Re: [PATCH] mmc: mxs-mmc: implement broken-cd

Lauri Hintsala
2012-09-17T14:40:53Z

Hi,

On 09/17/2012 05:01 PM, Chris Ball wrote:
> Hi,
>
> On Mon, Sep 17 2012, Lauri Hintsala wrote:
>> Is it OK to use broken-cd? broken-cd feature is documented as "There
>> is no card detection available; polling must be used". In this case
>> the card detect is not broken but it is unrouted so it is unavailable.
>>
>> Documentation about broken-cd has been added by commit:
>> https://git.kernel.org/?p=linux/kernel/git/cjb/mmc.git;a=commitdiff;h=abe1e05da365350ac282ba5f6831aae13d97074e
>
> I'm having trouble following the problem; it sounds like perhaps all you
> need is:
>
> if (of_find_property(np, "non-removable", NULL))
> mmc->caps |= MMC_CAP_NONREMOVABLE;
>
> Have you tried that?

Yes I have and it does not work. Current mxs-mmc driver uses polling
method and it reads the CARD_DETECT bit of STATUS register. In our case
card detect is signal is unrouted so SDIO device is never detect.

Another problem with NONREMOVABLE feature is in case where power cycle
or reset is done for SDIO device. A device drive doesn't detect HW
reset. After reset the device driver is still in running state and it
does not reinitialize the device. So after reset device stops to work.

Lauri