hwmon: (pmbus/ltc2978) Fix temperature reporting

On LTC2978, only READ_TEMPERATURE is supported. It reports
the internal junction temperature. This register is unpaged.

On LTC3880, READ_TEMPERATURE and READ_TEMPERATURE2 are supported.
READ_TEMPERATURE is paged and reports external temperatures.
READ_TEMPERATURE2 is unpaged and reports the internal junction
temperature.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org # 3.2+
Acked-by: Jean Delvare <khali@linux-fr.org>

drivers/hwmon/pmbus/ltc2978.c

@@ -59,7 +59,7 @@ enum chips { ltc2978, ltc3880 };
 struct ltc2978_data {
 	enum chips id;
 	int vin_min, vin_max;
-	int temp_min, temp_max;
+	int temp_min, temp_max[2];
 	int vout_min[8], vout_max[8];
 	int iout_max[2];
 	int temp2_max;
@@ -113,9 +113,10 @@ static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
 		ret = pmbus_read_word_data(client, page,
 					   LTC2978_MFR_TEMPERATURE_PEAK);
 		if (ret >= 0) {
-			if (lin11_to_val(ret) > lin11_to_val(data->temp_max))
-				data->temp_max = ret;
-			ret = data->temp_max;
+			if (lin11_to_val(ret)
+			    > lin11_to_val(data->temp_max[page]))
+				data->temp_max[page] = ret;
+			ret = data->temp_max[page];
 		}
 		break;
 	case PMBUS_VIRT_RESET_VOUT_HISTORY:
@@ -266,7 +267,7 @@ static int ltc2978_write_word_data(struct i2c_client *client, int page,
 		break;
 	case PMBUS_VIRT_RESET_TEMP_HISTORY:
 		data->temp_min = 0x7bff;
-		data->temp_max = 0x7c00;
+		data->temp_max[page] = 0x7c00;
 		ret = ltc2978_clear_peaks(client, page, data->id);
 		break;
 	default:
@@ -323,7 +324,8 @@ static int ltc2978_probe(struct i2c_client *client,
 	data->vin_min = 0x7bff;
 	data->vin_max = 0x7c00;
 	data->temp_min = 0x7bff;
-	data->temp_max = 0x7c00;
+	for (i = 0; i < ARRAY_SIZE(data->temp_max); i++)
+		data->temp_max[i] = 0x7c00;
 	data->temp2_max = 0x7c00;
 
 	switch (data->id) {