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sdio: put active devices into 1-bit mode during suspend

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And bring them back to 4-bit mode during resume.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Daniel Drake 2010-03-05 13:43:34 -08:00 committed by Linus Torvalds
parent 40216842dc
commit 6b5eda369a
2 changed files with 45 additions and 0 deletions
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43
drivers/mmc/core/sdio.c
View file

@ -187,6 +187,40 @@ static int sdio_disable_cd(struct mmc_card *card)
return mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
}
/*
* Devices that remain active during a system suspend are
* put back into 1-bit mode.
*/
static int sdio_disable_wide(struct mmc_card *card)
{
int ret;
u8 ctrl;
if (!(card->host->caps & MMC_CAP_4_BIT_DATA))
return 0;
if (card->cccr.low_speed && !card->cccr.wide_bus)
return 0;
ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_IF, 0, &ctrl);
if (ret)
return ret;
if (!(ctrl & SDIO_BUS_WIDTH_4BIT))
return 0;
ctrl &= ~SDIO_BUS_WIDTH_4BIT;
ctrl |= SDIO_BUS_ASYNC_INT;
ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
if (ret)
return ret;
mmc_set_bus_width(card->host, MMC_BUS_WIDTH_1);
return 0;
}
/*
* Test if the card supports high-speed mode and, if so, switch to it.
*/
@ -427,6 +461,12 @@ static int mmc_sdio_suspend(struct mmc_host *host)
}
}
if (!err && host->pm_flags & MMC_PM_KEEP_POWER) {
mmc_claim_host(host);
sdio_disable_wide(host->card);
mmc_release_host(host);
}
return err;
}
@ -441,6 +481,9 @@ static int mmc_sdio_resume(struct mmc_host *host)
mmc_claim_host(host);
err = mmc_sdio_init_card(host, host->ocr, host->card,
(host->pm_flags & MMC_PM_KEEP_POWER));
if (!err)
/* We may have switched to 1-bit mode during suspend. */
err = sdio_enable_wide(host->card);
if (!err && host->sdio_irqs)
mmc_signal_sdio_irq(host);
mmc_release_host(host);

2
include/linux/mmc/sdio.h
View file

@ -95,6 +95,8 @@
#define SDIO_BUS_WIDTH_1BIT 0x00
#define SDIO_BUS_WIDTH_4BIT 0x02
#define SDIO_BUS_ASYNC_INT 0x20
#define SDIO_BUS_CD_DISABLE 0x80 /* disable pull-up on DAT3 (pin 1) */
#define SDIO_CCCR_CAPS 0x08