1 // SPDX-License-Identifier: GPL-2.0-only
3  * gpio_backlight.c - Simple GPIO-controlled backlight
24 static int gpio_backlight_update_status(struct backlight_device *bl)  in gpio_backlight_update_status()  argument
26 	struct gpio_backlight *gbl = bl_get_data(bl);  in gpio_backlight_update_status()
28 	gpiod_set_value_cansleep(gbl->gpiod, backlight_get_brightness(bl));  in gpio_backlight_update_status()
33 static int gpio_backlight_check_fb(struct backlight_device *bl,  in gpio_backlight_check_fb()  argument
36 	struct gpio_backlight *gbl = bl_get_data(bl);  in gpio_backlight_check_fb()
38 	return !gbl->dev || gbl->dev == info->device;  in gpio_backlight_check_fb()
49 	struct device *dev = &pdev->dev;  in gpio_backlight_probe()
51 	struct device_node *of_node = dev->of_node;  in gpio_backlight_probe()
53 	struct backlight_device *bl;  in gpio_backlight_probe()  local
59 		return -ENOMEM;  in gpio_backlight_probe()
62 		gbl->dev = pdata->dev;  in gpio_backlight_probe()
64 	def_value = device_property_read_bool(dev, "default-on");  in gpio_backlight_probe()
66 	gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS);  in gpio_backlight_probe()
67 	if (IS_ERR(gbl->gpiod)) {  in gpio_backlight_probe()
68 		ret = PTR_ERR(gbl->gpiod);  in gpio_backlight_probe()
69 		if (ret != -EPROBE_DEFER)  in gpio_backlight_probe()
78 	bl = devm_backlight_device_register(dev, dev_name(dev), dev, gbl,  in gpio_backlight_probe()
80 	if (IS_ERR(bl)) {  in gpio_backlight_probe()
82 		return PTR_ERR(bl);  in gpio_backlight_probe()
86 	if (!of_node || !of_node->phandle)  in gpio_backlight_probe()
88 		bl->props.power = def_value ? FB_BLANK_UNBLANK  in gpio_backlight_probe()
90 	else if (gpiod_get_value_cansleep(gbl->gpiod) == 0)  in gpio_backlight_probe()
91 		bl->props.power = FB_BLANK_POWERDOWN;  in gpio_backlight_probe()
93 		bl->props.power = FB_BLANK_UNBLANK;  in gpio_backlight_probe()
95 	bl->props.brightness = 1;  in gpio_backlight_probe()
97 	init_brightness = backlight_get_brightness(bl);  in gpio_backlight_probe()
98 	ret = gpiod_direction_output(gbl->gpiod, init_brightness);  in gpio_backlight_probe()
104 	platform_set_drvdata(pdev, bl);  in gpio_backlight_probe()
109 	{ .compatible = "gpio-backlight" },
117 		.name		= "gpio-backlight",
126 MODULE_DESCRIPTION("GPIO-based Backlight Driver");
128 MODULE_ALIAS("platform:gpio-backlight");