drm/nv40/therm: improve selection between the old and the new style

The condition to select between the old and new style was a thinko
as rnndb orders chipsets based on their release date (or general
chronologie hw-wise) and not based on their chipset number.

As the nv40 family is a mess when it comes to numbers, this patch
introduces a switch-based selection between the old and new style.
Signed-off-by: Martin Peres <martin.peres@labri.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/subdev/therm/nv40.c

@@ -29,42 +29,68 @@ struct nv40_therm_priv {
 	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;