/*
 * 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
 *
 * 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 "py/nlr.h"
#include "py/runtime.h"
#include "py/mphal.h"
#include "py/gc.h"
#include "pin.h"
#include "nrf_gpio.h"
#include "nrfx_gpiote.h"

#if defined(NRF52840_XXAA)
#define NUM_OF_PINS 48
#else
#define NUM_OF_PINS 32
#endif

extern const pin_obj_t machine_board_pin_obj[];
extern const uint8_t machine_pin_num_of_board_pins;

/// \moduleref machine
/// \class Pin - control I/O pins
///
/// A pin is the basic object to control I/O pins.  It has methods to set
/// the mode of the pin (input, output, etc) and methods to get and set the
/// digital logic level.  For analog control of a pin, see the ADC class.
///
/// Usage Model:
///
/// All Board Pins are predefined as machine.Pin.board.Name
///
///     x1_pin = machine.Pin.board.X1
///
///     g = machine.Pin(machine.Pin.board.X1, machine.Pin.IN)
///
/// CPU pins which correspond to the board pins are available
/// as `machine.cpu.Name`. For the CPU pins, the names are the port letter
/// followed by the pin number. On the PYBv1.0, `machine.Pin.board.X1` and
/// `machine.Pin.cpu.B6` are the same pin.
///
/// You can also use strings:
///
///     g = machine.Pin('X1', machine.Pin.OUT)
///
/// Users can add their own names:
///
///     MyMapperDict = { 'LeftMotorDir' : machine.Pin.cpu.C12 }
///     machine.Pin.dict(MyMapperDict)
///     g = machine.Pin("LeftMotorDir", machine.Pin.OUT)
///
/// and can query mappings
///
///     pin = machine.Pin("LeftMotorDir")
///
/// Users can also add their own mapping function:
///
///     def MyMapper(pin_name):
///        if pin_name == "LeftMotorDir":
///            return machine.Pin.cpu.A0
///
///     machine.Pin.mapper(MyMapper)
///
/// So, if you were to call: `machine.Pin("LeftMotorDir", machine.Pin.OUT)`
/// then `"LeftMotorDir"` is passed directly to the mapper function.
///
/// To summarise, the following order determines how things get mapped into
/// an ordinal pin number:
///
/// 1. Directly specify a pin object
/// 2. User supplied mapping function
/// 3. User supplied mapping (object must be usable as a dictionary key)
/// 4. Supply a string which matches a board pin
/// 5. Supply a string which matches a CPU port/pin
///
/// You can set `machine.Pin.debug(True)` to get some debug information about
/// how a particular object gets mapped to a pin.

#define PIN_DEBUG (0)

// Pin class variables
#if PIN_DEBUG
static bool pin_class_debug;
#else
#define pin_class_debug (0)
#endif

void pin_init0(void) {
    MP_STATE_PORT(pin_class_mapper) = mp_const_none;
    MP_STATE_PORT(pin_class_map_dict) = mp_const_none;
    for (int i = 0; i < NUM_OF_PINS; i++) {
        MP_STATE_PORT(pin_irq_handlers)[i] = mp_const_none;
    }
    // Initialize GPIOTE if not done yet.
    if (!nrfx_gpiote_is_init()) {
        nrfx_gpiote_init(NRFX_GPIOTE_DEFAULT_CONFIG_IRQ_PRIORITY);
    }

    #if PIN_DEBUG
    pin_class_debug = false;
    #endif
}

// C API used to convert a user-supplied pin name into an ordinal pin number.
const pin_obj_t *pin_find(mp_obj_t user_obj) {
    const pin_obj_t *pin_obj;
    // If pin is SMALL_INT
    if (mp_obj_is_small_int(user_obj)) {
        uint8_t value = MP_OBJ_SMALL_INT_VALUE(user_obj);
        for (uint8_t i = 0; i < machine_pin_num_of_board_pins; i++) {
            if (machine_board_pin_obj[i].pin == value) {
                return &machine_board_pin_obj[i];
            }
        }
    }

