video/backlight/gpio_backlight.c

1 // SPDX-License-Identifier: GPL-2.0-only
3  * gpio_backlight.c - Simple GPIO-controlled backlight
6 #include <linux/backlight.h>
9 #include <linux/gpio/consumer.h>
28 	gpiod_set_value_cansleep(gbl->gpiod, backlight_get_brightness(bl));  in gpio_backlight_update_status()
38 	return gbl->fbdev == NULL || gbl->fbdev == info->dev;  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()
59 		return -ENOMEM;  in gpio_backlight_probe()
62 		gbl->fbdev = pdata->fbdev;  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()
81 		dev_err(dev, "failed to register backlight\n");  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_direction(gbl->gpiod) == 0 &&  in gpio_backlight_probe()
91 		 gpiod_get_value_cansleep(gbl->gpiod) == 0)  in gpio_backlight_probe()
92 		bl->props.power = FB_BLANK_POWERDOWN;  in gpio_backlight_probe()
94 		bl->props.power = FB_BLANK_UNBLANK;  in gpio_backlight_probe()
96 	bl->props.brightness = 1;  in gpio_backlight_probe()
99 	ret = gpiod_direction_output(gbl->gpiod, init_brightness);  in gpio_backlight_probe()
110 	{ .compatible = "gpio-backlight" },
118 		.name		= "gpio-backlight",
127 MODULE_DESCRIPTION("GPIO-based Backlight Driver");
129 MODULE_ALIAS("platform:gpio-backlight");