From 006ebd5de13854d6250eecc76866bbfad1ff7daf Mon Sep 17 00:00:00 2001 From: Ohad Ben-Cohen Date: Tue, 22 Sep 2009 16:45:07 -0700 Subject: 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 Acked-by: Matt Fleming Cc: Ian Molton Cc: "Roberto A. Foglietta" Cc: Philip Langdale Cc: Pierre Ossman Cc: David Vrabel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/mmc/core/sdio.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'drivers/mmc') diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c index 6f221dc029ad..2d24a123f0b0 100644 --- a/drivers/mmc/core/sdio.c +++ b/drivers/mmc/core/sdio.c @@ -164,6 +164,29 @@ static int sdio_enable_wide(struct mmc_card *card) return 0; } +/* + * 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. */ @@ -384,6 +407,13 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr) if (err) 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. */ -- cgit v1.2.3-59-g8ed1b