    // If a pin was provided, then use it
    if (mp_obj_is_type(user_obj, &pin_type)) {
        pin_obj = user_obj;
        if (pin_class_debug) {
            printf("Pin map passed pin ");
            mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
            printf("\n");
        }
        return pin_obj;
    }

    if (MP_STATE_PORT(pin_class_mapper) != mp_const_none) {
        pin_obj = mp_call_function_1(MP_STATE_PORT(pin_class_mapper), user_obj);
        if (pin_obj != mp_const_none) {
            if (!mp_obj_is_type(pin_obj, &pin_type)) {
                mp_raise_ValueError(MP_ERROR_TEXT("Pin.mapper didn't return a Pin object"));
            }
            if (pin_class_debug) {
                printf("Pin.mapper maps ");
                mp_obj_print(user_obj, PRINT_REPR);
                printf(" to ");
                mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
                printf("\n");
            }
            return pin_obj;
        }
        // The pin mapping function returned mp_const_none, fall through to
        // other lookup methods.
    }

    if (MP_STATE_PORT(pin_class_map_dict) != mp_const_none) {
        mp_map_t *pin_map_map = mp_obj_dict_get_map(MP_STATE_PORT(pin_class_map_dict));
        mp_map_elem_t *elem = mp_map_lookup(pin_map_map, user_obj, MP_MAP_LOOKUP);
        if (elem != NULL && elem->value != NULL) {
            pin_obj = elem->value;
            if (pin_class_debug) {
                printf("Pin.map_dict maps ");
                mp_obj_print(user_obj, PRINT_REPR);
                printf(" to ");
                mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
                printf("\n");
            }
            return pin_obj;
        }
    }

    // See if the pin name matches a board pin
    pin_obj = pin_find_named_pin(&pin_board_pins_locals_dict, user_obj);
    if (pin_obj) {
        if (pin_class_debug) {
            printf("Pin.board maps ");
            mp_obj_print(user_obj, PRINT_REPR);
            printf(" to ");
            mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
            printf("\n");
        }
        return pin_obj;
    }

    // See if the pin name matches a cpu pin
    pin_obj = pin_find_named_pin(&pin_cpu_pins_locals_dict, user_obj);
    if (pin_obj) {
        if (pin_class_debug) {
            printf("Pin.cpu maps ");
            mp_obj_print(user_obj, PRINT_REPR);
            printf(" to ");
            mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
            printf("\n");
        }
        return pin_obj;
    }

    mp_raise_ValueError(MP_ERROR_TEXT("not a valid pin identifier"));
}

/// \method __str__()
/// Return a string describing the pin object.
static void pin_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    pin_obj_t *self = self_in;

    char *pull = "PULL_DISABLED";
    switch (nrf_gpio_pin_pull_get(self->pin)) {
        case NRF_GPIO_PIN_PULLUP:
            pull = "PULL_UP";
            break;
        case NRF_GPIO_PIN_PULLDOWN:
            pull = "PULL_DOWN";
            break;
        default:
            break;
    }

    mp_printf(print, "Pin(%d, mode=%s, pull=%s)",
        self->pin,
        (nrf_gpio_pin_dir_get(self->pin) == NRF_GPIO_PIN_DIR_OUTPUT) ? "OUT" : "IN",
        pull);
}

static mp_obj_t pin_obj_init_helper(const pin_obj_t *pin, mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kw_args);

/// \classmethod \constructor(id, ...)
/// Create a new Pin object associated with the id.  If additional arguments are given,
/// they are used to initialise the pin.  See `init`.
static mp_obj_t pin_make_new(const mp_obj_type_t *type, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);

    // Run an argument through the mapper and return the result.
    const pin_obj_t *pin = pin_find(args[0]);

    if (n_args > 1 || n_kw > 0) {
        // pin mode given, so configure this GPIO
        mp_map_t kw_args;
        mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
        pin_obj_init_helper(pin, n_args - 1, args + 1, &kw_args);
    }

    return (mp_obj_t)pin;
}

// fast method for getting/setting pin value
static mp_obj_t pin_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
    mp_arg_check_num(n_args, n_kw, 0, 1, false);
    pin_obj_t *self = self_in;
    if (n_args == 0) {
        // get pin
        return MP_OBJ_NEW_SMALL_INT(mp_hal_pin_read(self));
    } else {
        // set pin
        mp_hal_pin_write(self, mp_obj_is_true(args[0]));
        return mp_const_none;
    }
}

static mp_obj_t pin_off(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    mp_hal_pin_low(self);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_off_obj, pin_off);

static mp_obj_t pin_on(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    mp_hal_pin_high(self);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_on_obj, pin_on);

