[PATCH 3/3] input: touchscreen: ad7879: add device tree support

[Stefan Agner <stefan@agner.ch>]

Add device tree support for the I2C variant of AD7879 (AD7879-1). This
allows to specify the touchscreen controller as a I2C client node.
Most of the options available as platform data are also available as
device tree properties. Exporting the GPIO is currently not possible
through device tree.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 .../bindings/input/touchscreen/ad7879-i2c.txt      | 47 ++++++++++++++++
 drivers/input/touchscreen/ad7879-i2c.c             | 63 +++++++++++++++++++++-
 drivers/input/touchscreen/ad7879-spi.c             |  3 +-
 drivers/input/touchscreen/ad7879.c                 |  2 +-
 drivers/input/touchscreen/ad7879.h                 |  1 +
 5 files changed, 113 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt

diff --git a/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
new file mode 100644
index 0000000..bf169a2
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
@@ -0,0 +1,47 @@
+* Analog Devices AD7879-1/AD7889-1 touchscreen interface (I2C)
+
+Required properties:
+- compatible: must be "adi,ad7879-1"
+- reg: i2c slave address
+- interrupt-parent: the phandle for the interrupt controller
+- interrupts: touch controller interrupt
+- resistance-plate-x		: total resistance of X-plate (for pressure
+				  calculation)
+- touchscreen-max-pressure	: maximum reported pressure
+- touchscreen-swapped-x-y	: X and Y axis are swapped (boolean)
+				  Swapping is done after inverting the axis
+Optional properties:
+- first-conversion-delay	: 0-12 in 128us steps (starting with 128us)
+				  13: 2.560ms
+				  14: 3.584ms
+				  15: 4.096ms
+- acquisition-time		: 0: 2us
+				  1: 4us
+				  2: 8us
+				  3: 16us
+- median-filter-size		: 0: disabled
+				  1: 4 measurements
+				  2: 8 measurements
+				  3: 16 measurements
+- averaging			: 0: 2 middle values (1 if median disabled)
+				  1: 4 middle values
+				  2: 8 middle values
+				  3: 16 values
+- conversion-interval:		: 0: convert one time only
+				  1-255: 515us + val * 35us (up to 9.440ms)
+
+Example:
+
+	ad7879@2c {
+		compatible = "adi,ad7879-1";
+		reg = <0x2c>;
+		interrupt-parent = <&gpio1>;
+		interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
+		resistance-plate-x = <120>;
+		touchscreen-max-pressure = <4096>;
+		first-conversion-delay = /bits/ 8 <3>;
+		acquisition-time = /bits/ 8 <1>;
+		median-filter-size = /bits/ 8 <2>;
+		averaging = /bits/ 8 <1>;
+		conversion-interval = /bits/ 8 <255>;
+	};
diff --git a/drivers/input/touchscreen/ad7879-i2c.c b/drivers/input/touchscreen/ad7879-i2c.c
index d66962c..08a2c9a 100644
--- a/drivers/input/touchscreen/ad7879-i2c.c
+++ b/drivers/input/touchscreen/ad7879-i2c.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/pm.h>
+#include <linux/input/ad7879.h>
 
 #include "ad7879.h"
 
@@ -54,9 +55,50 @@ static const struct ad7879_bus_ops ad7879_i2c_bus_ops = {
 	.write		= ad7879_i2c_write,
 };
 
