Re: BUG: Staging: fbtft: Switch to the gpio descriptor interface

On 10/07/2019 17:05, Nicolas Saenz Julienne wrote:

On Wed, 2019-07-10 at 16:31 +0800, Phil Reid wrote:

quoted

G'day Nishad,

I'm just wondering if the commit
c440eee1a7a1d0f "Staging: fbtft: Switch to the gpio descriptor interface"
was tested on anything.

I've had to apply the following patch to get my display functioning again.

in particular the devm_gpiod_get_index using dev->driver->name for the gpio
lookup seems
wrong.

FYI We've seen the same issue this week in opensuse's bugzilla and was testing
something very similar to the patch below. Phil do you plan on submitting your
fix?

Yes I can submit a patch tomorrow.

I just wasn't sure if it was working for anyone.

quoted

Also I've had to invert the polarity of the reset-gpios in the DT file for the
display to function.

this code:
	gpiod_set_value_cansleep(par->gpio.reset, 0);
	usleep_range(20, 40);
	gpiod_set_value_cansleep(par->gpio.reset, 1);

could be read as deasserting the reset line and then asserting it.
So I've had to specify and active high reset line in the DT.

Regards
Phil

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-

core.c
index 9b07bad..6fe7cb5 100644

--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c

@@ -79,18 +79,16 @@ static int fbtft_request_one_gpio(struct fbtft_par *par,
   	struct device_node *node = dev->of_node;
   	int ret = 0;

-	if (of_find_property(node, name, NULL)) {
-		*gpiop = devm_gpiod_get_index(dev, dev->driver->name, index,
-					      GPIOD_OUT_HIGH);
-		if (IS_ERR(*gpiop)) {
-			ret = PTR_ERR(*gpiop);
-			dev_err(dev,
-				"Failed to request %s GPIO:%d\n", name, ret);
-			return ret;
-		}
-		fbtft_par_dbg(DEBUG_REQUEST_GPIOS, par, "%s: '%s' GPIO\n",
-			      __func__, name);
+	*gpiop = devm_gpiod_get_index_optional(dev, name, index,
+				      GPIOD_OUT_HIGH);
+	if (IS_ERR(*gpiop)) {
+		ret = PTR_ERR(*gpiop);
+		dev_err(dev,
+			"Failed to request %s GPIO: (%d)\n", name, ret);
+		return ret;
   	}
+	fbtft_par_dbg(DEBUG_REQUEST_GPIOS, par, "%s: '%s' GPIO\n",
+		      __func__, name);

   	return ret;
   }

@@ -103,34 +101,34 @@ static int fbtft_request_gpios_dt(struct fbtft_par *par)
   	if (!par->info->device->of_node)
   		return -EINVAL;

-	ret = fbtft_request_one_gpio(par, "reset-gpios", 0, &par->gpio.reset);
+	ret = fbtft_request_one_gpio(par, "reset", 0, &par->gpio.reset);
   	if (ret)
   		return ret;
-	ret = fbtft_request_one_gpio(par, "dc-gpios", 0, &par->gpio.dc);
+	ret = fbtft_request_one_gpio(par, "dc", 0, &par->gpio.dc);
   	if (ret)
   		return ret;
-	ret = fbtft_request_one_gpio(par, "rd-gpios", 0, &par->gpio.rd);
+	ret = fbtft_request_one_gpio(par, "rd", 0, &par->gpio.rd);
   	if (ret)
   		return ret;
-	ret = fbtft_request_one_gpio(par, "wr-gpios", 0, &par->gpio.wr);
+	ret = fbtft_request_one_gpio(par, "wr", 0, &par->gpio.wr);
   	if (ret)
   		return ret;
-	ret = fbtft_request_one_gpio(par, "cs-gpios", 0, &par->gpio.cs);
+	ret = fbtft_request_one_gpio(par, "cs", 0, &par->gpio.cs);
   	if (ret)
   		return ret;
-	ret = fbtft_request_one_gpio(par, "latch-gpios", 0, &par->gpio.latch);
+	ret = fbtft_request_one_gpio(par, "latch", 0, &par->gpio.latch);
   	if (ret)
   		return ret;
   	for (i = 0; i < 16; i++) {
-		ret = fbtft_request_one_gpio(par, "db-gpios", i,
+		ret = fbtft_request_one_gpio(par, "db", i,
   					     &par->gpio.db[i]);
   		if (ret)
   			return ret;
-		ret = fbtft_request_one_gpio(par, "led-gpios", i,
+		ret = fbtft_request_one_gpio(par, "led", i,
   					     &par->gpio.led[i]);
   		if (ret)
   			return ret;
-		ret = fbtft_request_one_gpio(par, "aux-gpios", i,
+		ret = fbtft_request_one_gpio(par, "aux", i,
   					     &par->gpio.aux[i]);
   		if (ret)
   			return ret;

-- 
Regards
Phil Reid