sdio: enable wide bus mode
Enable 4-bit data bus mode, according to host and card
capabilities.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 62df8e1..48c465a 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -138,6 +138,32 @@
return ret;
}
+static int sdio_enable_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;
+
+ ctrl |= SDIO_BUS_WIDTH_4BIT;
+
+ 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_4);
+
+ return 0;
+}
+
/*
* Host is being removed. Free up the current card.
*/
@@ -300,6 +326,13 @@
mmc_set_clock(host, card->cis.max_dtr);
/*
+ * Switch to wider bus (if supported).
+ */
+ err = sdio_enable_wide(card);
+ if (err)
+ goto remove;
+
+ /*
* Initialize (but don't add) all present functions.
*/
for (i = 0;i < funcs;i++) {