1 // SPDX-License-Identifier: GPL-2.0-only
3  * gpio_backlight.c - Simple GPIO-controlled backlight
23 static int gpio_backlight_update_status(struct backlight_device *bl)  in gpio_backlight_update_status()  argument
25 	struct gpio_backlight *gbl = bl_get_data(bl);  in gpio_backlight_update_status()
27 	gpiod_set_value_cansleep(gbl->gpiod, backlight_get_brightness(bl));  in gpio_backlight_update_status()
32 static bool gpio_backlight_controls_device(struct backlight_device *bl,  in gpio_backlight_controls_device()  argument
35 	struct gpio_backlight *gbl = bl_get_data(bl);  in gpio_backlight_controls_device()
37 	return !gbl->dev || gbl->dev == display_dev;  in gpio_backlight_controls_device()
48 	struct device *dev = &pdev->dev;  in gpio_backlight_probe()
50 	struct device_node *of_node = dev->of_node;  in gpio_backlight_probe()
52 	struct backlight_device *bl;  in gpio_backlight_probe()  local
58 		return -ENOMEM;  in gpio_backlight_probe()
61 		gbl->dev = pdata->dev;  in gpio_backlight_probe()
63 	def_value = device_property_read_bool(dev, "default-on");  in gpio_backlight_probe()
65 	gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS);  in gpio_backlight_probe()
66 	if (IS_ERR(gbl->gpiod))  in gpio_backlight_probe()
67 		return dev_err_probe(dev, PTR_ERR(gbl->gpiod),  in gpio_backlight_probe()
73 	bl = devm_backlight_device_register(dev, dev_name(dev), dev, gbl,  in gpio_backlight_probe()
75 	if (IS_ERR(bl)) {  in gpio_backlight_probe()
77 		return PTR_ERR(bl);  in gpio_backlight_probe()
81 	if (!of_node || !of_node->phandle)  in gpio_backlight_probe()
83 		bl->props.power = def_value ? BACKLIGHT_POWER_ON  in gpio_backlight_probe()
85 	else if (gpiod_get_value_cansleep(gbl->gpiod) == 0)  in gpio_backlight_probe()
86 		bl->props.power = BACKLIGHT_POWER_OFF;  in gpio_backlight_probe()
88 		bl->props.power = BACKLIGHT_POWER_ON;  in gpio_backlight_probe()
90 	bl->props.brightness = 1;  in gpio_backlight_probe()
92 	init_brightness = backlight_get_brightness(bl);  in gpio_backlight_probe()
93 	ret = gpiod_direction_output(gbl->gpiod, init_brightness);  in gpio_backlight_probe()
99 	platform_set_drvdata(pdev, bl);  in gpio_backlight_probe()
104 	{ .compatible = "gpio-backlight" },
112 		.name		= "gpio-backlight",
121 MODULE_DESCRIPTION("GPIO-based Backlight Driver");
123 MODULE_ALIAS("platform:gpio-backlight");