1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 1dbc18576219..5005a6323165 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -942,6 +942,38 @@ u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
 	return ocr;
 }
 
+int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage)
+{
+	struct mmc_command cmd = {0};
+	int err = 0;
+
+	BUG_ON(!host);
+
+	/*
+	 * Send CMD11 only if the request is to switch the card to
+	 * 1.8V signalling.
+	 */
+	if (signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
+		cmd.opcode = SD_SWITCH_VOLTAGE;
+		cmd.arg = 0;
+		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+
+		err = mmc_wait_for_cmd(host, &cmd, 0);
+		if (err)
+			return err;
+
+		if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
+			return -EIO;
+	}
+
+	host->ios.signal_voltage = signal_voltage;
+
+	if (host->ops->start_signal_voltage_switch)
+		err = host->ops->start_signal_voltage_switch(host, &host->ios);
+
+	return err;
+}
+
 /*
  * Select timing parameters for host.
  */