[PATCH v4 6/8] iio: adc: add STMPE ADC devicetree bindings

[Philippe Schenker <dev@pschenker.ch>]

From: Stefan Agner <stefan@agner.ch>

This adds the devicetree bindings for the STMPE ADC. And corrects a
typo in st,sample-time it is rather "6 -> 124 clocks" according
to the datasheet and not 144.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
---

Changes in v4:
 - Put reformatting in a separate precursor patch.

Changes in v3:
 - Reformatted documentation for touchscreen to use tabs and have a better
   overview of the settings.
 - Added note which adc-settings will take precedence.
 - changed typo in sample-time setting from 144 clocks to 124 clocks, as stated
   in the datasheet.

Changes in v2:
 - Moved the bindings for ADC to the overlying mfd.
 - Reformatted for better readability

 .../devicetree/bindings/iio/adc/stmpe-adc.txt | 21 ++++++++++++
 .../bindings/input/touchscreen/stmpe.txt      | 32 +++++++++----------
 .../devicetree/bindings/mfd/stmpe.txt         | 14 ++++++++
 3 files changed, 51 insertions(+), 16 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt

diff --git a/Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt b/Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt
new file mode 100644
index 000000000000..480e66422625
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/stmpe-adc.txt
@@ -0,0 +1,21 @@
+STMPE ADC driver
+----------------
+
+Required properties:
+ - compatible: "st,stmpe-adc"
+
+Optional properties:
+Note that the ADC is shared with the STMPE touchscreen. ADC related settings
+have to be done in the mfd.
+- st,norequest-mask: bitmask specifying which ADC channels should _not_ be
+  requestable due to different usage (e.g. touch)
+
+Node name must be stmpe_adc and should be child node of stmpe node to
+which it belongs.
+
+Example:
+
+	stmpe_adc {
+		compatible = "st,stmpe-adc";
+		st,norequest-mask = <0x0F>; /* dont use ADC CH3-0 */
+	};
diff --git a/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt b/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
index 1d3f84308142..8e2b240882fa 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/stmpe.txt
@@ -5,18 +5,6 @@ Required properties:
  - compatible: "st,stmpe-ts"
 
 Optional properties:
-- st,sample-time	: ADC conversion time in number of clock.
-				0 -> 36 clocks		4 -> 80 clocks (recommended)
-				1 -> 44 clocks		5 -> 96 clocks
-				2 -> 56 clocks		6 -> 144 clocks
-				3 -> 64 clocks
-- st,mod-12b		: ADC Bit mode
-				0 -> 10bit ADC		1 -> 12bit ADC
-- st,ref-sel		: ADC reference source
-				0 -> internal		1 -> external
-- st,adc-freq		: ADC Clock speed
-				0 -> 1.625 MHz		2 || 3 -> 6.5 MHz
-				1 -> 3.25 MHz
 - st,ave-ctrl		: Sample average control
 				0 -> 1 sample
 				1 -> 2 samples
@@ -40,17 +28,29 @@ Optional properties:
 				0 -> 20 mA (typical 35mA max)
 				1 -> 50 mA (typical 80 mA max)
 
+Optional properties common with MFD (deprecated):
+ - st,sample-time	: ADC conversion time in number of clock.
+				0 -> 36 clocks		4 -> 80 clocks (recommended)
+				1 -> 44 clocks		5 -> 96 clocks
+				2 -> 56 clocks		6 -> 124 clocks
+				3 -> 64 clocks
+ - st,mod-12b		: ADC Bit mode
+				0 -> 10bit ADC		1 -> 12bit ADC
+ - st,ref-sel		: ADC reference source
+				0 -> internal		1 -> external
+ - st,adc-freq		: ADC Clock speed
+				0 -> 1.625 MHz		2 || 3 -> 6.5 MHz
+				1 -> 3.25 MHz
+
 Node name must be stmpe_touchscreen and should be child node of stmpe node to
 which it belongs.
 
+Note that common ADC settings of stmpe_touchscreen will take precedence.
+
 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>;
diff --git a/Documentation/devicetree/bindings/mfd/stmpe.txt b/Documentation/devicetree/bindings/mfd/stmpe.txt
index a46e7177195d..d4408a417193 100644
--- a/Documentation/devicetree/bindings/mfd/stmpe.txt
+++ b/Documentation/devicetree/bindings/mfd/stmpe.txt
@@ -14,6 +14,20 @@ Optional properties:
  - st,autosleep-timeout		: Valid entries (ms); 4, 16, 32, 64, 128, 256, 512 and 1024
  - irq-gpio			: If present, which GPIO to use for event IRQ
 
+Optional properties for devices with touch and ADC (STMPE811|STMPE610):
+ - st,sample-time		: ADC conversion time in number of clock.
+					0 -> 36 clocks		4 -> 80 clocks (recommended)
+					1 -> 44 clocks		5 -> 96 clocks
+					2 -> 56 clocks		6 -> 124 clocks
+					3 -> 64 clocks
+ - st,mod-12b			: ADC Bit mode
+					0 -> 10bit ADC		1 -> 12bit ADC
+ - st,ref-sel			: ADC reference source
+					0 -> internal		1 -> external
+ - st,adc-freq			: ADC Clock speed
+					0 -> 1.625 MHz		2 || 3 -> 6.5 MHz
+					1 -> 3.25 MHz
+
 Example:
 
 	stmpe1601: stmpe1601@40 {
-- 
2.19.2