stm32/dac: Deinit all DACs on soft reset.

DAC timed functions continue to run after a soft reset cycle, using
collected memory in the case of write_timed.

ports/stm32/dac.c

@@ -131,6 +131,13 @@ STATIC void dac_deinit(uint32_t dac_channel) {
     #endif
 }
 
+void dac_deinit_all(void) {
+    dac_deinit(DAC_CHANNEL_1);
+    #if !defined(STM32L452xx)
+    dac_deinit(DAC_CHANNEL_2);
+    #endif
+}
+
 STATIC void dac_config_channel(uint32_t dac_channel, uint32_t trig, uint32_t outbuf) {
     DAC->CR &= ~(DAC_CR_EN1 << dac_channel);
     uint32_t cr_off = DAC_CR_DMAEN1 | DAC_CR_MAMP1 | DAC_CR_WAVE1 | DAC_CR_TSEL1 | DAC_CR_TEN1;

ports/stm32/dac.h

@@ -28,4 +28,6 @@
 
 extern const mp_obj_type_t pyb_dac_type;
 
+void dac_deinit_all(void);
+
 #endif // MICROPY_INCLUDED_STM32_DAC_H

ports/stm32/main.c

@@ -654,6 +654,9 @@ soft_reset_exit:
     #if MICROPY_HW_ENABLE_CAN
     can_deinit_all();
     #endif
+    #if MICROPY_HW_ENABLE_DAC
+    dac_deinit_all();
+    #endif
     machine_deinit();
 
     #if MICROPY_PY_THREAD