Re: [PATCH] sdhci-fujitsu: add support for setting the CMD_DAT_DELAY attribute

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+ Vincent Yang (several emails, don't know which works)

On 2 November 2017 at 11:49, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
> On 2 November 2017 at 10:48, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>> On 2 November 2017 at 01:12, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
>>> On 2 November 2017 at 00:08, Rob Herring <robh@xxxxxxxxxx> wrote:
>>>> On Wed, Nov 01, 2017 at 12:21:32AM +0000, Ard Biesheuvel wrote:
>>>>> The Socionext SynQuacer SoC inherits this IP from Fujitsu, but
>>>>> requires the F_SDH30_CMD_DAT_DELAY bit to be set in the
>>>>> F_SDH30_ESD_CONTROL control register.
>>>>>
>>>>> So let's add an optional property to this device's binding, and
>>>>> set the attribute if it is present in the DT node.
>>>>>
>>>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>>>>> ---
>>>>>  Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt |  2 ++
>>>>>  drivers/mmc/host/sdhci_f_sdh30.c                        | 18 +++++++++++++++++-
>>>>>  2 files changed, 19 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt b/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt
>>>>> index de2c53cff4f1..9ad02f743ad0 100644
>>>>> --- a/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt
>>>>> +++ b/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt
>>>>> @@ -15,6 +15,8 @@ Required properties:
>>>>>  Optional properties:
>>>>>  - vqmmc-supply: phandle to the regulator device tree node, mentioned
>>>>>    as the VCCQ/VDD_IO supply in the eMMC/SD specs.
>>>>> +- cmd-dat-delay-select: boolean property indicating that this host requires
>>>>> +  the CMD_DAT_DELAY control to be enabled.
>>>>
>>>> Needs a vendor prefix unless this is a standard SDHCI bit (in which
>>>> case it should be documented in a common spot).
>>>>
>>>
>>> I suspect this is a non-standard thing, so I'll add the fujitsu prefix. Ulf?
>>
>> This is specific to the Fujitsu variant.
>>
>> However, what puzzles me is why this bit is needed for the Socionext
>> SynQuacer SoC, but not for other SoCs that uses this IP. That seems
>> weird (probably wrong).
>>
>> Moreover, the F_SDH30_CMD_DAT_DELAY register define is already there,
>> so I would rather suspect that it's something that did got fully
>> implemented. In other words, I don't think you need a new DT binding,
>> but rather try to implement it generically for the sdhci-f_sdh30
>> driver. Do you think that will work?
>>
>
> Do you mean set it unconditionally? That works for me, but I have no

Yes.

> way of testing whether it still works on other SoCs that use this IP.

Me neither!

Apparently there are no DTS in the kernel git that uses the
"fujitsu,mb86s70-sdhci-3.0".

I looped in Vincent Yang, let's hope he can provide us with some more
information.

Kind regards
Uffe
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