hwmon: (adm1275) Allow setting sample averaging

Current driver assume PWR_AVG and VI_AVG as 1 by default, and user needs
to set sample averaging via sysfs manually.

This patch parses the properties "adi,power-sample-average" and
"adi,volt-curr-sample-average" from device tree, and setting sample
averaging during probe. Input value must be one of value in the
list [1, 2, 4, 8, 16, 32, 64, 128].
Signed-off-by: Potin Lai <potin.lai@quantatw.com>
Link: https://lore.kernel.org/r/20220302123817.27025-2-potin.lai@quantatw.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/adm1275.c

@@ -475,6 +475,7 @@ static int adm1275_probe(struct i2c_client *client)
 	int vindex = -1, voindex = -1, cindex = -1, pindex = -1;
 	int tindex = -1;
 	u32 shunt;
+	u32 avg;
 
 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_READ_BYTE_DATA
@@ -687,7 +688,7 @@ static int adm1275_probe(struct i2c_client *client)
 		if ((config & (ADM1278_VOUT_EN | ADM1278_TEMP1_EN)) !=
 		    (ADM1278_VOUT_EN | ADM1278_TEMP1_EN)) {
 			config |= ADM1278_VOUT_EN | ADM1278_TEMP1_EN;
-			ret = i2c_smbus_write_byte_data(client,
+			ret = i2c_smbus_write_word_data(client,
 							ADM1275_PMON_CONFIG,
 							config);
 			if (ret < 0) {
@@ -756,6 +757,43 @@ static int adm1275_probe(struct i2c_client *client)
 		return -ENODEV;
 	}
 
+	if (data->have_power_sampling &&
+	    of_property_read_u32(client->dev.of_node,
+				 "adi,power-sample-average", &avg) == 0) {
+		if (!avg || avg > ADM1275_SAMPLES_AVG_MAX ||
+		    BIT(__fls(avg)) != avg) {
+			dev_err(&client->dev,
+				"Invalid number of power samples");
+			return -EINVAL;
+		}
+		ret = adm1275_write_pmon_config(data, client, true,
+						ilog2(avg));
+		if (ret < 0) {
+			dev_err(&client->dev,
+				"Setting power sample averaging failed with error %d",
+				ret);
+			return ret;
+		}
+	}
+
+	if (of_property_read_u32(client->dev.of_node,
+				"adi,volt-curr-sample-average", &avg) == 0) {
+		if (!avg || avg > ADM1275_SAMPLES_AVG_MAX ||
+		    BIT(__fls(avg)) != avg) {
+			dev_err(&client->dev,
+				"Invalid number of voltage/current samples");
+			return -EINVAL;
+		}
+		ret = adm1275_write_pmon_config(data, client, false,
+						ilog2(avg));
+		if (ret < 0) {
+			dev_err(&client->dev,
+				"Setting voltage and current sample averaging failed with error %d",
+				ret);
+			return ret;
+		}
+	}
+
 	if (voindex < 0)
 		voindex = vindex;
 	if (vindex >= 0) {