Input: goodix - add regulators suppot

Goodix CTP controllers require AVDD28, VDDIO regulators for power-on
sequence.

The delay between these regualtor operations as per Power-on Timing
from datasheet[1] is 0 (T1 >= 0 usec).

So, enable and disable these regulators in proper order using normal
regulator functions without any delay in between.

[1] GT5663 Datasheet_English_20151106_Rev.01
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/goodix.txt

@@ -19,6 +19,8 @@ Optional properties:
  - irq-gpios		: GPIO pin used for IRQ. The driver uses the
 			  interrupt gpio pin as output to reset the device.
  - reset-gpios		: GPIO pin used for reset
+ - AVDD28-supply	: Analog power supply regulator on AVDD28 pin
+ - VDDIO-supply		: GPIO power supply regulator on VDDIO pin
  - touchscreen-inverted-x
  - touchscreen-inverted-y
  - touchscreen-size-x

drivers/input/touchscreen/goodix.c

@@ -27,6 +27,7 @@
 #include <linux/delay.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
 #include <linux/of.h>
@@ -47,6 +48,8 @@ struct goodix_ts_data {
 	struct touchscreen_properties prop;
 	unsigned int max_touch_num;
 	unsigned int int_trigger_type;
+	struct regulator *avdd28;
+	struct regulator *vddio;
 	struct gpio_desc *gpiod_int;
 	struct gpio_desc *gpiod_rst;
 	u16 id;
@@ -532,6 +535,24 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
 		return -EINVAL;
 	dev = &ts->client->dev;
 
+	ts->avdd28 = devm_regulator_get(dev, "AVDD28");
+	if (IS_ERR(ts->avdd28)) {
+		error = PTR_ERR(ts->avdd28);
+		if (error != -EPROBE_DEFER)
+			dev_err(dev,
+				"Failed to get AVDD28 regulator: %d\n", error);
+		return error;
+	}
+
+	ts->vddio = devm_regulator_get(dev, "VDDIO");
+	if (IS_ERR(ts->vddio)) {
+		error = PTR_ERR(ts->vddio);
+		if (error != -EPROBE_DEFER)
+			dev_err(dev,
+				"Failed to get VDDIO regulator: %d\n", error);
+		return error;
+	}
+
 	/* Get the interrupt GPIO pin number */
 	gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
 	if (IS_ERR(gpiod)) {
@@ -764,6 +785,14 @@ static void goodix_config_cb(const struct firmware *cfg, void *ctx)
 	complete_all(&ts->firmware_loading_complete);
 }
 
+static void goodix_disable_regulators(void *arg)
+{
+	struct goodix_ts_data *ts = arg;
+
+	regulator_disable(ts->vddio);
+	regulator_disable(ts->avdd28);
+}
+
 static int goodix_ts_probe(struct i2c_client *client,
 			   const struct i2c_device_id *id)
 {
@@ -789,6 +818,29 @@ static int goodix_ts_probe(struct i2c_client *client,
 	if (error)
 		return error;
 
+	/* power up the controller */
+	error = regulator_enable(ts->avdd28);
+	if (error) {
+		dev_err(&client->dev,
+			"Failed to enable AVDD28 regulator: %d\n",
+			error);
+		return error;
+	}
+
+	error = regulator_enable(ts->vddio);
+	if (error) {
+		dev_err(&client->dev,
+			"Failed to enable VDDIO regulator: %d\n",
+			error);
+		regulator_disable(ts->avdd28);
+		return error;
+	}
+
+	error = devm_add_action_or_reset(&client->dev,
+					 goodix_disable_regulators, ts);
+	if (error)
+		return error;
+
 	if (ts->gpiod_int && ts->gpiod_rst) {
 		/* reset the controller */
 		error = goodix_reset(ts);