backlight: aw99706: Add support for Awinic AW99706 backlight

Add support for Awinic AW99706 backlight, which can be found in
tablet and notebook backlight, one case is the Lenovo Legion Y700
Gen4. This driver refers to the official datasheets and android
driver, they can be found in [1].

[1] https://www.awinic.com/en/productDetail/AW99706QNR

Signed-off-by: Junjie Cao <caojunjie650@gmail.com>
Tested-by: Pengyu Luo <mitltlatltl@gmail.com>
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20251109032240.3422503-3-caojunjie650@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: Lukaaa525

MAINTAINERS

@@ -4123,6 +4123,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/adc/avia-hx711.yaml
 F:	drivers/iio/adc/hx711.c
 
+AWINIC AW99706 WLED BACKLIGHT DRIVER
+M:	Junjie Cao <caojunjie650@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/backlight/awinic,aw99706.yaml
+F:	drivers/video/backlight/aw99706.c
+
 AX.25 NETWORK LAYER
 L:	linux-hams@vger.kernel.org
 S:	Orphan

drivers/video/backlight/Kconfig

@@ -156,6 +156,14 @@ config BACKLIGHT_ATMEL_LCDC
 	  If in doubt, it's safe to enable this option; it doesn't kick
 	  in unless the board's description says it's wired that way.
 
+config BACKLIGHT_AW99706
+	tristate "Backlight Driver for Awinic AW99706"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you have a LCD backlight connected to the WLED output of AW99706
+	  WLED output, say Y here to enable this driver.
+
 config BACKLIGHT_EP93XX
 	tristate "Cirrus EP93xx Backlight Driver"
 	depends on FB_EP93XX

drivers/video/backlight/Makefile

@@ -25,6 +25,7 @@ obj-$(CONFIG_BACKLIGHT_ADP8870)		+= adp8870_bl.o
 obj-$(CONFIG_BACKLIGHT_APPLE)		+= apple_bl.o
 obj-$(CONFIG_BACKLIGHT_APPLE_DWI)	+= apple_dwi_bl.o
 obj-$(CONFIG_BACKLIGHT_AS3711)		+= as3711_bl.o
+obj-$(CONFIG_BACKLIGHT_AW99706)		+= aw99706.o
 obj-$(CONFIG_BACKLIGHT_BD6107)		+= bd6107.o
 obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE)	+= backlight.o
 obj-$(CONFIG_BACKLIGHT_DA903X)		+= da903x_bl.o