ARM: OMAP3: mmc-twl4030 fix for vmmc = 0

Resolve longstanding issue noted by Adrian Hunter:  confusion
between settting VSEL=0 (which is 1.8V on MMC1) and poweroff.

Also, leave VSEL alone if we're just powering the regulator off.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/mmc-twl4030.c

@@ -178,7 +178,10 @@ static int twl_mmc_resume(struct device *dev, int slot)
 static int twl_mmc_set_voltage(struct twl_mmc_controller *c, int vdd)
 {
 	int ret;
-	u8 vmmc, dev_grp_val;
+	u8 vmmc = 0, dev_grp_val;
+
+	if (!vdd)
+		goto doit;
 
 	if (c->twl_vmmc_dev_grp == VMMC1_DEV_GRP) {
 		/* VMMC1:  max 220 mA.  And for 8-bit mode,
@@ -203,8 +206,7 @@ static int twl_mmc_set_voltage(struct twl_mmc_controller *c, int vdd)
 			/* error if VSIM needed */
 			break;
 		default:
-			vmmc = 0;
-			break;
+			return -EINVAL;
 		}
 	} else if (c->twl_vmmc_dev_grp == VMMC2_DEV_GRP) {
 		/* VMMC2:  max 100 mA */
@@ -230,21 +232,21 @@ static int twl_mmc_set_voltage(struct twl_mmc_controller *c, int vdd)
 			vmmc = VMMC2_315V;
 			break;
 		default:
-			vmmc = 0;
-			break;
+			return -EINVAL;
 		}
 	} else {
-		return 0;
+		return -EINVAL;
 	}
 
-	if (vmmc)
+doit:
+	if (vdd)
 		dev_grp_val = VMMC_DEV_GRP_P1;	/* Power up */
 	else
 		dev_grp_val = LDO_CLR;		/* Power down */
 
 	ret = twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER,
 					dev_grp_val, c->twl_vmmc_dev_grp);
-	if (ret)
+	if (ret || !vdd)
 		return ret;
 
 	ret = twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER,