[PATCH v1 1/5] dt-bindings: arm: mediatek: mmsys: add mt8195 SoC binding
Jason-JH Lin
jason-jh.lin at mediatek.com
Mon Jul 26 19:53:00 PDT 2021
Hi Enric,
On Mon, 2021-07-26 at 12:08 +0200, Enric Balletbo Serra wrote:
> Hi Jason,
>
> Missatge de Jason-JH Lin <jason-jh.lin at mediatek.com> del dia dl., 26
> de jul. 2021 a les 9:02:
> >
> > On Fri, 2021-07-23 at 13:13 +0200, Enric Balletbo Serra wrote:
> > > Hi Jason,
> > >
> > > Thank you for your patch.
> > >
> > > Missatge de jason-jh.lin <jason-jh.lin at mediatek.com> del dia dj.,
> > > 22
> > > de jul. 2021 a les 11:26:
> > > >
> > > > There are 2 display hardware path in mt8195, namely vdosys0 and
> > > > vdosys1, so add their definition in mtk-mmsys documentation.
> > > >
> > >
> > > Just having 2 display hardware paths is not a reason to have two
> > > compatibles, isn't the IP block the same? Why do you need to
> > > introduce
> > > the two compatibles?
> > >
> > > Thanks,
> > > Enric
> > >
> >
> > Hi Enric,
> >
> > Thanks for reviewing my patch.
> >
> > The reason for using two compatibles is that vdosys0 and vdosys1
> > are
> > different IP blocks.
> >
>
> With that there are different IP blocks, what do you mean? Do you
> mean
> that there are two completely different blocks with completely
> different functionalities?
>
> Or that there is the same IP block twice? I mean, of course, the
> registers are different but has exactly the same functionality.
>
They are not the same IP block twice.
Although both vdosys0 and vdosys1 will probe meiatek-drm driver, but
the components on their hardware path are different and their output
panel are also different.
> > Because mmsys provides clock control, other display function blocks
> > may
> > use them as clock provider.
> >
> > E.g.
> > 1. mmsys with compatible="mediatek,mt8195-vdosys0"
> > [v4,1/6] arm64: dts: mt8195: add display node for vdosys0
> >
> >
https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/20210723090233.24007-2-jason-jh.lin@mediatek.com/__;!!CTRNKA9wMg0ARbw!xHjKwv34W7ETFcmQPXRViylF2LbV7C7pE8OeJeNvA93jDdzr_ZBRRm8aIUCvAHSD_qGo$
> >
> >
> > ovl0: disp_ovl at 1c000000 {
> > ...
> > clocks = <&vdosys0 CLK_VDO0_DISP_OVL0>;
> > ...
> > };
> >
> > 2. mmsys with compatible="mediatek,mt8195-vdosys1"
> > [v2,06/14] arm64: dts: mt8195: add display node for vdosys1
> >
> >
https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/20210722094551.15255-7-nancy.lin@mediatek.com/__;!!CTRNKA9wMg0ARbw!xHjKwv34W7ETFcmQPXRViylF2LbV7C7pE8OeJeNvA93jDdzr_ZBRRm8aIUCvAP0FOfkc$
> >
> >
> > vdo1_rdma0: vdo1_rdma at 1c104000 {
> > ...
> > clocks = <&vdosys1 CLK_VDO1_MDP_RDMA0>;
> > ...
> > };
> >
>
> Note that I am talking without knowing the hardware in detail, but I
> am wondering why I can't have something like this, where every mmsys
> is a clock and reset controller provider.
>
> vdosys0: syscon at 14000000 {
> compatible = "mediatek,mt8195-mmsys", "syscon";
> reg = <0 0x14000000 0 0x1000>;
> #clock-cells = <1>;
> #reset-cells = <1>;
> };
>
> vdosys1: syscon at 15000000 {
> compatible = "mediatek,mt8195-mmsys", "syscon";
> reg = <0 0x15000000 0 0x1000>;
> #clock-cells = <1>;
> #reset-cells = <1>;
> };
>
> ovl0: disp_ovl at 1c000000 {
> ...
