Re: [PATCH 3/3] MMC: sdhci-dove: allow GPIOs to be used for card detection on Dove

Hi Guennadi,

On Mon, Nov 26 2012, Guennadi Liakhovetski wrote:

quoted

Guennadi, what are your thoughts about consolidating this reset logic
between the sdhci tasklet and slot-gpio?  It would certainly be nice to
use slot-gpio in cases like this one, so it's worth fixing.

Sure, this can be added. As for how - I see at least two possibilities: 
(1) put the complete above block in a new mmc host operation and just call 
it from the GPIO card-detect ISR, (2) taking into account, that many 
(nearly all? all?) host drivers keep a pointer to the current mrq in their 
private data struct, we could instead add such a pointer to struct 
mmc_host, then the check "request in progress" could also be generalised, 
and the operation would just have to reset the host and complete the 
request (in the sdhci case schedule the task).

They both sound pretty attractive.  Maybe we start out with (1), which
would create a patch we could more reasonably send to stable@ to get
slot-gpio handling the reset during transfers properly in older kernels,
and then refactor into (2) later?

Note, that there's already a .hw_reset() operation, used by sdhci-pci
only so far, still, it seems we cannot (easily) hijack it.

That one's implementing an eMMC 4.5 spec feature, not related to this
kind of reset.

Thanks!

- Chris.
-- 
Chris Ball   [off-list ref]   <http://printf.net/>
One Laptop Per Child