2012/9/27 Ulf Hansson <ulf.hansson@xxxxxxxxxx>: > On 27 September 2012 12:39, Kevin Liu <keyuan.liu@xxxxxxxxx> wrote: >> Hi, Ulf >> >> 2012/9/27 Ulf Hansson <ulf.hansson@xxxxxxxxxx>: >>> Hi Kevin, >>> >>> On 26 September 2012 13:38, Kevin Liu <keyuan.liu@xxxxxxxxx> wrote: >>>> From: Kevin Liu <kliu5@xxxxxxxxxxx> >>>> >>>> Mmc does NOT have special sequence requirements for 1.8v >>>> signal voltage setting compared to sd and sdio. >>>> Add a new 1.8v flag for mmc so as to use the same >>>> start_signal_voltage_switch interface. >>> >>> This problem is protocol issue and should not be solved in the host >>> driver. We have more issues for signal_voltage switch as well. >>> >>> Please have a look at Johan Rudholms patches: >>> [PATCH v2 1/2] mmc: core: Proper signal voltage switch >>> [PATCH v2 2/2] mmc: core: Power cycle card on voltage switch fail >>> >> I agree that we should do more things in protocal driver. >> But the real voltage switch work is still done in host driver. If we >> keep only one voltage switch interface, then we need to add a flag to >> distinguish sd/sdio or emmc. Or we should define two interfaces to >> call different host functions to handle this. >> Johan's patches can't solve my issue. > > I understand that your driver today take care of specific things for > sd/sdio. The reason for that is because of the protocol layer is not > doing the voltage switch properly. > The idea with Johans patches is resolve all these issues. Thus the > host driver will just be responsible for the actual voltage switch to > happen. So in the end your voltage switch function in the host is > supposed to be rather simple. > Ok, Johans new patch is reasonable so I will hold this patch. > If you still think you need to handle sd/sdio/eMMC in a specific > manner in your driver, there are always mmc_card_sdio|sd|mmc functions > you can use. > voltage_switch sometimes is called very early even before card type init. Thanks Kevin -- 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
