mmc: dw_mmc: disable biu clk if possible

We could disable biu clk if gpio card detect available,
or it is a non-removable device.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc-rockchip.c

@@ -13,6 +13,7 @@
 #include <linux/mmc/host.h>
 #include <linux/mmc/dw_mmc.h>
 #include <linux/of_address.h>
+#include <linux/mmc/slot-gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 

drivers/mmc/host/dw_mmc.c

@@ -3337,6 +3337,11 @@ int dw_mci_runtime_suspend(struct device *dev)
 
 	clk_disable_unprepare(host->ciu_clk);
 
+	if (host->cur_slot &&
+	    (mmc_can_gpio_cd(host->cur_slot->mmc) ||
+	     !mmc_card_is_removable(host->cur_slot->mmc)))
+		clk_disable_unprepare(host->biu_clk);
+
 	return err;
 }
 EXPORT_SYMBOL(dw_mci_runtime_suspend);
@@ -3346,6 +3351,14 @@ int dw_mci_runtime_resume(struct device *dev)
 	int ret = 0;
 	struct dw_mci *host = dev_get_drvdata(dev);
 
+	if (host->cur_slot &&
+	    (mmc_can_gpio_cd(host->cur_slot->mmc) ||
+	     !mmc_card_is_removable(host->cur_slot->mmc))) {
+		ret = clk_prepare_enable(host->biu_clk);
+		if (ret)
+			return ret;
+	}
+
 	ret = clk_prepare_enable(host->ciu_clk);
 	if (ret)
 		return ret;