[PATCH 1/2] dt-bindings: input: touchscreen: edt-ft5x06: add iovcc-supply

At the moment, the edt-ft5x06 driver can control a single regulator
("vcc"). However, some FocalTech touch controllers have an additional
IOVCC pin that should be supplied with the digital I/O voltage.

The I/O voltage might be provided by another regulator that should also
be kept on. Otherwise, the touchscreen can randomly stop functioning if
the regulator is turned off because no other components still require it.

Document (optional) support for controlling the regulator for IOVCC
using "iovcc-supply".

Cc: Ondrej Jirman <redacted>
Cc: Marco Felsch <redacted>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
 .../devicetree/bindings/input/touchscreen/edt-ft5x06.yaml        | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.yaml b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.yaml
index bfc3a8b5e118..2e8da7470513 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.yaml

@@ -56,6 +56,7 @@ properties:
   wakeup-source: true
 
   vcc-supply: true
+  iovcc-supply: true
 
   gain:
     description: Allows setting the sensitivity in the range from 0 to 31.

-- 
2.30.0

At the moment, the edt-ft5x06 driver can control a single regulator
("vcc"). However, some FocalTech touch controllers have an additional
IOVCC pin that should be supplied with the digital I/O voltage.

The I/O voltage might be provided by another regulator that should also
be kept on. Otherwise, the touchscreen can randomly stop functioning if
the regulator is turned off because no other components still require it.

Implement (optional) support for also enabling an "iovcc-supply".
IOVCC is needed whenever VCC is needed, so switch to the regulator bulk
APIs to request/enable/disable both when appropriate.

Cc: Ondrej Jirman <redacted>
Cc: Marco Felsch <redacted>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
 drivers/input/touchscreen/edt-ft5x06.c | 35 ++++++++++++++------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index 2eefbc2485bc..bf2e208112fe 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c

@@ -103,7 +103,7 @@ struct edt_ft5x06_ts_data {
 	struct touchscreen_properties prop;
 	u16 num_x;
 	u16 num_y;
-	struct regulator *vcc;
+	struct regulator_bulk_data regulators[2];
 
 	struct gpio_desc *reset_gpio;
 	struct gpio_desc *wake_gpio;

@@ -1066,7 +1066,7 @@ static void edt_ft5x06_disable_regulator(void *arg)
 {
 	struct edt_ft5x06_ts_data *data = arg;
 
-	regulator_disable(data->vcc);
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
 }
 
 static int edt_ft5x06_ts_probe(struct i2c_client *client,

@@ -1098,18 +1098,19 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
 
 	tsdata->max_support_points = chip_data->max_support_points;
 
-	tsdata->vcc = devm_regulator_get(&client->dev, "vcc");
-	if (IS_ERR(tsdata->vcc)) {
-		error = PTR_ERR(tsdata->vcc);
-		if (error != -EPROBE_DEFER)
-			dev_err(&client->dev,
-				"failed to request regulator: %d\n", error);
-		return error;
-	}
+	tsdata->regulators[0].supply = "vcc";
+	tsdata->regulators[1].supply = "iovcc";
+	error = devm_regulator_bulk_get(&client->dev,
+					ARRAY_SIZE(tsdata->regulators),
+					tsdata->regulators);
+	if (error)
+		return dev_err_probe(&client->dev, error,
+				     "failed to request regulators\n");
 
-	error = regulator_enable(tsdata->vcc);
+	error = regulator_bulk_enable(ARRAY_SIZE(tsdata->regulators),
+				      tsdata->regulators);
 	if (error < 0) {
-		dev_err(&client->dev, "failed to enable vcc: %d\n", error);
+		dev_err(&client->dev, "failed to enable regulators: %d\n", error);
 		return error;
 	}
 

@@ -1286,9 +1287,10 @@ static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev)
 	gpiod_set_value_cansleep(reset_gpio, 1);
 	usleep_range(1000, 2000);
 
