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>

1 files changed, 14 insertions, 9 deletions

diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 491dc9000655..2211a323db41 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/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)