Input: stmpe-ts - add DT support for stmpe touchscreen

This patch allows the STMPE Touchscreen driver to be successfully probed and
initialised when Device Tree support is enabled. Bindings are mentioned in
Documentation too.

Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/stmpe.txt

@@ -0,0 +1,43 @@
+STMPE Touchscreen
+----------------
+
+Required properties:
+ - compatible: "st,stmpe-ts"
+
+Optional properties:
+- st,sample-time: ADC converstion time in number of clock.  (0 -> 36 clocks, 1 ->
+  44 clocks, 2 -> 56 clocks, 3 -> 64 clocks, 4 -> 80 clocks, 5 -> 96 clocks, 6
+  -> 144 clocks), recommended is 4.
+- st,mod-12b: ADC Bit mode (0 -> 10bit ADC, 1 -> 12bit ADC)
+- st,ref-sel: ADC reference source (0 -> internal reference, 1 -> external
+  reference)
+- st,adc-freq: ADC Clock speed (0 -> 1.625 MHz, 1 -> 3.25 MHz, 2 || 3 -> 6.5 MHz)
+- st,ave-ctrl: Sample average control (0 -> 1 sample, 1 -> 2 samples, 2 -> 4
+  samples, 3 -> 8 samples)
+- st,touch-det-delay: Touch detect interrupt delay (0 -> 10 us, 1 -> 50 us, 2 ->
+  100 us, 3 -> 500 us, 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms) recommended
+  is 3
+- st,settling: Panel driver settling time (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3
+  -> 1 ms, 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms) recommended is 2
+- st,fraction-z: Length of the fractional part in z (fraction-z ([0..7]) = Count of
+  the fractional part) recommended is 7
+- st,i-drive: current limit value of the touchscreen drivers (0 -> 20 mA typical 35
+  mA max, 1 -> 50 mA typical 80 mA max)
+
+Node name must be stmpe_touchscreen and should be child node of stmpe node to
+which it belongs.
+
+Example:
+
+	stmpe_touchscreen {
+		compatible = "st,stmpe-ts";
+		st,sample-time = <4>;
+		st,mod-12b = <1>;
+		st,ref-sel = <0>;
+		st,adc-freq = <1>;
+		st,ave-ctrl = <1>;
+		st,touch-det-delay = <2>;
+		st,settling = <2>;
+		st,fraction-z = <7>;
+		st,i-drive = <1>;
+	};

drivers/input/touchscreen/stmpe-ts.c

@@ -17,6 +17,7 @@
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/device.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/input.h>
 #include <linux/slab.h>
@@ -262,11 +263,53 @@ static void stmpe_ts_close(struct input_dev *dev)
 			STMPE_TSC_CTRL_TSC_EN, 0);
 }
 
-static int __devinit stmpe_input_probe(struct platform_device *pdev)
+static void stmpe_ts_get_platform_info(struct platform_device *pdev,
+					struct stmpe_touch *ts)
 {
 	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
-	const struct stmpe_platform_data *pdata = stmpe->pdata;
-	const struct stmpe_ts_platform_data *ts_pdata = NULL;
+	struct device_node *np = pdev->dev.of_node;
+	struct stmpe_ts_platform_data *ts_pdata = NULL;
+
+	ts->stmpe = stmpe;
+
+	if (stmpe->pdata && stmpe->pdata->ts) {
+		ts_pdata = stmpe->pdata->ts;
+
+		ts->sample_time = ts_pdata->sample_time;
+		ts->mod_12b = ts_pdata->mod_12b;
+		ts->ref_sel = ts_pdata->ref_sel;
+		ts->adc_freq = ts_pdata->adc_freq;
+		ts->ave_ctrl = ts_pdata->ave_ctrl;
+		ts->touch_det_delay = ts_pdata->touch_det_delay;
+		ts->settling = ts_pdata->settling;
+		ts->fraction_z = ts_pdata->fraction_z;
+		ts->i_drive = ts_pdata->i_drive;
+	} else if (np) {
+		u32 val;
+
+		if (!of_property_read_u32(np, "st,sample-time", &val))
+			ts->sample_time = val;
+		if (!of_property_read_u32(np, "st,mod-12b", &val))
+			ts->mod_12b = val;
+		if (!of_property_read_u32(np, "st,ref-sel", &val))
+			ts->ref_sel = val;
+		if (!of_property_read_u32(np, "st,adc-freq", &val))
+			ts->adc_freq = val;
+		if (!of_property_read_u32(np, "st,ave-ctrl", &val))
+			ts->ave_ctrl = val;
+		if (!of_property_read_u32(np, "st,touch-det-delay", &val))
+			ts->touch_det_delay = val;
+		if (!of_property_read_u32(np, "st,settling", &val))
+			ts->settling = val;
+		if (!of_property_read_u32(np, "st,fraction-z", &val))
+			ts->fraction_z = val;
+		if (!of_property_read_u32(np, "st,i-drive", &val))
+			ts->i_drive = val;
+	}
+}
+
+static int __devinit stmpe_input_probe(struct platform_device *pdev)
+{
 	struct stmpe_touch *ts;
 	struct input_dev *idev;
 	int error;
@@ -285,24 +328,10 @@ static int __devinit stmpe_input_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	platform_set_drvdata(pdev, ts);
-	ts->stmpe = stmpe;
 	ts->idev = idev;
 	ts->dev = &pdev->dev;
 
-	if (pdata)
-		ts_pdata = pdata->ts;
-
-	if (ts_pdata) {
-		ts->sample_time = ts_pdata->sample_time;
-		ts->mod_12b = ts_pdata->mod_12b;
-		ts->ref_sel = ts_pdata->ref_sel;
-		ts->adc_freq = ts_pdata->adc_freq;
-		ts->ave_ctrl = ts_pdata->ave_ctrl;
-		ts->touch_det_delay = ts_pdata->touch_det_delay;
-		ts->settling = ts_pdata->settling;
-		ts->fraction_z = ts_pdata->fraction_z;
-		ts->i_drive = ts_pdata->i_drive;
-	}
+	stmpe_ts_get_platform_info(pdev, ts);
 
 	INIT_DELAYED_WORK(&ts->work, stmpe_work);
 

drivers/mfd/stmpe.c

@@ -411,6 +411,7 @@ static struct resource stmpe_ts_resources[] = {
 
 static struct mfd_cell stmpe_ts_cell = {
 	.name		= "stmpe-ts",
+	.of_compatible	= "st,stmpe-ts",
 	.resources	= stmpe_ts_resources,
 	.num_resources	= ARRAY_SIZE(stmpe_ts_resources),
 };