On Thu, Jul 19, 2018 at 12:46:45AM +0200, Ondřej Jirman wrote:

Hello Mylène,

On Wed, Jul 18, 2018 at 08:27:17PM +0200, Mylène Josserand wrote:

quoted

Add the support of regulator to use it as VCC source.

Signed-off-by: Mylène Josserand <redacted>
---
 .../bindings/input/touchscreen/edt-ft5x06.txt      |  1 +
 drivers/input/touchscreen/edt-ft5x06.c             | 29 ++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
index 025cf8c9324a..48e975b9c1aa 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt

@@ -30,6 +30,7 @@ Required properties:
 Optional properties:
  - reset-gpios: GPIO specification for the RESET input
  - wake-gpios:  GPIO specification for the WAKE input
+ - vcc-supply:  Regulator that supplies the touchscreen
 
  - pinctrl-names: should be "default"
  - pinctrl-0:   a phandle pointing to the pin settings for the

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index 1e18ca0d1b4e..aa94494b06b5 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c

@@ -39,6 +39,7 @@
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
 #include <linux/of_device.h>
+#include <linux/regulator/consumer.h>
 
 #define WORK_REGISTER_THRESHOLD		0x00
 #define WORK_REGISTER_REPORT_RATE	0x08

@@ -91,6 +92,7 @@ struct edt_ft5x06_ts_data {
 	struct touchscreen_properties prop;
 	u16 num_x;
 	u16 num_y;
+	struct regulator *vcc;
 
 	struct gpio_desc *reset_gpio;
 	struct gpio_desc *wake_gpio;

@@ -991,6 +993,22 @@ 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;
+	}
+
+	error = regulator_enable(tsdata->vcc);
+	if (error < 0) {
+		dev_err(&client->dev, "failed to enable vcc: %d\n",
+			error);
+		return error;
+	}
+
 	tsdata->reset_gpio = devm_gpiod_get_optional(&client->dev,
 						     "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(tsdata->reset_gpio)) {

You need to disable regulator here. We do not have
devm_regulator_enable() (and Mark had some concerns about mixing managed
and unmanaged APIs for regulators so we can't simply introduce it),
so I'd recommend using devm_add_action_or_reset() and iunstall custom
action to turn off regulator.

quoted

@@ -1120,20 +1138,31 @@ static int edt_ft5x06_ts_remove(struct i2c_client *client)
 static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
+	struct edt_ft5x06_ts_data *tsdata = i2c_get_clientdata(client);
 
 	if (device_may_wakeup(dev))
 		enable_irq_wake(client->irq);
 
+	regulator_disable(tsdata->vcc);
+

How will the touchscreen wakeup the system with interrupt if you power it off
on suspend? Perhaps guard this with device_may_wakeup() too? 

Exactly, it should be in an "else" branch.

Thanks.

-- 
Dmitry