> -----Original Message-----
> From: Girish K S [mailto:[email protected]]
> Sent: Wednesday, December 14, 2011 5:31 PM
> To: [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; Girish K S; Chris Ball
> Subject: [PATCH V1] mmc: core: Add host capability check for power
> class
>
> This patch adds a check whether the host supports maximum current value
> obtained from the device's extended csd register for a selected
> interface
> voltage and frequency.
>
> cc: Chris Ball <[email protected]>
> Signed-off-by: Girish K S <[email protected]>
> ---
> Changes in v1:
> reduced the number of comparisons as per Hein's suggestion
>
> drivers/mmc/core/mmc.c | 21 +++++++++++++++++++++
> include/linux/mmc/card.h | 4 ++++
> 2 files changed, 25 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 006e932..e7f1902 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -688,6 +688,27 @@ static int mmc_select_powerclass(struct mmc_card
> *card,
> pwrclass_val = (pwrclass_val & EXT_CSD_PWR_CL_4BIT_MASK) >>
> EXT_CSD_PWR_CL_4BIT_SHIFT;
>
> + if (pwrclass_val >= MMC_MAX_CURRENT_800)
> + pwrclass_val = MMC_MAX_CURRENT_800;
> + else if (pwrclass_val >= MMC_MAX_CURRENT_600)
> + pwrclass_val = MMC_MAX_CURRENT_600;
> + else if (pwrclass_val >= MMC_MAX_CURRENT_400)
> + pwrclass_val = MMC_MAX_CURRENT_400;
> + else if (pwrclass_val >= MMC_MAX_CURRENT_200)
> + pwrclass_val = MMC_MAX_CURRENT_200;
> + else
> + pwrclass_val = MMC_MAX_CURRENT_200;
Last else if and else can be combined as they are assigning the same value
to pwrclass_val.
> +
> + if ((pwrclass_val == MMC_MAX_CURRENT_800) &&
> + !(card->host->caps & MMC_CAP_MAX_CURRENT_800))
> + pwrclass_val = MMC_MAX_CURRENT_600;
> + if ((pwrclass_val == MMC_MAX_CURRENT_600) &&
> + !(card->host->caps & MMC_CAP_MAX_CURRENT_600))
> + pwrclass_val = MMC_MAX_CURRENT_400;
> + if ((pwrclass_val == MMC_MAX_CURRENT_400) &&
> + !(card->host->caps & MMC_CAP_MAX_CURRENT_400))
> + pwrclass_val = MMC_MAX_CURRENT_200;
> +
> /* If the power class is different from the default value */
> if (pwrclass_val > 0) {
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 9478a6b..c5e031a 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -195,6 +195,10 @@ struct mmc_part {
> #define MMC_BLK_DATA_AREA_GP (1<<2)
> };
>
> +#define MMC_MAX_CURRENT_200 (0)
> +#define MMC_MAX_CURRENT_400 (7)
> +#define MMC_MAX_CURRENT_600 (11)
> +#define MMC_MAX_CURRENT_800 (13)
> /*
> * MMC device
> */
> --
> 1.7.1
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