mmc: tmio: add flag to reduce delay after changing clock status

The docs for RCar Gen2 & 3 I have access to, mention delays of 5ms after
stop and 1ms after start. Make it possible to apply these values.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/tmio_mmc_pio.c

@@ -172,7 +172,8 @@ static void tmio_mmc_set_clock(struct tmio_mmc_host *host,
 		host->set_clk_div(host->pdev, (clk>>22) & 1);
 
 	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk & 0x1ff);
-	msleep(10);
+	if (!(host->pdata->flags & TMIO_MMC_FAST_CLK_CHG))
+		msleep(10);
 }
 
 static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
@@ -185,14 +186,14 @@ static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
 
 	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~0x0100 &
 		sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
-	msleep(10);
+	msleep(host->pdata->flags & TMIO_MMC_FAST_CLK_CHG ? 5 : 10);
 }
 
 static void tmio_mmc_clk_start(struct tmio_mmc_host *host)
 {
 	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, 0x0100 |
 		sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
-	msleep(10);
+	msleep(host->pdata->flags & TMIO_MMC_FAST_CLK_CHG ? 1 : 10);
 
 	/* implicit BUG_ON(!res) */
 	if (host->pdata->flags & TMIO_MMC_HAVE_HIGH_REG) {

include/linux/mfd/tmio.h

@@ -65,6 +65,10 @@
  * Some controllers can support SDIO IRQ signalling.
  */
 #define TMIO_MMC_SDIO_IRQ		(1 << 2)
+
+/* Some controllers don't need to wait 10ms for clock changes */
+#define TMIO_MMC_FAST_CLK_CHG		(1 << 3)
+
 /*
  * Some controllers require waiting for the SD bus to become
  * idle before writing to some registers.