Re: [PATCH RFC 1/8] dt-bindings: Document the hi6220 bindings for DRM driver

[Xinwei Kong <kong.kongxinwei@hisilicon.com>]

hi architt

On 2015/9/16 17:10, Archit Taneja wrote:
> Hi,
> 
> On 09/16/2015 02:04 PM, Xinwei Kong wrote:
>> hi architt
>>
>> On 2015/9/16 2:11, Rob Herring wrote:
>>> On 09/15/2015 04:37 AM, Xinwei Kong wrote:
>>>> This adds documentation of device tree bindings for the
>>>> Graphics Processing Unit of hi6220 SOC.
>>>>
>>>> Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
>>>> Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
>>>> Signed-off-by: Andy Green <andy.green@linaro.org>
>>>> Signed-off-by: Jiwen Qi <qijiwen@hisilicon.com>
>>>> Signed-off-by: Yu Gong <gongyu@hisilicon.com>
>>>> ---
>>>>   .../devicetree/bindings/gpu/hisilicon,hi6220.txt   | 69 ++++++++++++++++++++++
>>>>   1 file changed, 69 insertions(+)
>>>>   create mode 100644 Documentation/devicetree/bindings/gpu/hisilicon,hi6220.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/gpu/hisilicon,hi6220.txt b/Documentation/devicetree/bindings/gpu/hisilicon,hi6220.txt
>>>> new file mode 100644
>>>> index 0000000..173ac63
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/gpu/hisilicon,hi6220.txt
>>>> @@ -0,0 +1,69 @@
>>>> + * Hisilicon hi6220 Graphics Processing Unit for HiKey board
>>>> +
>>>> + ** display-subsystem: Master device for binding DRM sub-components
>>>
>>> DRM is a Linuxism that doesn't belong in the binding.
>>>
>>>> +    This master device is parent node and it will be responsible to bind all
>>>> +    sub-components devices node.
>>>
>>> Are these nodes a single block in the h/w? If not, you should describe
>>> the connection of sub-nodes with of-graph instead.
>>>
>>>> +    - Required properties :
>>>> +      - compatible: "hisilicon,display-subsystem".
>>>> +      - #address-cells, #size-cells: Must be present if the device has sub-nodes.
>>>> +      - ranges: to allow probing of subdevices.
>>>> +      - dma-coherent: Present if dma operations are coherent.
>>>> +
>>>> + ** ade: Graphic overlay, Graphic post-processing, display timing control.
>>>> +    This device is child node of display-subsystem
>>>> +    - Required properties :
>>>> +      - compatible: "hisilicon,hi6220-ade".
>>>> +      - reg: physical base address of the ADE register and length of memory
>>>> +    region.
>>>> +      - reg-names: Should contain the reg names "ade_base" and "media_base".
>>>> +      - interrupt: The interrupt number to the cpu. Defines the interrupt
>>>> +        by ADE.
>>>> +      - clocks: The clocks needed by the ADE module.
>>>> +      - clock-names: the name of the clocks.
>>>> +
>>>> + ** dsi: support mipi dsi interface
>>>> +    This device is child node of display-subsystem
>>>> +    - Required properties :
>>>> +      - compatible: "hisilicon,hi6220-dsi".
>>>> +      - reg: physical base address of the DSI register and length of memory
>>>> +    region.
>>>> +      - clocks: The clocks needed by the DSI module.
>>>> +      - clock-names: the name of the clocks.
>>>> +      -    encoder-slave: phandles to a 'encoder-slave' subnode which DSI connect
>>>> +        ADV7533 in order to support hdmi display.
>>>
>>> What the ADV7533 binding looks like is still being discussed.
>>> "encoder-slave" is certainly DRM specific and not how it should be done.
>>> Most likely, this needs to use the of-graph ports.
>>>
>> I dont how to implement the encoder bridge stuff in upstream,
>> you think that I will how to handle this part?
> 
> You can use of-graph ports to link the dsi output with the adv7533
> bridge.
> 
> An example of the binding looks like:
> 
> Documentation/devicetree/bindings/drm/msm/dsi.txt
> 
> The implementation of this on the dsi host side of drm/msm
> can be found in dsi_host_parse_dt, in:
> 
> drivers/gpu/drm/msm/dsi/dsi_host.c
> 
> You can get to know more about of-graph parsing here:
> 
> Documentation/devicetree/bindings/graph.txt
> 
I study your patch about of-graph parsing, I know that how to parse this
dts endpoint node. Then i dont kow how to use this device_node (which is
get by "of_graph_get_remote_port_parent" function.) to hook adv7533 operation.

can you give me some help to how to use the adv7533 interface by device_node or
other way to use adv7533?

> I'd started going through the drm/hisil patches. I'll
> share more comments there.
> 
> Thanks,
> Archit
> 
>>
>> Thank you
>> xinwei
>>
>>> Also, the ADV7533 connection is specific to HiKey. This binding should
>>> just generically describe how any bridge or panel is connected.
>>>
>>> Rob
>>>
>>> .
>>>
>>
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>