On Mon, Jan 13, 2025 at 02:42:51PM +0100, Ahmad Fatoum wrote: > The imx8m-clock.yaml binding covers the clock controller inside all > of the i.MX8M Q/M/N/P SoCs. All of them have in common that they > support two operating modes: nominal and overdrive mode. > > While the overdrive mode allows for higher frequencies for many IPs, > the nominal mode needs a lower SoC voltage, thereby reducing > heat generation and power usage. > > As increasing clock rates beyond the maximum permitted by the supplied > SoC voltage can lead to difficult to debug issues, device tree consumers > would benefit from knowing what mode is active to enforce the clock rate > limits that come with it. > > To facilitate this, extend the clock controller bindings with an > optional fsl,operating-mode property. This intentionally allows the > absence of the property, because there is no default suitable for all > boards: > > For i.MX8M Mini and Nano, the kernel SoC DTSIs has assigned-clock-rates > that are all achievable in nominal mode. For i.MX8MP, there are some > rates only validated for overdrive mode. > > But even for the i.MX8M Mini/Nano boards, we don't know what rates they > may configure at runtime, so it has not been possible so far to infer from > just the device tree what the mode is. > > Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/clock/imx8m-clock.yaml | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml > index c643d4a814786a1fc7e559140fe58911990f71bb..b03672255cae9462013a8a4e7a2adaff440f1420 100644 > --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml > +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml > @@ -43,6 +43,16 @@ properties: > ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-clock.h > for the full list of i.MX8M clock IDs. > > + fsl,operating-mode: > + $ref: /schemas/types.yaml#/definitions/string > + description: > + The operating mode of the SoC. This affects the maximum clock rates that > + can safely be configured by the clock controller. > + oneOf: > + - enum: > + - nominal > + - overdrive I remember fsl,operating-mode: enum: [nominal, overdrive] should work without oneOf Frank > + > required: > - compatible > - reg > @@ -109,6 +119,7 @@ examples: > <&clk_ext3>, <&clk_ext4>; > clock-names = "osc_32k", "osc_24m", "clk_ext1", "clk_ext2", > "clk_ext3", "clk_ext4"; > + fsl,operating-mode = "nominal"; > }; > > - | > > -- > 2.39.5 >
