hwmon: (it87) Report thermal sensor type as Intel PECI if appropriate

IT8721 and IT8728 support Intel PECI temperature reporting. Each sensor
can be programmed to display the temperature reported on the PECI interface.

If configured for Intel PECI, the driver reported the wrong sensor type for
the respective thermal sensor. Fix the code to correctly report it as
"Intel PECI (6)".

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Documentation/hwmon/it87

@@ -217,4 +217,5 @@ Temperature offset attributes
 The driver supports temp[1-3]_offset sysfs attributes to adjust the reported
 temperature for thermal diodes or diode-connected thermal transistors.
 If a temperature sensor is configured for thermistors, the attribute values
-are ignored.
+are ignored. If the thermal sensor type is Intel PECI, the temperature offset
+must be programmed to the critical CPU temperature.

drivers/hwmon/it87.c

@@ -231,6 +231,7 @@ static const u8 IT87_REG_TEMP_OFFSET[]	= { 0x56, 0x57, 0x59 };
 struct it87_devices {
 	const char *name;
 	u16 features;
+	u16 peci_mask;
 };
 
 #define FEAT_12MV_ADC		(1 << 0)
@@ -238,6 +239,7 @@ struct it87_devices {
 #define FEAT_OLD_AUTOPWM	(1 << 2)
 #define FEAT_16BIT_FANS		(1 << 3)
 #define FEAT_TEMP_OFFSET	(1 << 4)
+#define FEAT_TEMP_PECI		(1 << 5)
 
 static const struct it87_devices it87_devices[] = {
 	[it87] = {
@@ -263,12 +265,14 @@ static const struct it87_devices it87_devices[] = {
 	[it8721] = {
 		.name = "it8721",
 		.features = FEAT_NEWER_AUTOPWM | FEAT_12MV_ADC | FEAT_16BIT_FANS
-		  | FEAT_TEMP_OFFSET,
+		  | FEAT_TEMP_OFFSET | FEAT_TEMP_PECI,
+		.peci_mask = 0x05,
 	},
 	[it8728] = {
 		.name = "it8728",
 		.features = FEAT_NEWER_AUTOPWM | FEAT_12MV_ADC | FEAT_16BIT_FANS
-		  | FEAT_TEMP_OFFSET,
+		  | FEAT_TEMP_OFFSET | FEAT_TEMP_PECI,
+		.peci_mask = 0x07,
 	},
 	[it8782] = {
 		.name = "it8782",
@@ -285,6 +289,8 @@ static const struct it87_devices it87_devices[] = {
 #define has_newer_autopwm(data)	((data)->features & FEAT_NEWER_AUTOPWM)
 #define has_old_autopwm(data)	((data)->features & FEAT_OLD_AUTOPWM)
 #define has_temp_offset(data)	((data)->features & FEAT_TEMP_OFFSET)
+#define has_temp_peci(data, nr)	(((data)->features & FEAT_TEMP_PECI) && \
+				 ((data)->peci_mask & (1 << nr)))
 
 struct it87_sio_data {
 	enum chips type;
@@ -309,6 +315,7 @@ struct it87_data {
 	struct device *hwmon_dev;
 	enum chips type;
 	u16 features;
+	u16 peci_mask;
 
 	unsigned short addr;
 	const char *name;
@@ -617,6 +624,8 @@ static ssize_t show_temp_type(struct device *dev, struct device_attribute *attr,
 	struct it87_data *data = it87_update_device(dev);
 	u8 reg = data->sensor;	    /* In case value is updated while used */
 
+	if (has_temp_peci(data, nr) && (reg >> 6 == nr + 1))
+		return sprintf(buf, "6\n");  /* Intel PECI */
 	if (reg & (1 << nr))
 		return sprintf(buf, "3\n");  /* thermal diode */
 	if (reg & (8 << nr))
@@ -640,16 +649,20 @@ static ssize_t set_temp_type(struct device *dev, struct device_attribute *attr,
 	reg = it87_read_value(data, IT87_REG_TEMP_ENABLE);
 	reg &= ~(1 << nr);
 	reg &= ~(8 << nr);
+	if (has_temp_peci(data, nr) && (reg >> 6 == nr + 1 || val == 6))
+		reg &= 0x3f;
 	if (val == 2) {	/* backwards compatibility */
 		dev_warn(dev,
 			 "Sensor type 2 is deprecated, please use 4 instead\n");
 		val = 4;
 	}
-	/* 3 = thermal diode; 4 = thermistor; 0 = disabled */
+	/* 3 = thermal diode; 4 = thermistor; 6 = Intel PECI; 0 = disabled */
 	if (val == 3)
 		reg |= 1 << nr;
 	else if (val == 4)
 		reg |= 8 << nr;
+	else if (has_temp_peci(data, nr) && val == 6)
+		reg |= (nr + 1) << 6;
 	else if (val != 0)
 		return -EINVAL;
 
@@ -1966,6 +1979,7 @@ static int it87_probe(struct platform_device *pdev)
 	data->addr = res->start;
 	data->type = sio_data->type;
 	data->features = it87_devices[sio_data->type].features;
+	data->peci_mask = it87_devices[sio_data->type].peci_mask;
 	data->name = it87_devices[sio_data->type].name;
 	/*
 	 * IT8705F Datasheet 0.4.1, 3h == Version G.