thermal: pwm-fan: Add tach feedback support

Why?
The current implementation of the pwm-fan driver only writes
a pwm value to the HW when requested. There is no tachometer
rpm read back to check if the thermal performance is as
expected. This change aims to add the rpm offsets necessary
to maintain the desired fan rpm.

How?
A new work queue is added which gets the pwm fan rpm and checks
the same for a rpm diff tolerance value. In case the tolerance
value is exceeded, the next pwm corresponding to the next rpm
ramp index is written to the pwm controller.

Bug 200646929

Change-Id: Iff780a7edf98ca457ace10079149925adf06189d
Signed-off-by: Mantravadi Karthik <mkarthik@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2369412
Tested-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: Sandipan Patra <spatra@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 33 insertions, 1 deletions

diff --git a/include/linux/therm_est.h b/include/linux/therm_est.h
index 6cca50946..fa1ea7ffc 100644
--- a/include/linux/therm_est.h
+++ b/include/linux/therm_est.h
@@ -1,7 +1,7 @@
 /*
  * include/linux/therm_est.h
  *
- * Copyright (c) 2010-2019, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2010-2020, NVIDIA CORPORATION.  All rights reserved.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -177,6 +177,22 @@ struct fan_dev_data {
         u64 last_irq;
         u64 old_irq;
 
+        struct device_node *of_node_tach;
+        bool use_tach_feedback;
+        int rpm_diff_tolerance;
+        int fan_rpm_target_hit_count;
+        int fan_rpm_ramp_index;
+        int next_target_rpm;
+        int fan_ramp_time_ms;
+        struct delayed_work fan_ramp_pwm_work;
+        struct delayed_work fan_ramp_rpm_work;
+        struct device *pwm_tach_dev;
+        struct mutex pwm_set;
+        bool fan_rpm_in_limits;
+        int rpm_valid_retry_delay;
+        int rpm_invalid_retry_delay;
+        int rpm_valid_retry_count;
+
         bool   continuous_gov;
 };
 
@@ -222,4 +238,20 @@ struct therm_fan_estimator {
 
         bool is_continuous_gov;
 };
+
+#if IS_ENABLED(CONFIG_GENERIC_PWM_TACHOMETER)
+int pwm_tach_capture_rpm(struct device *dev);
+struct device *pwm_get_tach_dev(void);
+#else
+static inline int pwm_tach_capture_rpm(struct device *dev)
+{
+        return 0;
+}
+
+static inline struct device *pwm_get_tach_dev(void)
+{
+        return NULL;
+}
+#endif
+
 #endif /* _LINUX_THERM_EST_H */