[PATCH 4/6] Input: pixcir_i2c_ts - add RESET gpio

From: Dmitry Torokhov
Date: Mon Jul 06 2015 - 20:30:49 EST


From: Roger Quadros <rogerq@xxxxxx>

The controller has a RESET pin which is usually controlled over
a GPIO line. If such a GPIO is provided, perform a RESET
during probe.

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
.../bindings/input/touchscreen/pixcir_i2c_ts.txt | 3 +++
drivers/input/touchscreen/pixcir_i2c_ts.c | 22 ++++++++++++++++++++++
2 files changed, 25 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
index 6e55109..8eb240a 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
@@ -8,6 +8,9 @@ Required properties:
- touchscreen-size-x: horizontal resolution of touchscreen (in pixels)
- touchscreen-size-y: vertical resolution of touchscreen (in pixels)

+Optional properties:
+- reset-gpio: GPIO connected to the RESET line of the chip
+
Example:

i2c@00000000 {
diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
index 8965d7c..9d9ac08 100644
--- a/drivers/input/touchscreen/pixcir_i2c_ts.c
+++ b/drivers/input/touchscreen/pixcir_i2c_ts.c
@@ -36,6 +36,7 @@ struct pixcir_i2c_ts_data {
struct i2c_client *client;
struct input_dev *input;
struct gpio_desc *gpio_attb;
+ struct gpio_desc *gpio_reset;
const struct pixcir_ts_platform_data *pdata;
bool running;
int max_fingers; /* Max fingers supported in this instance */
@@ -189,6 +190,17 @@ static irqreturn_t pixcir_ts_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}

+static void pixcir_reset(struct pixcir_i2c_ts_data *tsdata)
+{
+ if (!IS_ERR_OR_NULL(tsdata->gpio_reset)) {
+ gpiod_set_value_cansleep(tsdata->gpio_reset, 1);
+ ndelay(100); /* datasheet section 1.2.3 says 80ns min. */
+ gpiod_set_value_cansleep(tsdata->gpio_reset, 0);
+ /* wait for controller ready. 100ms guess. */
+ msleep(100);
+ }
+}
+
static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts,
enum pixcir_power_mode mode)
{
@@ -529,6 +541,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
return error;
}

+ tsdata->gpio_reset = devm_gpiod_get_optional(dev, "reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(tsdata->gpio_reset)) {
+ error = PTR_ERR(tsdata->gpio_reset);
+ dev_err(dev, "Failed to request RESET gpio: %d\n", error);
+ return error;
+ }
+
error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
client->name, tsdata);
@@ -537,6 +557,8 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
return error;
}

+ pixcir_reset(tsdata);
+
/* Always be in IDLE mode to save power, device supports auto wake */
error = pixcir_set_power_mode(tsdata, PIXCIR_POWER_IDLE);
if (error) {
--
2.4.3.573.g4eafbef

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