[PATCH] adm1275: support PMBUS_VIRT_*_SAMPLES

[Adamski, Krzysztof (Nokia - PL/Wroclaw)]

The device supports setting the number of samples for averaging the
measurements. There are two separate settings - PWR_AVG for averaging
PIN and VI_AVG for averaging VIN/VAUX/IOUT, both being part of
PMON_CONFIG register. The values are stored as exponent of base 2 of the
actual number of samples that will be taken.

Signed-off-by: Krzysztof Adamski <krzysztof.adamski@xxxxxxxxx>
---
 drivers/hwmon/pmbus/adm1275.c | 68 ++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/adm1275.c b/drivers/hwmon/pmbus/adm1275.c
index f569372c9204..4efe1a9df563 100644
--- a/drivers/hwmon/pmbus/adm1275.c
+++ b/drivers/hwmon/pmbus/adm1275.c
@@ -23,6 +23,8 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/log2.h>
 #include "pmbus.h"
 
 enum chips { adm1075, adm1272, adm1275, adm1276, adm1278, adm1293, adm1294 };
@@ -78,6 +80,10 @@ enum chips { adm1075, adm1272, adm1275, adm1276, adm1278, adm1293, adm1294 };
 #define ADM1075_VAUX_OV_WARN		BIT(7)
 #define ADM1075_VAUX_UV_WARN		BIT(6)
 
+#define ADM1275_PWR_AVG_MASK		GENMASK(13, 11)
+#define ADM1275_VI_AVG_MASK		GENMASK(10, 8)
+#define ADM1275_SAMPLES_AVG_MAX	128
+
 struct adm1275_data {
 	int id;
 	bool have_oc_fault;
@@ -90,6 +96,7 @@ struct adm1275_data {
 	bool have_pin_max;
 	bool have_temp_max;
 	struct pmbus_driver_info info;
+	struct mutex lock;
 };
 
 #define to_adm1275_data(x)  container_of(x, struct adm1275_data, info)
@@ -164,6 +171,38 @@ static const struct coefficients adm1293_coefficients[] = {
 	[18] = { 7658, 0, -3 },		/* power, 21V, irange200 */
 };
 
+static inline int adm1275_read_pmon_config(struct i2c_client *client, u64 mask)
+{
+	int ret;
+
+	ret = i2c_smbus_read_word_data(client, ADM1275_PMON_CONFIG);
+	if (ret < 0)
+		return ret;
+
+	return FIELD_GET(mask, ret);
+}
+
+static inline int adm1275_write_pmon_config(struct i2c_client *client, u64 mask,
+					    u16 word)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct adm1275_data *data = to_adm1275_data(info);
+	int ret;
+
+	mutex_lock(&data->lock);
+	ret = i2c_smbus_read_word_data(client, ADM1275_PMON_CONFIG);
+	if (ret < 0) {
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+
+	word = FIELD_PREP(mask, word) | (ret & ~mask);
+	ret = i2c_smbus_write_word_data(client, ADM1275_PMON_CONFIG, word);
+	mutex_unlock(&data->lock);
+
+	return ret;
+}
+
 static int adm1275_read_word_data(struct i2c_client *client, int page, int reg)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
@@ -242,6 +281,19 @@ static int adm1275_read_word_data(struct i2c_client *client, int page, int reg)
 		if (!data->have_temp_max)
 			return -ENXIO;
 		break;
+	case PMBUS_VIRT_POWER_SAMPLES:
+		ret = adm1275_read_pmon_config(client, ADM1275_PWR_AVG_MASK);
+		if (ret < 0)
+			break;
+		ret = 1 << ret;
+		break;
+	case PMBUS_VIRT_IN_SAMPLES:
+	case PMBUS_VIRT_CURR_SAMPLES:
+		ret = adm1275_read_pmon_config(client, ADM1275_VI_AVG_MASK);
+		if (ret < 0)
+			break;
+		ret = 1 << ret;
+		break;
 	default:
 		ret = -ENODATA;
 		break;
@@ -286,6 +338,17 @@ static int adm1275_write_word_data(struct i2c_client *client, int page, int reg,
 	case PMBUS_VIRT_RESET_TEMP_HISTORY:
 		ret = pmbus_write_word_data(client, 0, ADM1278_PEAK_TEMP, 0);
 		break;
+	case PMBUS_VIRT_POWER_SAMPLES:
+		word = clamp_val(word, 1, ADM1275_SAMPLES_AVG_MAX);
+		ret = adm1275_write_pmon_config(client, ADM1275_PWR_AVG_MASK,
+						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(client, ADM1275_VI_AVG_MASK,
+						ilog2(word));
+		break;
 	default:
 		ret = -ENODATA;
 		break;
@@ -422,6 +485,8 @@ static int adm1275_probe(struct i2c_client *client,
 	if (!data)
 		return -ENOMEM;
 
+	mutex_init(&data->lock);
+
 	if (of_property_read_u32(client->dev.of_node,
 				 "shunt-resistor-micro-ohms", &shunt))
 		shunt = 1000; /* 1 mOhm if not set via DT */
@@ -439,7 +504,8 @@ static int adm1275_probe(struct i2c_client *client,
 	info->format[PSC_CURRENT_OUT] = direct;
 	info->format[PSC_POWER] = direct;
 	info->format[PSC_TEMPERATURE] = direct;
-	info->func[0] = PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
+	info->func[0] = PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+			PMBUS_HAVE_SAMPLES;
 
 	info->read_word_data = adm1275_read_word_data;
 	info->read_byte_data = adm1275_read_byte_data;
-- 
2.20.1