zephyr: Add support for board override of fan duty adjustment logic

The generic logic has proven to not work well on whiterun.
In order to mitigate that, while not affecting everyone else,
a custom fan duty adjustment logic needs to be implemented.
The behavior is controlled with CONFIG_CUSTOM_FAN_DUTY_CONTROL,
which will be enabled on whiterun in a another patch.
Some structs has been moved to the fan header, so that they can be
accessed from the custom logic.

BUG=b:276577324
BRANCH=none
TEST=make try_build_boards

Change-Id: Iff31b6526be83b8b0165c4490bafe26f131e6c84
Signed-off-by: Kornel Dulęba <korneld@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4423152
Reviewed-by: Keith Short <keithshort@chromium.org>
(cherry picked from commit 9c8a27f107801953e4a3c9612aa74b45940ad148)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4459714
Commit-Queue: Chao Gui <chaogui@google.com>
Reviewed-by: Diana Z <dzigterman@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>

3 files changed, 83 insertions, 52 deletions

diff --git a/include/fan.h b/include/fan.h
index 25068a653b..29552e0e6a 100644
--- a/include/fan.h
+++ b/include/fan.h
@@ -10,6 +10,7 @@
 
 #include "config.h"
 
+#include <stdbool.h>
 #include <stdint.h>
 
 #ifdef CONFIG_ZEPHYR
@@ -29,6 +30,38 @@ BUILD_ASSERT(FAN_CH_COUNT == CONFIG_PLATFORM_EC_NUM_FANS);
 #endif /* CONFIG_PLATFORM_EC_FAN */
 #endif /* CONFIG_ZEPHYR */
 
+/**
+ * STOPPED means not spinning.
+ *
+ * When setting fan rpm, some implementations in chip layer (npcx and it83xx)
+ * is to adjust fan pwm duty steps by steps. In this period, fan_status will
+ * be marked as CHANGING. After change is done, fan_status will become LOCKED.
+ *
+ * In the period of changing pwm duty, if it's trying to increase/decrease duty
+ * even when duty is already in upper/lower bound. Then this action won't work,
+ * and fan_status will be marked as FRUSTRATED.
+ *
+ * For other implementations in chip layer (mchp), there is no
+ * changing period. So they don't have CHANGING status.
+ * Just return status as LOCKED in normal spinning case, return STOPPED when
+ * not spinning, return FRUSTRATED when the related flags (which is read from
+ * chip's register) is set.
+ */
+enum fan_status {
+	FAN_STATUS_STOPPED = 0,
+	FAN_STATUS_CHANGING = 1,
+	FAN_STATUS_LOCKED = 2,
+	FAN_STATUS_FRUSTRATED = 3
+};
+
+/* Fan mode */
+enum fan_mode {
+	/* FAN rpm mode */
+	FAN_RPM = 0,
+	/* FAN duty mode */
+	FAN_DUTY,
+};
+
 struct fan_conf {
 	unsigned int flags;
 	/* Hardware channel number (the meaning is chip-specific) */
@@ -53,6 +86,26 @@ struct fan_t {
 	const struct fan_rpm *rpm;
 };
 
+/* Fan status data structure */
+struct fan_data {
+	/* Fan mode */
+	enum fan_mode current_fan_mode;
+	/* Actual rpm */
+	int rpm_actual;
+	/* Previous rpm */
+	int rpm_pre;
+	/* Target rpm */
+	int rpm_target;
+	/* Fan config flags */
+	unsigned int flags;
+	/* Automatic fan status */
+	enum fan_status auto_status;
+	/* Current PWM duty cycle percentage */
+	int pwm_percent;
+	/* Whether the PWM channel is enabled */
+	bool pwm_enabled;
+};
+
 /* Values for .flags field */
 /*   Enable automatic RPM control using tach input */
 #define FAN_USE_RPM_MODE BIT(0)
@@ -167,29 +220,6 @@ int fan_get_rpm_target(int ch);
 /* Is the fan stalled when it shouldn't be? */
 int fan_is_stalled(int ch);
 
