regulator: bd718x7: Bypass bogus warnings

When regulator consumer attempts to set enabled DVS regulator voltage,
the driver aborts with "Only DVS bucks can be changed when enabled".
In case the regulator is already set to specified voltage, do nothing
instead of failing outright.

When regulator consumer attempts to set enables regulator which cannot
be controlled because it is already always enabled, the driver aborts
with -EINVAL. Again, do nothing in such case and return 0, because the
request is really fulfilled, the regulator is enabled.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
diff --git a/drivers/power/regulator/bd71837.c b/drivers/power/regulator/bd71837.c
index 74011d6..d4f8da8 100644
--- a/drivers/power/regulator/bd71837.c
+++ b/drivers/power/regulator/bd71837.c
@@ -306,7 +306,7 @@
 	 * reseted to snvs state. Hence we can't set the state here.
 	 */
 	if (plat->enablemask == HW_STATE_CONTROL)
-		return -EINVAL;
+		return enable ? 0 : -EINVAL;
 
 	if (enable)
 		val = plat->enablemask;
@@ -315,6 +315,38 @@
 			       val);
 }
 
+static int bd71837_get_value(struct udevice *dev)
+{
+	unsigned int reg, range;
+	unsigned int tmp;
+	struct bd71837_plat *plat = dev_get_plat(dev);
+	int i;
+
+	reg = pmic_reg_read(dev->parent, plat->volt_reg);
+	if (((int)reg) < 0)
+		return reg;
+
+	range = reg & plat->rangemask;
+
+	reg &= plat->volt_mask;
+	reg >>= ffs(plat->volt_mask) - 1;
+
+	for (i = 0; i < plat->numranges; i++) {
+		struct bd71837_vrange *r = &plat->ranges[i];
+
+		if (plat->rangemask && ((plat->rangemask & range) !=
+		    r->rangeval))
+			continue;
+
+		if (!vrange_find_value(r, reg, &tmp))
+			return tmp;
+	}
+
+	pr_err("Unknown voltage value read from pmic\n");
+
+	return -EINVAL;
+}
+
 static int bd71837_set_value(struct udevice *dev, int uvolt)
 {
 	unsigned int sel;
@@ -330,6 +362,9 @@
 	 */
 	if (!plat->dvs)
 		if (bd71837_get_enable(dev)) {
+			/* If the value is already set, skip the warning. */
+			if (bd71837_get_value(dev) == uvolt)
+				return 0;
 			pr_err("Only DVS bucks can be changed when enabled\n");
 			return -EINVAL;
 		}
@@ -365,38 +400,6 @@
 			       plat->rangemask, sel);
 }
 
-static int bd71837_get_value(struct udevice *dev)
-{
-	unsigned int reg, range;
-	unsigned int tmp;
-	struct bd71837_plat *plat = dev_get_plat(dev);
-	int i;
-
-	reg = pmic_reg_read(dev->parent, plat->volt_reg);
-	if (((int)reg) < 0)
-		return reg;
-
-	range = reg & plat->rangemask;
-
-	reg &= plat->volt_mask;
-	reg >>= ffs(plat->volt_mask) - 1;
-
-	for (i = 0; i < plat->numranges; i++) {
-		struct bd71837_vrange *r = &plat->ranges[i];
-
-		if (plat->rangemask && ((plat->rangemask & range) !=
-		    r->rangeval))
-			continue;
-
-		if (!vrange_find_value(r, reg, &tmp))
-			return tmp;
-	}
-
-	pr_err("Unknown voltage value read from pmic\n");
-
-	return -EINVAL;
-}
-
 static int bd71837_regulator_probe(struct udevice *dev)
 {
 	struct bd71837_plat *plat = dev_get_plat(dev);