circuitpython/ports/nrf/modules/machine/spi.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
 * Copyright (c) 2016 - 2018 Glenn Ruben Bakke
 * Copyright (c) 2018 Ayke van Laethem
 *
 * 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 <string.h>

#include "py/runtime.h"

#if MICROPY_PY_MACHINE_HW_SPI

#include "py/nlr.h"
#include "py/mphal.h"
#include "extmod/machine_spi.h"
#include "pin.h"
#include "genhdr/pins.h"
#include "spi.h"
#if NRFX_SPI_ENABLED
#include "nrfx_spi.h"
#else
#include "nrfx_spim.h"
#endif

/// \moduleref machine
/// \class SPI - a controller-driven serial protocol
///
/// SPI is a serial protocol that is driven by a controller.  At the physical level
/// there are 3 lines: SCK, MOSI, MISO.
///
/// See usage model of I2C; SPI is very similar.  Main difference is
/// parameters to init the SPI bus:
///
///     from machine import SPI
///     spi = SPI(1, baudrate=600000, polarity=1, phase=0, crc=0x7)
///
/// Polarity can be
/// 0 or 1, and is the level the idle clock line sits at.  Phase can be 0 or 1
/// to sample data on the first or second clock edge respectively.  Crc can be
/// None for no CRC, or a polynomial specifier.
///
/// Additional method for SPI:
///
///     data = spi.send_recv(b'1234')        # send 4 bytes and receive 4 bytes
///     buf = bytearray(4)
///     spi.send_recv(b'1234', buf)          # send 4 bytes and receive 4 into buf
///     spi.send_recv(buf, buf)              # send/recv 4 bytes from/to buf

#if NRFX_SPIM_ENABLED

#define nrfx_spi_t                  nrfx_spim_t
#define nrfx_spi_config_t           nrfx_spim_config_t
#define nrfx_spi_xfer_desc_t        nrfx_spim_xfer_desc_t

#define NRFX_SPI_PIN_NOT_USED       NRFX_SPIM_PIN_NOT_USED
#define NRFX_SPI_INSTANCE           NRFX_SPIM_INSTANCE
#define NRF_SPI_BIT_ORDER_LSB_FIRST NRF_SPIM_BIT_ORDER_LSB_FIRST
#define NRF_SPI_BIT_ORDER_MSB_FIRST NRF_SPIM_BIT_ORDER_MSB_FIRST
#define NRF_SPI_MODE_0              NRF_SPIM_MODE_0
#define NRF_SPI_MODE_1              NRF_SPIM_MODE_1
#define NRF_SPI_MODE_2              NRF_SPIM_MODE_2
#define NRF_SPI_MODE_3              NRF_SPIM_MODE_3
#define NRF_SPI_FREQ_125K           NRF_SPIM_FREQ_125K
#define NRF_SPI_FREQ_250K           NRF_SPIM_FREQ_250K
#define NRF_SPI_FREQ_500K           NRF_SPIM_FREQ_500K
#define NRF_SPI_FREQ_1M             NRF_SPIM_FREQ_1M
#define NRF_SPI_FREQ_2M             NRF_SPIM_FREQ_2M
#define NRF_SPI_FREQ_4M             NRF_SPIM_FREQ_4M
#define NRF_SPI_FREQ_8M             NRF_SPIM_FREQ_8M

#define nrfx_spi_init               nrfx_spim_init
#define nrfx_spi_uninit             nrfx_spim_uninit
#define nrfx_spi_xfer               nrfx_spim_xfer

#endif // NRFX_SPIM_ENABLED

typedef struct _machine_hard_spi_obj_t {
    mp_obj_base_t       base;
    const nrfx_spi_t   * p_spi;    // Driver instance
    nrfx_spi_config_t  * p_config; // pointer to volatile part
} machine_hard_spi_obj_t;

STATIC const nrfx_spi_t machine_spi_instances[] = {
    NRFX_SPI_INSTANCE(0),
    NRFX_SPI_INSTANCE(1),
#if defined(NRF52_SERIES)
    NRFX_SPI_INSTANCE(2),
#if defined(NRF52840_XXAA) && NRFX_SPIM_ENABLED
    NRFX_SPI_INSTANCE(3),
#endif // NRF52840_XXAA && NRFX_SPIM_ENABLED
#endif // NRF52_SERIES
};

