Input: atmel_mxt_ts - add support for reset line

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>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
index 1852906..23e3abc 100644 (file)
--- 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 aeb4652..7659bc4 100644 (file)
--- 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);