hwmon: (pmbus/adm1275) Prepare for protected write to PMON_CONFIG

According to ADI, changing PMON_CONFIG while ADC is running can have
unexpected results. ADI recommends halting the ADC with PMON_CONTROL
before setting PMON_CONFIG and then resume after.

To prepare for this change, rename adm1275_read_pmon_config()
and adm1275_write_pmon_config() to adm1275_read_samples() and
adm1275_write_samples() to more accurately reflect the functionality
of the code. Introduce new function adm1275_write_pmon_config()
and use it for all code writing into the PMON_CONFIG register.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230614163605.3688964-2-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Author: groeck

drivers/hwmon/pmbus/adm1275.c

@@ -173,8 +173,8 @@ static const struct coefficients adm1293_coefficients[] = {
 	[18] = { 7658, 0, -3 },		/* power, 21V, irange200 */
 };
 
-static int adm1275_read_pmon_config(const struct adm1275_data *data,
-				    struct i2c_client *client, bool is_power)
+static int adm1275_read_samples(const struct adm1275_data *data,
+				struct i2c_client *client, bool is_power)
 {
 	int shift, ret;
 	u16 mask;
@@ -200,8 +200,23 @@ static int adm1275_read_pmon_config(const struct adm1275_data *data,
 }
 
 static int adm1275_write_pmon_config(const struct adm1275_data *data,
-				     struct i2c_client *client,
-				     bool is_power, u16 word)
+				     struct i2c_client *client, u16 word)
+{
+	int ret;
+
+	if (data->have_power_sampling)
+		ret = i2c_smbus_write_word_data(client, ADM1275_PMON_CONFIG,
+						word);
+	else
+		ret = i2c_smbus_write_byte_data(client, ADM1275_PMON_CONFIG,
+						word);
+
+	return ret;
+}
+
+static int adm1275_write_samples(const struct adm1275_data *data,
+				 struct i2c_client *client,
+				 bool is_power, u16 word)
 {
 	int shift, ret;
 	u16 mask;
@@ -219,14 +234,8 @@ static int adm1275_write_pmon_config(const struct adm1275_data *data,
 		return ret;
 
 	word = (ret & ~mask) | ((word << shift) & mask);
-	if (data->have_power_sampling)
-		ret = i2c_smbus_write_word_data(client, ADM1275_PMON_CONFIG,
-						word);
-	else
-		ret = i2c_smbus_write_byte_data(client, ADM1275_PMON_CONFIG,
-						word);
 
-	return ret;
+	return adm1275_write_pmon_config(data, client, word);
 }
 
 static int adm1275_read_word_data(struct i2c_client *client, int page,
@@ -321,14 +330,14 @@ static int adm1275_read_word_data(struct i2c_client *client, int page,
 	case PMBUS_VIRT_POWER_SAMPLES:
 		if (!data->have_power_sampling)
 			return -ENXIO;
-		ret = adm1275_read_pmon_config(data, client, true);
+		ret = adm1275_read_samples(data, client, true);
 		if (ret < 0)
 			break;
 		ret = BIT(ret);
 		break;
 	case PMBUS_VIRT_IN_SAMPLES:
 	case PMBUS_VIRT_CURR_SAMPLES:
-		ret = adm1275_read_pmon_config(data, client, false);
+		ret = adm1275_read_samples(data, client, false);
 		if (ret < 0)
 			break;
 		ret = BIT(ret);
@@ -381,14 +390,12 @@ static int adm1275_write_word_data(struct i2c_client *client, int page, int reg,
 		if (!data->have_power_sampling)
 			return -ENXIO;
 		word = clamp_val(word, 1, ADM1275_SAMPLES_AVG_MAX);
-		ret = adm1275_write_pmon_config(data, client, true,
-						ilog2(word));
+		ret = adm1275_write_samples(data, client, true, ilog2(word));
 		break;
 	case PMBUS_VIRT_IN_SAMPLES:
 	case PMBUS_VIRT_CURR_SAMPLES:
 		word = clamp_val(word, 1, ADM1275_SAMPLES_AVG_MAX);
-		ret = adm1275_write_pmon_config(data, client, false,
-						ilog2(word));
+		ret = adm1275_write_samples(data, client, false, ilog2(word));
 		break;
 	default:
 		ret = -ENODATA;
@@ -466,13 +473,14 @@ static const struct i2c_device_id adm1275_id[] = {
 MODULE_DEVICE_TABLE(i2c, adm1275_id);
 
 /* Enable VOUT & TEMP1 if not enabled (disabled by default) */
-static int adm1275_enable_vout_temp(struct i2c_client *client, int config)
+static int adm1275_enable_vout_temp(struct adm1275_data *data,
+				    struct i2c_client *client, int config)
 {
 	int ret;
 
 	if ((config & ADM1278_PMON_DEFCONFIG) != ADM1278_PMON_DEFCONFIG) {
 		config |= ADM1278_PMON_DEFCONFIG;
-		ret = i2c_smbus_write_word_data(client, ADM1275_PMON_CONFIG, config);
+		ret = adm1275_write_pmon_config(data, client, config);
 		if (ret < 0) {
 			dev_err(&client->dev, "Failed to enable VOUT/TEMP1 monitoring\n");
 			return ret;
@@ -634,7 +642,7 @@ static int adm1275_probe(struct i2c_client *client)
 			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
 			PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
 
-		ret = adm1275_enable_vout_temp(client, config);
+		ret = adm1275_enable_vout_temp(data, client, config);
 		if (ret)
 			return ret;
 
@@ -694,7 +702,7 @@ static int adm1275_probe(struct i2c_client *client)
 			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
 			PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
 
-		ret = adm1275_enable_vout_temp(client, config);
+		ret = adm1275_enable_vout_temp(data, client, config);
 		if (ret)
 			return ret;
 
@@ -766,8 +774,7 @@ static int adm1275_probe(struct i2c_client *client)
 				"Invalid number of power samples");
 			return -EINVAL;
 		}
-		ret = adm1275_write_pmon_config(data, client, true,
-						ilog2(avg));
+		ret = adm1275_write_samples(data, client, true, ilog2(avg));
 		if (ret < 0) {
 			dev_err(&client->dev,
 				"Setting power sample averaging failed with error %d",
@@ -784,8 +791,7 @@ static int adm1275_probe(struct i2c_client *client)
 				"Invalid number of voltage/current samples");
 			return -EINVAL;
 		}
-		ret = adm1275_write_pmon_config(data, client, false,
-						ilog2(avg));
+		ret = adm1275_write_samples(data, client, false, ilog2(avg));
 		if (ret < 0) {
 			dev_err(&client->dev,
 				"Setting voltage and current sample averaging failed with error %d",