From 6b5eda369ac3772dad416ef96d86064204d74770 Mon Sep 17 00:00:00 2001 From: Daniel Drake Date: Fri, 5 Mar 2010 13:43:34 -0800 Subject: sdio: put active devices into 1-bit mode during suspend And bring them back to 4-bit mode during resume. Signed-off-by: Daniel Drake Signed-off-by: Nicolas Pitre Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/mmc/core/sdio.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'drivers/mmc') diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c index 5840de106b69..2dd4cfe7ca17 100644 --- a/drivers/mmc/core/sdio.c +++ b/drivers/mmc/core/sdio.c @@ -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); -- cgit v1.2.1