STM32 driver: CAN timing docs

libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp

@@ -298,6 +298,12 @@ int CanIface::computeTimings(const uavcan::uint32_t target_bitrate, Timings& out
 
     /*
      * Final validation
+     * Helpful Python:
+     * def sample_point_from_btr(x):
+     *     assert 0b0011110010000000111111000000000 & x == 0
+     *     ts2,ts1,brp = (BTR>>20)&7, (BTR>>16)&15, BTR&511
+     *     return (1+ts1+1)/(1+ts1+1+ts2+1)
+     *
      */
     if ((target_bitrate != (pclk / (prescaler * (1 + solution.bs1 + solution.bs2)))) || !solution.isValid())
     {