[PATCH 0/2] Staging: fbtft: Fix probing of gpio descriptor

[PATCH 0/2] Staging: fbtft: Fix probing of gpio descriptor

[Phil Reid]

GPIO probing and reset polarity are broken.
Fix them.

Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")

Phil Reid (2):
  Staging: fbtft: Fix probing of gpio descriptor
  Staging: fbtft: Fix reset assertion when using gpio descriptor

 drivers/staging/fbtft/fbtft-core.c | 43 ++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

-- 
1.8.3.1

[PATCH 1/2] Staging: fbtft: Fix probing of gpio descriptor

[Phil Reid]

Conversion to use gpio descriptors broke all gpio lookups as
devm_gpiod_get_index was converted to use dev->driver->name for
the gpio name lookup. Fix this by using the name param. In
addition gpiod_get post-fixes the -gpios to the name so that
shouldn't be included in the call. However this then breaks the
of_find_property call to see if the gpio entry exists as all
fbtft treats all gpios as optional. So use devm_gpiod_get_index_optional
instead which achieves the same thing and is simpler.

Nishad confirmed the changes where only ever compile tested.

Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Signed-off-by: Phil Reid <preid@electromag.com.au>
---
 drivers/staging/fbtft/fbtft-core.c | 39 ++++++++++++++++++--------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 9b07bad..44b8074 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -76,21 +76,18 @@ static int fbtft_request_one_gpio(struct fbtft_par *par,
 				  struct gpio_desc **gpiop)
 {
 	struct device *dev = par->info->device;
-	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 +100,34 @@ 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;
-- 
1.8.3.1

[PATCH 2/2] Staging: fbtft: Fix reset assertion when using gpio descriptor

[Phil Reid]

Typically gpiod_set_value calls would assert the reset line and
then release it using the symantics of:
	gpiod_set_value(par->gpio.reset, 0);
	... delay
	gpiod_set_value(par->gpio.reset, 1);
And the gpio binding would specify the polarity.

Prior to conversion to gpiod calls the polarity in the DT
was ignored and assumed to be active low. Fix it so that
DT polarity is respected.

Signed-off-by: Phil Reid <preid@electromag.com.au>
---
 drivers/staging/fbtft/fbtft-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 44b8074..bc75025 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -231,9 +231,9 @@ static void fbtft_reset(struct fbtft_par *par)
 	if (!par->gpio.reset)
 		return;
 	fbtft_par_dbg(DEBUG_RESET, par, "%s()\n", __func__);
-	gpiod_set_value_cansleep(par->gpio.reset, 0);
-	usleep_range(20, 40);
 	gpiod_set_value_cansleep(par->gpio.reset, 1);
+	usleep_range(20, 40);
+	gpiod_set_value_cansleep(par->gpio.reset, 0);
 	msleep(120);
 }
 
-- 
1.8.3.1

Re: [PATCH 0/2] Staging: fbtft: Fix probing of gpio descriptor

[Nicolas Saenz Julienne]

[-- Attachment #1: Type: text/plain, Size: 827 bytes --]

On Thu, 2019-07-11 at 16:31 +0800, Phil Reid wrote:
> GPIO probing and reset polarity are broken.
> Fix them.
> 
> Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor
> interface")
> 
> Phil Reid (2):
>   Staging: fbtft: Fix probing of gpio descriptor
>   Staging: fbtft: Fix reset assertion when using gpio descriptor
> 
>  drivers/staging/fbtft/fbtft-core.c | 43 ++++++++++++++++++-------------------
> -
>  1 file changed, 20 insertions(+), 23 deletions(-)
> 

You can add my:

Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

The only issue I see is in the second patch, who should also have the same
'Fixes' tag.

BTW, while testing I found another issue, I'll send a fix shortly.

Kind regards,
Nicolas


[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[PATCH 0/2] Staging: fbtft: Fix probing of gpio descriptor

[Phil Reid]

GPIO probing and reset polarity are broken.
Fix them.

Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")

Changes from v2:
- Add fixes tag to "Fix reset assertion when using gpio descriptor"
- Add tested-by / reviewed-by tags

Phil Reid (2):
  Staging: fbtft: Fix probing of gpio descriptor
  Staging: fbtft: Fix reset assertion when using gpio descriptor

 drivers/staging/fbtft/fbtft-core.c | 43 ++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

-- 
1.8.3.1

[PATCH v2 1/2] Staging: fbtft: Fix probing of gpio descriptor

[Phil Reid]

Conversion to use gpio descriptors broke all gpio lookups as
devm_gpiod_get_index was converted to use dev->driver->name for
the gpio name lookup. Fix this by using the name param. In
addition gpiod_get post-fixes the -gpios to the name so that
shouldn't be included in the call. However this then breaks the
of_find_property call to see if the gpio entry exists as all
fbtft treats all gpios as optional. So use devm_gpiod_get_index_optional
instead which achieves the same thing and is simpler.

Nishad confirmed the changes where only ever compile tested.

Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Jan Sebastian Götte <linux@jaseg.net>
Signed-off-by: Phil Reid <preid@electromag.com.au>
---
 drivers/staging/fbtft/fbtft-core.c | 39 ++++++++++++++++++--------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 9b07bad..44b8074 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -76,21 +76,18 @@ static int fbtft_request_one_gpio(struct fbtft_par *par,
 				  struct gpio_desc **gpiop)
 {
 	struct device *dev = par->info->device;
-	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 +100,34 @@ 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;
-- 
1.8.3.1

[PATCH v2 2/2] Staging: fbtft: Fix reset assertion when using gpio descriptor

[Phil Reid]

Typically gpiod_set_value calls would assert the reset line and
then release it using the symantics of:
	gpiod_set_value(par->gpio.reset, 0);
	... delay
	gpiod_set_value(par->gpio.reset, 1);
And the gpio binding would specify the polarity.

Prior to conversion to gpiod calls the polarity in the DT
was ignored and assumed to be active low. Fix it so that
DT polarity is respected.

Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Jan Sebastian Götte <linux@jaseg.net>
Signed-off-by: Phil Reid <preid@electromag.com.au>
---
 drivers/staging/fbtft/fbtft-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 44b8074..bc75025 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -231,9 +231,9 @@ static void fbtft_reset(struct fbtft_par *par)
 	if (!par->gpio.reset)
 		return;
 	fbtft_par_dbg(DEBUG_RESET, par, "%s()\n", __func__);
-	gpiod_set_value_cansleep(par->gpio.reset, 0);
-	usleep_range(20, 40);
 	gpiod_set_value_cansleep(par->gpio.reset, 1);
+	usleep_range(20, 40);
+	gpiod_set_value_cansleep(par->gpio.reset, 0);
 	msleep(120);
 }
 
-- 
1.8.3.1