linux-kernel - [PATCH v2] Input: pixcir_i2c_ts

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Date:	Tue, 2 Jun 2015 12:33:34 +0300
From:	Roger Quadros <rogerq@...com>
To:	<dmitry.torokhov@...il.com>, <rydberg@...math.org>
CC:	<mugunthanvnm@...com>, <jg1.han@...sung.com>,
	<linux-input@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v2] Input: pixcir_i2c_ts - Add RESET gpio

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@...com>
---
  .../bindings/input/touchscreen/pixcir_i2c_ts.txt   |  3 ++
  drivers/input/touchscreen/pixcir_i2c_ts.c          | 37 ++++++++++++++++++++--
  include/linux/input/pixcir_ts.h                    |  1 +
  3 files changed, 38 insertions(+), 3 deletions(-)

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@...00000 {
diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
index 2c21071..80c956d 100644
--- a/drivers/input/touchscreen/pixcir_i2c_ts.c
+++ b/drivers/input/touchscreen/pixcir_i2c_ts.c
@@ -51,6 +51,19 @@ struct pixcir_report_data {
  	struct pixcir_touch touches[PIXCIR_MAX_SLOTS];
  };
  
+static void pixcir_reset(struct pixcir_i2c_ts_data *tsdata)
+{
+	const struct pixcir_ts_platform_data *pdata = tsdata->pdata;
+
+	if (gpio_is_valid(pdata->gpio_reset)) {
+		gpio_set_value(pdata->gpio_reset, 1);
+		ndelay(100);	/* datasheet section 1.2.3 says 80ns min. */
+		gpio_set_value(pdata->gpio_reset, 0);
+		/* wait for controller ready. 100ms guess. */
+		msleep(100);
+	}
+}
+
  static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
  			    struct pixcir_report_data *report)
  {
@@ -428,7 +441,8 @@ static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
  	pdata->chip = *(const struct pixcir_i2c_chip_data *)match->data;
  
  	pdata->gpio_attb = of_get_named_gpio(np, "attb-gpio", 0);
-	/* gpio_attb validity is checked in probe */
+	pdata->gpio_reset = of_get_named_gpio(np, "reset-gpio", 0);
+	/* gpio validity is checked in probe */
  
  	if (of_property_read_u32(np, "touchscreen-size-x", &pdata->x_max)) {
  		dev_err(dev, "Failed to get touchscreen-size-x property\n");
@@ -442,8 +456,9 @@ static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
  	}
  	pdata->y_max -= 1;
  
-	dev_dbg(dev, "%s: x %d, y %d, gpio %d\n", __func__,
-		pdata->x_max + 1, pdata->y_max + 1, pdata->gpio_attb);
+	dev_dbg(dev, "%s: x %d, y %d, ATTB gpio %d, RESET gpio %d\n", __func__,
+		pdata->x_max + 1, pdata->y_max + 1, pdata->gpio_attb,
+		pdata->gpio_reset);
  
  	return pdata;
  }
@@ -481,6 +496,10 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
  		return -EINVAL;
  	}
  
+	/* RESET gpio is optional */
+	if (!gpio_is_valid(pdata->gpio_reset))
+		dev_info(dev, "Invalid gpio_reset in pdata\n");
+
  	if (!pdata->chip.max_fingers) {
  		dev_err(dev, "Invalid max_fingers in pdata\n");
  		return -EINVAL;
@@ -530,6 +549,16 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
  
  	input_set_drvdata(input, tsdata);
  
+	if (gpio_is_valid(pdata->gpio_reset)) {
+		error = devm_gpio_request_one(dev, pdata->gpio_reset,
+					      GPIOF_OUT_INIT_LOW,
+					      "pixcir_i2c_reset");
+		if (error) {
+			dev_err(dev, "Failed to request RESET gpio\n");
+			return error;
+		}
+	}
+
  	error = devm_gpio_request_one(dev, pdata->gpio_attb,
  				      GPIOF_DIR_IN, "pixcir_i2c_attb");
  	if (error) {
@@ -545,6 +574,8 @@ 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) {
diff --git a/include/linux/input/pixcir_ts.h b/include/linux/input/pixcir_ts.h
index 7bae83b..5b204dd 100644
--- a/include/linux/input/pixcir_ts.h
+++ b/include/linux/input/pixcir_ts.h
@@ -58,6 +58,7 @@ struct pixcir_ts_platform_data {
  	int x_max;
  	int y_max;
  	int gpio_attb;		/* GPIO connected to ATTB line */
+	int gpio_reset;		/* GPIO to RESET line. Set to -1 if unused */
  	struct pixcir_i2c_chip_data chip;
  };
  
-- 
2.1.4


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