mmc: core: Put eMMC in Sleep mode before suspend

Put MMC to sleep if it supports SLEEP/AWAKE (CMD5) in the mmc suspend
so that Vcc (NAND core) can be cut to minimize power consumption.
eMMC put into SLEEP can respond to CMD0 or H/W reset or CMD5.
Current implemention on resume from suspend relies on CMD0 in
mmc_init_card to get out of SLEEP mode.

Signed-off-by: Balaji T K <balajitk@ti.com>
Acked-by: Venkatraman S <svenkatr@ti.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 5700b1c..f73fcee 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -553,6 +553,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
         * need to tell some cards to go back to the idle
         * state.  We wait 1ms to give cards time to
         * respond.
+        * mmc_go_idle is needed for eMMC that are asleep
         */
        mmc_go_idle(host);
 
@@ -900,16 +901,20 @@ static void mmc_detect(struct mmc_host *host)
  */
 static int mmc_suspend(struct mmc_host *host)
 {
+       int err = 0;
+
        BUG_ON(!host);
        BUG_ON(!host->card);
 
        mmc_claim_host(host);
-       if (!mmc_host_is_spi(host))
+       if (mmc_card_can_sleep(host))
+               err = mmc_card_sleep(host);
+       else if (!mmc_host_is_spi(host))
                mmc_deselect_cards(host);
        host->card->state &= ~MMC_STATE_HIGHSPEED;
        mmc_release_host(host);
 
-       return 0;
+       return err;
 }
 
 /*