/// \classmethod mapper([fun])
/// Get or set the pin mapper function.
static mp_obj_t pin_mapper(mp_uint_t n_args, const mp_obj_t *args) {
    if (n_args > 1) {
        MP_STATE_PORT(pin_class_mapper) = args[1];
        return mp_const_none;
    }
    return MP_STATE_PORT(pin_class_mapper);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pin_mapper_fun_obj, 1, 2, pin_mapper);
static MP_DEFINE_CONST_CLASSMETHOD_OBJ(pin_mapper_obj, (mp_obj_t)&pin_mapper_fun_obj);

/// \classmethod dict([dict])
/// Get or set the pin mapper dictionary.
static mp_obj_t pin_map_dict(mp_uint_t n_args, const mp_obj_t *args) {
    if (n_args > 1) {
        MP_STATE_PORT(pin_class_map_dict) = args[1];
        return mp_const_none;
    }
    return MP_STATE_PORT(pin_class_map_dict);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pin_map_dict_fun_obj, 1, 2, pin_map_dict);
static MP_DEFINE_CONST_CLASSMETHOD_OBJ(pin_map_dict_obj, (mp_obj_t)&pin_map_dict_fun_obj);

/// \classmethod af_list()
/// Returns an array of alternate functions available for this pin.
static mp_obj_t pin_af_list(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    mp_obj_t result = mp_obj_new_list(0, NULL);

    const pin_af_obj_t *af = self->af;
    for (mp_uint_t i = 0; i < self->num_af; i++, af++) {
        mp_obj_list_append(result, (mp_obj_t)af);
    }
    return result;
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_af_list_obj, pin_af_list);

#if PIN_DEBUG
/// \classmethod debug([state])
/// Get or set the debugging state (`True` or `False` for on or off).
static mp_obj_t pin_debug(mp_uint_t n_args, const mp_obj_t *args) {
    if (n_args > 1) {
        pin_class_debug = mp_obj_is_true(args[1]);
        return mp_const_none;
    }
    return mp_obj_new_bool(pin_class_debug);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pin_debug_fun_obj, 1, 2, pin_debug);
static MP_DEFINE_CONST_CLASSMETHOD_OBJ(pin_debug_obj, (mp_obj_t)&pin_debug_fun_obj);
#endif

// init(mode, pull=None, af=-1, *, value, alt)
static mp_obj_t pin_obj_init_helper(const pin_obj_t *self, 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_mode, MP_ARG_REQUIRED | MP_ARG_INT },
        { MP_QSTR_pull, MP_ARG_OBJ, {.u_obj = mp_const_none}},
        { MP_QSTR_af, MP_ARG_INT, {.u_int = -1}}, // legacy
        { MP_QSTR_value, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL}},
        { MP_QSTR_alt, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1}},
    };

    // parse args
    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);

    // get pull mode
    nrf_gpio_pin_pull_t pull = NRF_GPIO_PIN_NOPULL;
    if (args[1].u_obj != mp_const_none) {
        pull = (nrf_gpio_pin_pull_t)mp_obj_get_int(args[1].u_obj);
    }

    // if given, set the pin value before initialising to prevent glitches
    if (args[3].u_obj != MP_OBJ_NULL) {
        mp_hal_pin_write(self, mp_obj_is_true(args[3].u_obj));
    }


    // get io mode
    nrf_gpio_pin_dir_t mode = (nrf_gpio_pin_dir_t)args[0].u_int;

    // Connect input or not
    nrf_gpio_pin_input_t input = (mode == NRF_GPIO_PIN_DIR_INPUT) ? NRF_GPIO_PIN_INPUT_CONNECT
                                                                  : NRF_GPIO_PIN_INPUT_DISCONNECT;

    if (mode == NRF_GPIO_PIN_DIR_OUTPUT || mode == NRF_GPIO_PIN_DIR_INPUT) {
        nrf_gpio_cfg(self->pin,
            mode,
            input,
            pull,
            NRF_GPIO_PIN_S0S1,
            NRF_GPIO_PIN_NOSENSE);
    } else {
        mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("invalid pin mode: %d"), mode);
    }

    return mp_const_none;
}

static mp_obj_t pin_obj_init(mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    return pin_obj_init_helper(args[0], n_args - 1, args + 1, kw_args);
}
MP_DEFINE_CONST_FUN_OBJ_KW(pin_init_obj, 1, pin_obj_init);

