mmc: Add comment for Feedback clock enable

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>

diff --git a/drivers/mmc/s5p_mmc.c b/drivers/mmc/s5p_mmc.c
index f60e557..5767f37 100644 (file)
--- a/drivers/mmc/s5p_mmc.c
+++ b/drivers/mmc/s5p_mmc.c
@@ -397,6 +397,13 @@ static void mmc_set_ios(struct mmc *mmc)
                (1 << 14) |     /* Feedback Clock Enable for Rx Clock */
                (1 << 8);       /* SDCLK hold enable */
 
+       /*
+        * When entered boot mode, we used Tx Feedback Delay.
+        * So We need to set Feedback clock enable for Tx Clock.
+        * In normal mode, we need not Tx clock.
+        * If set that in normal mode, we should find out some problem
+        * (CRC error, Timeout error, etc..)
+        */
        if (mmc->boot_config & 0x7)
                val |= (1 << 15);       /* Feedback Clock Enable for Tx Clock */