[PATCH v4 1/2] hwmon: (adm1275) Allow setting sample averaging

[Potin Lai <potin.lai@quantatw.com>]

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 below 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].

Add property called "adi,power-sample-average-enable" for enabling
configuration of power sample averaging number.

Signed-off-by: Potin Lai <potin.lai@quantatw.com>
---
 drivers/hwmon/pmbus/adm1275.c | 40 +++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/hwmon/pmbus/adm1275.c b/drivers/hwmon/pmbus/adm1275.c
index d311e0557401..0afeaa1319cd 100644
--- a/drivers/hwmon/pmbus/adm1275.c
+++ b/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
@@ -756,6 +757,45 @@ static int adm1275_probe(struct i2c_client *client)
 		return -ENODEV;
 	}
 
+	if (data->have_power_sampling &&
+	    of_property_read_bool(client->dev.of_node,
+				 "adi,power-sample-average-enable") &&
+	    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 volt and curr 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) {
-- 
2.17.1