diff mbox series

[2/2] Input: atmel_mxt_ts: Support regulator supplies

Message ID 20201028101711.696423-2-linus.walleij@linaro.org
State New
Headers show
Series [1/2] Input: atmel_mxt_ts: Convert bindings to YAML and extend | expand

Commit Message

Linus Walleij Oct. 28, 2020, 10:17 a.m. UTC
This adds the code for the Atmel touchscreens such as
mXT224 to obtain power regulators for the supply voltages
AVDD and VDD. On mobile phones such as Samsung GT-I8190
(Golden) this is needed to explicitly bring power online.

We just enable the regulators at probe() and disable
them at remove() or in the errorpath for now.

As regulators are naturally stubbed if not available,
this should have no impact on existing systems.

Cc: Nick Dyer <nick@shmanahar.org>
Cc: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 37 +++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 98f17fa3a892..701269f9744f 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -24,6 +24,7 @@ 
 #include <linux/of.h>
 #include <linux/property.h>
 #include <linux/slab.h>
+#include <linux/regulator/consumer.h>
 #include <linux/gpio/consumer.h>
 #include <asm/unaligned.h>
 #include <media/v4l2-device.h>
@@ -309,6 +310,7 @@  struct mxt_data {
 	u8 multitouch;
 	struct t7_config t7_cfg;
 	struct mxt_dbg dbg;
+	struct regulator_bulk_data regulators[2];
 	struct gpio_desc *reset_gpio;
 	bool use_retrigen_workaround;
 
@@ -3134,6 +3136,21 @@  static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (error)
 		return error;
 
+	/*
+	 * VDDA is the analog voltage supply 2.57..3.47 V
+	 * VDD  is the digital voltage supply 1.71..3.47 V
+	 */
+	data->regulators[0].supply = "vdda";
+	data->regulators[1].supply = "vdd";
+	error = devm_regulator_bulk_get(&client->dev, ARRAY_SIZE(data->regulators),
+					data->regulators);
+	if (error) {
+		if (error != -EPROBE_DEFER)
+			dev_err(&client->dev, "Failed to get regulators %d\n",
+				error);
+		return error;
+	}
+
 	data->reset_gpio = devm_gpiod_get_optional(&client->dev,
 						   "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(data->reset_gpio)) {
@@ -3152,6 +3169,19 @@  static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	disable_irq(client->irq);
 
+	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators),
+				      data->regulators);
+	if (error) {
+		dev_err(&client->dev, "failed to enable regulators: %d\n",
+			error);
+		return error;
+	}
+	/*
+	 * The device takes 40ms to come up after power-on according
+	 * to the mXT224 datasheet, page 13.
+	 */
+	msleep(MXT_BACKUP_TIME);
+
 	if (data->reset_gpio) {
 		msleep(MXT_RESET_GPIO_TIME);
 		gpiod_set_value(data->reset_gpio, 1);
@@ -3160,7 +3190,7 @@  static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	error = mxt_initialize(data);
 	if (error)
-		return error;
+		goto err_disable_regulators;
 
 	error = sysfs_create_group(&client->dev.kobj, &mxt_attr_group);
 	if (error) {
@@ -3174,6 +3204,9 @@  static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 err_free_object:
 	mxt_free_input_device(data);
 	mxt_free_object_table(data);
+err_disable_regulators:
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators),
+			       data->regulators);
 	return error;
 }
 
@@ -3185,6 +3218,8 @@  static int mxt_remove(struct i2c_client *client)
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 	mxt_free_input_device(data);
 	mxt_free_object_table(data);
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators),
+			       data->regulators);
 
 	return 0;
 }