On Thu, Jul 22, 2010 at 2:35 PM, Roger Quadros <roger.quadros@xxxxxxxxx> wrote: > On 07/21/2010 08:33 PM, ext Ohad Ben-Cohen wrote: >> >> Add support for an SDIO device to stay powered off even without >> the presence of an SDIO function driver. A host should explicitly >> ask for it by means of MMC_CAP_DONT_POWER_CARD, and the SDIO >> function driver should know it needs to call sdio_claim_power >> before accessing the device. >> >> Signed-off-by: Ohad Ben-Cohen<ohad@xxxxxxxxxx> > > Shouldn't this be the default behaviour? If there is no function driver for > any of the functions of the card, then sdio core shold power off the card. > > I don't see a need for a special capability flag for this. > > in fact MMC_CAP_DONT_POWER_CARD does not seem like an mmc host's capability Totally agree. I didn't want to change the current behavior of the cards/funcs so I looked for a way to explicitly power down only specific cards. Alternatively we could power down all cards at the end mmc_attach_sdio, and then power them up selectively in sdio_bus_probe, just before calling probe. If the probe succeeds, the function driver takes over. If the probe fails, we can power them down again. Is that what you meant ? This would work both if the sdio function driver is already loaded, or will only be loaded at a later time. But I'm not too fond of the extra power on/off cycles that it will introduce for each card.. Thanks, Ohad. > flag, it seems more like a request from the board to keep the card powered > off. > > regards, > -roger > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
