| Message ID | 20241106090549.3684963-2-dario.binacchi@amarulasolutions.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Support spread spectrum clocking for i.MX8{M,N,P} PLLs | expand |
On Wed, Nov 06, 2024 at 09:57:57AM +0100, Dario Binacchi wrote: > The patch adds the DT bindings for enabling and tuning spread spectrum > clocking generation. We had long talks about this but nothing of it got reflected in commit msg. Sorry, I don't remember what I was talking in some particular patch month ago, so you will get the same questions over and over... > > Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com> > > --- > > Changes in v3: > - Added in v3 > - The dt-bindings have been moved from fsl,imx8m-anatop.yaml to > imx8m-clock.yaml. The anatop device (fsl,imx8m-anatop.yaml) is > indeed more or less a syscon, so it represents a memory area > accessible by ccm (imx8m-clock.yaml) to setup the PLLs. > > .../bindings/clock/imx8m-clock.yaml | 46 +++++++++++++++++++ > 1 file changed, 46 insertions(+) > > diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml > index c643d4a81478..7920393e518e 100644 > --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml > +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml > @@ -43,6 +43,40 @@ 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,ssc-clocks: > + $ref: /schemas/types.yaml#/definitions/phandle-array > + description: > + Phandles of the PLL with spread spectrum generation hardware capability. > + minItems: 1 > + maxItems: 4 1. How is it possible that you change spread spectrum of some clocks from main Clock Controller, while this device is not a consumer of them? Basically this means that this device does not have these clocks but yet you claim that it needs to configure spread for them! It's contradictory to me and nohing got explained in commit msg about it. I am pretty sure I asked about this alrady. 2. Why is this array flexible in size? Best regards, Krzysztof
On 06/11/2024 15:10, Krzysztof Kozlowski wrote: > On Wed, Nov 06, 2024 at 09:57:57AM +0100, Dario Binacchi wrote: >> The patch adds the DT bindings for enabling and tuning spread spectrum >> clocking generation. > > We had long talks about this but nothing of it got reflected in commit > msg. Sorry, I don't remember what I was talking in some particular patch > month ago, so you will get the same questions over and over... > >> >> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com> >> >> --- >> >> Changes in v3: >> - Added in v3 >> - The dt-bindings have been moved from fsl,imx8m-anatop.yaml to >> imx8m-clock.yaml. The anatop device (fsl,imx8m-anatop.yaml) is >> indeed more or less a syscon, so it represents a memory area >> accessible by ccm (imx8m-clock.yaml) to setup the PLLs. >> >> .../bindings/clock/imx8m-clock.yaml | 46 +++++++++++++++++++ >> 1 file changed, 46 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml >> index c643d4a81478..7920393e518e 100644 >> --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml >> +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml >> @@ -43,6 +43,40 @@ 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,ssc-clocks: >> + $ref: /schemas/types.yaml#/definitions/phandle-array >> + description: >> + Phandles of the PLL with spread spectrum generation hardware capability. >> + minItems: 1 >> + maxItems: 4 > > 1. How is it possible that you change spread spectrum of some clocks from > main Clock Controller, while this device is not a consumer of them? > Basically this means that this device does not have these clocks but yet > you claim that it needs to configure spread for them! It's contradictory > to me and nohing got explained in commit msg about it. I am pretty sure > I asked about this alrady. I digged my previous answer and it was pretty clear here: 18:44 <krzk> You can, but I still have the same concerns. How this device - which does not take any clock input, has no clocks at all - can depend on spread spectrum of some PLLs? Thsi device does not have clocks. 18:50 <krzk> device has no clocks, I checked now third time 18:50 <krzk> If device has clocks, it must have clocks property So again, you do not need this property at all. I repeated it multiple times - you are supposed to use clocks property. > > 2. Why is this array flexible in size? > > Best regards, > Krzysztof > Best regards, Krzysztof
diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml index c643d4a81478..7920393e518e 100644 --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml @@ -43,6 +43,40 @@ 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,ssc-clocks: + $ref: /schemas/types.yaml#/definitions/phandle-array + description: + Phandles of the PLL with spread spectrum generation hardware capability. + minItems: 1 + maxItems: 4 + + fsl,ssc-modfreq-hz: + description: + The values of modulation frequency (Hz unit) of spread spectrum + clocking for each PLL. + minItems: 1 + maxItems: 4 + + fsl,ssc-modrate-percent: + description: + The percentage values of modulation rate of spread spectrum + clocking for each PLL. + minItems: 1 + maxItems: 4 + + fsl,ssc-modmethod: + $ref: /schemas/types.yaml#/definitions/string-array + description: + The modulation techniques of spread spectrum clocking for + each PLL. + minItems: 1 + maxItems: 4 + items: + enum: + - down-spread + - up-spread + - center-spread + required: - compatible - reg @@ -76,6 +110,11 @@ allOf: - const: clk_ext2 - const: clk_ext3 - const: clk_ext4 + fsl,ssc-clocks: false + fsl,ssc-modfreq-hz: false + fsl,ssc-modrate-percent: false + fsl,ssc-modmethod: false + else: properties: clocks: @@ -101,6 +140,8 @@ additionalProperties: false examples: # Clock Control Module node: - | + #include <dt-bindings/clock/imx8mm-clock.h> + clock-controller@30380000 { compatible = "fsl,imx8mm-ccm"; reg = <0x30380000 0x10000>; @@ -109,6 +150,11 @@ examples: <&clk_ext3>, <&clk_ext4>; clock-names = "osc_32k", "osc_24m", "clk_ext1", "clk_ext2", "clk_ext3", "clk_ext4"; + fsl,ssc-clocks = <&clk IMX8MM_AUDIO_PLL1>, + <&clk IMX8MM_VIDEO_PLL1>; + fsl,ssc-modfreq-hz = <6818>, <2419>; + fsl,ssc-modrate-percent = <3>, <7>; + fsl,ssc-modmethod = "down-spread", "center-spread"; }; - |
The patch adds the DT bindings for enabling and tuning spread spectrum clocking generation. Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com> --- Changes in v3: - Added in v3 - The dt-bindings have been moved from fsl,imx8m-anatop.yaml to imx8m-clock.yaml. The anatop device (fsl,imx8m-anatop.yaml) is indeed more or less a syscon, so it represents a memory area accessible by ccm (imx8m-clock.yaml) to setup the PLLs. .../bindings/clock/imx8m-clock.yaml | 46 +++++++++++++++++++ 1 file changed, 46 insertions(+)