-	ret = regulator_disable(tsdata->vcc);
+	ret = regulator_bulk_disable(ARRAY_SIZE(tsdata->regulators),
+				     tsdata->regulators);
 	if (ret)
-		dev_warn(dev, "Failed to disable vcc\n");
+		dev_warn(dev, "Failed to disable regulators\n");
 
 	return 0;
 }

@@ -1319,9 +1321,10 @@ static int __maybe_unused edt_ft5x06_ts_resume(struct device *dev)
 		gpiod_set_value_cansleep(reset_gpio, 1);
 		usleep_range(5000, 6000);
 
-		ret = regulator_enable(tsdata->vcc);
+		ret = regulator_bulk_enable(ARRAY_SIZE(tsdata->regulators),
+					    tsdata->regulators);
 		if (ret) {
-			dev_err(dev, "Failed to enable vcc\n");
+			dev_err(dev, "Failed to enable regulators\n");
 			return ret;
 		}
 

-- 
2.30.0

Hi Stephan,

thanks for the patch :) Please see my inline comments.

On 21-01-08 20:23, Stephan Gerhold wrote:

Is there an enabling order we must follow?

It would be nice to have a patch in front of this one which handles the
support for dev_err_probe().

Regards,
  Marco

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Hi Marco,

thanks for the review!

On Mon, Jan 11, 2021 at 09:36:12AM +0100, Marco Felsch wrote:

Hi Stephan,

thanks for the patch :) Please see my inline comments.

On 21-01-08 20:23, Stephan Gerhold wrote:

quoted

At the moment, the edt-ft5x06 driver can control a single regulator
("vcc"). However, some FocalTech touch controllers have an additional
IOVCC pin that should be supplied with the digital I/O voltage.

The I/O voltage might be provided by another regulator that should also
be kept on. Otherwise, the touchscreen can randomly stop functioning if
the regulator is turned off because no other components still require it.

Implement (optional) support for also enabling an "iovcc-supply".
IOVCC is needed whenever VCC is needed, so switch to the regulator bulk
APIs to request/enable/disable both when appropriate.

Cc: Ondrej Jirman <redacted>
Cc: Marco Felsch <redacted>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
 drivers/input/touchscreen/edt-ft5x06.c | 35 ++++++++++++++------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index 2eefbc2485bc..bf2e208112fe 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c

@@ -103,7 +103,7 @@ struct edt_ft5x06_ts_data {
 	struct touchscreen_properties prop;
 	u16 num_x;
 	u16 num_y;
-	struct regulator *vcc;
+	struct regulator_bulk_data regulators[2];

Is there an enabling order we must follow?

I don't know, sadly. The datasheets I was able to find do not mention
anything about this; the power-on sequence only includes the VDD line.

I tried several suspend/resume cycles with both regulators set up and it
worked fine, which could mean that I was lucky or that the order does
not matter. :)

What do you think?

quoted

 	struct gpio_desc *reset_gpio;
 	struct gpio_desc *wake_gpio;

@@ -1066,7 +1066,7 @@ static void edt_ft5x06_disable_regulator(void *arg)
 {
 	struct edt_ft5x06_ts_data *data = arg;
 
-	regulator_disable(data->vcc);
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
 }
 
 static int edt_ft5x06_ts_probe(struct i2c_client *client,

@@ -1098,18 +1098,19 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
 
 	tsdata->max_support_points = chip_data->max_support_points;
 
-	tsdata->vcc = devm_regulator_get(&client->dev, "vcc");
-	if (IS_ERR(tsdata->vcc)) {
-		error = PTR_ERR(tsdata->vcc);
-		if (error != -EPROBE_DEFER)
-			dev_err(&client->dev,
-				"failed to request regulator: %d\n", error);
-		return error;
-	}
+	tsdata->regulators[0].supply = "vcc";
+	tsdata->regulators[1].supply = "iovcc";
+	error = devm_regulator_bulk_get(&client->dev,
+					ARRAY_SIZE(tsdata->regulators),
+					tsdata->regulators);
+	if (error)
+		return dev_err_probe(&client->dev, error,
+				     "failed to request regulators\n");

It would be nice to have a patch in front of this one which handles the
support for dev_err_probe().

OK, I can send a v2 with the dev_err_probe() change separated into an
extra patch.

