pinctrl: sophgo: avoid to modify untouched bit when setting cv1800 pinconf

[ Upstream commit ef1a5121ae3da02372fcb66d9632ed3d47ad5637 ]

When setting pinconf configuration for cv1800 SoC, the driver just writes
the value. It may zero some bits of the pinconf register and cause some
unexpected error. Add a mask to avoid this.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Link: https://lore.kernel.org/20250211051801.470800-2-inochiama@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/pinctrl/sophgo/pinctrl-cv18xx.c

@@ -574,10 +574,10 @@ static int cv1800_pinconf_compute_config(struct cv1800_pinctrl *pctrl,
 					 struct cv1800_pin *pin,
 					 unsigned long *configs,
 					 unsigned int num_configs,
-					 u32 *value)
+					 u32 *value, u32 *mask)
 {
 	int i;
-	u32 v = 0;
+	u32 v = 0, m = 0;
 	enum cv1800_pin_io_type type;
 	int ret;
 
@@ -596,10 +596,12 @@ static int cv1800_pinconf_compute_config(struct cv1800_pinctrl *pctrl,
 		case PIN_CONFIG_BIAS_PULL_DOWN:
 			v &= ~PIN_IO_PULLDOWN;
 			v |= FIELD_PREP(PIN_IO_PULLDOWN, arg);
+			m |= PIN_IO_PULLDOWN;
 			break;
 		case PIN_CONFIG_BIAS_PULL_UP:
 			v &= ~PIN_IO_PULLUP;
 			v |= FIELD_PREP(PIN_IO_PULLUP, arg);
+			m |= PIN_IO_PULLUP;
 			break;
 		case PIN_CONFIG_DRIVE_STRENGTH_UA:
 			ret = cv1800_pinctrl_oc2reg(pctrl, pin, arg);
@@ -607,6 +609,7 @@ static int cv1800_pinconf_compute_config(struct cv1800_pinctrl *pctrl,
 				return ret;
 			v &= ~PIN_IO_DRIVE;
 			v |= FIELD_PREP(PIN_IO_DRIVE, ret);
+			m |= PIN_IO_DRIVE;
 			break;
 		case PIN_CONFIG_INPUT_SCHMITT_UV:
 			ret = cv1800_pinctrl_schmitt2reg(pctrl, pin, arg);
@@ -614,6 +617,7 @@ static int cv1800_pinconf_compute_config(struct cv1800_pinctrl *pctrl,
 				return ret;
 			v &= ~PIN_IO_SCHMITT;
 			v |= FIELD_PREP(PIN_IO_SCHMITT, ret);
+			m |= PIN_IO_SCHMITT;
 			break;
 		case PIN_CONFIG_POWER_SOURCE:
 			/* Ignore power source as it is always fixed */
@@ -621,10 +625,12 @@ static int cv1800_pinconf_compute_config(struct cv1800_pinctrl *pctrl,
 		case PIN_CONFIG_SLEW_RATE:
 			v &= ~PIN_IO_OUT_FAST_SLEW;
 			v |= FIELD_PREP(PIN_IO_OUT_FAST_SLEW, arg);
+			m |= PIN_IO_OUT_FAST_SLEW;
 			break;
 		case PIN_CONFIG_BIAS_BUS_HOLD:
 			v &= ~PIN_IO_BUS_HOLD;
 			v |= FIELD_PREP(PIN_IO_BUS_HOLD, arg);
+			m |= PIN_IO_BUS_HOLD;
 			break;
 		default:
 			return -ENOTSUPP;
@@ -632,17 +638,19 @@ static int cv1800_pinconf_compute_config(struct cv1800_pinctrl *pctrl,
 	}
 
 	*value = v;
+	*mask = m;
 
 	return 0;
 }
 
 static int cv1800_pin_set_config(struct cv1800_pinctrl *pctrl,
 				 unsigned int pin_id,
-				 u32 value)
+				 u32 value, u32 mask)
 {
 	struct cv1800_pin *pin = cv1800_get_pin(pctrl, pin_id);
 	unsigned long flags;
 	void __iomem *addr;
+	u32 reg;
 
 	if (!pin)
 		return -EINVAL;
@@ -650,7 +658,10 @@ static int cv1800_pin_set_config(struct cv1800_pinctrl *pctrl,
 	addr = cv1800_pinctrl_get_component_addr(pctrl, &pin->conf);
 
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
-	writel(value, addr);
+	reg = readl(addr);
+	reg &= ~mask;
+	reg |= value;
+	writel(reg, addr);
 	raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
 	return 0;
@@ -662,16 +673,17 @@ static int cv1800_pconf_set(struct pinctrl_dev *pctldev,
 {
 	struct cv1800_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
 	struct cv1800_pin *pin = cv1800_get_pin(pctrl, pin_id);
-	u32 value;
+	u32 value, mask;
 
 	if (!pin)
 		return -ENODEV;
 
 	if (cv1800_pinconf_compute_config(pctrl, pin,
-					  configs, num_configs, &value))
+					  configs, num_configs,
+					  &value, &mask))
 		return -ENOTSUPP;
 
-	return cv1800_pin_set_config(pctrl, pin_id, value);
+	return cv1800_pin_set_config(pctrl, pin_id, value, mask);
 }
 
 static int cv1800_pconf_group_set(struct pinctrl_dev *pctldev,
@@ -682,7 +694,7 @@ static int cv1800_pconf_group_set(struct pinctrl_dev *pctldev,
 	struct cv1800_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
 	const struct group_desc *group;
 	const struct cv1800_pin_mux_config *pinmuxs;
-	u32 value;
+	u32 value, mask;
 	int i;
 
 	group = pinctrl_generic_get_group(pctldev, gsel);
@@ -692,11 +704,12 @@ static int cv1800_pconf_group_set(struct pinctrl_dev *pctldev,
 	pinmuxs = group->data;
 
 	if (cv1800_pinconf_compute_config(pctrl, pinmuxs[0].pin,
-					  configs, num_configs, &value))
+					  configs, num_configs,
+					  &value, &mask))
 		return -ENOTSUPP;
 
 	for (i = 0; i < group->grp.npins; i++)
-		cv1800_pin_set_config(pctrl, group->grp.pins[i], value);
+		cv1800_pin_set_config(pctrl, group->grp.pins[i], value, mask);
 
 	return 0;
 }