regulator: pickable ranges: don't always cache vsel

Some PMICs treat the vsel_reg same as apply-bit. Eg, when voltage range
is changed, the new voltage setting is not taking effect until the vsel
register is written.

Add a flag 'range_applied_by_vsel' to the regulator desc to indicate this
behaviour and to force the vsel value to be written to hardware if range
was changed, even if the old selector was same as the new one.
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://msgid.link/r/ZktCpcGZdgHWuN_L@fedoraSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/helpers.c

@@ -161,6 +161,32 @@ int regulator_get_voltage_sel_pickable_regmap(struct regulator_dev *rdev)
 }
 EXPORT_SYMBOL_GPL(regulator_get_voltage_sel_pickable_regmap);
 
+static int write_separate_vsel_and_range(struct regulator_dev *rdev,
+					 unsigned int sel, unsigned int range)
+{
+	bool range_updated;
+	int ret;
+
+	ret = regmap_update_bits_base(rdev->regmap, rdev->desc->vsel_range_reg,
+				      rdev->desc->vsel_range_mask,
+				      range, &range_updated, false, false);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some PMICs treat the vsel_reg same as apply-bit. Force it to be
+	 * written if the range changed, even if the old selector was same as
+	 * the new one
+	 */
+	if (rdev->desc->range_applied_by_vsel && range_updated)
+		return regmap_write_bits(rdev->regmap,
+					rdev->desc->vsel_reg,
+					rdev->desc->vsel_mask, sel);
+
+	return regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
+				  rdev->desc->vsel_mask, sel);
+}
+
 /**
  * regulator_set_voltage_sel_pickable_regmap - pickable range set_voltage_sel
  *
@@ -199,21 +225,12 @@ int regulator_set_voltage_sel_pickable_regmap(struct regulator_dev *rdev,
 	range = rdev->desc->linear_range_selectors_bitfield[i];
 	range <<= ffs(rdev->desc->vsel_range_mask) - 1;
 
-	if (rdev->desc->vsel_reg == rdev->desc->vsel_range_reg) {
-		ret = regmap_update_bits(rdev->regmap,
-					 rdev->desc->vsel_reg,
+	if (rdev->desc->vsel_reg == rdev->desc->vsel_range_reg)
+		ret = regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
 					 rdev->desc->vsel_range_mask |
 					 rdev->desc->vsel_mask, sel | range);
-	} else {
-		ret = regmap_update_bits(rdev->regmap,
-					 rdev->desc->vsel_range_reg,
-					 rdev->desc->vsel_range_mask, range);
-		if (ret)
-			return ret;
-
-		ret = regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
-				  rdev->desc->vsel_mask, sel);
-	}
+	else
+		ret = write_separate_vsel_and_range(rdev, sel, range);
 
 	if (ret)
 		return ret;

include/linux/regulator/driver.h

@@ -299,6 +299,8 @@ enum regulator_type {
  * @vsel_range_reg: Register for range selector when using pickable ranges
  *		    and ``regulator_map_*_voltage_*_pickable`` functions.
  * @vsel_range_mask: Mask for register bitfield used for range selector
+ * @range_applied_by_vsel: A flag to indicate that changes to vsel_range_reg
+ *			   are only effective after vsel_reg is written
  * @vsel_reg: Register for selector when using ``regulator_map_*_voltage_*``
  * @vsel_mask: Mask for register bitfield used for selector
  * @vsel_step: Specify the resolution of selector stepping when setting
@@ -389,6 +391,7 @@ struct regulator_desc {
 
 	unsigned int vsel_range_reg;
 	unsigned int vsel_range_mask;
+	bool range_applied_by_vsel;
 	unsigned int vsel_reg;
 	unsigned int vsel_mask;
 	unsigned int vsel_step;