1 // SPDX-License-Identifier: GPL-2.0-only
4  * Based on code and know-how from the Samsung GT-S7710
39 	gpiod_set_value_cansleep(ktd253->gpiod, 1);  in ktd253_backlight_set_max_ratio()
62 	gpiod_set_value(ktd253->gpiod, 0);  in ktd253_backlight_stepdown()
64 	gpiod_set_value(ktd253->gpiod, 1);  in ktd253_backlight_stepdown()
65 	ns = ktime_get_ns() - ns;  in ktd253_backlight_stepdown()
67 		dev_err(ktd253->dev, "PCM on backlight took too long (%llu ns)\n", ns);  in ktd253_backlight_stepdown()
68 		return -EAGAIN;  in ktd253_backlight_stepdown()
77 	int brightness = backlight_get_brightness(bl);  in ktd253_backlight_update_status()  local
79 	u16 current_ratio = ktd253->ratio;  in ktd253_backlight_update_status()
82 	dev_dbg(ktd253->dev, "new brightness/ratio: %d/32\n", brightness);  in ktd253_backlight_update_status()
84 	target_ratio = brightness;  in ktd253_backlight_update_status()
91 		gpiod_set_value_cansleep(ktd253->gpiod, 0);  in ktd253_backlight_update_status()
97 		ktd253->ratio = 0;  in ktd253_backlight_update_status()
113 		if (ret == -EAGAIN) {  in ktd253_backlight_update_status()
119 			gpiod_set_value_cansleep(ktd253->gpiod, 0);  in ktd253_backlight_update_status()
127 			current_ratio--;  in ktd253_backlight_update_status()
130 	ktd253->ratio = current_ratio;  in ktd253_backlight_update_status()
132 	dev_dbg(ktd253->dev, "new ratio set to %d/32\n", target_ratio);  in ktd253_backlight_update_status()
144 	struct device *dev = &pdev->dev;  in ktd253_backlight_probe()
148 	u32 brightness;  in ktd253_backlight_probe()  local
153 		return -ENOMEM;  in ktd253_backlight_probe()
154 	ktd253->dev = dev;  in ktd253_backlight_probe()
156 	ret = device_property_read_u32(dev, "max-brightness", &max_brightness);  in ktd253_backlight_probe()
160 		/* Clamp brightness to hardware max */  in ktd253_backlight_probe()
161 		dev_err(dev, "illegal max brightness specified\n");  in ktd253_backlight_probe()
165 	ret = device_property_read_u32(dev, "default-brightness", &brightness);  in ktd253_backlight_probe()
167 		brightness = KTD253_DEFAULT_RATIO;  in ktd253_backlight_probe()
168 	if (brightness > max_brightness) {  in ktd253_backlight_probe()
169 		/* Clamp default brightness to max brightness */  in ktd253_backlight_probe()
170 		dev_err(dev, "default brightness exceeds max brightness\n");  in ktd253_backlight_probe()
171 		brightness = max_brightness;  in ktd253_backlight_probe()
174 	ktd253->gpiod = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);  in ktd253_backlight_probe()
175 	if (IS_ERR(ktd253->gpiod))  in ktd253_backlight_probe()
176 		return dev_err_probe(dev, PTR_ERR(ktd253->gpiod),  in ktd253_backlight_probe()
178 	gpiod_set_consumer_name(ktd253->gpiod, dev_name(dev));  in ktd253_backlight_probe()
188 	bl->props.max_brightness = max_brightness;  in ktd253_backlight_probe()
189 	/* When we just enable the GPIO line we set max brightness */  in ktd253_backlight_probe()
190 	if (brightness) {  in ktd253_backlight_probe()
191 		bl->props.brightness = brightness;  in ktd253_backlight_probe()
192 		bl->props.power = BACKLIGHT_POWER_ON;  in ktd253_backlight_probe()
194 		bl->props.brightness = 0;  in ktd253_backlight_probe()
195 		bl->props.power = BACKLIGHT_POWER_OFF;  in ktd253_backlight_probe()
198 	ktd253->bl = bl;  in ktd253_backlight_probe()
214 		.name = "ktd253-backlight",
224 MODULE_ALIAS("platform:ktd253-backlight");