Input: add common DT binding for touchscreens

Add common DT binding documentation for touchscreen devices and
implement input_parse_touchscreen_of_params, which parses the common
properties and configures the input device accordingly.

The method currently does not interpret the axis inversion properties,
since there is no matching flag in the generic linux input device.

Reviewed-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 50 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 43389c097b02..8e07fe8505fd 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -11,6 +11,10 @@ menuconfig INPUT_TOUCHSCREEN
 
 if INPUT_TOUCHSCREEN
 
+config OF_TOUCHSCREEN
+        def_tristate INPUT
+        depends on INPUT && OF
+
 config TOUCHSCREEN_88PM860X
         tristate "Marvell 88PM860x touchscreen"
         depends on MFD_88PM860X
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 71a97559ce68..4d479fb0a768 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -6,6 +6,7 @@
 
 wm97xx-ts-y := wm97xx-core.o
 
+obj-$(CONFIG_OF_TOUCHSCREEN)            += of_touchscreen.o
 obj-$(CONFIG_TOUCHSCREEN_88PM860X)      += 88pm860x-ts.o
 obj-$(CONFIG_TOUCHSCREEN_AD7877)        += ad7877.o
 obj-$(CONFIG_TOUCHSCREEN_AD7879)        += ad7879.o
diff --git a/drivers/input/touchscreen/of_touchscreen.c b/drivers/input/touchscreen/of_touchscreen.c
new file mode 100644
index 000000000000..f8f9b84230b1
--- /dev/null
+++ b/drivers/input/touchscreen/of_touchscreen.c
@@ -0,0 +1,45 @@
+/*
+ *  Generic DT helper functions for touchscreen devices
+ *
+ *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/of.h>
+#include <linux/input.h>
+#include <linux/input/touchscreen.h>
+
+/**
+ * touchscreen_parse_of_params - parse common touchscreen DT properties
+ * @dev: device that should be parsed
+ *
+ * This function parses common DT properties for touchscreens and setups the
+ * input device accordingly. The function keeps previously setuped default
+ * values if no value is specified via DT.
+ */
+void touchscreen_parse_of_params(struct input_dev *dev)
+{
+        struct device_node *np = dev->dev.parent->of_node;
+        struct input_absinfo *absinfo;
+
+        input_alloc_absinfo(dev);
+        if (!dev->absinfo)
+                return;
+
+        absinfo = &dev->absinfo[ABS_X];
+        of_property_read_u32(np, "touchscreen-size-x", &absinfo->maximum);
+        of_property_read_u32(np, "touchscreen-fuzz-x", &absinfo->fuzz);
+
+        absinfo = &dev->absinfo[ABS_Y];
+        of_property_read_u32(np, "touchscreen-size-y", &absinfo->maximum);
+        of_property_read_u32(np, "touchscreen-fuzz-y", &absinfo->fuzz);
+
+        absinfo = &dev->absinfo[ABS_PRESSURE];
+        of_property_read_u32(np, "touchscreen-max-pressure", &absinfo->maximum);
+        of_property_read_u32(np, "touchscreen-fuzz-pressure", &absinfo->fuzz);
+}
+EXPORT_SYMBOL(touchscreen_parse_of_params);