hwmon: (it87) Add support to detect sensor type AMDTSI

Add test for sensor type AMDTSI which is available on certain recent
chipsets.
Signed-off-by: Frank Crawford <frank@crawford.emu.id.au>
Link: https://lore.kernel.org/r/20230707123005.956415-4-frank@crawford.emu.id.auSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/it87.c

@@ -221,6 +221,10 @@ static bool fix_pwm_polarity;
  * Super-I/O configuration space.
  */
 #define IT87_REG_VID           0x0a
+
+/* Interface Selection register on other chips */
+#define IT87_REG_IFSEL         0x0a
+
 /*
  * The IT8705F and IT8712F earlier than revision 0x08 use register 0x0b
  * for fan divisors. Later IT8712F revisions must use 16-bit tachometer
@@ -1170,14 +1174,37 @@ static int get_temp_type(struct it87_data *data, int index)
 	 * 0 = disabled
 	 */
 	u8 reg, extra;
-	int type = 0;
+	int ttype, type = 0;
+
+	/* Detect PECI vs. AMDTSI */
+	ttype = 6;
+	if ((has_temp_peci(data, index)) || data->type == it8721 ||
+	    data->type == it8720) {
+		extra = it87_read_value(data, IT87_REG_IFSEL);
+		if ((extra & 0x70) == 0x40)
+			ttype = 5;
+	}
 
-	reg = data->sensor;	/* In case value is updated while used */
-	extra = data->extra;
+	reg = it87_read_value(data, IT87_REG_TEMP_ENABLE);
+
+	/* Per chip special detection */
+	switch (data->type) {
+	case it8622:
+		if (!(reg & 0xc0) && index == 3)
+			type = ttype;
+		break;
+	default:
+		break;
+	}
+
+	if (type || index >= 3)
+		return type;
+
+	extra = it87_read_value(data, IT87_REG_TEMP_EXTRA);
 
 	if ((has_temp_peci(data, index) && (reg >> 6 == index + 1)) ||
 	    (has_temp_old_peci(data, index) && (extra & 0x80)))
-		type = 6;	/* Intel PECI */
+		type = ttype;	/* Intel PECI or AMDTSI */
 	else if (reg & BIT(index))
 		type = 3;	/* thermal diode */
 	else if (reg & BIT(index + 3))