> clocks = <&vdosys0 CLK_VDO0_DISP_OVL0>;
> ...
> };
>
> vdo1_rdma0: vdo1_rdma at 1c104000 {
> ...
> clocks = <&vdosys1 CLK_VDO1_MDP_RDMA0>;
> ...
> };
>
> What are the differences between vdosys0 and vdosys1 from a hardware
> point of view?
>
> Cheers,
> Enric
>
> > Regards,
> > Jason-JH.Lin
> >
From a hardware point of view, the components and the ouptut panel of
vdosys0 and vdosys1:
1. The components on meiatek-drm of vdosys0 are OVL0, RDMA0, COLOR0,
CCORR, AAL0, GAMMA, DITHER, DSC0, MERGE0, DP_INTF0 and its output panel
is eDP.
2. The components on meiatek-drm of vdosys1 are PSEUDO_OVL, MERGE5,
DP_INTF1 and its ouptut panel is DP.
The resaon for using two compatibales is that we use different driver
data in mtk-mmsys.c and mtk_drm_drv.c to identify the corresponding
mmsys is vdosys0 or vdosys1.
Their driver data in mtk_drm_drv.c is defined here:
[v4,4/6] drm/mediatek: add mediatek-drm of vdosys0 support for mt8195
https://patchwork.kernel.org/project/linux-mediatek/patch/20210723090233.24007-5-jason-jh.lin@mediatek.com/
[v2,14/14] drm/mediatek: add mediatek-drm of vdosys1 support for MT8195
https://patchwork.kernel.org/project/linux-mediatek/patch/20210722094551.15255-15-nancy.lin@mediatek.com/
I think using the same compatible is unable to do this. Or do you have
other suggestions to do this with the same compatibe?
Regards,
Jason-JH.Lin
> > > > Signed-off-by: jason-jh.lin <jason-jh.lin at mediatek.com>
> > > > ---
> > > > this patch is base on [1][2]
> > > >
> > > > [1] dt-bindings: arm: mediatek: mmsys: convert to YAML format
> > > > -
> > > >
https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/20210519161847.3747352-1-fparent@baylibre.com/__;!!CTRNKA9wMg0ARbw!ycgPEK4yBDojiiZJC2E9mGwvxJbaLqhyUxzJIq0ckEP-JVteBcjFdc6ixkNbmknH8f2P$
> > > >
> > > > [2] dt-bindings: arm: mediatek: mmsys: add MT8365 SoC binding
> > > > -
> > > >
https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/20210519161847.3747352-2-fparent@baylibre.com/__;!!CTRNKA9wMg0ARbw!ycgPEK4yBDojiiZJC2E9mGwvxJbaLqhyUxzJIq0ckEP-JVteBcjFdc6ixkNbmju2GBrD$
> > > >
> > > > ---
> > > > .../devicetree/bindings/arm/mediatek/mediatek,mmsys.yaml
> > > > |
> > > > 2 ++
> > > > 1 file changed, 2 insertions(+)
> > > >
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys
> > > > .yam
> > > > l
> > > > b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys
> > > > .yam
> > > > l
> > > > index 2d4ff0ce387b..0789a9614f12 100644
> > > > ---
> > > > a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys
> > > > .yam
> > > > l
> > > > +++
> > > > b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys
> > > > .yam
> > > > l
> > > > @@ -30,6 +30,8 @@ properties:
> > > > - mediatek,mt8173-mmsys
> > > > - mediatek,mt8183-mmsys
> > > > - mediatek,mt8365-mmsys
> > > > + - mediatek,mt8195-vdosys0
> > > > + - mediatek,mt8195-vdosys1
> > > > - const: syscon
> > > > - items:
> > > > - const: mediatek,mt7623-mmsys
> > > > --
> > > > 2.18.0
> > > >
> >
> > --
--
Jason-JH Lin <jason-jh.lin at mediatek.com>
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