esp8266: Implement software SPI class.

Supports speeds up to 500k baud, polarity=0/1, phase=0/1, and using any
pins.  Only supports MSB output at the moment.

6 files changed, 235 insertions, 0 deletions

diff --git a/esp8266/Makefile b/esp8266/Makefile
index 9bf6bc2c23..66337be035 100644
--- a/esp8266/Makefile
+++ b/esp8266/Makefile
@@ -62,6 +62,7 @@ SRC_C = \
 	modpybrtc.c \
 	modpybadc.c \
 	modpybi2c.c \
+	modpybspi.c \
 	modesp.c \
 	modnetwork.c \
 	modutime.c \
diff --git a/esp8266/esp8266.ld b/esp8266/esp8266.ld
index 26776682cd..84301959ed 100644
--- a/esp8266/esp8266.ld
+++ b/esp8266/esp8266.ld
@@ -133,6 +133,7 @@ SECTIONS
         *modpybpin.o(.literal*, .text*)
         *modpybrtc.o(.literal*, .text*)
         *modpybadc.o(.literal*, .text*)
+        *modpybspi.o(.literal*, .text*)
         *modesp.o(.literal* .text*)
         *modnetwork.o(.literal* .text*)
         *moduos.o(.literal* .text*)
diff --git a/esp8266/modmachine.c b/esp8266/modmachine.c
index 1d096a4d57..41f246993c 100644
--- a/esp8266/modmachine.c
+++ b/esp8266/modmachine.c
@@ -143,6 +143,7 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_Timer), MP_ROM_PTR(&esp_timer_type) },
     { MP_ROM_QSTR(MP_QSTR_Pin), MP_ROM_PTR(&pyb_pin_type) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&pyb_i2c_type) },
+    { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&pyb_spi_type) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(machine_module_globals, machine_module_globals_table);
diff --git a/esp8266/modpyb.h b/esp8266/modpyb.h
index e691805f98..7b8f887149 100644
--- a/esp8266/modpyb.h
+++ b/esp8266/modpyb.h
@@ -2,6 +2,7 @@ extern const mp_obj_type_t pyb_pin_type;
 extern const mp_obj_type_t pyb_adc_type;
 extern const mp_obj_type_t pyb_rtc_type;
 extern const mp_obj_type_t pyb_i2c_type;
+extern const mp_obj_type_t pyb_spi_type;
 
