Hi Rob,

On 2018-05-31 10:45 PM, Rob Herring wrote:

On Wed, May 30, 2018 at 10:27 PM,  [off-list ref] wrote:

quoted

From: Levin Du <redacted>

In Rockchip RK3328, the output only GPIO_MUTE pin, originally for codec
mute control, can also be used for general purpose. It is manipulated by
the GRF_SOC_CON10 register.

Signed-off-by: Levin Du <redacted>

---

Changes in v3:
- Change from general gpio-syscon to specific rk3328-gpio-mute

Changes in v2:
- Rename gpio_syscon10 to gpio_mute in doc

Changes in v1:
- Refactured for general gpio-syscon usage for Rockchip SoCs.
- Add doc rockchip,gpio-syscon.txt

  .../bindings/gpio/rockchip,rk3328-gpio-mute.txt    | 28 +++++++++++++++++++
  drivers/gpio/gpio-syscon.c                         | 31 ++++++++++++++++++++++
  2 files changed, 59 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/gpio/rockchip,rk3328-gpio-mute.txt

diff --git a/Documentation/devicetree/bindings/gpio/rockchip,rk3328-gpio-mute.txt b/Documentation/devicetree/bindings/gpio/rockchip,rk3328-gpio-mute.txt
new file mode 100644
index 0000000..10bc632
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/rockchip,rk3328-gpio-mute.txt

@@ -0,0 +1,28 @@
+Rockchip RK3328 GPIO controller dedicated for the GPIO_MUTE pin.
+
+In Rockchip RK3328, the output only GPIO_MUTE pin, originally for codec mute
+control, can also be used for general purpose. It is manipulated by the
+GRF_SOC_CON10 register.
+
+Required properties:
+- compatible: Should contain "rockchip,rk3328-gpio-mute".
+- gpio-controller: Marks the device node as a gpio controller.
+- #gpio-cells: Should be 2. The first cell is the pin number and
+  the second cell is used to specify the gpio polarity:
+    0 = Active high,
+    1 = Active low.
+
+Example:
+
+       grf: syscon at ff100000 {
+               compatible = "rockchip,rk3328-grf", "syscon", "simple-mfd";
+
+               gpio_mute: gpio-mute {

Node names should be generic:

gpio {

This also means you can't add another GPIO node in the future and
you'll have to live with "rockchip,rk3328-gpio-mute" covering more
than 1 GPIO if you do need to add more GPIOs.

As the first line describes, this GPIO controller is dedicated for the 
GPIO_MUTE pin.
There's only one GPIO pin in the GRF_SOC_CON10 register. Therefore the 
gpio_mute
name is proper IMHO.

quoted

+                       compatible = "rockchip,rk3328-gpio-mute";
+                       gpio-controller;
+                       #gpio-cells = <2>;
+               };
+       };
+
+Note: The gpio_mute node should be declared as the child of the GRF (General
+Register File) node. The GPIO_MUTE pin is referred to as <&gpio_mute 0>.

This is wrong because you should have 2 cells. The phandle doesn't
count as a cell.

Rob

Thanks for pointing that out. So it should be:

 ?? The GPIO_MUTE pin is referred to as <&gpio_mute 0 POLARITY>.


Thanks,
Levin