Hi, Oleksij > On 03.09.19 08:37, Anson Huang wrote: > > Hi, Oleksij > > > >> On 03.09.19 16:03, Anson Huang wrote: > >>> NXP i.MX8QXP is an ARMv8 SoC with a Cortex-M4 core inside as system > >>> controller, the system controller is in charge of system power, > >>> clock and power key event etc. management, Linux kernel has to > >>> communicate with system controller via MU (message unit) IPC to get > >>> power key event, add binding doc for i.MX system controller power key > driver. > >>> > >>> Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx> > >>> --- > >>> Changes since V1: > >>> - remove "wakeup-source" property, as it is NOT needed for SCU > >> interrupt; > >>> - remove "status" in example. > >>> --- > >>> .../devicetree/bindings/arm/freescale/fsl,scu.txt | 14 > >> ++++++++++++++ > >>> 1 file changed, 14 insertions(+) > >>> > >>> diff --git > >>> a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > >>> b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > >>> index c149fad..f93e2e4 100644 > >>> --- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > >>> +++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > >>> @@ -157,6 +157,15 @@ Required properties: > >>> Optional properties: > >>> - timeout-sec: contains the watchdog timeout in seconds. > >>> > >>> +Power key bindings based on SCU Message Protocol > >>> +------------------------------------------------------------ > >>> + > >>> +Required properties: > >>> +- compatible: should be: > >>> + "fsl,imx8qxp-sc-pwrkey" > >>> + followed by "fsl,imx-sc-pwrkey"; > >>> +- linux,keycodes: See > >>> +Documentation/devicetree/bindings/input/keys.txt > >> > >> linux,keycodes is required parameter. So, this kay cab be anything. > >> Why the compatible is called pwrkey? Probably it is better to call it "*-sc- > key" > > > > This key is kind of special, it is ON/OFF button which is designed for > > power key purpose, it has HW function such as long pressing it would > > shutdown the system power, so we always use it as power key, NOT > general key, does it make sense? > > I assume, OF devs will argue: DT is describing hardware not software. > On other hand, software will get notification about assertion/deassertion of > this key. So, it is just normal key. If, for some reason, it will trigger world > destruction, if it is pressed too long... probably no body cares. > You can provide fsl,imx-sc-key as additional compatible. In case linux will > need some quirks, we still can fall back to more precise compatible > "fsl,imx8qxp-sc-pwrkey". I am OK with that, so I will use "fsl,imx-sc-key" as additional compatible and also present in driver. Anson.
