Messages in this thread | | | Date | Mon, 8 Apr 2013 15:58:05 +0200 | From | Hector Palacios <> | Subject | Re: [PATCH RFC] ARM: dts: mxs: leave card detect out of common mmc pins config |
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On 04/08/2013 02:48 PM, Shawn Guo wrote: > On Mon, Apr 08, 2013 at 12:12:20PM +0200, Hector Palacios wrote: >> MicroSD card sockets don't usually have card detect line. This pin >> is actually not needed for the MMC to work and it is more of a >> platform design decission to have it. >> The card detect pin already has a configuration entry of its own: >> 'mmc0_cd_cfg' so we complete the iomux configuration here and let >> platforms to include it or not depending on whether the card detect >> line is routed to the SD socket. >> > Sounds sensible. > >> Signed-off-by: Hector Palacios <hector.palacios@digi.com> >> --- >> >> Hello, >> >> All imx28 based platforms except 'bluegiga,apx4devkit' and >> 'schulercontrol,imx28-sps1', use 'mmc0_cd_cfg' in their mmc configuration >> so please check whether this patch would break these platforms. >> > I just tested the patch on imx28-evk and card-detection still works. So > patches applied, thanks.
The EVK and most platforms will work because they are using 'mmc0_cd_cfg' so actually this patch does not change anything on them. Platforms 'bluegiga,apx4devkit' and 'schulercontrol,imx28-sps1' however are not referencing 'mmc0_cd_cfg' so after applying this patch they will have unconfigured CD line and they may break. The driver will call get_cd() upon probing, which returns the status of the CD line. Please check these two platforms before applying.
In fact I was looking now at how to skip the calling of get_cd() hook when you specify 'non-removable' in the Device Tree. According to the bindings document:
- non-removable: non-removable slot (like eMMC); *assume always present.*
This property is not handled in mxs-mmc.c but even if I add the code to handle it and set MMC_CAP_NONREMOVABLE flag, the get_cd() is called at least once and returning with the status of CD line. I think this is wrong because it should assume the card is present. The CD line may not be connected at all and may have any value.
Regards, -- Héctor Palacios -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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