diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
index 9fb66aa..1721611 100644
--- a/drivers/pinctrl/pinctrl-st.c
+++ b/drivers/pinctrl/pinctrl-st.c
@@ -410,25 +410,27 @@ static void st_pinconf_set_config(struct st_pio_control *pc,
 	unsigned int oe_value, pu_value, od_value;
 	unsigned long mask = BIT(pin);
 
-	regmap_field_read(output_enable, &oe_value);
-	regmap_field_read(pull_up, &pu_value);
-	regmap_field_read(open_drain, &od_value);
-
-	/* Clear old values */
-	oe_value &= ~mask;
-	pu_value &= ~mask;
-	od_value &= ~mask;
-
-	if (config & ST_PINCONF_OE)
-		oe_value |= mask;
-	if (config & ST_PINCONF_PU)
-		pu_value |= mask;
-	if (config & ST_PINCONF_OD)
-		od_value |= mask;
-
-	regmap_field_write(output_enable, oe_value);
-	regmap_field_write(pull_up, pu_value);
-	regmap_field_write(open_drain, od_value);
+	if (output_enable) {
+		regmap_field_read(output_enable, &oe_value);
+		oe_value &= ~mask;
+		if (config & ST_PINCONF_OE)
+			oe_value |= mask;
+		regmap_field_write(output_enable, oe_value);
+	}
+	if (pull_up) {
+		regmap_field_read(pull_up, &pu_value);
+		pu_value &= ~mask;
+		if (config & ST_PINCONF_PU)
+			pu_value |= mask;
+		regmap_field_write(pull_up, pu_value);
+	}
+	if (open_drain) {
+		regmap_field_read(open_drain, &od_value);
+		od_value &= ~mask;
+		if (config & ST_PINCONF_OD)
+			od_value |= mask;
+		regmap_field_write(open_drain, od_value);
+	}
 }
 
 static void st_pctl_set_function(struct st_pio_control *pc,
@@ -439,6 +441,9 @@ static void st_pctl_set_function(struct st_pio_control *pc,
 	int pin = st_gpio_pin(pin_id);
 	int offset = pin * 4;
 
+	if (!alt)
+		return;
+
 	regmap_field_read(alt, &val);
 	val &= ~(0xf << offset);
 	val |= function << offset;
@@ -571,22 +576,28 @@ static void st_pinconf_set_retime_dedicated(struct st_pinctrl *info,
 	regmap_field_write(rt_d->rt[pin], retime_config);
 }
 
-static void st_pinconf_get_direction(struct st_pio_control *pc,
-	int pin, unsigned long *config)
+static void st_pinconf_get_direction(struct st_pio_control *pc, int pin,
+				     unsigned long *config)
 {
 	unsigned int oe_value, pu_value, od_value;
 
-	regmap_field_read(pc->oe, &oe_value);
-	regmap_field_read(pc->pu, &pu_value);
-	regmap_field_read(pc->od, &od_value);
+	if (pc->oe) {
+		regmap_field_read(pc->oe, &oe_value);
+		if (oe_value & BIT(pin))
+			ST_PINCONF_PACK_OE(*config);
+	}
 
-	if (oe_value & BIT(pin))
-		ST_PINCONF_PACK_OE(*config);
-	if (pu_value & BIT(pin))
-		ST_PINCONF_PACK_PU(*config);
-	if (od_value & BIT(pin))
-		ST_PINCONF_PACK_OD(*config);
+	if (pc->pu) {
+		regmap_field_read(pc->pu, &pu_value);
+		if (pu_value & BIT(pin))
+			ST_PINCONF_PACK_PU(*config);
+	}
 
+	if (pc->od) {
+		regmap_field_read(pc->od, &od_value);
+		if (od_value & BIT(pin))
+			ST_PINCONF_PACK_OD(*config);
+	}
 }
 
 static int st_pinconf_get_retime_packed(struct st_pinctrl *info,
@@ -1105,8 +1116,21 @@ static int st_pctl_dt_setup_retime(struct st_pinctrl *info,
 	return -EINVAL;
 }
 
-static int st_parse_syscfgs(struct st_pinctrl *info,
-		int bank, struct device_node *np)
+
+static struct regmap_field *st_pc_get_value(struct device *dev,
+					    struct regmap *regmap, int bank,
+					    int data, int lsb, int msb)
+{
+	struct reg_field reg = REG_FIELD((data + bank) * 4, lsb, msb);
+
+	if (data < 0)
+		return NULL;
+
+	return devm_regmap_field_alloc(dev, regmap, reg);
+}
+
+static void st_parse_syscfgs(struct st_pinctrl *info, int bank,
+			     struct device_node *np)
 {
 	const struct st_pctl_data *data = info->data;
 	/**
@@ -1116,29 +1140,21 @@ static int st_parse_syscfgs(struct st_pinctrl *info,
 	 */
 	int lsb = (bank%4) * ST_GPIO_PINS_PER_BANK;
 	int msb = lsb + ST_GPIO_PINS_PER_BANK - 1;
-	struct reg_field alt_reg = REG_FIELD((data->alt + bank) * 4, 0, 31);
-	struct reg_field oe_reg = REG_FIELD((data->oe + bank/4) * 4, lsb, msb);
-	struct reg_field pu_reg = REG_FIELD((data->pu + bank/4) * 4, lsb, msb);
-	struct reg_field od_reg = REG_FIELD((data->od + bank/4) * 4, lsb, msb);
 	struct st_pio_control *pc = &info->banks[bank].pc;
 	struct device *dev = info->dev;
 	struct regmap *regmap  = info->regmap;
 
-	pc->alt = devm_regmap_field_alloc(dev, regmap, alt_reg);
-	pc->oe = devm_regmap_field_alloc(dev, regmap, oe_reg);
-	pc->pu = devm_regmap_field_alloc(dev, regmap, pu_reg);
-	pc->od = devm_regmap_field_alloc(dev, regmap, od_reg);
-
-	if (IS_ERR(pc->alt) || IS_ERR(pc->oe) ||
-			IS_ERR(pc->pu) || IS_ERR(pc->od))
-		return -EINVAL;
+	pc->alt = st_pc_get_value(dev, regmap, bank, data->alt, 0, 31);
+	pc->oe = st_pc_get_value(dev, regmap, bank/4, data->oe, lsb, msb);
+	pc->pu = st_pc_get_value(dev, regmap, bank/4, data->pu, lsb, msb);
+	pc->od = st_pc_get_value(dev, regmap, bank/4, data->od, lsb, msb);
 
 	/* retime avaiable for all pins by default */
 	pc->rt_pin_mask = 0xff;
 	of_property_read_u32(np, "st,retime-pin-mask", &pc->rt_pin_mask);
 	st_pctl_dt_setup_retime(info, bank, pc);
 
-	return 0;
+	return;
 }
 
 /*
