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zephyr/machine_spi: Add support for hardware SPI.
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Adds support for hardware SPI to the zephyr port.  Consistent with other
ports, such as rp2 and stm32, we only implement the SPI protocol functions
(init and transfer).  Explicit sck/mosi/miso selection is not supported
and new SPI instances are initialized with default values.
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Julia-Hathaway authored and dpgeorge committed Jul 5, 2021
1 parent 8a5bfe4 commit 3966f67
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Showing 8 changed files with 233 additions and 0 deletions.
1 change: 1 addition & 0 deletions ports/zephyr/CMakeLists.txt
Expand Up @@ -38,6 +38,7 @@ set(MICROPY_SOURCE_PORT
main.c
help.c
machine_i2c.c
machine_spi.c
machine_pin.c
machine_uart.c
modbluetooth_zephyr.c
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9 changes: 9 additions & 0 deletions ports/zephyr/README.md
Expand Up @@ -15,6 +15,7 @@ Features supported at this time:
* `utime` module for time measurements and delays.
* `machine.Pin` class for GPIO control, with IRQ support.
* `machine.I2C` class for I2C control.
* `machine.SPI` class for SPI control.
* `usocket` module for networking (IPv4/IPv6).
* "Frozen modules" support to allow to bundle Python modules together
with firmware. Including complete applications, including with
Expand Down Expand Up @@ -135,6 +136,14 @@ Example of using I2C to scan for I2C slaves:
i2c = I2C("I2C_0")
i2c.scan()

Example of using SPI to write a buffer to the MOSI pin:

from machine import SPI

spi = SPI("SPI_0")
spi.init(baudrate=500000, polarity=1, phase=1, bits=8, firstbit=SPI.MSB)
spi.write(b'abcd')


Minimal build
-------------
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1 change: 1 addition & 0 deletions ports/zephyr/boards/frdm_k64f.conf
Expand Up @@ -3,6 +3,7 @@ CONFIG_NET_L2_ETHERNET=y

# Hardware features
CONFIG_I2C=y
CONFIG_SPI=y

# Sensor drivers
CONFIG_FXOS8700=y
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2 changes: 2 additions & 0 deletions ports/zephyr/boards/mimxrt685_evk_cm33.conf
@@ -0,0 +1,2 @@
# Hardware features
CONFIG_SPI=y
211 changes: 211 additions & 0 deletions ports/zephyr/machine_spi.c
@@ -0,0 +1,211 @@
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright 2021 NXP
*
* 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 <zephyr.h>
#include <drivers/spi.h>

#include "py/runtime.h"
#include "py/gc.h"
#include "py/mphal.h"
#include "py/mperrno.h"
#include "extmod/machine_spi.h"
#include "modmachine.h"

#if MICROPY_PY_MACHINE_SPI

#define DEFAULT_SPI_BAUDRATE (50000)
#define DEFAULT_SPI_POLARITY (0)
#define DEFAULT_SPI_PHASE (0)
#define DEFAULT_SPI_BITS (8)
#define DEFAULT_SPI_FIRSTBIT (SPI_TRANSFER_MSB)
#define SPI_LOOP (0) // For testing, enable loop mode by setting SPI_LOOP (1)

typedef struct _machine_hard_spi_obj_t {
mp_obj_base_t base;
const struct device *dev;
struct spi_config config;
} machine_hard_spi_obj_t;

STATIC void machine_hard_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_hard_spi_obj_t *self = self_in;
mp_printf(print, "SPI(%s, baudrate=%u, polarity=%u, phase=%u, bits=%u, firstbit=%s)",
self->dev->name,
self->config.frequency,
(self->config.operation & 0x2) >> 1,
(self->config.operation & 0x4) >> 2,
(self->config.operation & ~0x1F) >> 5,
((self->config.operation & 0x10) >> 4) == SPI_TRANSFER_MSB ? "MSB" : "LSB");
}

mp_obj_t machine_hard_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
enum {ARG_id, ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit, ARG_sck, ARG_mosi, ARG_miso};

static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_baudrate, MP_ARG_INT, {.u_int = DEFAULT_SPI_BAUDRATE} },
{ MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_POLARITY} },
{ MP_QSTR_phase, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_PHASE} },
{ MP_QSTR_bits, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_BITS} },
{ MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_FIRSTBIT} },
{ 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_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

const char *dev_name = mp_obj_str_get_str(args[ARG_id].u_obj);
const struct device *dev = device_get_binding(dev_name);

if (dev == NULL) {
mp_raise_ValueError(MP_ERROR_TEXT("device not found"));
}

if ((args[ARG_sck].u_obj != MP_OBJ_NULL) || (args[ARG_miso].u_obj != MP_OBJ_NULL) || (args[ARG_mosi].u_obj != MP_OBJ_NULL)) {
mp_raise_NotImplementedError(MP_ERROR_TEXT("explicit choice of sck/miso/mosi is not implemented"));
}

struct spi_config cfg = {
.frequency = args[ARG_baudrate].u_int,
.operation = (SPI_OP_MODE_MASTER |
args[ARG_polarity].u_int << 1 |
args[ARG_phase].u_int << 2 |
SPI_LOOP << 3 |
args[ARG_firstbit].u_int << 4 |
args[ARG_bits].u_int << 5 |
SPI_LINES_SINGLE),
.slave = 0,
.cs = NULL
};

machine_hard_spi_obj_t *self = m_new_obj(machine_hard_spi_obj_t);

self->base.type = &machine_hard_spi_type;
self->dev = dev;
self->config = cfg;

return MP_OBJ_FROM_PTR(self);
}

STATIC void machine_hard_spi_init(mp_obj_base_t *obj, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum {ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit};

static const mp_arg_t allowed_args[] = {
{ MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_phase, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_bits, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
};

