AP_HAL_ChibiOS: add support for alternate alarm PWM group

account for inverted alarms and build on boards without PWM
enable alarm based on pwm
shutdown alarm channel if using a different one

libraries/AP_HAL_ChibiOS/RCOutput.cpp

@@ -22,6 +22,7 @@
 #include <AP_BoardConfig/AP_BoardConfig.h>
 #include <AP_HAL/utility/RingBuffer.h>
 #include "GPIO.h"
+#include "Util.h"
 #include "hwdef/common/stm32_util.h"
 #include "hwdef/common/watchdog.h"
 #include <AP_InternalError/AP_InternalError.h>
@@ -80,6 +81,18 @@ void RCOutput::init()
             uint8_t chan = group.chan[j];
             if (SRV_Channels::is_GPIO(chan+chan_offset)) {
                 group.chan[j] = CHAN_DISABLED;
+            } else if (SRV_Channels::is_alarm(chan+chan_offset)
+                || SRV_Channels::is_alarm_inverted(chan+chan_offset)) {
+                // alarm takes the whole timer
+                group.ch_mask = 0;
+                group.current_mode = MODE_PWM_NONE;
+                for (uint8_t k = 0; k < 4; k++) {
+                    group.chan[k] = CHAN_DISABLED;
+                    group.pwm_cfg.channels[k].mode = PWM_OUTPUT_DISABLED;
+                }
+                ChibiOS::Util::from(hal.util)->toneAlarm_init(group.pwm_cfg, group.pwm_drv, j,
+                    SRV_Channels::is_alarm(chan+chan_offset));
+                break;
             }
 #endif
             if (group.chan[j] != CHAN_DISABLED) {

libraries/AP_HAL_ChibiOS/Util.cpp

@@ -29,7 +29,7 @@
 #include <AP_Common/ExpandingString.h>
 #include "sdcard.h"
 #include "shared_dma.h"
-#if defined(HAL_PWM_ALARM) || HAL_DSHOT_ALARM || HAL_CANMANAGER_ENABLED
+#if defined(HAL_PWM_ALARM) || HAL_DSHOT_ALARM || HAL_CANMANAGER_ENABLED || HAL_USE_PWM == TRUE
 #include <AP_Notify/AP_Notify.h>
 #endif
 #if HAL_ENABLE_SAVE_PERSISTENT_PARAMS
@@ -158,6 +158,8 @@ Util::safety_state Util::safety_switch_state(void)
 
 #ifdef HAL_PWM_ALARM
 struct Util::ToneAlarmPwmGroup Util::_toneAlarm_pwm_group = HAL_PWM_ALARM;
+#elif HAL_USE_PWM == TRUE
+struct Util::ToneAlarmPwmGroup Util::_toneAlarm_pwm_group = {};
 #endif
 
 uint8_t  Util::_toneAlarm_types = 0;
@@ -170,7 +172,7 @@ bool Util::toneAlarm_init(uint8_t types)
 #endif
     _toneAlarm_types = types;
 
-#if !defined(HAL_PWM_ALARM) && !HAL_DSHOT_ALARM && !HAL_CANMANAGER_ENABLED
+#if HAL_USE_PWM != TRUE && !HAL_DSHOT_ALARM && !HAL_CANMANAGER_ENABLED
     // Nothing to do
     return false;
 #else
@@ -178,9 +180,26 @@ bool Util::toneAlarm_init(uint8_t types)
 #endif
 }
 
-void Util::toneAlarm_set_buzzer_tone(float frequency, float volume, uint32_t duration_ms)
+#if HAL_USE_PWM == TRUE
+bool Util::toneAlarm_init(const PWMConfig& pwm_cfg, PWMDriver* pwm_drv, pwmchannel_t chan, bool active_high)
 {
 #ifdef HAL_PWM_ALARM
+    pwmStop(_toneAlarm_pwm_group.pwm_drv);
+#endif
+    _toneAlarm_pwm_group.pwm_cfg = pwm_cfg;
+    _toneAlarm_pwm_group.pwm_drv = pwm_drv;
+    _toneAlarm_pwm_group.pwm_cfg.period = 1000;
+    _toneAlarm_pwm_group.pwm_cfg.channels[chan].mode = active_high ? PWM_OUTPUT_ACTIVE_HIGH : PWM_OUTPUT_ACTIVE_LOW;
+    _toneAlarm_pwm_group.chan = chan;
+    pwmStart(_toneAlarm_pwm_group.pwm_drv, &_toneAlarm_pwm_group.pwm_cfg);
+    return true;
+}
+#endif
+
+void Util::toneAlarm_set_buzzer_tone(float frequency, float volume, uint32_t duration_ms)
+{
+#if HAL_USE_PWM == TRUE
+    if (_toneAlarm_pwm_group.pwm_drv != nullptr) {
         if (is_zero(frequency) || is_zero(volume)) {
             pwmDisableChannel(_toneAlarm_pwm_group.pwm_drv, _toneAlarm_pwm_group.chan);
         } else {
@@ -189,7 +208,8 @@ void Util::toneAlarm_set_buzzer_tone(float frequency, float volume, uint32_t dur
 
             pwmEnableChannel(_toneAlarm_pwm_group.pwm_drv, _toneAlarm_pwm_group.chan, roundf(volume*_toneAlarm_pwm_group.pwm_cfg.frequency/frequency)/2);
         }
-#endif // HAL_PWM_ALARM
+    }
+#endif // HAL_USE_PWM
 #if HAL_DSHOT_ALARM
     // don't play the motors while flying
     if (!(_toneAlarm_types & AP_Notify::Notify_Buzz_DShot) || get_soft_armed() || hal.rcout->get_dshot_esc_type() != RCOutput::DSHOT_ESC_BLHELI) {

libraries/AP_HAL_ChibiOS/Util.h

@@ -60,6 +60,9 @@ public:
     bool get_system_id_unformatted(uint8_t buf[], uint8_t &len) override;
 
     bool toneAlarm_init(uint8_t types) override;
+#if HAL_USE_PWM == TRUE
+    bool toneAlarm_init(const PWMConfig& pwm_cfg, PWMDriver* pwm_drv, pwmchannel_t chan, bool active_high);
+#endif
     void toneAlarm_set_buzzer_tone(float frequency, float volume, uint32_t duration_ms) override;
     static uint8_t _toneAlarm_types;
 
@@ -104,7 +107,7 @@ public:
     void set_soft_armed(const bool b) override;
 
 private:
-#ifdef HAL_PWM_ALARM
+#if HAL_USE_PWM == TRUE
     struct ToneAlarmPwmGroup {
         pwmchannel_t chan;
         PWMConfig pwm_cfg;

libraries/AP_HAL_ChibiOS/hwdef/KakuteH7Mini/hwdef.dat

@@ -38,6 +38,7 @@ PC13 BUZZER OUTPUT LOW PULLDOWN GPIO(80)
 define HAL_BUZZER_PIN 80
 define HAL_BUZZER_ON 1
 define HAL_BUZZER_OFF 0
+define HAL_PWM_ALT_ALARM
 
 # PA10 IO-debug-console
 PA11 OTG_FS_DM OTG1