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Commit d0b3cfee authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'backlight-next-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight 

Pull backlight updates from Lee Jones:
 "Core Frameworks
   - Obtain scale type through sysfs

  New Functionality:
   - Provide Device Tree functionality in rave-sp-backlight
   - Calculate if scale type is (non-)linear in pwm_bl

  Fix-ups:
   - Simplify code in lm3630a_bl
   - Trivial rename/whitespace/typo fixes in lms283gf05
   - Remove superfluous NULL check in tosa_lcd
   - Fix power state initialisation in gpio_backlight
   - List supported file in MAINTAINERS

  Bug Fixes:
   - Kconfig - default to not building unless requested in
     {LED,BACKLIGHT}_CLASS_DEVICE"

* tag 'backlight-next-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: pwm_bl: Set scale type for brightness curves specified in the DT
  backlight: pwm_bl: Set scale type for CIE 1931 curves
  backlight: Expose brightness curve type through sysfs
  MAINTAINERS: Add entry for stable backlight sysfs ABI documentation
  backlight: gpio-backlight: Correct initial power state handling
  video: backlight: tosa_lcd: drop check because i2c_unregister_device() is NULL safe
  video: backlight: Drop default m for {LCD,BACKLIGHT_CLASS_DEVICE}
  backlight: lms283gf05: Fix a typo in the description passed to 'devm_gpio_request_one()'
  backlight: lm3630a: Switch to use fwnode_property_count_uXX()
  backlight: rave-sp: Leave initial state and register with correct device
parents 299d14d4 c0b64faf

Documentation/ABI/testing/sysfs-class-backlight

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+26 −0
Original line number Diff line number Diff line 
What:		/sys/class/backlight/<backlight>/scale

Date:		July 2019

KernelVersion:	5.4

Contact:	Daniel Thompson <daniel.thompson@linaro.org>

Description:

		Description of the scale of the brightness curve.



		The human eye senses brightness approximately logarithmically,

		hence linear changes in brightness are perceived as being

		non-linear. To achieve a linear perception of brightness changes

		controls like sliders need to apply a logarithmic mapping for

		backlights with a linear brightness curve.



		Possible values of the attribute are:



		unknown

		  The scale of the brightness curve is unknown.



		linear

		  The brightness changes linearly with each step. Brightness

		  controls should apply a logarithmic mapping for a linear

		  perception.



		non-linear

		  The brightness changes non-linearly with each step. Brightness

		  controls should use a linear mapping for a linear perception.

MAINTAINERS

+2 −0
Original line number Diff line number Diff line
@@ -2921,6 +2921,8 @@ F: drivers/video/backlight/ 
F:	include/linux/backlight.h

F:	include/linux/pwm_backlight.h

F:	Documentation/devicetree/bindings/leds/backlight

F:	Documentation/ABI/stable/sysfs-class-backlight

F:	Documentation/ABI/testing/sysfs-class-backlight















BATMAN ADVANCED















M:	Marek Lindner <mareklindner@neomailbox.ch>

































drivers/video/backlight/Kconfig



+0
−2




























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@@ -10,7 +10,6 @@ menu "Backlight & LCD device support"













#















config LCD_CLASS_DEVICE















        tristate "Lowlevel LCD controls"













	default m















	help















	  This framework adds support for low-level control of LCD.















	  Some framebuffer devices connect to platform-specific LCD modules










@@ -143,7 +142,6 @@ endif # LCD_CLASS_DEVICE













#















config BACKLIGHT_CLASS_DEVICE















        tristate "Lowlevel Backlight controls"













	default m















	help















	  This framework adds support for low-level control of the LCD















          backlight. This includes support for brightness and power.

































drivers/video/backlight/backlight.c



+19
−0




























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@@ -32,6 +32,12 @@ static const char *const backlight_types[] = {













	[BACKLIGHT_FIRMWARE] = "firmware",















};





























static const char *const backlight_scale_types[] = {













	[BACKLIGHT_SCALE_UNKNOWN]	= "unknown",













	[BACKLIGHT_SCALE_LINEAR]	= "linear",













	[BACKLIGHT_SCALE_NON_LINEAR]	= "non-linear",













};





























#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \















			   defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))















/* This callback gets called when something important happens inside a










@@ -246,6 +252,18 @@ static ssize_t actual_brightness_show(struct device *dev,













}















static DEVICE_ATTR_RO(actual_brightness);





























static ssize_t scale_show(struct device *dev,













		struct device_attribute *attr, char *buf)













{













	struct backlight_device *bd = to_backlight_device(dev);



























	if (WARN_ON(bd->props.scale > BACKLIGHT_SCALE_NON_LINEAR))













		return sprintf(buf, "unknown\n");



























	return sprintf(buf, "%s\n", backlight_scale_types[bd->props.scale]);













}













static DEVICE_ATTR_RO(scale);





























static struct class *backlight_class;































#ifdef CONFIG_PM_SLEEP










@@ -292,6 +310,7 @@ static struct attribute *bl_device_attrs[] = {













	&dev_attr_brightness.attr,















	&dev_attr_actual_brightness.attr,















	&dev_attr_max_brightness.attr,













	&dev_attr_scale.attr,















	&dev_attr_type.attr,















	NULL,















};

































drivers/video/backlight/gpio_backlight.c



+20
−4




























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Diff line








@@ -59,13 +59,11 @@ static int gpio_backlight_probe_dt(struct platform_device *pdev,













				   struct gpio_backlight *gbl)















{















	struct device *dev = &pdev->dev;













	enum gpiod_flags flags;















	int ret;































	gbl->def_value = device_property_read_bool(dev, "default-on");













	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;





























	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);













	gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS);















	if (IS_ERR(gbl->gpiod)) {















		ret = PTR_ERR(gbl->gpiod);

























@@ -79,6 +77,22 @@ static int gpio_backlight_probe_dt(struct platform_device *pdev,













	return 0;















}





























static int gpio_backlight_initial_power_state(struct gpio_backlight *gbl)













{













	struct device_node *node = gbl->dev->of_node;



























	/* Not booted with device tree or no phandle link to the node */













	if (!node || !node->phandle)













		return gbl->def_value ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;



























	/* if the enable GPIO is disabled, do not enable the backlight */













	if (gpiod_get_value_cansleep(gbl->gpiod) == 0)













		return FB_BLANK_POWERDOWN;



























	return FB_BLANK_UNBLANK;













}











































static int gpio_backlight_probe(struct platform_device *pdev)















{















	struct gpio_backlight_platform_data *pdata =










@@ -136,7 +150,9 @@ static int gpio_backlight_probe(struct platform_device *pdev)













		return PTR_ERR(bl);















	}





























	bl->props.brightness = gbl->def_value;













	bl->props.power = gpio_backlight_initial_power_state(gbl);













	bl->props.brightness = 1;





























	backlight_update_status(bl);































	platform_set_drvdata(pdev, bl);