Op 26 sep. 2012, om 13:37 heeft "Hebbar, Gururaja" <gururaja.hebbar@xxxxxx> het volgende geschreven: > On Wed, Sep 12, 2012 at 17:32:38, Hebbar, Gururaja wrote: >> On Wed, Sep 12, 2012 at 14:19:51, S, Venkatraman wrote: >>> On Tue, Sep 4, 2012 at 6:39 PM, Hebbar, Gururaja <gururaja.hebbar@xxxxxx> wrote: >>>> HSMMC IP on AM33xx need a special setting to handle High-speed cards. >>>> Other platforms like TI81xx, OMAP4 may need this as-well. This depends >>>> on the HSMMC IP timing closure done for the high speed cards. >>>> >>>> From AM335x TRM (SPRUH73F - 18.3.12 Output Signals Generation) >>>> >>>> The MMC/SD/SDIO output signals can be driven on either falling edge or >>>> rising edge depending on the SD_HCTL[2] HSPE bit. This feature allows >>>> to reach better timing performance, and thus to increase data transfer >>>> frequency. >>>> >>>> There are few pre-requisites for enabling the HSPE bit >>>> - Controller should support High-Speed-Enable Bit and >>>> - Controller should not be using DDR Mode and >>>> - Controller should advertise that it supports High Speed in >>>> capabilities register and >>>> - MMC/SD clock coming out of controller > 25MHz >>>> >>> >>> The patch is well written. But then, I don't see a need for a DT >>> binding for this feature. >> >> My reasons for DT Binding >> 1. Not all platforms using this driver has this bit (OMAP2) >> 2. Not all platforms using this driver needs this bit to be enabled (OMAP4) >> 3. Platforms which require this bit this to be set needs a method to inform >> driver. >> >> In order to not disturb old/unsupported platforms, I chose this DT method. >> >>> By definition, HS implies 25MHz or above, so that check seems to be >>> redundant as well. >> >> There are chances that the platform Max Clock output from HSMMC IP is < than >> 25 MHz even if the card is High Speed. In such cases it would be better to >> Confirm that the Clock output is actually > 25 MHz >> >> Kindly correct me if I am wrong. >> >>> Meanwhile, I'll check with HSPE enabled on OMAP. >>> > > Gentle Ping. > > Matt Poter recently submitted EDMA related patches as RFC. He confirmed that > basic mmc is working on AM335x with his edma patches. > > Above patch is required to get High-speed cards working on AM335x. > > I haven't seen any review comments for this. Can this be pulled in for 3.7? I had trouble applying this to 3.6-rc7, is that a known problem and should I try linux-next? regards, Koen-- 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
