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Subject[PATCHv2 2/2] Input: atmel_mxt_ts: Add support for reset line
Date
Provide support for controlling reset pin. If this is not driven
correctly the device will be held in reset and will not respond.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
---
.../devicetree/bindings/input/atmel,maxtouch.txt | 2 ++
drivers/input/touchscreen/atmel_mxt_ts.c | 22 ++++++++++++++++++++++
2 files changed, 24 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
index 1852906517ab..23e3abc3fdef 100644
--- a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
+++ b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
@@ -22,6 +22,8 @@ Optional properties for main touchpad device:
experiment to determine which bit corresponds to which input. Use
KEY_RESERVED for unused padding values.

+- reset-gpios: GPIO specifier for the touchscreen's reset pin (active low)
+
Example:

touch@4b {
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 9a7b8eba64a6..599f92363188 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -28,6 +28,7 @@
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/slab.h>
+#include <linux/gpio/consumer.h>
#include <asm/unaligned.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
@@ -300,6 +301,7 @@ struct mxt_data {
u8 multitouch;
struct t7_config t7_cfg;
struct mxt_dbg dbg;
+ struct gpio_desc *reset_gpio;

/* Cached parameters from object table */
u16 T5_address;
@@ -3133,6 +3135,14 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
init_completion(&data->reset_completion);
init_completion(&data->crc_completion);

+ data->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(data->reset_gpio)) {
+ error = PTR_ERR(data->reset_gpio);
+ dev_err(&client->dev, "Failed to get reset gpio: %d\n", error);
+ return error;
+ }
+
error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
mxt_interrupt,
pdata->irqflags | IRQF_ONESHOT,
@@ -3142,6 +3152,18 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
return error;
}

+ if (data->reset_gpio) {
+ data->in_bootloader = true;
+ msleep(MXT_RESET_TIME);
+ reinit_completion(&data->bl_completion);
+ gpiod_set_value(data->reset_gpio, 1);
+ error = mxt_wait_for_completion(data, &data->bl_completion,
+ MXT_RESET_TIMEOUT);
+ if (error)
+ return error;
+ data->in_bootloader = false;
+ }
+
disable_irq(client->irq);

error = mxt_initialize(data);
--
2.13.2
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