 typedef struct _pyb_pin_obj_t {
     mp_obj_base_t base;
diff --git a/esp8266/modpybspi.c b/esp8266/modpybspi.c
new file mode 100644
index 0000000000..70933e04dc
--- /dev/null
+++ b/esp8266/modpybspi.c
@@ -0,0 +1,217 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 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 <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+#include "ets_sys.h"
+#include "etshal.h"
+#include "ets_alt_task.h"
+
+#include "py/runtime.h"
+#include "py/stream.h"
+#include "modpyb.h"
+
+typedef struct _pyb_spi_obj_t {
+    mp_obj_base_t base;
+    uint32_t baudrate;
+    uint8_t polarity;
+    uint8_t phase;
+    pyb_pin_obj_t *sck;
+    pyb_pin_obj_t *mosi;
+    pyb_pin_obj_t *miso;
+} pyb_spi_obj_t;
+
+STATIC void mp_hal_spi_transfer(pyb_spi_obj_t *self, size_t src_len, const uint8_t *src_buf, size_t dest_len, uint8_t *dest_buf) {
+    // only MSB transfer is implemented
+    uint32_t delay_half = 500000 / self->baudrate + 1;
+    for (size_t i = 0; i < src_len || i < dest_len; ++i) {
+        uint8_t data_out;
+        if (src_len == 1) {
+            data_out = src_buf[0];
+        } else {
+            data_out = src_buf[i];
+        }
+        uint8_t data_in = 0;
+        for (int j = 0; j < 8; ++j, data_out <<= 1) {
+            pin_set(self->mosi->phys_port, (data_out >> 7) & 1);
+            if (self->phase == 0) {
+                ets_delay_us(delay_half);
+                pin_set(self->sck->phys_port, 1 - self->polarity);
+            } else {
+                pin_set(self->sck->phys_port, 1 - self->polarity);
+                ets_delay_us(delay_half);
+            }
+            data_in = (data_in << 1) | pin_get(self->miso->phys_port);
+            if (self->phase == 0) {
+                ets_delay_us(delay_half);
+                pin_set(self->sck->phys_port, self->polarity);
+            } else {
+                pin_set(self->sck->phys_port, self->polarity);
+                ets_delay_us(delay_half);
+            }
+        }
+        if (dest_len != 0) {
+            dest_buf[i] = data_in;
+        }
+        // make sure pending tasks have a chance to run
+        ets_loop_iter();
+    }
+}
+
+/******************************************************************************/
+// MicroPython bindings for SPI
+
+STATIC void pyb_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    pyb_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_printf(print, "SPI(baudrate=%u, polarity=%u, phase=%u, sck=%u, mosi=%u, miso=%u)",
+        self->baudrate, self->polarity, self->phase, self->sck->phys_port, self->mosi->phys_port, self->miso->phys_port);
+}
+
+STATIC void pyb_spi_init_helper(pyb_spi_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_sck, ARG_mosi, ARG_miso };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_polarity, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_phase, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_miso, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    if (args[ARG_baudrate].u_int != -1) {
+        self->baudrate = args[ARG_baudrate].u_int;
+    }
+    if (args[ARG_polarity].u_int != -1) {
+        self->polarity = args[ARG_polarity].u_int;
+    }
+    if (args[ARG_phase].u_int != -1) {
+        self->phase = args[ARG_phase].u_int;
+    }
+    if (args[ARG_sck].u_obj != MP_OBJ_NULL) {
+        self->sck = mp_obj_get_pin_obj(args[ARG_sck].u_obj);
+    }
+    if (args[ARG_mosi].u_obj != MP_OBJ_NULL) {
+        self->mosi = mp_obj_get_pin_obj(args[ARG_mosi].u_obj);
+    }
+    if (args[ARG_miso].u_obj != MP_OBJ_NULL) {
+        self->miso = mp_obj_get_pin_obj(args[ARG_miso].u_obj);
+    }
+}
+
+STATIC mp_obj_t pyb_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, true);
+    pyb_spi_obj_t *self = m_new_obj(pyb_spi_obj_t);
+    self->base.type = &pyb_spi_type;
+    // set defaults
+    self->baudrate = 500000;
+    self->polarity = 0;
+    self->phase = 0;
+    self->sck = NULL;
+    self->mosi = NULL;
+    self->miso = NULL;
+    mp_map_t kw_args;
+    mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
+    pyb_spi_init_helper(self, n_args, args, &kw_args);
+    return MP_OBJ_FROM_PTR(self);
+}
+
+STATIC mp_obj_t pyb_spi_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
+    pyb_spi_init_helper(args[0], n_args - 1, args + 1, kw_args);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_KW(pyb_spi_init_obj, 1, pyb_spi_init);
+
+STATIC mp_obj_t pyb_spi_read(size_t n_args, const mp_obj_t *args) {
+    pyb_spi_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    uint8_t write_byte = 0;
+    if (n_args == 3) {
+        write_byte = mp_obj_get_int(args[2]);
+    }
+    vstr_t vstr;
+    vstr_init_len(&vstr, mp_obj_get_int(args[1]));
+    mp_hal_spi_transfer(self, 1, &write_byte, vstr.len, (uint8_t*)vstr.buf);
+    return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_spi_read_obj, 2, 3, pyb_spi_read);
+
+STATIC mp_obj_t pyb_spi_readinto(size_t n_args, const mp_obj_t *args) {
+    pyb_spi_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
+    uint8_t write_byte = 0;
+    if (n_args == 3) {
+        write_byte = mp_obj_get_int(args[2]);
+    }
+    mp_hal_spi_transfer(self, 1, &write_byte, bufinfo.len, (uint8_t*)bufinfo.buf);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_spi_readinto_obj, 2, 3, pyb_spi_readinto);
+
+STATIC mp_obj_t pyb_spi_write(mp_obj_t self_in, mp_obj_t wr_buf_in) {
+    pyb_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_buffer_info_t src_buf;
+    mp_get_buffer_raise(wr_buf_in, &src_buf, MP_BUFFER_READ);
+    mp_hal_spi_transfer(self, src_buf.len, (const uint8_t*)src_buf.buf, 0, NULL);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(pyb_spi_write_obj, pyb_spi_write);
+
+STATIC mp_obj_t pyb_spi_write_readinto(mp_obj_t self_in, mp_obj_t wr_buf_in, mp_obj_t rd_buf_in) {
+    pyb_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_buffer_info_t src_buf;
+    mp_get_buffer_raise(wr_buf_in, &src_buf, MP_BUFFER_READ);
+    mp_buffer_info_t dest_buf;
+    mp_get_buffer_raise(rd_buf_in, &dest_buf, MP_BUFFER_WRITE);
+    if (src_buf.len != dest_buf.len) {
+        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "buffers must be the same length"));
+    }
+    mp_hal_spi_transfer(self, src_buf.len, (const uint8_t*)src_buf.buf, dest_buf.len, (uint8_t*)dest_buf.buf);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_3(pyb_spi_write_readinto_obj, pyb_spi_write_readinto);
+
+STATIC const mp_rom_map_elem_t pyb_spi_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_spi_init_obj) },
+    { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&pyb_spi_read_obj) },
+    { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&pyb_spi_readinto_obj) },
+    { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&pyb_spi_write_obj) },
+    { MP_ROM_QSTR(MP_QSTR_write_readinto), MP_ROM_PTR(&pyb_spi_write_readinto_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(pyb_spi_locals_dict, pyb_spi_locals_dict_table);
+
+const mp_obj_type_t pyb_spi_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_SPI,
+    .print = pyb_spi_print,
+    .make_new = pyb_spi_make_new,
+    .locals_dict = (mp_obj_dict_t*)&pyb_spi_locals_dict,
+};
diff --git a/esp8266/qstrdefsport.h b/esp8266/qstrdefsport.h
index 6f43784201..5c1cbfd85c 100644
--- a/esp8266/qstrdefsport.h
+++ b/esp8266/qstrdefsport.h
@@ -155,6 +155,20 @@ Q(buf)
 Q(addr)
 Q(n)
 
+// SPI
+Q(SPI)
+Q(init)
+Q(baudrate)
+Q(phase)
+Q(polarity)
+Q(sck)
+Q(mosi)
+Q(miso)
+Q(read)
+Q(readinto)
+Q(write)
+Q(write_readinto)
+
 // utime
 Q(utime)
 Q(localtime)