Re: [PATCH] qcom: sdhci-msm: enable the DLL clock

[Ulf Hansson]

On 12 April 2016 at 00:11, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
> On 04/11, Ulf Hansson wrote:
>> + Adrian
>>
>> On 5 April 2016 at 09:46, Sreedhar Sambangi <ssambang@xxxxxxxxxxxxxx> wrote:
>> > The DLL clock has to be enabled until the correct
>> > clock frequency is delivered to DLL
>> > '1'(default) - DLL clock is disabled
>> > '0' - dll clock has legacly clock enable.
>> >
>> > Signed-off-by: Varadarajan Narayanan <varada@xxxxxxxxxxxxxx>
>> > Signed-off-by: Sreedhar Sambangi <ssambang@xxxxxxxxxxxxxx>
>>
>> Adrian Hunter is the maintainer for sdhci, next time make sure to post to him.
>>
>> As this seems like fairly trivial change I decided to pick it up
>> anyway. So applied for next!
>>
>> Note, that I changed the prefix of the commit message header to "mmc".
>>
>
> I'm not sure this patch is actually right. In the downstream
> sources we do quite a few more reads and writes if we need to
> poke this second DLL configuration register. Furthermore, on
> msm8974 and apq8084 this register doesn't even exist so writing
> to it may cause problems if it isn't write ignored (I haven't
> checked).
>
> I think we should follow the downstream kernel design instead.
> Namely, reading the major/minor version registers to figure out
> if we should be touching this register in the first place, and
> then adding a clock property to the DT binding for the XO source
> so we can determine the XO frequency. It seems that we need this
> frequency to figure out how to program the second DLL
> configuration register appropriately.

Stephen,

Thanks for reviewing. I have dropped this patch for now.

Kind regards
Uffe