hwmon: (max31827) Update bits with shutdown_write()

Added 'mask' parameter to the shutdown_write() function. Now it can
either write or update bits, depending on the value of mask. This is
needed, because for alarms a write is necessary, but for resolution only
the resolution bits should be updated.

Signed-off-by: Daniel Matyas <daniel.matyas@analog.com>
Link: https://lore.kernel.org/r/20231031182158.124608-3-daniel.matyas@analog.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/max31827.c

@@ -81,7 +81,7 @@ static const struct regmap_config max31827_regmap = {
 };
 
 static int shutdown_write(struct max31827_state *st, unsigned int reg,
-			  unsigned int val)
+			  unsigned int mask, unsigned int val)
 {
 	unsigned int cfg;
 	unsigned int cnv_rate;
@@ -98,7 +98,10 @@ static int shutdown_write(struct max31827_state *st, unsigned int reg,
 	mutex_lock(&st->lock);
 
 	if (!st->enable) {
-		ret = regmap_write(st->regmap, reg, val);
+		if (!mask)
+			ret = regmap_write(st->regmap, reg, val);
+		else
+			ret = regmap_update_bits(st->regmap, reg, mask, val);
 		goto unlock;
 	}
 
@@ -113,7 +116,11 @@ static int shutdown_write(struct max31827_state *st, unsigned int reg,
 	if (ret)
 		goto unlock;
 
-	ret = regmap_write(st->regmap, reg, val);
+	if (!mask)
+		ret = regmap_write(st->regmap, reg, val);
+	else
+		ret = regmap_update_bits(st->regmap, reg, mask, val);
+
 	if (ret)
 		goto unlock;
 
@@ -131,7 +138,7 @@ static int write_alarm_val(struct max31827_state *st, unsigned int reg,
 {
 	val = MAX31827_M_DGR_TO_16_BIT(val);
 
-	return shutdown_write(st, reg, val);
+	return shutdown_write(st, reg, 0, val);
 }
 
 static umode_t max31827_is_visible(const void *state,