mmc: Board-specific MMC power initializations

Some devices may use non-standard combinations of regulators to power MMC:
this allows these devices to provide a board-specific MMC power init function
to set everything up in their own way.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Tom Rini <trini@ti.com>

drivers/mmc/mmc.c

@@ -1277,6 +1277,11 @@ block_dev_desc_t *mmc_get_dev(int dev)
 }
 #endif
 
+/* board-specific MMC power initializations. */
+__weak void board_mmc_power_init(void)
+{
+}
+
 int mmc_start_init(struct mmc *mmc)
 {
 	int err;
@@ -1293,6 +1298,8 @@ int mmc_start_init(struct mmc *mmc)
 	if (mmc->has_init)
 		return 0;
 
+	board_mmc_power_init();
+
 	/* made sure it's not NULL earlier */
 	err = mmc->cfg->ops->init(mmc);
 

include/mmc.h

@@ -385,6 +385,7 @@ struct mmc *mmc_spi_init(uint bus, uint cs, uint speed, uint mode);
 int mmc_legacy_init(int verbose);
 #endif
 
+void board_mmc_power_init(void);
 int board_mmc_init(bd_t *bis);
 int cpu_mmc_init(bd_t *bis);
 int mmc_get_env_addr(struct mmc *mmc, int copy, u32 *env_addr);