Thanks!
Stephan

quoted

 
-	error = regulator_enable(tsdata->vcc);
+	error = regulator_bulk_enable(ARRAY_SIZE(tsdata->regulators),
+				      tsdata->regulators);
 	if (error < 0) {
-		dev_err(&client->dev, "failed to enable vcc: %d\n", error);
+		dev_err(&client->dev, "failed to enable regulators: %d\n", error);
 		return error;
 	}
 

@@ -1286,9 +1287,10 @@ static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev)
 	gpiod_set_value_cansleep(reset_gpio, 1);
 	usleep_range(1000, 2000);
 
-	ret = regulator_disable(tsdata->vcc);
+	ret = regulator_bulk_disable(ARRAY_SIZE(tsdata->regulators),
+				     tsdata->regulators);
 	if (ret)
-		dev_warn(dev, "Failed to disable vcc\n");
+		dev_warn(dev, "Failed to disable regulators\n");
 
 	return 0;
 }

@@ -1319,9 +1321,10 @@ static int __maybe_unused edt_ft5x06_ts_resume(struct device *dev)
 		gpiod_set_value_cansleep(reset_gpio, 1);
 		usleep_range(5000, 6000);
 
-		ret = regulator_enable(tsdata->vcc);
+		ret = regulator_bulk_enable(ARRAY_SIZE(tsdata->regulators),
+					    tsdata->regulators);
 		if (ret) {
-			dev_err(dev, "Failed to enable vcc\n");
+			dev_err(dev, "Failed to enable regulators\n");
 			return ret;
 		}
 

-- 
2.30.0

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

On 21-01-11 10:26, Stephan Gerhold wrote:

Hi Marco,

thanks for the review!

On Mon, Jan 11, 2021 at 09:36:12AM +0100, Marco Felsch wrote:

quoted

Hi Stephan,

thanks for the patch :) Please see my inline comments.

On 21-01-08 20:23, Stephan Gerhold wrote:

quoted

At the moment, the edt-ft5x06 driver can control a single regulator
("vcc"). However, some FocalTech touch controllers have an additional
IOVCC pin that should be supplied with the digital I/O voltage.

The I/O voltage might be provided by another regulator that should also
be kept on. Otherwise, the touchscreen can randomly stop functioning if
the regulator is turned off because no other components still require it.

Implement (optional) support for also enabling an "iovcc-supply".
IOVCC is needed whenever VCC is needed, so switch to the regulator bulk
APIs to request/enable/disable both when appropriate.

Cc: Ondrej Jirman <redacted>
Cc: Marco Felsch <redacted>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
 drivers/input/touchscreen/edt-ft5x06.c | 35 ++++++++++++++------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index 2eefbc2485bc..bf2e208112fe 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c

@@ -103,7 +103,7 @@ struct edt_ft5x06_ts_data {
 	struct touchscreen_properties prop;
 	u16 num_x;
 	u16 num_y;
-	struct regulator *vcc;
+	struct regulator_bulk_data regulators[2];

Is there an enabling order we must follow?

I don't know, sadly. The datasheets I was able to find do not mention
anything about this; the power-on sequence only includes the VDD line.

I've goolged a bit :)

Check this: https://focuslcds.com/content/FT5X26.pdf, page 12 of 32

There it is mentioned that we need to enable it first and add a 10us
delay till we can enable the vdd line. So unfortunately the bulk_api
can't be used as it is today. Another solution could be to extended the
bulk api to respect on/off delays.

Regards,
  Marco

I tried several suspend/resume cycles with both regulators set up and it
worked fine, which could mean that I was lucky or that the order does
not matter. :)

What do you think?

quoted

quoted

 	struct gpio_desc *reset_gpio;
 	struct gpio_desc *wake_gpio;

@@ -1066,7 +1066,7 @@ static void edt_ft5x06_disable_regulator(void *arg)
 {
 	struct edt_ft5x06_ts_data *data = arg;
 
-	regulator_disable(data->vcc);
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
 }
 
 static int edt_ft5x06_ts_probe(struct i2c_client *client,

@@ -1098,18 +1098,19 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
 
 	tsdata->max_support_points = chip_data->max_support_points;
 
