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-rw-r--r--drivers/mmc/core/sdio.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 6f221dc029a..2d24a123f0b 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -165,6 +165,29 @@ static int sdio_enable_wide(struct mmc_card *card)
}
/*
+ * If desired, disconnect the pull-up resistor on CD/DAT[3] (pin 1)
+ * of the card. This may be required on certain setups of boards,
+ * controllers and embedded sdio device which do not need the card's
+ * pull-up. As a result, card detection is disabled and power is saved.
+ */
+static int sdio_disable_cd(struct mmc_card *card)
+{
+ int ret;
+ u8 ctrl;
+
+ if (!card->cccr.disable_cd)
+ return 0;
+
+ ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_IF, 0, &ctrl);
+ if (ret)
+ return ret;
+
+ ctrl |= SDIO_BUS_CD_DISABLE;
+
+ return mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
+}
+
+/*
* Test if the card supports high-speed mode and, if so, switch to it.
*/
static int sdio_enable_hs(struct mmc_card *card)
@@ -385,6 +408,13 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr)
goto remove;
/*
+ * If needed, disconnect card detection pull-up resistor.
+ */
+ err = sdio_disable_cd(card);
+ if (err)
+ goto remove;
+
+ /*
* Initialize (but don't add) all present functions.
*/
for (i = 0;i < funcs;i++) {