diff mbox series

[1/1] dt-bindings: adc-keys.txt: clarify description

Message ID 20201222110815.24121-1-xypron.glpk@gmx.de
State Accepted
Commit 698dc0cf944772a79a9aa417e647c0f7587e51df
Headers show
Series [1/1] dt-bindings: adc-keys.txt: clarify description | expand

Commit Message

Heinrich Schuchardt Dec. 22, 2020, 11:08 a.m. UTC
The current description of ADC keys is not precise enough.

"when this key is pressed" leaves it open if a key is considered pressed
below or above the threshold. This has led to confusion:
drivers/input/keyboard/adc-keys.c ignores the meaning of thresholds and
sets the key that is closest to press-threshold-microvolt.

This patch nails down the definitions and provides an interpretation of the
supplied example.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
I know that this file needs to be converted to YAML. But lets first get the
text right.
---
 .../devicetree/bindings/input/adc-keys.txt    | 22 +++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

--
2.29.2

Comments

Rob Herring (Arm) Jan. 3, 2021, 4:38 p.m. UTC | #1
On Tue, 22 Dec 2020 12:08:15 +0100, Heinrich Schuchardt wrote:
> The current description of ADC keys is not precise enough.

> 

> "when this key is pressed" leaves it open if a key is considered pressed

> below or above the threshold. This has led to confusion:

> drivers/input/keyboard/adc-keys.c ignores the meaning of thresholds and

> sets the key that is closest to press-threshold-microvolt.

> 

> This patch nails down the definitions and provides an interpretation of the

> supplied example.

> 

> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

> ---

> I know that this file needs to be converted to YAML. But lets first get the

> text right.

> ---

>  .../devicetree/bindings/input/adc-keys.txt    | 22 +++++++++++++++++--

>  1 file changed, 20 insertions(+), 2 deletions(-)

> 


Acked-by: Rob Herring <robh@kernel.org>
Dmitry Torokhov Jan. 5, 2021, 10:21 p.m. UTC | #2
On Tue, Dec 22, 2020 at 12:08:15PM +0100, Heinrich Schuchardt wrote:
> The current description of ADC keys is not precise enough.
> 
> "when this key is pressed" leaves it open if a key is considered pressed
> below or above the threshold. This has led to confusion:
> drivers/input/keyboard/adc-keys.c ignores the meaning of thresholds and
> sets the key that is closest to press-threshold-microvolt.
> 
> This patch nails down the definitions and provides an interpretation of the
> supplied example.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

Applied, thank you.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/input/adc-keys.txt b/Documentation/devicetree/bindings/input/adc-keys.txt
index e551814629b4..6c8be6a9ace2 100644
--- a/Documentation/devicetree/bindings/input/adc-keys.txt
+++ b/Documentation/devicetree/bindings/input/adc-keys.txt
@@ -5,7 +5,8 @@  Required properties:
  - compatible: "adc-keys"
  - io-channels: Phandle to an ADC channel
  - io-channel-names = "buttons";
- - keyup-threshold-microvolt: Voltage at which all the keys are considered up.
+ - keyup-threshold-microvolt: Voltage above or equal to which all the keys are
+			      considered up.

 Optional properties:
 	- poll-interval: Poll interval time in milliseconds
@@ -17,7 +18,12 @@  Each button (key) is represented as a sub-node of "adc-keys":
 Required subnode-properties:
 	- label: Descriptive name of the key.
 	- linux,code: Keycode to emit.
-	- press-threshold-microvolt: Voltage ADC input when this key is pressed.
+	- press-threshold-microvolt: voltage above or equal to which this key is
+				     considered pressed.
+
+No two values of press-threshold-microvolt may be the same.
+All values of press-threshold-microvolt must be less than
+keyup-threshold-microvolt.

 Example:

@@ -47,3 +53,15 @@  Example:
 			press-threshold-microvolt = <500000>;
 		};
 	};
+
++--------------------------------+------------------------+
+| 2.000.000 <= value             | no key pressed         |
++--------------------------------+------------------------+
+| 1.500.000 <= value < 2.000.000 | KEY_VOLUMEUP pressed   |
++--------------------------------+------------------------+
+| 1.000.000 <= value < 1.500.000 | KEY_VOLUMEDOWN pressed |
++--------------------------------+------------------------+
+|   500.000 <= value < 1.000.000 | KEY_ENTER pressed      |
++--------------------------------+------------------------+
+|              value <   500.000 | no key pressed         |
++--------------------------------+------------------------+