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>

extmod/extmod.cmake

@@ -6,6 +6,7 @@ set(MICROPY_OOFATFS_DIR "${MICROPY_DIR}/lib/oofatfs")
 set(MICROPY_SOURCE_EXTMOD
     ${MICROPY_DIR}/shared/libc/abort_.c
     ${MICROPY_DIR}/shared/libc/printf.c
+    ${MICROPY_EXTMOD_DIR}/machine_bitstream.c
     ${MICROPY_EXTMOD_DIR}/machine_i2c.c
     ${MICROPY_EXTMOD_DIR}/machine_mem.c
     ${MICROPY_EXTMOD_DIR}/machine_pulse.c

extmod/machine_bitstream.c

@@ -0,0 +1,65 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Jim Mussared
+ * Copyright (c) 2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "py/mphal.h"
+#include "extmod/machine_bitstream.h"
+
+#if MICROPY_PY_MACHINE_BITSTREAM
+
+// Timing is a 4-tuple of (high_time_0, low_time_0, high_time_1, low_time_1)
+// suitable for driving WS2812.
+#define MICROPY_MACHINE_BITSTREAM_TYPE_HIGH_LOW (0)
+
+// machine.bitstream(pin, encoding, (timing), bytes)
+STATIC mp_obj_t machine_bitstream_(size_t n_args, const mp_obj_t *args) {
+    mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(args[0]);
+    int encoding = mp_obj_get_int(args[1]);
+
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[3], &bufinfo, MP_BUFFER_READ);
+
+    switch (encoding) {
+        case MICROPY_MACHINE_BITSTREAM_TYPE_HIGH_LOW: {
+            uint32_t timing_ns[4];
+            mp_obj_t *timing;
+            mp_obj_get_array_fixed_n(args[2], 4, &timing);
+            for (size_t i = 0; i < 4; ++i) {
+                timing_ns[i] = mp_obj_get_int(timing[i]);
+            }
+            machine_bitstream_high_low(pin, timing_ns, bufinfo.buf, bufinfo.len);
+            break;
+        }
+        default:
+            mp_raise_ValueError(MP_ERROR_TEXT("encoding"));
+    }
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bitstream_obj, 4, 4, machine_bitstream_);
+
+#endif // MICROPY_PY_MACHINE_BITSTREAM

extmod/machine_bitstream.h

@@ -0,0 +1,37 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Jim Mussared
+ * Copyright (c) 2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_EXTMOD_MACHINE_BITSTREAM_H
+#define MICROPY_INCLUDED_EXTMOD_MACHINE_BITSTREAM_H
+
+#include "py/obj.h"
+#include "py/mphal.h"
+
+void machine_bitstream_high_low(mp_hal_pin_obj_t pin, uint32_t *timing_ns, const uint8_t *buf, size_t len);
+
+MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bitstream_obj);
+
+#endif // MICROPY_INCLUDED_EXTMOD_MACHINE_BITSTREAM_H

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 \