Re: [PATCH 3/3] mmc: omap_hsmmc: enable SDIO card interrupts

[David Vrabel <david.vrabel@csr.com>]

Madhusudhan wrote:
> 
>> -----Original Message-----
>> From: David Vrabel [mailto:david.vrabel@csr.com]
>> Sent: Wednesday, February 10, 2010 5:52 AM
>> To: linux-mmc@vger.kernel.org
>> Cc: David Vrabel; linux-omap@vger.kernel.org; madhu.cr@ti.com
>> Subject: [PATCH 3/3] mmc: omap_hsmmc: enable SDIO card interrupts
>>
>> Enable the use of SDIO card interrupts.  This requires setting ENAWAKEUP
>> in SYSCONFIG and IWE in HTCL to allow the MMC block to wake-up when in
>> smart-idle mode.
>>
>> FCLK must be enabled while SDIO interrupts are enabled or the MMC block
>> won't wake-up.
>>
> 
> I am curious to know the system behavior with this patch. Does the FCLK
> remain enabled forever if a SDIO card is detected on the bus?

Only if card interrupts are enabled.  The card irq is disabled when the 
sdio_irq_thread exits.

This is why I think that smart-idle mode needs to be used (it's turned
on by default on the MMC controller) but I don't understand the
clock/clockdomain code to see if that's doing the right thing.

If smart-idle mode is used then we don't need to disable FCLK manually 
to save power.  This will simplify the driver a bit.

David