[PATCH 2/2] pmic: pca9450: clear PRESET_EN bit for BUCK1/2/3 voltage settings

[Heiko Thiery <heiko.thiery@gmail.com>]

The regulator driver uses the DVS registers PCA9450_REG_BUCKxOUT_DVS0 to
set the voltage for the buck regulators 1, 2 and 3. This has no effect as the
PRESET_EN bit is set by default and therefore the preset values are used
instead, which are set to 850 mV.

This is a port of the same change in the Linux kernel:
98b94b6e38ca0 ("regulator: pca9450: Clear PRESET_EN bit to fix BUCK1/2/3 voltage setting")

Cc: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
---
 drivers/power/pmic/pca9450.c | 6 ++++++
 include/power/pca9450.h      | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/drivers/power/pmic/pca9450.c b/drivers/power/pmic/pca9450.c
index fecab0496f..1c59362ab4 100644
--- a/drivers/power/pmic/pca9450.c
+++ b/drivers/power/pmic/pca9450.c
@@ -94,6 +94,12 @@ static int pca9450_probe(struct udevice *dev)
 
 	priv->regmap = syscon_node_to_regmap(dev_ofnode(dev));
 
+	/* Clear PRESET_EN bit in BUCK123_DVS to use DVS registers */
+	if (CONFIG_IS_ENABLED(DM_REGULATOR_PCA9450)) {
+		ret = regmap_update_bits(priv->regmap, PCA9450_BUCK123_DVS,
+					 BUCK123_PRESET_EN, 0);
+	}
+
 	if (dev_read_bool(dev, "nxp,wdog_b-warm-reset"))
 		reset_ctrl = WDOG_B_CFG_WARM;
 	else
diff --git a/include/power/pca9450.h b/include/power/pca9450.h
index bf9be7d6bb..60e37c671a 100644
--- a/include/power/pca9450.h
+++ b/include/power/pca9450.h
@@ -67,6 +67,9 @@ enum {
 #define PCA9450_LDO34_MASK		0x1f
 #define PCA9450_LDO5_MASK		0x0f
 
+/* PCA9450_REG_BUCK123_PRESET_EN bit */
+#define BUCK123_PRESET_EN		0x80
+
 /* PCA9450_REG_RESET_CTRL bits */
 #define WDOG_B_CFG_MASK			0xC0
 #define WDOG_B_CFG_NONE			0x00
-- 
2.30.2