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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>
This commit is contained in:
Ohad Ben-Cohen 2009-09-22 16:45:07 -07:00 committed by Linus Torvalds
parent 653f41b52d
commit 006ebd5de1
2 changed files with 32 additions and 1 deletions
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30
drivers/mmc/core/sdio.c
View File

@ -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.
*/

3
include/linux/mmc/card.h
View File

@ -64,7 +64,8 @@ struct sdio_cccr {
low_speed:1,
wide_bus:1,
high_power:1,
high_speed:1;
high_speed:1,
disable_cd:1;
};
struct sdio_cis {