Thinking a bit about this patch tonight:
2010/6/22 Rabin Vincent <rabin.vincent@xxxxxxxxxxxxxx>:
> Platforms may have some external power control which need to be
> controlled from board specific code. This is the case for some versions
> of the MOP500 board (U8500 platform).
>
> Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
> Signed-off-by: Rabin Vincent <rabin.vincent@xxxxxxxxxxxxxx>
> ---
> drivers/mmc/host/mmci.c | 3 ++-
> include/linux/amba/mmci.h | 6 ++++--
> 2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 322958f..63eb7f4 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -483,7 +483,8 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> * power control behind this translate function.
> */
> if (!host->vcc && host->plat->translate_vdd)
> - pwr |= host->plat->translate_vdd(mmc_dev(mmc), ios->vdd);
> + pwr |= host->plat->translate_vdd(mmc_dev(mmc), ios->vdd,
> + ios->power_mode);
> /* The ST version does not have this, fall through to POWER_ON */
> if (host->hw_designer != AMBA_VENDOR_ST) {
> pwr |= MCI_PWR_UP;
> diff --git a/include/linux/amba/mmci.h b/include/linux/amba/mmci.h
> index f9d1bb5..61b5810 100644
> --- a/include/linux/amba/mmci.h
> +++ b/include/linux/amba/mmci.h
> @@ -17,7 +17,8 @@
> * mmc/host.h
> * @translate_vdd: a callback function to translate a MMC_VDD_*
> * mask into a value to be binary or:ed and written into the
> - * MMCIPWR register of the block
> + * MMCIPWR register of the block. May also control external power
> + * based on the power_mode.
Actually this callback is named like that for a reason: it is to be used
to translate the MMC_VDD_* into a u8:4 bitmask for the MMCIPWR
register, 4 bits possibly routed out of the PL180 block on some
designs (never seen in practice, but could be used in theory).
So it translates a voltage into a 4-bit bitmask, hence the name.
Now the semantics are altered to have other side-effects in
the platform, so the function should be renamed, something like
platform_vdd_handler() would be more appropriate.
Yours,
Linus Walleij
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