STATIC nrfx_spi_config_t configs[MP_ARRAY_SIZE(machine_spi_instances)];

STATIC const machine_hard_spi_obj_t machine_hard_spi_obj[] = {
    {{&machine_spi_type}, .p_spi = &machine_spi_instances[0], .p_config = &configs[0]},
    {{&machine_spi_type}, .p_spi = &machine_spi_instances[1], .p_config = &configs[1]},
#if defined(NRF52_SERIES)
    {{&machine_spi_type}, .p_spi = &machine_spi_instances[2], .p_config = &configs[2]},
#if defined(NRF52840_XXAA) && NRFX_SPIM_ENABLED
    {{&machine_spi_type}, .p_spi = &machine_spi_instances[3], .p_config = &configs[3]},
#endif // NRF52840_XXAA && NRFX_SPIM_ENABLED
#endif // NRF52_SERIES
};

void spi_init0(void) {
}

STATIC int spi_find(mp_obj_t id) {
    if (mp_obj_is_str(id)) {
        // given a string id
        const char *port = mp_obj_str_get_str(id);
        if (0) {
        #ifdef MICROPY_HW_SPI0_NAME
        } else if (strcmp(port, MICROPY_HW_SPI0_NAME) == 0) {
            return 1;
        #endif
        }
        mp_raise_ValueError(MP_ERROR_TEXT("SPI doesn't exist"));
    } else {
        // given an integer id
        int spi_id = mp_obj_get_int(id);
        if (spi_id >= 0 && spi_id < MP_ARRAY_SIZE(machine_hard_spi_obj)) {
            return spi_id;
        }
        mp_raise_ValueError(MP_ERROR_TEXT("SPI doesn't exist"));
    }
}

void spi_transfer(const machine_hard_spi_obj_t * self, size_t len, const void * src, void * dest) {
    nrfx_spi_xfer_desc_t xfer_desc = {
        .p_tx_buffer = src,
        .tx_length   = len,
        .p_rx_buffer = dest,
        .rx_length   = len
    };

    nrfx_spi_xfer(self->p_spi, &xfer_desc, 0);
}

/******************************************************************************/
/* MicroPython bindings for machine API                                       */

// for make_new
enum {
    ARG_NEW_id,
    ARG_NEW_baudrate,
    ARG_NEW_polarity,
    ARG_NEW_phase,
    ARG_NEW_bits,
    ARG_NEW_firstbit,
    ARG_NEW_sck,
    ARG_NEW_mosi,
    ARG_NEW_miso
};

// for init
enum {
    ARG_INIT_baudrate,
    ARG_INIT_polarity,
    ARG_INIT_phase,
    ARG_INIT_bits,
    ARG_INIT_firstbit
};

STATIC mp_obj_t machine_hard_spi_make_new(mp_arg_val_t *args);
STATIC void machine_hard_spi_init(mp_obj_t self, mp_arg_val_t *args);
STATIC void machine_hard_spi_deinit(mp_obj_t self);

/* common code for both soft and hard implementations *************************/

STATIC mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_id,       MP_ARG_OBJ, {.u_obj = MP_OBJ_NEW_SMALL_INT(-1)} },
        { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 1000000} },
        { MP_QSTR_polarity, MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_phase,    MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_bits,     MP_ARG_INT, {.u_int = 8} },
        { MP_QSTR_firstbit, MP_ARG_INT, {.u_int = 0 /* SPI_FIRSTBIT_MSB */} },
        { MP_QSTR_sck,      MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_mosi,     MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_miso,     MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    };

    // parse args
    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);

    if (args[ARG_NEW_id].u_obj == MP_OBJ_NEW_SMALL_INT(-1)) {
        // TODO: implement soft SPI
        // return machine_soft_spi_make_new(args);
        return mp_const_none;
    } else {
        // hardware peripheral id given
        return machine_hard_spi_make_new(args);
    }
}

STATIC mp_obj_t machine_spi_init(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 1000000} },
        { MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_bits,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 8} },
        { MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
    };

    // parse args
    mp_obj_t self = pos_args[0];
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

    // dispatch to specific implementation
    if (mp_obj_get_type(self) == &machine_spi_type) {
        machine_hard_spi_init(self, args);
    }

