drm/nouveau/pm: manual pwm fanspeed management for nv40+ boards

Exposes the following sysfs entries:
- fan0_input: read the rotational speed of the fan (poll a bit during 250ms)
- pwm0: set the pwm duty cycle
- pwm0_min/max: set the minimum/maximum pwm value

v2 (Ben Skeggs):
- nv50 pwm controller code removed in favour of other more complete code
- FAN_RPM -> FAN_SENSE
- merged FAN_SENSE readout into common code, not at all nv50-specific
- protected fanspeed changes with perflvl_wr
- formatting tidying
- added some comments where things are shaky

v3 (Martin Peres)
- ensure duty min/max from thermal table are sane

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Martin Peres <martin.peres@ensi-bourges.fr>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 2c8ebf6..432be65 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -521,6 +521,11 @@ struct nouveau_pm_memtimings {
 	int nr_timing;
 };
 
+struct nouveau_pm_fan {
+	u32 min_duty;
+	u32 max_duty;
+};
+
 struct nouveau_pm_engine {
 	struct nouveau_pm_voltage voltage;
 	struct nouveau_pm_level perflvl[NOUVEAU_PM_MAX_LEVEL];
@@ -528,6 +533,7 @@ struct nouveau_pm_engine {
 	struct nouveau_pm_memtimings memtimings;
 	struct nouveau_pm_temp_sensor_constants sensor_constants;
 	struct nouveau_pm_threshold_temp threshold_temp;
+	struct nouveau_pm_fan fan;
 	u32 pwm_divisor;
 
 	struct nouveau_pm_level boot;