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 <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>
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 @@
}
/*
+ * 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 @@
}
}
+ 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 @@
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);