linux-kernel - Re: [linux-sunxi] [PATCH 1/2] ARM: sun8i: v3s: add device nodes for DE2 display pipeline

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Date:   Thu, 25 May 2017 22:28:24 +0800
From:   Icenowy Zheng <icenowy@...c.io>
To:     wens@...e.org, Chen-Yu Tsai <wens@...e.org>
CC:     Maxime Ripard <maxime.ripard@...e-electrons.com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [linux-sunxi] [PATCH 1/2] ARM: sun8i: v3s: add device nodes for DE2 display pipeline



于 2017年5月25日 GMT+08:00 下午10:20:33, Chen-Yu Tsai <wens@...e.org> 写到:
>On Thu, May 25, 2017 at 9:54 PM, Icenowy Zheng <icenowy@...c.io> wrote:
>>
>>
>> 于 2017年5月25日 GMT+08:00 下午4:37:31, Chen-Yu Tsai <wens@...e.org> 写到:
>>>On Wed, May 24, 2017 at 7:17 PM, Icenowy Zheng <icenowy@...c.io>
>wrote:
>>>> Allwinner V3s SoC features a "Display Engine 2.0" with only one
>mixer
>>>> and only one TCON connected to this mixer, which have RGB LCD
>output.
>>>>
>>>> Add device nodes for this display pipeline.
>>>>
>>>> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
>>>> ---
>>>>  arch/arm/boot/dts/sun8i-v3s.dtsi | 83
>>>++++++++++++++++++++++++++++++++++++++++
>>>>  1 file changed, 83 insertions(+)
>>>>
>>>> diff --git a/arch/arm/boot/dts/sun8i-v3s.dtsi
>>>b/arch/arm/boot/dts/sun8i-v3s.dtsi
>>>> index a49ebef53c91..3a06dc5b3746 100644
>>>> --- a/arch/arm/boot/dts/sun8i-v3s.dtsi
>>>> +++ b/arch/arm/boot/dts/sun8i-v3s.dtsi
>>>> @@ -61,6 +61,12 @@
>>>>                 };
>>>>         };
>>>>
>>>> +       de: display-engine {
>>>> +               compatible = "allwinner,sun8i-v3s-display-engine";
>>>> +               allwinner,pipelines = <&mixer0>;
>>>> +               status = "disabled";
>>>> +       };
>>>> +
>>>>         timer {
>>>>                 compatible = "arm,armv7-timer";
>>>>                 interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) |
>>>IRQ_TYPE_LEVEL_LOW)>,
>>>> @@ -95,6 +101,83 @@
>>>>                 #size-cells = <1>;
>>>>                 ranges;
>>>>
>>>> +               display_clocks: clock@...0000 {
>>>> +                       compatible = "allwinner,sun8i-v3s-de2-clk";
>>>> +                       reg = <0x01000000 0x100000>;
>>>> +                       clocks = <&ccu CLK_DE>,
>>>> +                                <&ccu CLK_BUS_DE>;
>>>> +                       clock-names = "mod",
>>>> +                                     "bus";
>>>> +                       resets = <&ccu RST_BUS_DE>;
>>>> +                       #clock-cells = <1>;
>>>> +                       #reset-cells = <1>;
>>>> +               };
>>>> +
>>>> +               mixer0: mixer@...0000 {
>>>
>>>Since there's only one, can you drop the numbering suffix?
>>>Same with the TCON.
>>
>> I just want to keep the consistency with dual-pipeline SoCs. (H3,
>A64, H5, etc)
>>
>> However, if dropping it is better, I will drop it -- I think usually
>for things
>> that is available for multiple on some SoCs and single on others,
>> we keep the 0 in node name...
>
>You might want that if you were going to include it in another SoC's
>dtsi
>file, such as the situation with A23/A33. However that is not the case
>here.
>Moreover, the datasheet lists them without the number.

OK...

>
>>
>>>
>>>> +                       compatible =
>"allwinner,sun8i-v3s-de2-mixer";
>>>> +                       reg = <0x01100000 0x100000>;
>>>
>>>The display engine also has an interrupt. Please list it
>>
>> It's a overall interrupt for DE2, not mixer interrupt.
>>
>> I will add it after we have proper interrupt chaining facility for
>DE2.
>>
>> It cannot fit here in mixer node.
>
>Could you elaborate? If it is just shared, then listing it several
>times
>is OK. If the interrupt registers are not in this address space, then

The interrupt dealing code is still not so clear, and totally not
present in BSP DE2 code (the BSP just didn't use the interrupt).

We doesn't even know where the interrupt register is, and we cannot
promise it's not broken (as their is even no application of it in BSP).

So it couldn't be added now.

>I agree, it needs to be dealt with separately and not added here.
>However
>some thought should be given about how the device tree binding should
>be.
>
>ChenYu
>
>>
>>>
>>>ChenYu
>>
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