mmc: core: debugfs: Add signal_voltage to ios dump

Signed-off-by: Johan Rudholm <johan.rudholm@stericsson.com>
Reviewed-by: Philip Rakity <prakity@nvidia.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/debugfs.c

@@ -144,6 +144,22 @@ static int mmc_ios_show(struct seq_file *s, void *data)
 	}
 	seq_printf(s, "timing spec:\t%u (%s)\n", ios->timing, str);
 
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_330:
+		str = "3.30 V";
+		break;
+	case MMC_SIGNAL_VOLTAGE_180:
+		str = "1.80 V";
+		break;
+	case MMC_SIGNAL_VOLTAGE_120:
+		str = "1.20 V";
+		break;
+	default:
+		str = "invalid";
+		break;
+	}
+	seq_printf(s, "signal voltage:\t%u (%s)\n", ios->chip_select, str);
+
 	return 0;
 }