/// \method value([value])
/// Get or set the digital logic level of the pin:
///
///   - With no argument, return 0 or 1 depending on the logic level of the pin.
///   - With `value` given, set the logic level of the pin.  `value` can be
///   anything that converts to a boolean.  If it converts to `True`, the pin
///   is set high, otherwise it is set low.
static mp_obj_t pin_value(mp_uint_t n_args, const mp_obj_t *args) {
    return pin_call(args[0], n_args - 1, 0, args + 1);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pin_value_obj, 1, 2, pin_value);

/// \method low()
/// Set the pin to a low logic level.
static mp_obj_t pin_low(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    mp_hal_pin_low(self);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_low_obj, pin_low);

/// \method high()
/// Set the pin to a high logic level.
static mp_obj_t pin_high(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    mp_hal_pin_high(self);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_high_obj, pin_high);

/// \method name()
/// Get the pin name.
static mp_obj_t pin_name(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    return MP_OBJ_NEW_QSTR(self->name);
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_name_obj, pin_name);

/// \method names()
/// Returns the cpu and board names for this pin.
static mp_obj_t pin_names(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    mp_obj_t result = mp_obj_new_list(0, NULL);
    mp_obj_list_append(result, MP_OBJ_NEW_QSTR(self->name));

    mp_map_t *map = mp_obj_dict_get_map((mp_obj_t)&pin_board_pins_locals_dict);
    mp_map_elem_t *elem = map->table;

    for (mp_uint_t i = 0; i < map->used; i++, elem++) {
        if (elem->value == self) {
            mp_obj_list_append(result, elem->key);
        }
    }
    return result;
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_names_obj, pin_names);

/// \method port()
/// Get the pin port.
static mp_obj_t pin_port(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    return MP_OBJ_NEW_SMALL_INT(self->pin / 32);
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_port_obj, pin_port);

/// \method pin()
/// Get the pin number.
static mp_obj_t pin_pin(mp_obj_t self_in) {
    pin_obj_t *self = self_in;
    return MP_OBJ_NEW_SMALL_INT(self->pin);
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_pin_obj, pin_pin);

/// \method mode()
/// Returns the currently configured mode of the pin. The integer returned
/// will match one of the allowed constants for the mode argument to the init
/// function.
static mp_obj_t pin_mode(mp_obj_t self_in) {
    return mp_const_none; // TODO: MP_OBJ_NEW_SMALL_INT(pin_get_mode(self_in));
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_mode_obj, pin_mode);

/// \method pull()
/// Returns the currently configured pull of the pin. The integer returned
/// will match one of the allowed constants for the pull argument to the init
/// function.
static mp_obj_t pin_pull(mp_obj_t self_in) {
    return mp_const_none; // TODO: MP_OBJ_NEW_SMALL_INT(pin_get_pull(self_in));
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_pull_obj, pin_pull);

/// \method af()
/// Returns the currently configured alternate-function of the pin. The
/// integer returned will match one of the allowed constants for the af
/// argument to the init function.
static mp_obj_t pin_af(mp_obj_t self_in) {
    return mp_const_none; // TODO: MP_OBJ_NEW_SMALL_INT(pin_get_af(self_in));
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_af_obj, pin_af);


static void pin_common_irq_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action) {
    mp_obj_t pin_handler = MP_STATE_PORT(pin_irq_handlers)[pin];
    mp_obj_t pin_number = MP_OBJ_NEW_SMALL_INT(pin);
    const pin_obj_t *pin_obj = pin_find(pin_number);

    if (pin_handler != mp_const_none) {
        #if MICROPY_ENABLE_SCHEDULER
        mp_sched_lock();
        #endif
        // When executing code within a handler we must lock the GC to prevent
        // any memory allocations.  We must also catch any exceptions.
        gc_lock();
        nlr_buf_t nlr;
        if (nlr_push(&nlr) == 0) {
            mp_call_function_1(pin_handler, (mp_obj_t)pin_obj);
            nlr_pop();
        } else {
            // Uncaught exception; disable the callback so it doesn't run again.
            MP_STATE_PORT(pin_irq_handlers)[pin] = mp_const_none;
            nrfx_gpiote_in_uninit(pin);
            mp_printf(MICROPY_ERROR_PRINTER, "uncaught exception in interrupt handler for Pin('%q')\n", pin_obj->name);
            mp_obj_print_exception(&mp_plat_print, MP_OBJ_FROM_PTR(nlr.ret_val));
        }
        gc_unlock();
        #if MICROPY_ENABLE_SCHEDULER
        mp_sched_unlock();
        #endif
    }
}

