mmc: add a new mmc parameter to disable mmc clock

mmc clock has to be disabled in certain cases like during
the voltage switch sequence. Modify mmc_set_clock function
to take disable as an argument that signifies if the
clock has to be enabled or disabled.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

drivers/mmc/fsl_esdhc.c

@@ -665,7 +665,7 @@ static int esdhc_init_common(struct fsl_esdhc_priv *priv, struct mmc *mmc)
 #endif
 
 	/* Set the initial clock speed */
-	mmc_set_clock(mmc, 400000);
+	mmc_set_clock(mmc, 400000, false);
 
 	/* Disable the BRR and BWR bits in IRQSTAT */
 	esdhc_clrbits32(&regs->irqstaten, IRQSTATEN_BRR | IRQSTATEN_BWR);

drivers/mmc/mmc.c

@@ -1214,7 +1214,7 @@ static int mmc_set_ios(struct mmc *mmc)
 }
 #endif
 
-int mmc_set_clock(struct mmc *mmc, uint clock)
+int mmc_set_clock(struct mmc *mmc, uint clock, bool disable)
 {
 	if (clock > mmc->cfg->f_max)
 		clock = mmc->cfg->f_max;
@@ -1223,6 +1223,7 @@ int mmc_set_clock(struct mmc *mmc, uint clock)
 		clock = mmc->cfg->f_min;
 
 	mmc->clock = clock;
+	mmc->clk_disable = disable;
 
 	return mmc_set_ios(mmc);
 }
@@ -1322,7 +1323,7 @@ static int sd_select_mode_and_width(struct mmc *mmc)
 
 				/* configure the bus mode (host) */
 				mmc_select_mode(mmc, mwt->mode);
-				mmc_set_clock(mmc, mmc->tran_speed);
+				mmc_set_clock(mmc, mmc->tran_speed, false);
 
 				err = sd_read_ssr(mmc);
 				if (!err)
@@ -1333,7 +1334,7 @@ static int sd_select_mode_and_width(struct mmc *mmc)
 error:
 				/* revert to a safer bus speed */
 				mmc_select_mode(mmc, SD_LEGACY);
-				mmc_set_clock(mmc, mmc->tran_speed);
+				mmc_set_clock(mmc, mmc->tran_speed, false);
 			}
 		}
 	}
@@ -1476,7 +1477,7 @@ static int mmc_select_mode_and_width(struct mmc *mmc)
 
 			/* configure the bus mode (host) */
 			mmc_select_mode(mmc, mwt->mode);
-			mmc_set_clock(mmc, mmc->tran_speed);
+			mmc_set_clock(mmc, mmc->tran_speed, false);
 
 			/* do a transfer to check the configuration */
 			err = mmc_read_and_compare_ext_csd(mmc);
@@ -1950,7 +1951,7 @@ static void mmc_set_initial_state(struct mmc *mmc)
 
 	mmc_select_mode(mmc, MMC_LEGACY);
 	mmc_set_bus_width(mmc, 1);
-	mmc_set_clock(mmc, 0);
+	mmc_set_clock(mmc, 0, false);
 }
 
 static int mmc_power_on(struct mmc *mmc)

include/mmc.h

@@ -472,6 +472,7 @@ struct mmc {
 	void *priv;
 	uint has_init;
 	int high_capacity;
+	bool clk_disable; /* true if the clock can be turned off */
 	uint bus_width;
 	uint clock;
 	enum mmc_voltage signal_voltage;
@@ -567,7 +568,16 @@ int mmc_unbind(struct udevice *dev);
 int mmc_initialize(bd_t *bis);
 int mmc_init(struct mmc *mmc);
 int mmc_read(struct mmc *mmc, u64 src, uchar *dst, int size);
-int mmc_set_clock(struct mmc *mmc, uint clock);
+
+/**
+ * mmc_set_clock() - change the bus clock
+ * @mmc:	MMC struct
+ * @clock:	bus frequency in Hz
+ * @disable:	flag indicating if the clock must on or off
+ * @return 0 if OK, -ve on error
+ */
+int mmc_set_clock(struct mmc *mmc, uint clock, bool disable);
+
 struct mmc *find_mmc_device(int dev_num);
 int mmc_set_dev(int dev_num);
 void print_mmc_devices(char separator);