diff options
| author | Ohad Ben-Cohen <ohad@wizery.com> | 2009-09-22 16:45:07 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 07:39:36 -0700 |
| commit | 006ebd5de13854d6250eecc76866bbfad1ff7daf (patch) | |
| tree | 49cf0715227e1da36745bbb50b6b94f341db3986 /drivers/mmc | |
| parent | 653f41b52dfc63fecf4a2333f13be28b159a918c (diff) | |
sdio: add CD disable support
Add support to disconnect the pull-up resistor on CD/DAT[3] (pin 1)
of the card. This may be desired on certain setups of boards,
controllers and embedded sdio devices which do not need the card's
pull-up. As a result, card detection is disabled and power is saved.
[akpm@linux-foundation.org: simplify sdio_disable_cd() a bit]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Philip Langdale <philipl@overt.org>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/core/sdio.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c index 6f221dc029a..2d24a123f0b 100644 --- a/drivers/mmc/core/sdio.c +++ b/drivers/mmc/core/sdio.c @@ -165,6 +165,29 @@ static int sdio_enable_wide(struct mmc_card *card) } /* + * If desired, disconnect the pull-up resistor on CD/DAT[3] (pin 1) + * of the card. This may be required on certain setups of boards, + * controllers and embedded sdio device which do not need the card's + * pull-up. As a result, card detection is disabled and power is saved. + */ +static int sdio_disable_cd(struct mmc_card *card) +{ + int ret; + u8 ctrl; + + if (!card->cccr.disable_cd) + return 0; + + ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_IF, 0, &ctrl); + if (ret) + return ret; + + ctrl |= SDIO_BUS_CD_DISABLE; + + return mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL); +} + +/* * Test if the card supports high-speed mode and, if so, switch to it. */ static int sdio_enable_hs(struct mmc_card *card) @@ -385,6 +408,13 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr) goto remove; /* + * If needed, disconnect card detection pull-up resistor. + */ + err = sdio_disable_cd(card); + if (err) + goto remove; + + /* * Initialize (but don't add) all present functions. */ for (i = 0;i < funcs;i++) { |