Re: [PATCH 1/2] mmc: core: Support all MMC capabilities whenbooting from Device Tree

[Philip Rakity]

On 17 Oct 2012, at 14:38, Arnd Bergmann <arnd@xxxxxxxx> wrote:

> On Monday 15 October 2012, Lee Jones wrote:
>>> and so on. What are you actually missing in the properties that
>>> are already there?
>> 
>> MMC_CAP_ERASE
> 
> This one seems to be set unconditionally on some controllers but
> not on others. Why would it need to be configurable?
> 
>> MMC_CAP_UHS_SDR12
>> MMC_CAP_UHS_SDR25
>> MMC_CAP_UHS_DDR50
> 
> Could this be derived from max-frequency?

The problem is the controller may signal it supports DDR but the host cannot.  For example no voltage at correct level.
Same issue with 8 bit support.  Controller could say supports it but board has only 4 "wires"
> 
>> MMC_CAP_1_8V_DDR
> 
> Right, I suppose we need this. Should we have a minimum and maximum
> voltage added to the common properties for this?
> 
>> MMC_CAP2_DETECT_ON_ERR
>> MMC_CAP2_NO_SLEEP_CMD
> 
> I don't see these ones being set anywhere, but they were both
> added by Ulf. Maybe he can comment on if or why they are needed
> in devicetree, rather than being set by the driver unconditionally
> or for specific versions of the host controller.
> 
> 	Arnd
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/