Move fan-specific PWM logic to fan module

Better define the scope of the tachometer variables by moving them to
the fan module. `fan_update_duty` is renamed to `fan_event` to reflect
that it handles more than just updating the PWM duties.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

src/board/system76/common/acpi.c

@@ -3,6 +3,7 @@
 #include <board/acpi.h>
 #include <board/battery.h>
 #include <board/dgpu.h>
+#include <board/fan.h>
 #include <board/gpio.h>
 #include <board/kbled.h>
 #include <board/lid.h>
@@ -162,13 +163,13 @@ uint8_t acpi_read(uint8_t addr) {
         ACPI_8(0xCC, sci_extra);
 
         ACPI_8(0xCE, FAN1_PWM);
-        ACPI_16(0xD0, pwm_tach0_rpm);
+        ACPI_16(0xD0, fan1_rpm);
 #if CONFIG_HAVE_DGPU
         ACPI_8(0xCD, dgpu_temp);
 #endif // CONFIG_HAVE_DGPU
 #ifdef FAN2_PWM
         ACPI_8(0xCF, FAN2_PWM);
-        ACPI_16(0xD2, pwm_tach1_rpm);
+        ACPI_16(0xD2, fan2_rpm);
 #endif // FAN2_PWM
 
 #if HAVE_LED_AIRPLANE_N

src/board/system76/common/fan.c

@@ -13,6 +13,18 @@ bool fan_max = false;
 static uint8_t last_fan1_duty = 0;
 static uint8_t last_fan2_duty = 0;
 
+uint16_t fan1_rpm = 0;
+uint16_t fan2_rpm = 0;
+
+#define TACH_FREQ (CONFIG_CLOCK_FREQ_KHZ * 1000UL)
+
+// Fan Speed (RPM) = 60 / (1/fs sec * {FnTMRR, FnRLRR} * P)
+// - n: 1 or 2
+// - P: the numbers of square pulses per revolution
+// - fs: sample rate (FreqEC / 128)
+// - {FnTMRR, FnTLRR} = 0000h: Fan Speed is zero
+#define TACH_TO_RPM(x) (60UL * TACH_FREQ / 128UL / 2UL / (x))
+
 #define FAN_POINT(T, D) { .temp = (int16_t)(T), .duty = PWM_DUTY(D) }
 
 #if SMOOTH_FANS != 0
@@ -219,33 +231,50 @@ static uint8_t fan_get_duty(const struct Fan *const fan, int16_t temp) {
     return duty;
 }
 
-void fan_update_duty(void) {
+static uint16_t fan_get_tach0_rpm(void) {
+    uint16_t rpm = (F1TMRR << 8) | F1TLRR;
+
+    if (rpm)
+        rpm = TACH_TO_RPM(rpm);
+
+    return rpm;
+}
+
+static uint16_t fan_get_tach1_rpm(void) {
+    uint16_t rpm = (F2TMRR << 8) | F2TLRR;
+
+    if (rpm)
+        rpm = TACH_TO_RPM(rpm);
+
+    return rpm;
+}
+
+void fan_event(void) {
 #if CONFIG_HAVE_DGPU
     int16_t sys_temp = MAX(peci_temp, dgpu_temp);
 #else
     int16_t sys_temp = peci_temp;
 #endif
 
-    uint8_t fan1_duty = fan_get_duty(&FAN1, sys_temp);
-#ifdef FAN2_PWM
-    uint8_t fan2_duty = fan_get_duty(&FAN2, sys_temp);
-#endif // FAN2_PWM
-
     // set FAN1 duty
+    uint8_t fan1_duty = fan_get_duty(&FAN1, sys_temp);
     if (fan1_duty != FAN1_PWM) {
         TRACE("FAN1 fan_duty_raw=%d\n", fan1_duty);
         last_fan1_duty = fan1_duty = fan_smooth(last_fan1_duty, fan1_duty);
         FAN1_PWM = fan_max ? MAX_FAN_SPEED : fan1_duty;
         TRACE("FAN1 fan_duty_smoothed=%d\n", fan1_duty);
     }
+    fan1_rpm = fan_get_tach0_rpm();
 
