/video/backlight/led_bl.c | 246 > +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 254 insertions(+) > create mode 100644 drivers/video/backlight/led_bl.c > > diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig > index 0505b796d743..d1336196aba2 100644 > --- a/drivers/video/backlight/Kconfig > +++ b/drivers/video/backlight/Kconfig > @@ -453,6 +453,13 @@ config BACKLIGHT_BD6107 > help > If you have a Rohm BD6107 say Y to enable the backlight driver. > > +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 > > endif # BACKLIGHT_LCD_SUPPORT > diff --git a/drivers/video/backlight/Makefile > b/drivers/video/backlight/Makefile > index d67073f9d421..ecd321daee21 100644 > --- a/drivers/video/backlight/Makefile > +++ b/drivers/video/backlight/Makefile > @@ -54,3 +54,4 @@ obj-$(CONFIG_BACKLIGHT_SKY81452) += sky81452-backlight.o > obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o > obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o > obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.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..1befc8ce5964 > --- /dev/null > +++ b/drivers/video/backlight/led_bl.c > @@ -0,0 +1,246 @@ > +/* > + * Copyright 2015 Texas Instruments > + * > + * Author: Tomi Valkeinen <[email protected]> > + * > + * Based on pwm_bl.c > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; version 2 of the License. > + */ > +#include <linux/backlight.h> > +#include <linux/gpio/consumer.h> > +#include <linux/leds.h> > +#include <linux/of_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) { > + if (priv->power_supply) { > + 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); > + > + if (priv->power_supply) > + 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) { > + dev_err(dev, "failed to find 'brightness-levels'\n"); > + 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) { > + dev_err(dev, "failed to parse 'brightness-levels'\n"); > + return ret; > + } > + > + ret = of_property_read_u32(node, "default-brightness-level", &value); > + if (ret < 0) { > + dev_err(dev, "failed to parse 'default-brightness-level'\n"); > + 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; > + > + priv->led_cdev = of_led_get(node); > + if (IS_ERR(priv->led_cdev)) { > + dev_err(dev, "failed to get LED device\n"); > + return PTR_ERR(priv->led_cdev); > + } > + > + 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; > + > + ret = led_bl_parse_dt(&pdev->dev, priv); > + if (ret < 0) { > + 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_optional(&pdev->dev, "power"); > + if (IS_ERR(priv->power_supply)) { > + ret = PTR_ERR(priv->power_supply); > + > + if (ret == -ENODEV) { > + priv->power_supply = NULL; > + } else { > + 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: > + if (priv->led_cdev) > + led_put(priv->led_cdev); > + > + 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); > + > + led_put(priv->led_cdev); > + > + 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");
-- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
