Re: [PATCH 1/7] dt-bindings: display: renesas,du: Document Renesas R-Car R8A779MD M3Le

[Marek Vasut <marek.vasut@mailbox.org>]

On 4/29/26 11:57 AM, Geert Uytterhoeven wrote:

Hello Geert,

> On Sun, 19 Apr 2026 at 21:37, Marek Vasut
> <marek.vasut+renesas@mailbox.org> wrote:
>> Extend the Renesas DU display bindings to support the Renesas R-Car
>> R8A779MD M3Le SoC. This SoC is similar to R-Car R8A77965 M3-N SoC,
>> except the HDMI port@1 is not present.
> 
> "and DU1 is unused." (whatever that may mean...)

Fixed in V2.

>> +++ b/Documentation/devicetree/bindings/display/renesas,du.yaml
>> @@ -42,6 +42,7 @@ properties:
>>         - renesas,du-r8a779a0 # for R-Car V3U compatible DU
>>         - renesas,du-r8a779g0 # for R-Car V4H compatible DU
>>         - renesas,du-r8a779h0 # for R-Car V4M compatible DU
>> +      - renesas,du-r8a779md # for R-Car M3Le compatible DU
> 
> I am not sure you need a new compatible value: is the DU really
> different than on R-Car M3-N, or does it just lack some wiring? ...
It seems the DU is identical to the M3N one, so I will add another entry 
to R8A77965 DU to handle the M3Le one, just like R8A774B1 and R8A774E1 
DUs . I hope that is acceptable, and also addresses the feedback on this 
patch ?

I dumped the VSP and FCP versions on M3N and M3Le and compared them, and 
I also wrote and read-back the CMM registers to confirm CMM IPs are all 
present on both M3N and M3Le:

FCP is identical on M3N and M3Le:
fe950000.fcp FCP_VCR=0x106
fe96f000.fcp FCP_VCR=0x106
fe9af000.fcp FCP_VCR=0x106
fea27000.fcp FCP_VCR=0x106
fea2f000.fcp FCP_VCR=0x106

VSP is identical on M3N and M3Le:
fe960000.vsp IP_VERSION=0x01011504
fe9a0000.vsp IP_VERSION=0x01011404
fea20000.vsp IP_VERSION=0x01011904
fea28000.vsp IP_VERSION=0x01011704

CMMs are present on M3N and M3Le, tested with write of bits 28 and 24 
into CM2_CLU_CTRL and then readback:
fea40000.cmm CM2_CLU_CTRL readback 0x11000000
fea50000.cmm CM2_CLU_CTRL readback 0x11000000
fea70000.cmm CM2_CLU_CTRL readback 0x11000000

And it does indeed look like we do have DOTCLKIN1 .