    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(machine_spi_init_obj, 1, machine_spi_init);

STATIC mp_obj_t machine_spi_deinit(mp_obj_t self) {
    // dispatch to specific implementation
    if (mp_obj_get_type(self) == &machine_spi_type) {
        machine_hard_spi_deinit(self);
    }
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_spi_deinit_obj, machine_spi_deinit);

STATIC const mp_rom_map_elem_t machine_spi_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_spi_init_obj) },
    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_spi_deinit_obj) },

    { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_machine_spi_read_obj) },
    { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_machine_spi_readinto_obj) },
    { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_machine_spi_write_obj) },
    { MP_ROM_QSTR(MP_QSTR_write_readinto), MP_ROM_PTR(&mp_machine_spi_write_readinto_obj) },

    { MP_ROM_QSTR(MP_QSTR_MSB), MP_ROM_INT(NRF_SPI_BIT_ORDER_MSB_FIRST) },
    { MP_ROM_QSTR(MP_QSTR_LSB), MP_ROM_INT(NRF_SPI_BIT_ORDER_LSB_FIRST) },
};

STATIC MP_DEFINE_CONST_DICT(machine_spi_locals_dict, machine_spi_locals_dict_table);

/* code for hard implementation ***********************************************/

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(%u)", self->p_spi->drv_inst_idx);
}

STATIC mp_obj_t machine_hard_spi_make_new(mp_arg_val_t *args) {
    // get static peripheral object
    int spi_id = spi_find(args[ARG_NEW_id].u_obj);
    const machine_hard_spi_obj_t *self = &machine_hard_spi_obj[spi_id];

    // here we would check the sck/mosi/miso pins and configure them
    if (args[ARG_NEW_sck].u_obj != MP_OBJ_NULL
        && args[ARG_NEW_mosi].u_obj != MP_OBJ_NULL
        && args[ARG_NEW_miso].u_obj != MP_OBJ_NULL) {

        self->p_config->sck_pin  = mp_hal_get_pin_obj(args[ARG_NEW_sck].u_obj)->pin;
        self->p_config->mosi_pin = mp_hal_get_pin_obj(args[ARG_NEW_mosi].u_obj)->pin;
        self->p_config->miso_pin = mp_hal_get_pin_obj(args[ARG_NEW_miso].u_obj)->pin;
    } else {
        self->p_config->sck_pin  = MICROPY_HW_SPI0_SCK;
        self->p_config->mosi_pin = MICROPY_HW_SPI0_MOSI;
        self->p_config->miso_pin = MICROPY_HW_SPI0_MISO;
    }

    // Manually trigger slave select from upper layer.
    self->p_config->ss_pin = NRFX_SPI_PIN_NOT_USED;

#ifdef NRF51
    self->p_config->irq_priority = 3;
#else
    self->p_config->irq_priority = 6;
#endif

    mp_obj_t self_obj = MP_OBJ_FROM_PTR(self);
    machine_hard_spi_init(self_obj, &args[1]); // Skip instance id param.

    return self_obj;
}

STATIC void machine_hard_spi_init(mp_obj_t self_in, mp_arg_val_t *args) {

    const machine_hard_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);

    int baudrate = args[ARG_INIT_baudrate].u_int;

    if (baudrate <= 125000) {
        self->p_config->frequency = NRF_SPI_FREQ_125K;
    } else if (baudrate <= 250000) {
        self->p_config->frequency = NRF_SPI_FREQ_250K;
    } else if (baudrate <= 500000) {
        self->p_config->frequency = NRF_SPI_FREQ_500K;
    } else if (baudrate <= 1000000) {
        self->p_config->frequency = NRF_SPI_FREQ_1M;
    } else if (baudrate <= 2000000) {
        self->p_config->frequency = NRF_SPI_FREQ_2M;
    } else if (baudrate <= 4000000) {
        self->p_config->frequency = NRF_SPI_FREQ_4M;
    } else if (baudrate <= 8000000) {
        self->p_config->frequency = NRF_SPI_FREQ_8M;
#if defined(NRF52840_XXAA) && NRFX_SPIM_ENABLED
    } else if (baudrate <= 16000000) {
        self->p_config->frequency = NRF_SPIM_FREQ_16M;
    } else if (baudrate <= 32000000) {
        self->p_config->frequency = NRF_SPIM_FREQ_32M;
#endif // NRF52840_XXAA && NRFX_SPIM_ENABLED
    } else { // Default
        self->p_config->frequency = NRF_SPI_FREQ_1M;
    }

