extmod: Add machine.bitstream.

This is a generic API for synchronously bit-banging data on a pin.

Initially this adds a single supported encoding, which supports controlling
WS2812 LEDs.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

py/mpconfig.h

@@ -1470,6 +1470,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_MACHINE (0)
 #endif
 
+// Whether to include: bitstream
+#ifndef MICROPY_PY_MACHINE_BITSTREAM
+#define MICROPY_PY_MACHINE_BITSTREAM (0)
+#endif
+
 // Whether to include: time_pulse_us
 #ifndef MICROPY_PY_MACHINE_PULSE
 #define MICROPY_PY_MACHINE_PULSE (0)

py/py.mk

@@ -184,6 +184,7 @@ PY_EXTMOD_O_BASENAME = \
 	extmod/moducryptolib.o \
 	extmod/modubinascii.o \
 	extmod/virtpin.o \
+	extmod/machine_bitstream.o \
 	extmod/machine_mem.o \
 	extmod/machine_pinbase.o \
 	extmod/machine_signal.o \