1 files changed, 31 insertions, 15 deletions

diff --git a/drivers/hwmon/sbtsi_temp.c b/drivers/hwmon/sbtsi_temp.c
index 3c839f56c460..a6c439e376ff 100644
--- a/drivers/hwmon/sbtsi_temp.c
+++ b/drivers/hwmon/sbtsi_temp.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
+#include <linux/bitfield.h>
 
 /*
  * SB-TSI registers only support SMBus byte data access. "_INT" registers are
@@ -29,8 +30,22 @@
 #define SBTSI_REG_TEMP_HIGH_DEC		0x13 /* RW */
 #define SBTSI_REG_TEMP_LOW_DEC		0x14 /* RW */
 
+/*
+ * Bit for reporting value with temperature measurement range.
+ * bit == 0: Use default temperature range (0C to 255.875C).
+ * bit == 1: Use extended temperature range (-49C to +206.875C).
+ */
+#define SBTSI_CONFIG_EXT_RANGE_SHIFT	2
+/*
+ * ReadOrder bit specifies the reading order of integer and decimal part of
+ * CPU temperature for atomic reads. If bit == 0, reading integer part triggers
+ * latching of the decimal part, so integer part should be read first.
+ * If bit == 1, read order should be reversed.
+ */
 #define SBTSI_CONFIG_READ_ORDER_SHIFT	5
 
+#define SBTSI_TEMP_EXT_RANGE_ADJ	49000
+
 #define SBTSI_TEMP_MIN	0
 #define SBTSI_TEMP_MAX	255875
 
@@ -38,6 +53,8 @@
 struct sbtsi_data {
 	struct i2c_client *client;
 	struct mutex lock;
+	bool ext_range_mode;
+	bool read_order;
 };
 
 /*
@@ -74,23 +91,11 @@ static int sbtsi_read(struct device *dev, enum hwmon_sensor_types type,
 {
 	struct sbtsi_data *data = dev_get_drvdata(dev);
 	s32 temp_int, temp_dec;
-	int err;
 
 	switch (attr) {
 	case hwmon_temp_input:
-		/*
-		 * ReadOrder bit specifies the reading order of integer and
-		 * decimal part of CPU temp for atomic reads. If bit == 0,
-		 * reading integer part triggers latching of the decimal part,
-		 * so integer part should be read first. If bit == 1, read
-		 * order should be reversed.
-		 */
-		err = i2c_smbus_read_byte_data(data->client, SBTSI_REG_CONFIG);
-		if (err < 0)
-			return err;
-
 		mutex_lock(&data->lock);
-		if (err & BIT(SBTSI_CONFIG_READ_ORDER_SHIFT)) {
+		if (data->read_order) {
 			temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
 			temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
 		} else {
@@ -122,6 +127,8 @@ static int sbtsi_read(struct device *dev, enum hwmon_sensor_types type,
 		return temp_dec;
 
 	*val = sbtsi_reg_to_mc(temp_int, temp_dec);
+	if (data->ext_range_mode)
+		*val -= SBTSI_TEMP_EXT_RANGE_ADJ;
 
 	return 0;
 }
@@ -146,6 +153,8 @@ static int sbtsi_write(struct device *dev, enum hwmon_sensor_types type,
 		return -EINVAL;
 	}
 
+	if (data->ext_range_mode)
+		val += SBTSI_TEMP_EXT_RANGE_ADJ;
 	val = clamp_val(val, SBTSI_TEMP_MIN, SBTSI_TEMP_MAX);
 	sbtsi_mc_to_reg(val, &temp_int, &temp_dec);
 
@@ -203,6 +212,7 @@ static int sbtsi_probe(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct device *hwmon_dev;
 	struct sbtsi_data *data;
+	int err;
 
 	data = devm_kzalloc(dev, sizeof(struct sbtsi_data), GFP_KERNEL);
 	if (!data)
@@ -211,8 +221,14 @@ static int sbtsi_probe(struct i2c_client *client)
 	data->client = client;
 	mutex_init(&data->lock);
 
-	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data, &sbtsi_chip_info,
-							 NULL);
+	err = i2c_smbus_read_byte_data(data->client, SBTSI_REG_CONFIG);
+	if (err < 0)
+		return err;
+	data->ext_range_mode = FIELD_GET(BIT(SBTSI_CONFIG_EXT_RANGE_SHIFT), err);
+	data->read_order = FIELD_GET(BIT(SBTSI_CONFIG_READ_ORDER_SHIFT), err);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
+							 &sbtsi_chip_info, NULL);
 
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }