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>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 62df8e177585..48c465a8e34e 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -138,6 +138,32 @@ out:
         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 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr)
         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++) {