Commit a5554f1b authored by Duje Mihanović's avatar Duje Mihanović Committed by Lee Jones
Browse files

backlight: Add Kinetic KTD2801 Backlight support 



KTD2801 is a LED backlight driver IC found in samsung,coreprimevelte.
The brightness can be set using PWM or the ExpressWire protocol. Add
support for the KTD2801.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarDuje Mihanović <duje.mihanovic@skole.hr>
Link: https://lore.kernel.org/r/20240125-ktd2801-v5-4-e22da232a825@skole.hr


Signed-off-by: default avatarLee Jones <lee@kernel.org>
parent 922235a9

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -12052,6 +12052,12 @@ S: Maintained 
F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml

F:	drivers/video/backlight/ktd253-backlight.c









KTD2801 BACKLIGHT DRIVER









M:	Duje Mihanović <duje.mihanovic@skole.hr>









S:	Maintained









F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd2801.yaml









F:	drivers/video/backlight/ktd2801-backlight.c

















KTEST









M:	Steven Rostedt <rostedt@goodmis.org>









M:	John Hawley <warthog9@eaglescrag.net>
































drivers/video/backlight/Kconfig



+7
−0






























Original line number
Diff line number
Diff line







@@ -183,6 +183,13 @@ config BACKLIGHT_KTD253







	  which is a 1-wire GPIO-controlled backlight found in some mobile









	  phones.



















config BACKLIGHT_KTD2801









	tristate "Backlight Driver for Kinetic KTD2801"









	select LEDS_EXPRESSWIRE









	help









	  Say Y to enable the backlight driver for the Kinetic KTD2801 1-wire









	  GPIO-controlled backlight found in Samsung Galaxy Core Prime VE LTE.



















config BACKLIGHT_KTZ8866









	tristate "Backlight Driver for Kinetic KTZ8866"









	depends on I2C
































drivers/video/backlight/Makefile



+1
−0






























Original line number
Diff line number
Diff line







@@ -34,6 +34,7 @@ obj-$(CONFIG_BACKLIGHT_HP680)		+= hp680_bl.o







obj-$(CONFIG_BACKLIGHT_HP700)		+= jornada720_bl.o









obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO)	+= ipaq_micro_bl.o









obj-$(CONFIG_BACKLIGHT_KTD253)		+= ktd253-backlight.o









obj-$(CONFIG_BACKLIGHT_KTD2801)		+= ktd2801-backlight.o









obj-$(CONFIG_BACKLIGHT_KTZ8866)		+= ktz8866.o









obj-$(CONFIG_BACKLIGHT_LM3533)		+= lm3533_bl.o









obj-$(CONFIG_BACKLIGHT_LM3630A)		+= lm3630a_bl.o
































drivers/video/backlight/ktd2801-backlight.c
0 → 100644



+128
−0






























Original line number
Diff line number
Diff line









// SPDX-License-Identifier: GPL-2.0-only









/*









 * Datasheet:









 * https://www.kinet-ic.com/uploads/web/KTD2801/KTD2801-04b.pdf









 */









#include <linux/backlight.h>









#include <linux/gpio/consumer.h>









#include <linux/leds-expresswire.h>









#include <linux/platform_device.h>









#include <linux/property.h>



















#define KTD2801_DEFAULT_BRIGHTNESS	100









#define KTD2801_MAX_BRIGHTNESS		255



















/* These values have been extracted from Samsung's driver. */









const struct expresswire_timing ktd2801_timing = {









	.poweroff_us = 2600,









	.detect_delay_us = 150,









	.detect_us = 270,









	.data_start_us = 5,









	.short_bitset_us = 5,









	.long_bitset_us = 15,









	.end_of_data_low_us = 10,









	.end_of_data_high_us = 350









};



















struct ktd2801_backlight {









	struct expresswire_common_props props;









	struct backlight_device *bd;









	bool was_on;









};



















static int ktd2801_update_status(struct backlight_device *bd)









{









	struct ktd2801_backlight *ktd2801 = bl_get_data(bd);









	u8 brightness = (u8) backlight_get_brightness(bd);



















	if (backlight_is_blank(bd)) {









		expresswire_power_off(&ktd2801->props);









		ktd2801->was_on = false;









		return 0;









	}



















	if (!ktd2801->was_on) {









		expresswire_enable(&ktd2801->props);









		ktd2801->was_on = true;









	}



















	expresswire_write_u8(&ktd2801->props, brightness);



















	return 0;









}



















static const struct backlight_ops ktd2801_backlight_ops = {









	.update_status = ktd2801_update_status,









};



















static int ktd2801_backlight_probe(struct platform_device *pdev)









{









	struct device *dev = &pdev->dev;









	struct backlight_device *bd;









	struct ktd2801_backlight *ktd2801;









	u32 brightness, max_brightness;









	int ret;



















	ktd2801 = devm_kzalloc(dev, sizeof(*ktd2801), GFP_KERNEL);









	if (!ktd2801)









		return -ENOMEM;









	ktd2801->was_on = true;









	ktd2801->props.timing = ktd2801_timing;



















	ret = device_property_read_u32(dev, "max-brightness", &max_brightness);









	if (ret)









		max_brightness = KTD2801_MAX_BRIGHTNESS;









	if (max_brightness > KTD2801_MAX_BRIGHTNESS) {









		dev_err(dev, "illegal max brightness specified\n");









		max_brightness = KTD2801_MAX_BRIGHTNESS;









	}



















	ret = device_property_read_u32(dev, "default-brightness", &brightness);









	if (ret)









		brightness = KTD2801_DEFAULT_BRIGHTNESS;









	if (brightness > max_brightness) {









		dev_err(dev, "default brightness exceeds max\n");









		brightness = max_brightness;









	}



















	ktd2801->props.ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_OUT_HIGH);









	if (IS_ERR(ktd2801->props.ctrl_gpio))









		return dev_err_probe(dev, PTR_ERR(ktd2801->props.ctrl_gpio),









				"failed to get backlight GPIO");









	gpiod_set_consumer_name(ktd2801->props.ctrl_gpio, dev_name(dev));



















	bd = devm_backlight_device_register(dev, dev_name(dev), dev, ktd2801,









			&ktd2801_backlight_ops, NULL);









	if (IS_ERR(bd))









		return dev_err_probe(dev, PTR_ERR(bd),









				"failed to register backlight");



















	bd->props.max_brightness = max_brightness;









	bd->props.brightness = brightness;



















	ktd2801->bd = bd;









	platform_set_drvdata(pdev, bd);









	backlight_update_status(bd);



















	return 0;









}



















static const struct of_device_id ktd2801_of_match[] = {









	{ .compatible = "kinetic,ktd2801" },









	{ }









};









MODULE_DEVICE_TABLE(of, ktd2801_of_match);



















static struct platform_driver ktd2801_backlight_driver = {









	.driver = {









		.name = "ktd2801-backlight",









		.of_match_table = ktd2801_of_match,









	},









	.probe = ktd2801_backlight_probe,









};









module_platform_driver(ktd2801_backlight_driver);



















MODULE_IMPORT_NS(EXPRESSWIRE);









MODULE_AUTHOR("Duje Mihanović <duje.mihanovic@skole.hr>");









MODULE_DESCRIPTION("Kinetic KTD2801 Backlight Driver");









MODULE_LICENSE("GPL");