text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2015-2017 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 "microbit/microbitdal.h"
  
  extern "C" {
  
  #include "py/runtime.h"
  #include "microbit/modmicrobit.h"
  
  typedef struct _microbit_i2c_obj_t {
      mp_obj_base_t base;
      MicroPythonI2C *i2c;
  } microbit_i2c_obj_t;
  
  STATIC mp_obj_t microbit_i2c_init(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
      static const mp_arg_t allowed_args[] = {
          { MP_QSTR_freq, MP_ARG_INT, {.u_int = 100000} },
          { MP_QSTR_sda, MP_ARG_OBJ, {.u_obj = mp_const_none } },
          { MP_QSTR_scl, MP_ARG_OBJ, {.u_obj = mp_const_none } },
      };
  
      // parse args
      microbit_i2c_obj_t *self = (microbit_i2c_obj_t*)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);
  
  
      PinName p_sda = I2C_SDA0;
      PinName p_scl = I2C_SCL0;
  
      if (args[1].u_obj != mp_const_none) {
          p_sda = (PinName)microbit_obj_get_pin_name(args[1].u_obj);
      }
      if (args[2].u_obj != mp_const_none) {
          p_scl = (PinName)microbit_obj_get_pin_name(args[2].u_obj);
      }
      self->i2c->set_pins(p_sda, p_scl);
  
      self->i2c->frequency(args[0].u_int);
  
      // Call underlying mbed i2c_reset to reconfigure the pins and reset the peripheral
      i2c_reset(self->i2c->get_i2c_obj());
  
      return mp_const_none;
  }
  MP_DEFINE_CONST_FUN_OBJ_KW(microbit_i2c_init_obj, 1, microbit_i2c_init);
  
  // Probe the given I2C address with an empty write to see if a device responds with an ACK
  STATIC bool i2c_probe(i2c_t *obj, uint8_t address) {
      obj->i2c->ADDRESS = address;
      obj->i2c->SHORTS = 0;
      obj->i2c->TASKS_STARTTX = 1;
      obj->i2c->EVENTS_STOPPED = 0;
      obj->i2c->TASKS_STOP = 1;
      uint32_t timeout = 10000;
      while (!obj->i2c->EVENTS_STOPPED && timeout > 0) {
          --timeout;
      }
      bool ack = timeout > 0 && obj->i2c->ERRORSRC == 0;
      i2c_reset(obj);
      return ack;
  }
  
  STATIC mp_obj_t microbit_i2c_scan(mp_obj_t self_in) {
      microbit_i2c_obj_t *self = (microbit_i2c_obj_t*)MP_OBJ_TO_PTR(self_in);
      i2c_t *obj = self->i2c->get_i2c_obj();
      mp_obj_t list = mp_obj_new_list(0, NULL);
      // 7-bit addresses 0b0000xxx and 0b1111xxx are reserved
      for (int addr = 0x08; addr < 0x78; ++addr) {
          if (i2c_probe(obj, addr)) {
              mp_obj_list_append(list, MP_OBJ_NEW_SMALL_INT(addr));
          }
      }
      return list;
  }
  MP_DEFINE_CONST_FUN_OBJ_1(microbit_i2c_scan_obj, microbit_i2c_scan);
  
  STATIC mp_obj_t microbit_i2c_read(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
      static const mp_arg_t allowed_args[] = {
          { MP_QSTR_addr,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
          { MP_QSTR_n,        MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
          { MP_QSTR_repeat,   MP_ARG_BOOL, {.u_bool = false} },
      };
  
      // parse args
      microbit_i2c_obj_t *self = (microbit_i2c_obj_t*)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);
  
      // do the I2C read
      vstr_t vstr;
      vstr_init_len(&vstr, args[1].u_int);
      int err = self->i2c->read(args[0].u_int << 1, vstr.buf, vstr.len, args[2].u_bool);
      if (err != MICROBIT_OK) {
          nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "I2C read error %d", err));
      }
      // return bytes object with read data
      return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
  }
  MP_DEFINE_CONST_FUN_OBJ_KW(microbit_i2c_read_obj, 1, microbit_i2c_read);
  
  STATIC mp_obj_t microbit_i2c_write(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
      static const mp_arg_t allowed_args[] = {
          { MP_QSTR_addr,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
          { MP_QSTR_buf,      MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
          { MP_QSTR_repeat,   MP_ARG_BOOL, {.u_bool = false} },
      };
  
      // parse args
      microbit_i2c_obj_t *self = (microbit_i2c_obj_t*)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);
  
      // do the I2C write
      mp_buffer_info_t bufinfo;
      mp_get_buffer_raise(args[1].u_obj, &bufinfo, MP_BUFFER_READ);
      int err = self->i2c->write(args[0].u_int << 1, (char*)bufinfo.buf, bufinfo.len, args[2].u_bool);
      if (err != MICROBIT_OK) {
          nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "I2C write error %d", err));
      }
      return mp_const_none;
  
  }
  MP_DEFINE_CONST_FUN_OBJ_KW(microbit_i2c_write_obj, 1, microbit_i2c_write);
  
  STATIC const mp_map_elem_t microbit_i2c_locals_dict_table[] = {
      { MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&microbit_i2c_init_obj },
      { MP_OBJ_NEW_QSTR(MP_QSTR_scan), (mp_obj_t)&microbit_i2c_scan_obj },
      { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&microbit_i2c_read_obj },
      { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&microbit_i2c_write_obj },
  };
  
  STATIC MP_DEFINE_CONST_DICT(microbit_i2c_locals_dict, microbit_i2c_locals_dict_table);
  
  const mp_obj_type_t microbit_i2c_type = {
      { &mp_type_type },
      .name = MP_QSTR_MicroBitI2C,
      .print = NULL,
      .make_new = NULL,
      .call = NULL,
      .unary_op = NULL,
      .binary_op = NULL,
      .attr = NULL,
      .subscr = NULL,
      .getiter = NULL,
      .iternext = NULL,
      .buffer_p = {NULL},
      .protocol = NULL,
      .parent = NULL,
      .locals_dict = (mp_obj_dict_t*)&microbit_i2c_locals_dict,
  };
  
  const microbit_i2c_obj_t microbit_i2c_obj = {
      {&microbit_i2c_type},
      .i2c = &ubit_i2c,
  };
  
  }
  