On 18/04/14 18:51, Tony Lindgren wrote:

quoted

+	gpio = of_get_gpio(node, 0);
+	if (gpio_is_valid(gpio) || gpio == -ENOENT) {
+		ddata->enable_gpio = gpio;
+	} else {
+		dev_err(&pdev->dev, "failed to parse enable gpio\n");
+		return gpio;
+	}

We should set the GPIO polarity based on the OF_GPIO_ACTIVE_LOW like
gpio_backlight_probe_dt is doing. 

Instead of doing it with the old gpio API, and checking the 'active'
flag everywhere, I think we can use the new gpiod API which handles the
polarity automatically.

I attached prototype patches (based on -rc2) for panel dpi using that
approach. It's a bit messier than I'd like, because for non-DT boot we
need to request the gpio using the old API, and then convert it to
gpio_desc. We can remove that code when all the boards use DT.

I've compiled tested this only, as I don't have DPI panels I could use.
I did try similar approach for TFP410, and it seemed to work fine.

 Tomi