On Wed, 19 Feb 2020, Pavel Machek wrote: > Hi! > > > > > > > > It would be good to get LED backlight to work in clean way for 5.6 > > > > > > > kernel. > > > > > ... > > > > > > > [If you have an idea what else is needed, it would be welcome; it > > > > > > > works for me in development tree but not in tree I'd like to > > > > > > > upstream.] > > > > > > > > > > > > > > Lee, would you be willing to take "backlight: add led-backlight > > > > > > > driver"? Would it help if I got "leds: Add managed API to get a LED > > > > > > > from a device driver" and "leds: Add of_led_get() and led_put()" into > > > > > > > for_next tree of the LED subsystem? > > > > > > > > > > > > It looks like you have an open question from Tony on v10. > > > > > > > > > > > > Is that patch orthogonal, or are there depend{ants,encies}? > > > > > > > > > > Uhh looks like we messed up a bit with integration. Now droid4 > > > > > LCD backlight can no longer be enabled at all manually in v5.6-rc1 > > > > > without the "add led-backlight driver" patch.. Should we just > > > > > merge it to fix it rather than start scrambling with other > > > > > temporary hacks? > > > > > > > > We should just merge the "add led-backlight driver". Everything should > > > > be ready for it. I'm sorry if I broke something working, I was not > > > > aware it worked at all. > > > > > > > > Unfortunately, this is backlight code, not LED, so I can't just merge it. > > > > > > Please go ahead. Apply my Acked-by and merge away ASAP. > > > > > > Acked-by: Lee Jones <lee.jones@xxxxxxxxxx> > > > > OK best to merge the driver via the LED tree: > > > > Acked-by: Tony Lindgren <tony@xxxxxxxxxxx> > > Tested-by: Tony Lindgren <tony@xxxxxxxxxxx> > > Is the patch below the one both of you are talking about? > > Hmm. I should s/default-brightness-level/default-brightness/ > below. > > Lee, I can of course take it (thanks), but won't Kconfig/Makefile > pieces cause rejects? It might be still better if you took it. I can > hand-edit it and submit it in form for easy application... tommorow. My suggestion would be to send it to Linus ASAP. Ideally it would get into the -rcs, as it 'fixes' things. > Best regards, > > Pavel > > commit 81a2daadf8dd6c8e0cbc3b60246932436be3c714 > Author: Tomi Valkeinen <tomi.valkeinen@xxxxxx> > Date: Thu Oct 3 10:28:12 2019 +0200 > > backlight: add led-backlight driver > > 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@xxxxxx> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxx> > Acked-by: Pavel Machek <pavel@xxxxxx> > Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> > > diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig > index 4c8f73394aac..93836ef872f5 100644 > --- a/drivers/video/backlight/Kconfig > +++ b/drivers/video/backlight/Kconfig > @@ -463,6 +463,13 @@ 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 961fb553b9c0..5e13242f31d6 100644 > --- a/drivers/video/backlight/Makefile > +++ b/drivers/video/backlight/Makefile > @@ -60,3 +60,4 @@ 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..3f66549997c8 > --- /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@xxxxxx> > + * > + * 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_of_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"); > -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog