[PATCH 5/5] SDIO: put active devices into 1-bit mode during suspend

Nicolas Pitre
2010-02-09T20:29:53Z

From: Daniel Drake <dsd@laptop.org>

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>
---
drivers/mmc/core/sdio.c | 43 +++++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/sdio.h | 2 ++
2 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 5840de1..2dd4cfe 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -188,6 +188,40 @@ static int sdio_disable_cd(struct mmc_card *card)
}

/*
+ * 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.
*/
static int sdio_enable_hs(struct mmc_card *card)
@@ -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);
diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h
index 47ba464..0ebaef5 100644
--- a/include/linux/mmc/sdio.h
+++ b/include/linux/mmc/sdio.h
@@ -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
--
1.7.0.rc2.1.g694b5