drm/radeon/kms: add support for internal thermal sensors (v3)

rv6xx/rv7xx/evergreen families supported; older asics did
not have an internal thermal sensor.

Note, not all oems use the internal thermal sensor, so it's
only exposed in cases where it is used.

Note also, that most laptops use an oem specific ACPI solution for
GPU thermal information rather than using the internal thermal
sensor directly.

v2: export millidegrees celsius, use hwmon device properly.
v3: fix Kconfig

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

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 057192acdd36..1b7da39cc587 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -39,6 +39,23 @@
 static void evergreen_gpu_init(struct radeon_device *rdev);
 void evergreen_fini(struct radeon_device *rdev);
 
+/* get temperature in millidegrees */
+u32 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)
+                actual_temp = 255;
+        else
+                actual_temp = (temp >> 1) & 0xff;
+
+        return actual_temp * 1000;
+}
+
 void evergreen_pm_misc(struct radeon_device *rdev)
 {
         int req_ps_idx = rdev->pm.requested_power_state_index;