drm/radeon/kms: rv6xx+ thermal sensor fixes

Some fixes to the thermal sensor code:
- handle negative numbers
- properly handle temp calculation on different asics

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/evergreen.c

@@ -97,26 +97,29 @@ u32 evergreen_page_flip(struct radeon_device *rdev, int crtc_id, u64 crtc_base)
 }
 
 /* get temperature in millidegrees */
-u32 evergreen_get_temp(struct radeon_device *rdev)
+int evergreen_get_temp(struct radeon_device *rdev)
 {
 	u32 temp = (RREG32(CG_MULT_THERMAL_STATUS) & ASIC_T_MASK) >>
 		ASIC_T_SHIFT;
 	u32 actual_temp = 0;
 
-	if ((temp >> 10) & 1)
-		actual_temp = 0;
-	else if ((temp >> 9) & 1)
+	if (temp & 0x400)
+		actual_temp = -256;
+	else if (temp & 0x200)
 		actual_temp = 255;
-	else
-		actual_temp = (temp >> 1) & 0xff;
+	else if (temp & 0x100) {
+		actual_temp = temp & 0x1ff;
+		actual_temp |= ~0x1ff;
+	} else
+		actual_temp = temp & 0xff;
 
-	return actual_temp * 1000;
+	return (actual_temp * 1000) / 2;
 }
 
-u32 sumo_get_temp(struct radeon_device *rdev)
+int sumo_get_temp(struct radeon_device *rdev)
 {
 	u32 temp = RREG32(CG_THERMAL_STATUS) & 0xff;
-	u32 actual_temp = (temp >> 1) & 0xff;
+	int actual_temp = temp - 49;
 
 	return actual_temp * 1000;
 }

drivers/gpu/drm/radeon/r600.c

@@ -97,12 +97,16 @@ void r600_irq_disable(struct radeon_device *rdev);
 static void r600_pcie_gen2_enable(struct radeon_device *rdev);
 
 /* get temperature in millidegrees */
-u32 rv6xx_get_temp(struct radeon_device *rdev)
+int rv6xx_get_temp(struct radeon_device *rdev)
 {
 	u32 temp = (RREG32(CG_THERMAL_STATUS) & ASIC_T_MASK) >>
 		ASIC_T_SHIFT;
+	int actual_temp = temp & 0xff;
 
-	return temp * 1000;
+	if (temp & 0x100)
+		actual_temp -= 256;
+
+	return actual_temp * 1000;
 }
 
 void r600_pm_get_dynpm_state(struct radeon_device *rdev)

drivers/gpu/drm/radeon/radeon.h

@@ -179,10 +179,10 @@ void radeon_combios_get_power_modes(struct radeon_device *rdev);
 void radeon_atombios_get_power_modes(struct radeon_device *rdev);
 void radeon_atom_set_voltage(struct radeon_device *rdev, u16 level);
 void rs690_pm_info(struct radeon_device *rdev);
-extern u32 rv6xx_get_temp(struct radeon_device *rdev);
-extern u32 rv770_get_temp(struct radeon_device *rdev);
-extern u32 evergreen_get_temp(struct radeon_device *rdev);
-extern u32 sumo_get_temp(struct radeon_device *rdev);
+extern int rv6xx_get_temp(struct radeon_device *rdev);
+extern int rv770_get_temp(struct radeon_device *rdev);
+extern int evergreen_get_temp(struct radeon_device *rdev);
+extern int sumo_get_temp(struct radeon_device *rdev);
 
 /*
  * Fences.

drivers/gpu/drm/radeon/radeon_pm.c

@@ -430,7 +430,7 @@ static ssize_t radeon_hwmon_show_temp(struct device *dev,
 {
 	struct drm_device *ddev = pci_get_drvdata(to_pci_dev(dev));
 	struct radeon_device *rdev = ddev->dev_private;
-	u32 temp;
+	int temp;
 
 	switch (rdev->pm.int_thermal_type) {
 	case THERMAL_TYPE_RV6XX:

drivers/gpu/drm/radeon/rv770.c

@@ -78,18 +78,23 @@ u32 rv770_page_flip(struct radeon_device *rdev, int crtc_id, u64 crtc_base)
 }
 
 /* get temperature in millidegrees */
-u32 rv770_get_temp(struct radeon_device *rdev)
+int rv770_get_temp(struct radeon_device *rdev)
 {
 	u32 temp = (RREG32(CG_MULT_THERMAL_STATUS) & ASIC_T_MASK) >>
 		ASIC_T_SHIFT;
-	u32 actual_temp = 0;
-
-	if ((temp >> 9) & 1)
-		actual_temp = 0;
-	else
-		actual_temp = (temp >> 1) & 0xff;
-
-	return actual_temp * 1000;
+	int actual_temp;
+
+	if (temp & 0x400)
+		actual_temp = -256;
+	else if (temp & 0x200)
+		actual_temp = 255;
+	else if (temp & 0x100) {
+		actual_temp = temp & 0x1ff;
+		actual_temp |= ~0x1ff;
+	} else
+		actual_temp = temp & 0xff;
+
+	return (actual_temp * 1000) / 2;
 }
 
 void rv770_pm_misc(struct radeon_device *rdev)