-/**
- * STOPPED means not spinning.
- *
- * When setting fan rpm, some implementations in chip layer (npcx and it83xx)
- * is to adjust fan pwm duty steps by steps. In this period, fan_status will
- * be marked as CHANGING. After change is done, fan_status will become LOCKED.
- *
- * In the period of changing pwm duty, if it's trying to increase/decrease duty
- * even when duty is already in upper/lower bound. Then this action won't work,
- * and fan_status will be marked as FRUSTRATED.
- *
- * For other implementations in chip layer (mchp), there is no
- * changing period. So they don't have CHANGING status.
- * Just return status as LOCKED in normal spinning case, return STOPPED when
- * not spinning, return FRUSTRATED when the related flags (which is read from
- * chip's register) is set.
- */
-enum fan_status {
-	FAN_STATUS_STOPPED = 0,
-	FAN_STATUS_CHANGING = 1,
-	FAN_STATUS_LOCKED = 2,
-	FAN_STATUS_FRUSTRATED = 3
-};
 enum fan_status fan_get_status(int ch);
 
 /* Initialize the HW according to the desired flags */
@@ -201,4 +231,20 @@ void fan_set_count(int count);
 
 int is_thermal_control_enabled(int idx);
 
+#ifdef CONFIG_ZEPHYR
+extern struct fan_data fan_data[];
+
+/**
+ * This function sets PWM duty based on target RPM.
+ *
+ * The target and current RPM values in fan_data entry that
+ * corresponds to selected fan has to be updated before this
+ * function is called.
+ *
+ * @param ch    Fan number (index into fan_data[] and fans[])
+ * Return       Fan status (see fan_status enum definition)
+ */
+enum fan_status board_override_fan_control_duty(int ch);
+#endif
+
 #endif /* __CROS_EC_FAN_H */
diff --git a/zephyr/Kconfig.temperature b/zephyr/Kconfig.temperature
index bd977b2832..84e65907e4 100644
--- a/zephyr/Kconfig.temperature
+++ b/zephyr/Kconfig.temperature
@@ -117,6 +117,14 @@ config PLATFORM_EC_CUSTOM_FAN_CONTROL
 	  Enable fan custom control to let projects define
 	  their own fan control mechanism by EC.
 
+config PLATFORM_EC_CUSTOM_FAN_DUTY_CONTROL
+	bool "Fan custom control support"
+	default n
+	help
+	  Enable fan duty custom control to let projects define
+	  their own fan duty control mechanism by implementing
+	  the routine board_override_fan_control_duty().
+
 if PLATFORM_EC_FAN
 
 config PLATFORM_EC_NUM_FANS
diff --git a/zephyr/shim/src/fan.c b/zephyr/shim/src/fan.c
index 9978e6f4ca..69c23fa9fd 100644
--- a/zephyr/shim/src/fan.c
+++ b/zephyr/shim/src/fan.c
@@ -62,34 +62,6 @@ DT_INST_FOREACH_CHILD(0, FAN_CONFIGS)
 
 const struct fan_t fans[FAN_CH_COUNT] = { DT_INST_FOREACH_CHILD(0, FAN_INST) };
 
-/* Fan mode */
-enum fan_mode {
-	/* FAN rpm mode */
-	FAN_RPM = 0,
-	/* FAN duty mode */
-	FAN_DUTY,
-};
-
-/* Fan status data structure */
-struct fan_data {
-	/* Fan mode */
-	enum fan_mode current_fan_mode;
-	/* Actual rpm */
-	int rpm_actual;
-	/* Previous rpm */
-	int rpm_pre;
-	/* Target rpm */
-	int rpm_target;
-	/* Fan config flags */
-	unsigned int flags;
-	/* Automatic fan status */
-	enum fan_status auto_status;
-	/* Current PWM duty cycle percentage */
-	int pwm_percent;
-	/* Whether the PWM channel is enabled */
-	bool pwm_enabled;
-};
-
 /* Data structure to define PWM and tachometer. */
 struct fan_config {
 	struct pwm_dt_spec pwm;
@@ -97,7 +69,7 @@ struct fan_config {
 	const struct device *tach;
 };
 
-static struct fan_data fan_data[FAN_CH_COUNT];
+struct fan_data fan_data[FAN_CH_COUNT];
 static const struct fan_config fan_config[FAN_CH_COUNT] = {
 	DT_INST_FOREACH_CHILD(0, FAN_CONTROL_INST)
 };
@@ -268,8 +240,13 @@ static void fan_tick_func_rpm(int ch)
 	/* Get actual rpm */
 	data->rpm_actual = fan_rpm(ch);
 
+	/* TODO: b/279132492 */
+#ifdef CONFIG_PLATFORM_EC_CUSTOM_FAN_DUTY_CONTROL
+	data->auto_status = board_override_fan_control_duty(ch);
+#else
 	/* Do smart fan stuff */
 	data->auto_status = fan_smart_control(ch);
+#endif
 }
 
 static void fan_tick_func_duty(int ch)