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

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2017-11-02 19:00 GMT+08:00 Ulf Hansson <ulf.hansson@xxxxxxxxxx>:
> + 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!

Hi all, I can not yet get contact with IP owner because it is a
holiday in Japan.
Around two years ago, F_SDH30_CMD_DAT_DELAY was a new feature of this IP.
I will update the latest information as soon as I get it.

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

Around two years ago, sdhci_f_sdh30_driver was a portion for mb86s70 SoC
patch series, but finally the patch series did not fully go upstream.

Kind regards
Vincent

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