-	tsdata->vcc = devm_regulator_get(&client->dev, "vcc");
-	if (IS_ERR(tsdata->vcc)) {
-		error = PTR_ERR(tsdata->vcc);
-		if (error != -EPROBE_DEFER)
-			dev_err(&client->dev,
-				"failed to request regulator: %d\n", error);
-		return error;
-	}
+	tsdata->regulators[0].supply = "vcc";
+	tsdata->regulators[1].supply = "iovcc";
+	error = devm_regulator_bulk_get(&client->dev,
+					ARRAY_SIZE(tsdata->regulators),
+					tsdata->regulators);
+	if (error)
+		return dev_err_probe(&client->dev, error,
+				     "failed to request regulators\n");

It would be nice to have a patch in front of this one which handles the
support for dev_err_probe().

OK, I can send a v2 with the dev_err_probe() change separated into an
extra patch.

Thanks!
Stephan

quoted

quoted

 
-	error = regulator_enable(tsdata->vcc);
+	error = regulator_bulk_enable(ARRAY_SIZE(tsdata->regulators),
+				      tsdata->regulators);
 	if (error < 0) {
-		dev_err(&client->dev, "failed to enable vcc: %d\n", error);
+		dev_err(&client->dev, "failed to enable regulators: %d\n", error);
 		return error;
 	}
 

@@ -1286,9 +1287,10 @@ static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev)
 	gpiod_set_value_cansleep(reset_gpio, 1);
 	usleep_range(1000, 2000);
 
-	ret = regulator_disable(tsdata->vcc);
+	ret = regulator_bulk_disable(ARRAY_SIZE(tsdata->regulators),
+				     tsdata->regulators);
 	if (ret)
-		dev_warn(dev, "Failed to disable vcc\n");
+		dev_warn(dev, "Failed to disable regulators\n");
 
 	return 0;
 }

@@ -1319,9 +1321,10 @@ static int __maybe_unused edt_ft5x06_ts_resume(struct device *dev)
 		gpiod_set_value_cansleep(reset_gpio, 1);
 		usleep_range(5000, 6000);
 
-		ret = regulator_enable(tsdata->vcc);
+		ret = regulator_bulk_enable(ARRAY_SIZE(tsdata->regulators),
+					    tsdata->regulators);
 		if (ret) {
-			dev_err(dev, "Failed to enable vcc\n");
+			dev_err(dev, "Failed to enable regulators\n");
 			return ret;
 		}
 

-- 
2.30.0

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

On Mon, Jan 11, 2021 at 10:45:38AM +0100, Marco Felsch wrote:

On 21-01-11 10:26, Stephan Gerhold wrote:

quoted

On Mon, Jan 11, 2021 at 09:36:12AM +0100, Marco Felsch wrote:

quoted

On 21-01-08 20:23, Stephan Gerhold wrote:

quoted

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index 2eefbc2485bc..bf2e208112fe 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c

@@ -103,7 +103,7 @@ struct edt_ft5x06_ts_data {
 	struct touchscreen_properties prop;
 	u16 num_x;
 	u16 num_y;
-	struct regulator *vcc;
+	struct regulator_bulk_data regulators[2];

Is there an enabling order we must follow?

I don't know, sadly. The datasheets I was able to find do not mention
anything about this; the power-on sequence only includes the VDD line.

I've goolged a bit :)

Check this: https://focuslcds.com/content/FT5X26.pdf, page 12 of 32

Thanks! I looked at several datasheets, that's probably one of the few I
did not look at. :(

There it is mentioned that we need to enable it first and add a 10us
delay till we can enable the vdd line. So unfortunately the bulk_api
can't be used as it is today. Another solution could be to extended the
bulk api to respect on/off delays.

I think for two regulators like here it's still manageable to
get/enable/disable/put them separately, so I will just revert the bulk
API change in v2.

Thanks again!
Stephan

On Mon, Jan 11, 2021 at 10:26:25AM +0100, Stephan Gerhold wrote:

On Mon, Jan 11, 2021 at 09:36:12AM +0100, Marco Felsch wrote:

quoted

On 21-01-08 20:23, Stephan Gerhold wrote:

...

quoted

quoted

+	if (error)
+		return dev_err_probe(&client->dev, error,
+				     "failed to request regulators\n");

It would be nice to have a patch in front of this one which handles the
support for dev_err_probe().

