[PATCH v2] Input: tsc2007 - use GPIO descriptor

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This switches the TSC2007 to use a GPIO descriptor to read
the pendown GPIO line.

As this will make the gpiolib start to respect polarity
inversion flags on the GPIO lines, drop the inversion when
reading the line with gpio_get_value(), fix two offenders
in the i.MX device trees, and also emphasize the importance
of marking the polarity right in the device tree bindings.

Cc: Denis Carikli <denis@xxxxxxxxxx>
Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>
Cc: NXP Linux Team <linux-imx@xxxxxxx>
Cc: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
ChangeLog v1->v2:
- Drop inversion on the GPIO descriptor value, rely on the
  gpiolib to handle polarity inversion.
- Comb through device trees, identify two offenders, fix
  them as part of the patch for a clean cut.
- Also fix the device tree bindings.
---
 .../bindings/input/touchscreen/tsc2007.txt         |  5 +++--
 arch/arm/boot/dts/imx35-eukrea-cpuimx35.dtsi       |  3 ++-
 arch/arm/boot/dts/imx51-eukrea-cpuimx51.dtsi       |  3 ++-
 drivers/input/touchscreen/tsc2007.h                |  4 +++-
 drivers/input/touchscreen/tsc2007_core.c           | 14 +++++++-------
 5 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt b/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
index ed00f61b8c08..b08b54d49699 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
@@ -7,7 +7,8 @@ Required properties:
 
 Optional properties:
 - gpios: the interrupt gpio the chip is connected to (trough the penirq pin).
-  The penirq pin goes to low when the panel is touched.
+  The penirq pin goes to low when the panel is touched, so make sure to tag
+  the GPIO line with GPIO_ACTIVE_LOW.
   (see GPIO binding[1] for more details).
 - interrupts: (gpio) interrupt to which the chip is connected
   (see interrupt binding[0]).
@@ -31,7 +32,7 @@ Example:
 			reg = <0x49>;
 			interrupt-parent = <&gpio4>;
 			interrupts = <0x0 0x8>;
-			gpios = <&gpio4 0 0>;
+			gpios = <&gpio4 0 GPIO_ACTIVE_LOW>;
 			ti,x-plate-ohms = <180>;
 		};
 
diff --git a/arch/arm/boot/dts/imx35-eukrea-cpuimx35.dtsi b/arch/arm/boot/dts/imx35-eukrea-cpuimx35.dtsi
index 17bd2a97609a..b8ac60622936 100644
--- a/arch/arm/boot/dts/imx35-eukrea-cpuimx35.dtsi
+++ b/arch/arm/boot/dts/imx35-eukrea-cpuimx35.dtsi
@@ -3,6 +3,7 @@
  * Copyright 2013 Eukréa Electromatique <denis@xxxxxxxxxx>
  */
 
+#include <dt-bindings/gpio/gpio.h>
 #include "imx35.dtsi"
 
 / {
@@ -33,7 +34,7 @@
 
 	tsc2007: tsc2007@48 {
 		compatible = "ti,tsc2007";
-		gpios = <&gpio3 2 0>;
+		gpios = <&gpio3 2 GPIO_ACTIVE_LOW>;
 		interrupt-parent = <&gpio3>;
 		interrupts = <0x2 0x8>;
 		pinctrl-names = "default";
diff --git a/arch/arm/boot/dts/imx51-eukrea-cpuimx51.dtsi b/arch/arm/boot/dts/imx51-eukrea-cpuimx51.dtsi
index c2a929ba8ceb..016d0bc64bdb 100644
--- a/arch/arm/boot/dts/imx51-eukrea-cpuimx51.dtsi
+++ b/arch/arm/boot/dts/imx51-eukrea-cpuimx51.dtsi
@@ -3,6 +3,7 @@
  * Copyright 2013 Eukréa Electromatique <denis@xxxxxxxxxx>
  */
 
+#include <dt-bindings/gpio/gpio.h>
 #include "imx51.dtsi"
 
 / {
@@ -33,7 +34,7 @@
 
 	tsc2007: tsc2007@49 {
 		compatible = "ti,tsc2007";
-		gpios = <&gpio4 0 1>;
+		gpios = <&gpio4 0 GPIO_ACTIVE_LOW>;
 		interrupt-parent = <&gpio4>;
 		interrupts = <0x0 0x8>;
 		pinctrl-names = "default";
diff --git a/drivers/input/touchscreen/tsc2007.h b/drivers/input/touchscreen/tsc2007.h
index 91c60bf6dcaf..0306c38b56c7 100644
--- a/drivers/input/touchscreen/tsc2007.h
+++ b/drivers/input/touchscreen/tsc2007.h
@@ -49,6 +49,8 @@
 #define READ_X		(ADC_ON_12BIT | TSC2007_MEASURE_X)
 #define PWRDOWN		(TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
 
+struct gpio_desc;
+
 struct ts_event {
 	u16	x;
 	u16	y;
@@ -69,7 +71,7 @@ struct tsc2007 {
 	int			fuzzy;
 	int			fuzzz;
 
-	unsigned int		gpio;
+	struct gpio_desc	*gpiod;
 	int			irq;
 
 	wait_queue_head_t	wait;
diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c
index 3b80abfc1eca..0eadd6d86fa0 100644
--- a/drivers/input/touchscreen/tsc2007_core.c
+++ b/drivers/input/touchscreen/tsc2007_core.c
@@ -23,7 +23,7 @@
 #include <linux/interrupt.h>
 #include <linux/i2c.h>
 #include <linux/of_device.h>
-#include <linux/of_gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/platform_data/tsc2007.h>
 #include "tsc2007.h"
 
@@ -226,7 +226,7 @@ static int tsc2007_get_pendown_state_gpio(struct device *dev)
 	struct i2c_client *client = to_i2c_client(dev);
 	struct tsc2007 *ts = i2c_get_clientdata(client);
 
-	return !gpio_get_value(ts->gpio);
+	return gpiod_get_value(ts->gpiod);
 }
 
 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
@@ -266,13 +266,13 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 		return -EINVAL;
 	}
 
-	ts->gpio = of_get_gpio(np, 0);
-	if (gpio_is_valid(ts->gpio))
+	ts->gpiod = devm_gpiod_get_optional(&client->dev, NULL, GPIOD_IN);
+	if (IS_ERR(ts->gpiod))
+		return PTR_ERR(ts->gpiod);
+	if (ts->gpiod)
 		ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
 	else
-		dev_warn(&client->dev,
-			 "GPIO not specified in DT (of_get_gpio returned %d)\n",
-			 ts->gpio);
+		dev_warn(&client->dev, "GPIO not specified in DT\n");
 
 	return 0;
 }
-- 
2.21.0




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