+static struct ad7879_platform_data *ad7879_parse_dt(struct device *dev)
+{
+	struct ad7879_platform_data *pdata;
+	struct device_node *np = dev->of_node;
+	int err;
+	u32 tmp;
+
+	if (!np)
+		return NULL;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	err = of_property_read_u32(np, "resistance-plate-x", &tmp);
+	if (err) {
+		dev_err(dev, "failed to get resistance-plate-x property\n");
+		return ERR_PTR(err);
+	}
+	pdata->x_plate_ohms = (u16)tmp;
+
+	err = of_property_read_u32(np, "touchscreen-max-pressure", &tmp);
+	if (err) {
+		dev_err(dev, "failed to get touchscreen-max-pressure property\n");
+		return ERR_PTR(err);
+	}
+	pdata->pressure_min = (u16)tmp;
+
+	of_property_read_u8(np, "first-conversion-delay", &pdata->first_conversion_delay);
+	of_property_read_u8(np, "acquisition-time", &pdata->acquisition_time);
+	of_property_read_u8(np, "median-filter-size", &pdata->median);
+	of_property_read_u8(np, "averaging", &pdata->averaging);
+	of_property_read_u8(np, "conversion-interval", &pdata->pen_down_acc_interval);
+
+	pdata->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
+
+	return pdata;
+}
+
 static int ad7879_i2c_probe(struct i2c_client *client,
 				      const struct i2c_device_id *id)
 {
+	struct ad7879_platform_data *pdata;
 	struct ad7879 *ts;
 
 	if (!i2c_check_functionality(client->adapter,
@@ -65,7 +107,17 @@ static int ad7879_i2c_probe(struct i2c_client *client,
 		return -EIO;
 	}
 
-	ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq,
+	pdata = dev_get_platdata(&client->dev);
+
+	if (!pdata && IS_ENABLED(CONFIG_OF))
+		pdata = ad7879_parse_dt(&client->dev);
+
+	if (IS_ERR_OR_NULL(pdata)) {
+		dev_err(&client->dev, "Need platform data\n");
+		return PTR_ERR(pdata);
+	}
+
+	ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq, pdata,
 			  &ad7879_i2c_bus_ops);
 	if (IS_ERR(ts))
 		return PTR_ERR(ts);
@@ -91,10 +143,19 @@ static const struct i2c_device_id ad7879_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, ad7879_id);
 
+#ifdef CONFIG_OF
+static const struct of_device_id ad7879_dt_ids[] = {
+	{ .compatible = "adi,ad7879-1", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
+#endif
+
 static struct i2c_driver ad7879_i2c_driver = {
 	.driver = {
 		.name	= "ad7879",
 		.pm	= &ad7879_pm_ops,
+		.of_match_table = of_match_ptr(ad7879_dt_ids),
 	},
 	.probe		= ad7879_i2c_probe,
 	.remove		= ad7879_i2c_remove,
diff --git a/drivers/input/touchscreen/ad7879-spi.c b/drivers/input/touchscreen/ad7879-spi.c
index 48033c2..8ebe604 100644
--- a/drivers/input/touchscreen/ad7879-spi.c
+++ b/drivers/input/touchscreen/ad7879-spi.c
@@ -128,7 +128,8 @@ static int ad7879_spi_probe(struct spi_device *spi)
 	        return err;
 	}
 
-	ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
+	ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, pdata,
+			  dev_get_platdata(&spi->dev), &ad7879_spi_bus_ops);
 	if (IS_ERR(ts))
 		return PTR_ERR(ts);
 
diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
index e290e7b..e763c77 100644
--- a/drivers/input/touchscreen/ad7879.c
+++ b/drivers/input/touchscreen/ad7879.c
@@ -486,9 +486,9 @@ static inline void ad7879_gpio_remove(struct ad7879 *ts)
 #endif
 
 struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
+			    struct ad7879_platform_data *pdata,
 			    const struct ad7879_bus_ops *bops)
 {
-	struct ad7879_platform_data *pdata = dev_get_platdata(dev);
 	struct ad7879 *ts;
 	struct input_dev *input_dev;
 	int err;
diff --git a/drivers/input/touchscreen/ad7879.h b/drivers/input/touchscreen/ad7879.h
index 6fd13c4..fa363a0 100644
--- a/drivers/input/touchscreen/ad7879.h
+++ b/drivers/input/touchscreen/ad7879.h
@@ -24,6 +24,7 @@ struct ad7879_bus_ops {
 extern const struct dev_pm_ops ad7879_pm_ops;
 
 struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned irq,
+			    struct ad7879_platform_data *pdata,
 			    const struct ad7879_bus_ops *bops);
 void ad7879_remove(struct ad7879 *);
 
-- 
2.7.0