OK, I can send a v2 with the dev_err_probe() change separated into an
extra patch.

AFAIR Dmitry has strong opinion against dev_err_probe(). But I might be
mistaken.

-- 
With Best Regards,
Andy Shevchenko

On Mon, Jan 11, 2021 at 12:22:36PM +0200, Andy Shevchenko wrote:

On Mon, Jan 11, 2021 at 10:26:25AM +0100, Stephan Gerhold wrote:

quoted

On Mon, Jan 11, 2021 at 09:36:12AM +0100, Marco Felsch wrote:

quoted

On 21-01-08 20:23, Stephan Gerhold wrote:

...

quoted

quoted

quoted

+	if (error)
+		return dev_err_probe(&client->dev, error,
+				     "failed to request regulators\n");

It would be nice to have a patch in front of this one which handles the
support for dev_err_probe().

OK, I can send a v2 with the dev_err_probe() change separated into an
extra patch.

AFAIR Dmitry has strong opinion against dev_err_probe(). But I might be
mistaken.

Hmm, yeah actually it seems like there was a patch for this already:
https://lore.kernel.org/linux-input/20200827185829.30096-12-krzk@kernel.org/

I guess it's better to not include this here then...

Thanks,
Stephan

Hi,

On Mon, Jan 11, 2021 at 11:10:16AM +0100, Stephan Gerhold wrote:

On Mon, Jan 11, 2021 at 10:45:38AM +0100, Marco Felsch wrote:

quoted

On 21-01-11 10:26, Stephan Gerhold wrote:

quoted

On Mon, Jan 11, 2021 at 09:36:12AM +0100, Marco Felsch wrote:

quoted

On 21-01-08 20:23, Stephan Gerhold wrote:

quoted

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index 2eefbc2485bc..bf2e208112fe 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c

@@ -103,7 +103,7 @@ struct edt_ft5x06_ts_data {
 	struct touchscreen_properties prop;
 	u16 num_x;
 	u16 num_y;
-	struct regulator *vcc;
+	struct regulator_bulk_data regulators[2];

Is there an enabling order we must follow?

I don't know, sadly. The datasheets I was able to find do not mention
anything about this; the power-on sequence only includes the VDD line.

I've goolged a bit :)

Check this: https://focuslcds.com/content/FT5X26.pdf, page 12 of 32

Thanks! I looked at several datasheets, that's probably one of the few I
did not look at. :(

quoted

There it is mentioned that we need to enable it first and add a 10us
delay till we can enable the vdd line. So unfortunately the bulk_api
can't be used as it is today. Another solution could be to extended the
bulk api to respect on/off delays.

I think for two regulators like here it's still manageable to
get/enable/disable/put them separately, so I will just revert the bulk
API change in v2.

While implementing this I noticed that the power-up sequence in probe()
does not quite seem right. The power-up sequence implemented by Marco in
edt_ft5x06_ts_resume() seems to match the datasheet(s) but in probe() we
enable VCC before doing anything with the reset line.

So before I add the IOVCC regulator I will try to refactor the code a
bit to make this consistent. :)

Thanks,
Stephan

On Fri, 08 Jan 2021 20:23:36 +0100, Stephan Gerhold wrote:

At the moment, the edt-ft5x06 driver can control a single regulator
("vcc"). However, some FocalTech touch controllers have an additional
IOVCC pin that should be supplied with the digital I/O voltage.

The I/O voltage might be provided by another regulator that should also
be kept on. Otherwise, the touchscreen can randomly stop functioning if
the regulator is turned off because no other components still require it.

Document (optional) support for controlling the regulator for IOVCC
using "iovcc-supply".

Cc: Ondrej Jirman <redacted>
Cc: Marco Felsch <redacted>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
 .../devicetree/bindings/input/touchscreen/edt-ft5x06.yaml        | 1 +
 1 file changed, 1 insertion(+)

Acked-by: Rob Herring <robh@kernel.org>