drm/radeon/dpm: grab fan info from vbios

Required for fan control support.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -1623,6 +1623,11 @@ struct radeon_pm {
 	/* internal thermal controller on rv6xx+ */
 	enum radeon_int_thermal_type int_thermal_type;
 	struct device	        *int_hwmon_dev;
+	/* fan control parameters */
+	bool                    no_fan;
+	u8                      fan_pulses_per_revolution;
+	u8                      fan_min_rpm;
+	u8                      fan_max_rpm;
 	/* dpm */
 	bool                    dpm_enabled;
 	struct radeon_dpm       dpm;

drivers/gpu/drm/radeon/radeon_atombios.c

@@ -2248,6 +2248,14 @@ static void radeon_atombios_add_pplib_thermal_controller(struct radeon_device *r
 
 	/* add the i2c bus for thermal/fan chip */
 	if (controller->ucType > 0) {
+		if (controller->ucFanParameters & ATOM_PP_FANPARAMETERS_NOFAN)
+			rdev->pm.no_fan = true;
+		rdev->pm.fan_pulses_per_revolution =
+			controller->ucFanParameters & ATOM_PP_FANPARAMETERS_TACHOMETER_PULSES_PER_REVOLUTION_MASK;
+		if (rdev->pm.fan_pulses_per_revolution) {
+			rdev->pm.fan_min_rpm = controller->ucFanMinRPM;
+			rdev->pm.fan_max_rpm = controller->ucFanMaxRPM;
+		}
 		if (controller->ucType == ATOM_PP_THERMALCONTROLLER_RV6xx) {
 			DRM_INFO("Internal thermal controller %s fan control\n",
 				 (controller->ucFanParameters &