hwmon: (pmbus) Add get_voltage/set_voltage ops

The pmbus core does not have operations for getting or setting voltage.
Add functions get/set voltage for the dynamic regulator framework.
Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
Link: https://lore.kernel.org/r/20220503104631.3515715-5-marten.lindahl@axis.com
[groeck: cosmetic alignment / empty line fixes]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/pmbus_core.c

@@ -2634,11 +2634,78 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
 	return 0;
 }
 
+static int pmbus_regulator_get_voltage(struct regulator_dev *rdev)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	struct pmbus_sensor s = {
+		.page = rdev_get_id(rdev),
+		.class = PSC_VOLTAGE_OUT,
+		.convert = true,
+	};
+
+	s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_READ_VOUT);
+	if (s.data < 0)
+		return s.data;
+
+	return (int)pmbus_reg2data(data, &s) * 1000; /* unit is uV */
+}
+
+static int pmbus_regulator_set_voltage(struct regulator_dev *rdev, int min_uv,
+				       int max_uv, unsigned int *selector)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	struct pmbus_sensor s = {
+		.page = rdev_get_id(rdev),
+		.class = PSC_VOLTAGE_OUT,
+		.convert = true,
+		.data = -1,
+	};
+	int val = DIV_ROUND_CLOSEST(min_uv, 1000); /* convert to mV */
+	int low, high;
+
+	*selector = 0;
+
+	if (pmbus_check_word_register(client, s.page, PMBUS_MFR_VOUT_MIN))
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_MFR_VOUT_MIN);
+	if (s.data < 0) {
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_VOUT_MARGIN_LOW);
+		if (s.data < 0)
+			return s.data;
+	}
+	low = pmbus_reg2data(data, &s);
+
+	s.data = -1;
+	if (pmbus_check_word_register(client, s.page, PMBUS_MFR_VOUT_MAX))
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_MFR_VOUT_MAX);
+	if (s.data < 0) {
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_VOUT_MARGIN_HIGH);
+		if (s.data < 0)
+			return s.data;
+	}
+	high = pmbus_reg2data(data, &s);
+
+	/* Make sure we are within margins */
+	if (low > val)
+		val = low;
+	if (high < val)
+		val = high;
+
+	val = pmbus_data2reg(data, &s, val);
+
+	return _pmbus_write_word_data(client, s.page, PMBUS_VOUT_COMMAND, (u16)val);
+}
+
 const struct regulator_ops pmbus_regulator_ops = {
 	.enable = pmbus_regulator_enable,
 	.disable = pmbus_regulator_disable,
 	.is_enabled = pmbus_regulator_is_enabled,
 	.get_error_flags = pmbus_regulator_get_error_flags,
+	.get_voltage = pmbus_regulator_get_voltage,
+	.set_voltage = pmbus_regulator_set_voltage,
 };
 EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);