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);

machine_hard_spi_obj_t *self = (machine_hard_spi_obj_t *)obj;

uint32_t baudrate;
uint16_t operation = self->config.operation;

if (args[ARG_baudrate].u_int != -1) {
baudrate = args[ARG_baudrate].u_int;
} else {
baudrate = self->config.frequency;
}

if (args[ARG_polarity].u_int != -1) {
operation = (operation & ~0x2) | (args[ARG_polarity].u_int << 1);
}

if (args[ARG_phase].u_int != -1) {
operation = (operation & ~0x4) | (args[ARG_phase].u_int << 2);
}

if (args[ARG_bits].u_int != -1) {
operation = (operation & 0x1F) | (args[ARG_bits].u_int << 5);
}

if (args[ARG_firstbit].u_int != -1) {
operation = (operation & ~0x10) | (args[ARG_firstbit].u_int << 4);
}

struct spi_config cfg = {
.frequency = baudrate,
.operation = operation,
.slave = 0,
.cs = NULL
};

self->config = cfg;
}

STATIC void machine_hard_spi_transfer(mp_obj_base_t *obj, size_t len, const uint8_t *src, uint8_t *dest) {
machine_hard_spi_obj_t *self = (machine_hard_spi_obj_t *)obj;

int ret;

struct spi_buf tx_bufs[1];
tx_bufs[0].buf = (uint8_t *)src;
tx_bufs[0].len = len;
const struct spi_buf_set tx = {
.buffers = tx_bufs,
.count = ARRAY_SIZE(tx_bufs)
};

struct spi_buf rx_bufs[1];
rx_bufs[0].buf = dest;
rx_bufs[0].len = len;
const struct spi_buf_set rx = {
.buffers = rx_bufs,
.count = ARRAY_SIZE(rx_bufs)
};

ret = spi_transceive(self->dev, &self->config, &tx, &rx);

if (ret < 0) {
mp_raise_OSError(-ret);
}
}

STATIC const mp_machine_spi_p_t machine_hard_spi_p = {
.init = machine_hard_spi_init,
.transfer = machine_hard_spi_transfer,
};

const mp_obj_type_t machine_hard_spi_type = {
{ &mp_type_type },
.name = MP_QSTR_SPI,
.print = machine_hard_spi_print,
.make_new = machine_hard_spi_make_new,
.protocol = &machine_hard_spi_p,
.locals_dict = (mp_obj_dict_t *)&mp_machine_spi_locals_dict,
};

#endif // MICROPY_PY_MACHINE_SPI
4 changes: 4 additions & 0 deletions ports/zephyr/modmachine.c
Expand Up @@ -36,6 +36,7 @@
#include "extmod/machine_signal.h"
#include "extmod/machine_pulse.h"
#include "extmod/machine_i2c.h"
#include "extmod/machine_spi.h"
#include "modmachine.h"

#if MICROPY_PY_MACHINE
Expand Down Expand Up @@ -70,6 +71,9 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
#if MICROPY_PY_MACHINE_I2C
{ MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&machine_hard_i2c_type) },
#endif
#if MICROPY_PY_MACHINE_SPI
{ MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&machine_hard_spi_type) },
#endif
{ MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&machine_uart_type) },
{ MP_ROM_QSTR(MP_QSTR_Pin), MP_ROM_PTR(&machine_pin_type) },
{ MP_ROM_QSTR(MP_QSTR_Signal), MP_ROM_PTR(&machine_signal_type) },
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1 change: 1 addition & 0 deletions ports/zephyr/modmachine.h
Expand Up @@ -5,6 +5,7 @@

extern const mp_obj_type_t machine_pin_type;
extern const mp_obj_type_t machine_hard_i2c_type;
extern const mp_obj_type_t machine_hard_spi_type;
extern const mp_obj_type_t machine_uart_type;

MP_DECLARE_CONST_FUN_OBJ_0(machine_info_obj);
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4 changes: 4 additions & 0 deletions ports/zephyr/mpconfigport.h
Expand Up @@ -29,6 +29,7 @@
#include "autoconf.h"
// Included here to get basic Zephyr environment (macros, etc.)
#include <zephyr.h>
#include <drivers/spi.h>

// Usually passed from Makefile
#ifndef MICROPY_HEAP_SIZE
Expand Down Expand Up @@ -62,6 +63,9 @@
#define MICROPY_PY_MICROPYTHON_MEM_INFO (1)
#define MICROPY_PY_MACHINE (1)
#define MICROPY_PY_MACHINE_I2C (1)
#define MICROPY_PY_MACHINE_SPI (1)
#define MICROPY_PY_MACHINE_SPI_MSB (SPI_TRANSFER_MSB)
#define MICROPY_PY_MACHINE_SPI_LSB (SPI_TRANSFER_LSB)
#define MICROPY_PY_MACHINE_PIN_MAKE_NEW mp_pin_make_new
#define MICROPY_MODULE_WEAK_LINKS (1)
#define MICROPY_PY_STRUCT (0)
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