Re: [v10 1/2] dt/bindings: clk: Add YAML schemas for LS1028A Display Clock bindings

Michael Walle
2019-12-02T21:32:20Z

Am 2019-12-02 19:47, schrieb Rob Herring:
> On Wed, Nov 27, 2019 at 06:15:24PM +0800, Wen He wrote:
>> LS1028A has a clock domain PXLCLK0 used for provide pixel clocks to
>> Display
>> output interface. Add a YAML schema for this.
>>
>> Signed-off-by: Wen He <wen.he_1@nxp.com>
>> Signed-off-by: Michael Walle <michael@walle.cc>
>> ---
>> change in v10:
>> - Add optional feild 'vco-frequency'.
>>
>> .../devicetree/bindings/clock/fsl,plldig.yaml | 54
>> +++++++++++++++++++
>> 1 file changed, 54 insertions(+)
>> create mode 100644
>> Documentation/devicetree/bindings/clock/fsl,plldig.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/clock/fsl,plldig.yaml
>> b/Documentation/devicetree/bindings/clock/fsl,plldig.yaml
>> new file mode 100644
>> index 000000000000..ee5b5c61a471
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/clock/fsl,plldig.yaml
>> @@ -0,0 +1,54 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/bindings/clock/fsl,plldig.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: NXP QorIQ Layerscape LS1028A Display PIXEL Clock Binding
>> +
>> +maintainers:
>> + - Wen He <wen.he_1@nxp.com>
>> +
>> +description: |
>> + NXP LS1028A has a clock domain PXLCLK0 used for the Display output
>> + interface in the display core, as implemented in TSMC CLN28HPM PLL.
>> + which generate and offers pixel clocks to Display.
>> +
>> +properties:
>> + compatible:
>> + const: fsl,ls1028a-plldig
>> +
>> + reg:
>> + maxItems: 1
>> +
>> + '#clock-cells':
>> + const: 0
>> +
>> + vco-frequency:
>
> Needs vendor prefix and unit suffix:
>
> fsl,vco-hz
>
> Or you could perhaps just use 'clock-frequency'.

Ok, fsl,vco-hz sounds good. clock-frequency sounds like it is the
output.

-michael

>> + $ref: '/schemas/types.yaml#/definitions/uint32'
>> + description: Optional for VCO frequency of the PLL in Hertz.
>> + The VCO frequency of this PLL cannot be changed during
>> runtime
>> + only at startup. Therefore, the output frequencies are very
>> + limited and might not even closely match the requested
>> frequency.
>> + To work around this restriction the user may specify its own
>> + desired VCO frequency for the PLL. The frequency has to be in
>> the
>> + range of 650000000 to 1300000000.
>> + If not set, the default frequency is 1188000000.
>
> A bunch of constraints you've listed here that should be schema rather
> than freeform text:
>
> minimum: 650000000
> maximum: 1300000000
> default: 1188000000
>
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - clocks
>> + - '#clock-cells'
>> +
>> +examples:
>> + # Display PIXEL Clock node:
>> + - |
>> + dpclk: clock-display@f1f0000 {
>> + compatible = "fsl,ls1028a-plldig";
>> + reg = <0x0 0xf1f0000 0x0 0xffff>;
>> + #clock-cells = <0>;
>> + clocks = <&osc_27m>;
>> + };
>> +
>> +...
>> --
>> 2.17.1
>>