On Sun, Jul 04, 2021 at 11:36:41AM +0200, Stephan Gerhold wrote:
> On Sun, Jul 04, 2021 at 03:40:44PM +0800, Shawn Guo wrote:
> > It's not always the case that reboot mode value gets stored in PON
> > register. For example, Sony Xperia M4 Aqua phone (MSM8939) uses a
> > different set of mode value and stores them in IMEM. Add property
> > 'qcom,mode-in-imem' to distinguish this mechanism from the existing one.
> >
> > Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
> > ---
> > .../bindings/power/reset/qcom,pon.yaml | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml b/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
> > index 7764c804af1d..a6270e39b7a2 100644
> > --- a/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
> > +++ b/Documentation/devicetree/bindings/power/reset/qcom,pon.yaml
> > @@ -23,6 +23,10 @@ properties:
> > reg:
> > maxItems: 1
> >
> > + qcom,mode-in-imem:
> > + description: Reboot mode is stored in IMEM rather than PON register
> > + type: boolean
> > +
> > patternProperties:
> > "^mode-.+":
> > $ref: /schemas/types.yaml#/definitions/uint32
> > @@ -35,6 +39,7 @@ required:
> > additionalProperties: false
> >
> > examples:
> > + # Example 1: Reboot mode is stored in PON register
> > - |
> > pmic {
> > #address-cells = <1>;
> > @@ -47,3 +52,17 @@ examples:
> > mode-recovery = <0x1>;
> > };
> > };
> > + # Example 2: Reboot mode is stored in IMEM
> > + - |
> > + pmic {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + pon@800 {
> > + compatible = "qcom,pm8916-pon";
> > + reg = <0x860065c>;
>
> This is quite strange. pon@800 is a node of the PM8916 PMIC,
> so the reg should refer to the address inside the PMIC, not some memory
> address of the SoC. dtc will probably warn about this too since the unit
> address (@800) should match the first reg. (At least on W=1.)
Fair point.
> Actually we already have some devices using IMEM for the reboot mode,
> like this (qcom-msm8974.dtsi plus qcom-msm8974-fairphone-fp2.dts):
>
> imem@fe805000 {
> compatible = "syscon", "simple-mfd";
> reg = <0xfe805000 0x1000>;
>
> reboot-mode {
> compatible = "syscon-reboot-mode";
> offset = <0x65c>;
> mode-normal = <0x77665501>;
> mode-bootloader = <0x77665500>;
> mode-recovery = <0x77665502>;
> };
> };
>
> Perhaps it would be cleaner to add a property to disable the reboot mode
> functionality of pm8916-pon and then set it up like this?
Ah, yes, this is sensible. Thanks for the msm8974 example!
Shawn
