stm32/can: Add "auto_restart" option to constructor and init() method.

Author: dpgeorge

docs/library/pyb.CAN.rst

@@ -49,7 +49,7 @@ Class Methods
 Methods
 -------
 
-.. method:: CAN.init(mode, extframe=False, prescaler=100, \*, sjw=1, bs1=6, bs2=8)
+.. method:: CAN.init(mode, extframe=False, prescaler=100, \*, sjw=1, bs1=6, bs2=8, auto_restart=False)
 
    Initialise the CAN bus with the given parameters:
 
@@ -64,6 +64,8 @@ Methods
        it can be between 1 and 1024 inclusive
      - *bs2* defines the location of the transmit point in units of the time quanta;
        it can be between 1 and 16 inclusive
+     - *auto_restart* sets whether the controller will automatically try and restart
+       communications after entering the bus-off state
 
    The time quanta tq is the basic unit of time for the CAN bus.  tq is the CAN
    prescaler value divided by PCLK1 (the frequency of internal peripheral bus 1);

ports/stm32/can.c

@@ -307,34 +307,32 @@ STATIC void pyb_can_print(const mp_print_t *print, mp_obj_t self_in, mp_print_ki
     if (!self->is_enabled) {
         mp_printf(print, "CAN(%u)", self->can_id);
     } else {
-        mp_printf(print, "CAN(%u, CAN.", self->can_id);
         qstr mode;
         switch (self->can.Init.Mode) {
             case CAN_MODE_NORMAL: mode = MP_QSTR_NORMAL; break;
             case CAN_MODE_LOOPBACK: mode = MP_QSTR_LOOPBACK; break;
             case CAN_MODE_SILENT: mode = MP_QSTR_SILENT; break;
             case CAN_MODE_SILENT_LOOPBACK: default: mode = MP_QSTR_SILENT_LOOPBACK; break;
         }
-        mp_printf(print, "%q, extframe=", mode);
-        if (self->extframe) {
-            mode = MP_QSTR_True;
-        } else {
-            mode = MP_QSTR_False;
-        }
-        mp_printf(print, "%q)", mode);
+        mp_printf(print, "CAN(%u, CAN.%q, extframe=%q, auto_restart=%q)",
+            self->can_id,
+            mode,
+            self->extframe ? MP_QSTR_True : MP_QSTR_False,
+            (self->can.Instance->MCR & CAN_MCR_ABOM) ? MP_QSTR_True : MP_QSTR_False);
     }
 }
 
 // init(mode, extframe=False, prescaler=100, *, sjw=1, bs1=6, bs2=8)
 STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_mode, ARG_extframe, ARG_prescaler, ARG_sjw, ARG_bs1, ARG_bs2 };
+    enum { ARG_mode, ARG_extframe, ARG_prescaler, ARG_sjw, ARG_bs1, ARG_bs2, ARG_auto_restart };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_mode,         MP_ARG_REQUIRED | MP_ARG_INT,   {.u_int  = CAN_MODE_NORMAL} },
         { MP_QSTR_extframe,     MP_ARG_BOOL,                    {.u_bool = false} },
         { MP_QSTR_prescaler,    MP_ARG_INT,                     {.u_int  = 100} },
         { MP_QSTR_sjw,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 1} },
         { MP_QSTR_bs1,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 6} },
         { MP_QSTR_bs2,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 8} },
+        { MP_QSTR_auto_restart, MP_ARG_KW_ONLY | MP_ARG_BOOL,   {.u_bool = false} },
     };
 
     // parse args
@@ -352,7 +350,7 @@ STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, size_t n_args, const mp
     init->BS1 = ((args[ARG_bs1].u_int - 1) & 0xf) << 16;
     init->BS2 = ((args[ARG_bs2].u_int - 1) & 7) << 20;
     init->TTCM = DISABLE;
-    init->ABOM = DISABLE;
+    init->ABOM = args[ARG_auto_restart].u_bool ? ENABLE : DISABLE;
     init->AWUM = DISABLE;
     init->NART = DISABLE;
     init->RFLM = DISABLE;