[PATCH v3 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. Allowed input value from 1 to 128. If the
inputed value is not power of 2, the sample averaging number will be
configured with the smaller and cloest power of 2.

- adi,power-sample-average
- adi,volt-curr-sample-average

Signed-off-by: Potin Lai <potin.lai@quantatw.com>
---
 drivers/hwmon/pmbus/adm1275.c | 36 +++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/hwmon/pmbus/adm1275.c b/drivers/hwmon/pmbus/adm1275.c
index d311e0557401..212c7f3c59b0 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 +757,41 @@ 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 > ADM1275_SAMPLES_AVG_MAX || avg < 1)
+			return -EINVAL;
+		dev_info(&client->dev,
+			"Setting power sample averaging number to %u",
+			BIT(ilog2(avg)));
+		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 > ADM1275_SAMPLES_AVG_MAX || avg < 1)
+			return -EINVAL;
+		dev_info(&client->dev,
+			"Setting voltage and current sample averaging number to %u",
+			BIT(ilog2(avg)));
+		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