    // Active high
    if (args[ARG_INIT_polarity].u_int == 0) {
        if (args[ARG_INIT_phase].u_int == 0) {
            // First clock edge
            self->p_config->mode = NRF_SPI_MODE_0;
        } else {
            // Second clock edge
            self->p_config->mode = NRF_SPI_MODE_1;
        }
    // Active low
    } else {
        if (args[ARG_INIT_phase].u_int == 0) {
            // First clock edge
            self->p_config->mode = NRF_SPI_MODE_2;
        } else {
            // Second clock edge
            self->p_config->mode = NRF_SPI_MODE_3;
        }
    }

    self->p_config->orc  = 0xFF; // Overrun character
    self->p_config->bit_order = (args[ARG_INIT_firstbit].u_int == 0) ? NRF_SPI_BIT_ORDER_MSB_FIRST : NRF_SPI_BIT_ORDER_LSB_FIRST;

    // Set context to this instance of SPI
    nrfx_err_t err_code = nrfx_spi_init(self->p_spi, self->p_config, NULL, (void *)self);

    if (err_code == NRFX_ERROR_INVALID_STATE) {
        // Instance already initialized, deinitialize first.
        nrfx_spi_uninit(self->p_spi);
        // Initialize again.
        nrfx_spi_init(self->p_spi, self->p_config, NULL, (void *)self);
    }
}

STATIC void machine_hard_spi_deinit(mp_obj_t self_in) {
    const machine_hard_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
    nrfx_spi_uninit(self->p_spi);
}

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


STATIC mp_obj_t mp_machine_spi_read(size_t n_args, const mp_obj_t *args) {
    vstr_t vstr;
    vstr_init_len(&vstr, mp_obj_get_int(args[1]));
    memset(vstr.buf, n_args == 3 ? mp_obj_get_int(args[2]) : 0, vstr.len);
    spi_transfer(args[0], vstr.len, vstr.buf, vstr.buf);
    return mp_obj_new_bytes_from_vstr(&vstr);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_read_obj, 2, 3, mp_machine_spi_read);

STATIC mp_obj_t mp_machine_spi_readinto(size_t n_args, const mp_obj_t *args) {
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
    memset(bufinfo.buf, n_args == 3 ? mp_obj_get_int(args[2]) : 0, bufinfo.len);
    spi_transfer(args[0], bufinfo.len, bufinfo.buf, bufinfo.buf);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_readinto_obj, 2, 3, mp_machine_spi_readinto);

STATIC mp_obj_t mp_machine_spi_write(mp_obj_t self, mp_obj_t wr_buf) {
    mp_buffer_info_t src;
    mp_get_buffer_raise(wr_buf, &src, MP_BUFFER_READ);
    spi_transfer(self, src.len, (const uint8_t*)src.buf, NULL);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(mp_machine_spi_write_obj, mp_machine_spi_write);

STATIC mp_obj_t mp_machine_spi_write_readinto(mp_obj_t self, mp_obj_t wr_buf, mp_obj_t rd_buf) {
    mp_buffer_info_t src;
    mp_get_buffer_raise(wr_buf, &src, MP_BUFFER_READ);
    mp_buffer_info_t dest;
    mp_get_buffer_raise(rd_buf, &dest, MP_BUFFER_WRITE);
    if (src.len != dest.len) {
        mp_raise_ValueError(MP_ERROR_TEXT("buffers must be the same length"));
    }
    spi_transfer(self, src.len, src.buf, dest.buf);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_3(mp_machine_spi_write_readinto_obj, mp_machine_spi_write_readinto);


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

MP_DEFINE_CONST_OBJ_TYPE(
    machine_spi_type,
    MP_QSTR_SPI,
    MP_TYPE_FLAG_NONE,
    make_new, machine_spi_make_new,
    print, machine_hard_spi_print,
    protocol, &machine_hard_spi_p,
    locals_dict, &machine_spi_locals_dict
    );

#endif // MICROPY_PY_MACHINE_HW_SPI