2  * gpio_backlight.c - Simple GPIO-controlled backlight
9 #include <linux/backlight.h>
12 #include <linux/gpio.h> /* Only for legacy support */
13 #include <linux/gpio/consumer.h>
34 	int brightness = bl->props.brightness;  in gpio_backlight_update_status()
36 	if (bl->props.power != FB_BLANK_UNBLANK ||  in gpio_backlight_update_status()
37 	    bl->props.fb_blank != FB_BLANK_UNBLANK ||  in gpio_backlight_update_status()
38 	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))  in gpio_backlight_update_status()
41 	gpiod_set_value_cansleep(gbl->gpiod, brightness);  in gpio_backlight_update_status()
51 	return gbl->fbdev == NULL || gbl->fbdev == info->dev;  in gpio_backlight_check_fb()
63 	struct device *dev = &pdev->dev;  in gpio_backlight_probe_dt()
64 	struct device_node *np = dev->of_node;  in gpio_backlight_probe_dt()
68 	gbl->def_value = of_property_read_bool(np, "default-on");  in gpio_backlight_probe_dt()
69 	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;  in gpio_backlight_probe_dt()
71 	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);  in gpio_backlight_probe_dt()
72 	if (IS_ERR(gbl->gpiod)) {  in gpio_backlight_probe_dt()
73 		ret = PTR_ERR(gbl->gpiod);  in gpio_backlight_probe_dt()
75 		if (ret != -EPROBE_DEFER) {  in gpio_backlight_probe_dt()
88 		dev_get_platdata(&pdev->dev);  in gpio_backlight_probe()
92 	struct device_node *np = pdev->dev.of_node;  in gpio_backlight_probe()
96 		dev_err(&pdev->dev,  in gpio_backlight_probe()
98 		return -ENODEV;  in gpio_backlight_probe()
101 	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);  in gpio_backlight_probe()
103 		return -ENOMEM;  in gpio_backlight_probe()
105 	gbl->dev = &pdev->dev;  in gpio_backlight_probe()
113 		 * Legacy platform data GPIO retrieveal. Do not expand  in gpio_backlight_probe()
119 		gbl->fbdev = pdata->fbdev;  in gpio_backlight_probe()
120 		gbl->def_value = pdata->def_value;  in gpio_backlight_probe()
121 		flags |= gbl->def_value ? GPIOF_INIT_HIGH : GPIOF_INIT_LOW;  in gpio_backlight_probe()
123 		ret = devm_gpio_request_one(gbl->dev, pdata->gpio, flags,  in gpio_backlight_probe()
124 					    pdata ? pdata->name : "backlight");  in gpio_backlight_probe()
126 			dev_err(&pdev->dev, "unable to request GPIO\n");  in gpio_backlight_probe()
129 		gbl->gpiod = gpio_to_desc(pdata->gpio);  in gpio_backlight_probe()
130 		if (!gbl->gpiod)  in gpio_backlight_probe()
131 			return -EINVAL;  in gpio_backlight_probe()
137 	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),  in gpio_backlight_probe()
138 					&pdev->dev, gbl, &gpio_backlight_ops,  in gpio_backlight_probe()
141 		dev_err(&pdev->dev, "failed to register backlight\n");  in gpio_backlight_probe()
145 	bl->props.brightness = gbl->def_value;  in gpio_backlight_probe()
154 	{ .compatible = "gpio-backlight" },
163 		.name		= "gpio-backlight",
172 MODULE_DESCRIPTION("GPIO-based Backlight Driver");
174 MODULE_ALIAS("platform:gpio-backlight");