 #ifdef FAN2_PWM
     // set FAN2 duty
+    uint8_t fan2_duty = fan_get_duty(&FAN2, sys_temp);
     if (fan2_duty != FAN2_PWM) {
         TRACE("FAN2 fan_duty_raw=%d\n", fan2_duty);
         last_fan2_duty = fan2_duty = fan_smooth(last_fan2_duty, fan2_duty);
         FAN2_PWM = fan_max ? MAX_FAN_SPEED : fan2_duty;
         TRACE("FAN2 fan_duty_smoothed=%d\n", fan2_duty);
     }
+    fan2_rpm = fan_get_tach1_rpm();
 #endif
 }

src/board/system76/common/include/board/fan.h

@@ -44,7 +44,12 @@ struct Fan {
 
 extern bool fan_max;
 
+// NOTE: These are used instead of the functions directly for ACPI to prevent
+// double reads of the tachometer values.
+extern uint16_t fan1_rpm;
+extern uint16_t fan2_rpm;
+
 void fan_reset(void);
-void fan_update_duty(void);
+void fan_event(void);
 
 #endif // _BOARD_FAN_H

src/board/system76/common/include/board/pwm.h

@@ -3,15 +3,6 @@
 #ifndef _BOARD_PWM_H
 #define _BOARD_PWM_H
 
-#include <ec/pwm.h>
-
-// NOTE: These are used instead of the functions directly for ACPI to prevent
-// double reads of the tachometer values.
-extern int16_t pwm_tach0_rpm;
-extern int16_t pwm_tach1_rpm;
-
 void pwm_init(void);
-int16_t pwm_get_tach0_rpm(void);
-int16_t pwm_get_tach1_rpm(void);
 
 #endif // _BOARD_PWM_H

src/board/system76/common/main.c

@@ -137,13 +137,7 @@ void main(void) {
                 peci_read_temp();
                 dgpu_read_temp();
 
-                // Update fan speeds
-                fan_update_duty();
-
-                // NOTE: These values are reported to ACPI. Update them at the
-                // same interval as the fan duties.
-                pwm_tach0_rpm = pwm_get_tach0_rpm();
-                pwm_tach1_rpm = pwm_get_tach1_rpm();
+                fan_event();
             }
 
             // Only run the following once per interval

src/board/system76/common/pwm.c

@@ -1,20 +1,9 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
 #include <board/pwm.h>
+#include <ec/pwm.h>
 #include <common/macro.h>
 
-#define TACH_FREQ (CONFIG_CLOCK_FREQ_KHZ * 1000UL)
-
-// Fan Speed (RPM) = 60 / (1/fs sec * {FnTMRR, FnRLRR} * P)
-// - n: 1 or 2
-// - P: the numbers of square pulses per revolution
-// - fs: sample rate (FreqEC / 128)
-// - {FnTMRR, FnTLRR} = 0000h: Fan Speed is zero
-#define TACH_TO_RPM(x) (60UL * TACH_FREQ / 128UL / 2UL / (x))
-
-int16_t pwm_tach0_rpm = -1;
-int16_t pwm_tach1_rpm = -1;
-
 void pwm_init(void) {
     // Set T0CHSEL to TACH0A and T1CHSEL to TACH1A
     TSWCTLR = 0;
@@ -49,21 +38,3 @@ void pwm_init(void) {
     // Enable PWM
     ZTIER = BIT(1);
 }
-
-int16_t pwm_get_tach0_rpm(void) {
-    uint16_t rpm = (F1TMRR << 8) | F1TLRR;
-
-    if (rpm)
-        rpm = TACH_TO_RPM(rpm);
-
-    return rpm;
-}
-
-int16_t pwm_get_tach1_rpm(void) {
-    uint16_t rpm = (F2TMRR << 8) | F2TLRR;
-
-    if (rpm)
-        rpm = TACH_TO_RPM(rpm);
-
-    return rpm;
-}