struct nouveau_therm_priv base;
 };
 
+enum nv40_sensor_style { INVALID_STYLE = -1, OLD_STYLE = 0, NEW_STYLE = 1 };
+
+static enum nv40_sensor_style
+nv40_sensor_style(struct nouveau_therm *therm)
+{
+       struct nouveau_device *device = nv_device(therm);
+
+       switch (device->chipset) {
+       case 0x43:
+       case 0x44:
+       case 0x4a:
+       case 0x47:
+               return OLD_STYLE;
+
+       case 0x46:
+       case 0x49:
+       case 0x4b:
+       case 0x4e:
+       case 0x4c:
+       case 0x67:
+       case 0x68:
+       case 0x63:
+               return NEW_STYLE;
+       default:
+               return INVALID_STYLE;
+       }
+}
+
 static int
 nv40_sensor_setup(struct nouveau_therm *therm)
 {
-       struct nouveau_device *device = nv_device(therm);
+       enum nv40_sensor_style style = nv40_sensor_style(therm);
 
        /* enable ADC readout and disable the ALARM threshold */
-       if (device->chipset >= 0x46) {
+       if (style == NEW_STYLE) {
                nv_mask(therm, 0x15b8, 0x80000000, 0);
                nv_wr32(therm, 0x15b0, 0x80003fff);
                mdelay(10); /* wait for the temperature to stabilize */
                return nv_rd32(therm, 0x15b4) & 0x3fff;
-       } else {
+       } else if (style == OLD_STYLE) {
                nv_wr32(therm, 0x15b0, 0xff);
                return nv_rd32(therm, 0x15b4) & 0xff;
-       }
+       } else
+               return -ENODEV;
 }
 
 static int
 nv40_temp_get(struct nouveau_therm *therm)
 {
        struct nouveau_therm_priv *priv = (void *)therm;
-       struct nouveau_device *device = nv_device(therm);
        struct nvbios_therm_sensor *sensor = &priv->bios_sensor;
+       enum nv40_sensor_style style = nv40_sensor_style(therm);
        int core_temp;
 
-       if (device->chipset >= 0x46) {
+       if (style == NEW_STYLE) {
                nv_wr32(therm, 0x15b0, 0x80003fff);
                core_temp = nv_rd32(therm, 0x15b4) & 0x3fff;
-       } else {
+       } else if (style == OLD_STYLE) {
                nv_wr32(therm, 0x15b0, 0xff);
                core_temp = nv_rd32(therm, 0x15b4) & 0xff;
-       }
-
-       /* Setup the sensor if the temperature is 0 */
-       if (core_temp == 0)
-               core_temp = nv40_sensor_setup(therm);
+       } else
+               return -ENODEV;
 
        if (sensor->slope_div == 0)
                sensor->slope_div = 1;