regulator: Make core more chatty about some errors

Prevent some head scratching by making the core log about some rare but
possible errors with invalid voltage ranges and modes being set.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -151,8 +151,11 @@ static int regulator_check_voltage(struct regulator_dev *rdev,
 	if (*min_uV < rdev->constraints->min_uV)
 		*min_uV = rdev->constraints->min_uV;
 
-	if (*min_uV > *max_uV)
+	if (*min_uV > *max_uV) {
+		rdev_err(rdev, "unsupportable voltage range: %d-%duV\n",
+			 min_uV, max_uV);
 		return -EINVAL;
+	}
 
 	return 0;
 }
@@ -205,8 +208,11 @@ static int regulator_check_current_limit(struct regulator_dev *rdev,
 	if (*min_uA < rdev->constraints->min_uA)
 		*min_uA = rdev->constraints->min_uA;
 
-	if (*min_uA > *max_uA)
+	if (*min_uA > *max_uA) {
+		rdev_err(rdev, "unsupportable current range: %d-%duA\n",
+			 min_uA, max_uA);
 		return -EINVAL;
+	}
 
 	return 0;
 }
@@ -221,6 +227,7 @@ static int regulator_mode_constrain(struct regulator_dev *rdev, int *mode)
 	case REGULATOR_MODE_STANDBY:
 		break;
 	default:
+		rdev_err(rdev, "invalid mode %x specified\n", *mode);
 		return -EINVAL;
 	}