| Message ID | 20190910132734.9544-5-jjhiblot@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add a generic driver for LED-based backlight | expand |
On Tue, Sep 10, 2019 at 03:27:34PM +0200, Jean-Jacques Hiblot wrote: > From: Tomi Valkeinen <tomi.valkeinen@ti.com> > > 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. Multiple LEDs can be used for a single backlight. > > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> > Acked-by: Pavel Machek <pavel@ucw.cz> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> > --- > drivers/video/backlight/Kconfig | 7 + > drivers/video/backlight/Makefile | 1 + > drivers/video/backlight/led_bl.c | 260 +++++++++++++++++++++++++++++++ > 3 files changed, 268 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..6044390d8b88 > --- /dev/null > +++ b/drivers/video/backlight/led_bl.c > @@ -0,0 +1,260 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/ > + * Author: Tomi Valkeinen <tomi.valkeinen@ti.com> > + * > + * Based on pwm_bl.c > + */ > + > +#include <linux/backlight.h> > +#include <linux/leds.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > + > +struct led_bl_data { > + struct device *dev; > + struct backlight_device *bl_dev; > + struct led_classdev **leds; > + bool enabled; > + int nb_leds; > + unsigned int *levels; > + unsigned int default_brightness; > + unsigned int max_brightness; > +}; > + > +static void led_bl_set_brightness(struct led_bl_data *priv, int level) > +{ > + int i; > + int bkl_brightness; > + > + if (priv->levels) > + bkl_brightness = priv->levels[level]; > + else > + bkl_brightness = level; > + > + for (i = 0; i < priv->nb_leds; i++) > + led_set_brightness(priv->leds[i], bkl_brightness); > + > + priv->enabled = true; > +} > + > +static void led_bl_power_off(struct led_bl_data *priv) > +{ > + int i; > + > + if (!priv->enabled) > + return; > + > + for (i = 0; i < priv->nb_leds; i++) > + led_set_brightness(priv->leds[i], LED_OFF); > + > + 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_get_leds(struct device *dev, > + struct led_bl_data *priv) > +{ > + int i, nb_leds, ret; > + struct device_node *node = dev->of_node; > + struct led_classdev **leds; > + unsigned int max_brightness; > + unsigned int default_brightness; > + > + ret = of_count_phandle_with_args(node, "leds", NULL); > + if (ret < 0) { > + dev_err(dev, "Unable to get led count\n"); > + return -EINVAL; > + } > + > + nb_leds = ret; > + if (nb_leds < 1) { > + dev_err(dev, "At least one LED must be specified!\n"); > + return -EINVAL; > + } > + > + leds = devm_kzalloc(dev, sizeof(struct led_classdev *) * nb_leds, > + GFP_KERNEL); > + if (!leds) > + return -ENOMEM; > + > + for (i = 0; i < nb_leds; i++) { > + leds[i] = devm_led_get(dev, i); > + if (IS_ERR(leds[i])) > + return PTR_ERR(leds[i]); > + } > + > + /* check that the LEDs all have the same brightness range */ > + max_brightness = leds[0]->max_brightness; > + for (i = 1; i < nb_leds; i++) { > + if (max_brightness != leds[i]->max_brightness) { > + dev_err(dev, "LEDs must have identical ranges\n"); > + return -EINVAL; > + } > + } > + > + /* get the default brightness from the first LED from the list */ > + default_brightness = leds[0]->brightness; > + > + priv->nb_leds = nb_leds; > + priv->leds = leds; > + priv->max_brightness = max_brightness; > + priv->default_brightness = default_brightness; > + > + return 0; > +} > + > +static int led_bl_parse_levels(struct device *dev, > + struct led_bl_data *priv) > +{ > + struct device_node *node = dev->of_node; > + int num_levels; > + u32 value; > + int ret; > + > + if (!node) > + return -ENODEV; > + > + num_levels = of_property_count_u32_elems(node, "brightness-levels"); > + if (num_levels > 1) { > + int i; > + unsigned int db; > + u32 *levels = NULL; > + > + 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; > + > + /* > + * Try to map actual LED brightness to backlight brightness > + * level > + */ > + db = priv->default_brightness; > + for (i = 0 ; i < num_levels; i++) { > + if ((i && db > levels[i-1]) && db <= levels[i]) > + break; > + } > + priv->default_brightness = i; > + priv->max_brightness = num_levels - 1; > + priv->levels = levels; > + } else if (num_levels >= 0) > + dev_warn(dev, "Not enough levels defined\n"); > + > + ret = of_property_read_u32(node, "default-brightness-level", &value); > + if (!ret && value <= priv->max_brightness) > + priv->default_brightness = value; > + else if (!ret && value > priv->max_brightness) > + dev_warn(dev, "Invalid default brightness. Ignoring it\n"); > + > + return 0; > +} > + > +static int led_bl_probe(struct platform_device *pdev) > +{ > + struct backlight_properties props; > + struct led_bl_data *priv; > + int ret, i; > + > + 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_get_leds(&pdev->dev, priv); > + if (ret) > + return ret; > + > + ret = led_bl_parse_levels(&pdev->dev, priv); > + if (ret < 0) { > + dev_err(&pdev->dev, "Failed to parse DT data\n"); > + return ret; > + } > + > + memset(&props, 0, sizeof(struct backlight_properties)); > + props.type = BACKLIGHT_RAW; > + props.max_brightness = priv->max_brightness; > + props.brightness = priv->default_brightness; > + props.power = (priv->default_brightness > 0) ? FB_BLANK_POWERDOWN : > + FB_BLANK_UNBLANK; > + 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"); > + return PTR_ERR(priv->bl_dev); > + } > + > + for (i = 0; i < priv->nb_leds; i++) > + led_sysfs_disable(priv->leds[i]); > + > + backlight_update_status(priv->bl_dev); > + > + return 0; > +} > + > +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; > + int i; > + > + backlight_device_unregister(bl); > + > + led_bl_power_off(priv); > + for (i = 0; i < priv->nb_leds; i++) > + led_sysfs_enable(priv->leds[i]); > + > + 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 >
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..6044390d8b88 --- /dev/null +++ b/drivers/video/backlight/led_bl.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/ + * Author: Tomi Valkeinen <tomi.valkeinen@ti.com> + * + * Based on pwm_bl.c + */ + +#include <linux/backlight.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +struct led_bl_data { + struct device *dev; + struct backlight_device *bl_dev; + struct led_classdev **leds; + bool enabled; + int nb_leds; + unsigned int *levels; + unsigned int default_brightness; + unsigned int max_brightness; +}; + +static void led_bl_set_brightness(struct led_bl_data *priv, int level) +{ + int i; + int bkl_brightness; + + if (priv->levels) + bkl_brightness = priv->levels[level]; + else + bkl_brightness = level; + + for (i = 0; i < priv->nb_leds; i++) + led_set_brightness(priv->leds[i], bkl_brightness); + + priv->enabled = true; +} + +static void led_bl_power_off(struct led_bl_data *priv) +{ + int i; + + if (!priv->enabled) + return; + + for (i = 0; i < priv->nb_leds; i++) + led_set_brightness(priv->leds[i], LED_OFF); + + 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_get_leds(struct device *dev, + struct led_bl_data *priv) +{ + int i, nb_leds, ret; + struct device_node *node = dev->of_node; + struct led_classdev **leds; + unsigned int max_brightness; + unsigned int default_brightness; + + ret = of_count_phandle_with_args(node, "leds", NULL); + if (ret < 0) { + dev_err(dev, "Unable to get led count\n"); + return -EINVAL; + } + + nb_leds = ret; + if (nb_leds < 1) { + dev_err(dev, "At least one LED must be specified!\n"); + return -EINVAL; + } + + leds = devm_kzalloc(dev, sizeof(struct led_classdev *) * nb_leds, + GFP_KERNEL); + if (!leds) + return -ENOMEM; + + for (i = 0; i < nb_leds; i++) { + leds[i] = devm_led_get(dev, i); + if (IS_ERR(leds[i])) + return PTR_ERR(leds[i]); + } + + /* check that the LEDs all have the same brightness range */ + max_brightness = leds[0]->max_brightness; + for (i = 1; i < nb_leds; i++) { + if (max_brightness != leds[i]->max_brightness) { + dev_err(dev, "LEDs must have identical ranges\n"); + return -EINVAL; + } + } + + /* get the default brightness from the first LED from the list */ + default_brightness = leds[0]->brightness; + + priv->nb_leds = nb_leds; + priv->leds = leds; + priv->max_brightness = max_brightness; + priv->default_brightness = default_brightness; + + return 0; +} + +static int led_bl_parse_levels(struct device *dev, + struct led_bl_data *priv) +{ + struct device_node *node = dev->of_node; + int num_levels; + u32 value; + int ret; + + if (!node) + return -ENODEV; + + num_levels = of_property_count_u32_elems(node, "brightness-levels"); + if (num_levels > 1) { + int i; + unsigned int db; + u32 *levels = NULL; + + 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; + + /* + * Try to map actual LED brightness to backlight brightness + * level + */ + db = priv->default_brightness; + for (i = 0 ; i < num_levels; i++) { + if ((i && db > levels[i-1]) && db <= levels[i]) + break; + } + priv->default_brightness = i; + priv->max_brightness = num_levels - 1; + priv->levels = levels; + } else if (num_levels >= 0) + dev_warn(dev, "Not enough levels defined\n"); + + ret = of_property_read_u32(node, "default-brightness-level", &value); + if (!ret && value <= priv->max_brightness) + priv->default_brightness = value; + else if (!ret && value > priv->max_brightness) + dev_warn(dev, "Invalid default brightness. Ignoring it\n"); + + return 0; +} + +static int led_bl_probe(struct platform_device *pdev) +{ + struct backlight_properties props; + struct led_bl_data *priv; + int ret, i; + + 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_get_leds(&pdev->dev, priv); + if (ret) + return ret; + + ret = led_bl_parse_levels(&pdev->dev, priv); + if (ret < 0) { + dev_err(&pdev->dev, "Failed to parse DT data\n"); + return ret; + } + + memset(&props, 0, sizeof(struct backlight_properties)); + props.type = BACKLIGHT_RAW; + props.max_brightness = priv->max_brightness; + props.brightness = priv->default_brightness; + props.power = (priv->default_brightness > 0) ? FB_BLANK_POWERDOWN : + FB_BLANK_UNBLANK; + 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"); + return PTR_ERR(priv->bl_dev); + } + + for (i = 0; i < priv->nb_leds; i++) + led_sysfs_disable(priv->leds[i]); + + backlight_update_status(priv->bl_dev); + + return 0; +} + +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; + int i; + + backlight_device_unregister(bl); + + led_bl_power_off(priv); + for (i = 0; i < priv->nb_leds; i++) + led_sysfs_enable(priv->leds[i]); + + 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");