static mp_obj_t pin_irq(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
    enum {ARG_handler, ARG_trigger, ARG_wake};
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_handler, MP_ARG_OBJ | MP_ARG_REQUIRED,  {.u_obj = mp_const_none} },
        { MP_QSTR_trigger, MP_ARG_INT,  {.u_int = NRF_GPIOTE_POLARITY_LOTOHI | NRF_GPIOTE_POLARITY_HITOLO} },
        { MP_QSTR_wake,    MP_ARG_BOOL, {.u_bool = false} },
    };
    pin_obj_t *self = MP_OBJ_TO_PTR(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);

    nrfx_gpiote_pin_t pin = self->pin;

    nrfx_gpiote_in_config_t config = NRFX_GPIOTE_CONFIG_IN_SENSE_TOGGLE(true);
    if (args[ARG_trigger].u_int == NRF_GPIOTE_POLARITY_LOTOHI) {
        config.sense = NRF_GPIOTE_POLARITY_LOTOHI;
    } else if (args[ARG_trigger].u_int == NRF_GPIOTE_POLARITY_HITOLO) {
        config.sense = NRF_GPIOTE_POLARITY_HITOLO;
    }
    config.pull = NRF_GPIO_PIN_PULLUP;

    nrfx_err_t err_code = nrfx_gpiote_in_init(pin, &config, pin_common_irq_handler);
    if (err_code == NRFX_ERROR_INVALID_STATE) {
        // Re-init if already configured.
        nrfx_gpiote_in_uninit(pin);
        nrfx_gpiote_in_init(pin, &config, pin_common_irq_handler);
    }

    MP_STATE_PORT(pin_irq_handlers)[pin] = args[ARG_handler].u_obj;

    nrfx_gpiote_in_event_enable(pin, true);

    // return the irq object
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_KW(pin_irq_obj, 1, pin_irq);

static const mp_rom_map_elem_t pin_locals_dict_table[] = {
    // instance methods
    { MP_ROM_QSTR(MP_QSTR_init),    MP_ROM_PTR(&pin_init_obj) },
    { MP_ROM_QSTR(MP_QSTR_value),   MP_ROM_PTR(&pin_value_obj) },
    { MP_ROM_QSTR(MP_QSTR_off),     MP_ROM_PTR(&pin_off_obj) },
    { MP_ROM_QSTR(MP_QSTR_on),      MP_ROM_PTR(&pin_on_obj) },
    { MP_ROM_QSTR(MP_QSTR_low),     MP_ROM_PTR(&pin_low_obj) },
    { MP_ROM_QSTR(MP_QSTR_high),    MP_ROM_PTR(&pin_high_obj) },
    { MP_ROM_QSTR(MP_QSTR_name),    MP_ROM_PTR(&pin_name_obj) },
    { MP_ROM_QSTR(MP_QSTR_names),   MP_ROM_PTR(&pin_names_obj) },
    { MP_ROM_QSTR(MP_QSTR_af_list), MP_ROM_PTR(&pin_af_list_obj) },
    { MP_ROM_QSTR(MP_QSTR_port),    MP_ROM_PTR(&pin_port_obj) },
    { MP_ROM_QSTR(MP_QSTR_pin),     MP_ROM_PTR(&pin_pin_obj) },
    { MP_ROM_QSTR(MP_QSTR_mode),    MP_ROM_PTR(&pin_mode_obj) },
    { MP_ROM_QSTR(MP_QSTR_pull),    MP_ROM_PTR(&pin_pull_obj) },
    { MP_ROM_QSTR(MP_QSTR_af),      MP_ROM_PTR(&pin_af_obj) },
    { MP_ROM_QSTR(MP_QSTR_irq),     MP_ROM_PTR(&pin_irq_obj) },

    // class methods
    { MP_ROM_QSTR(MP_QSTR_mapper),  MP_ROM_PTR(&pin_mapper_obj) },
    { MP_ROM_QSTR(MP_QSTR_dict),    MP_ROM_PTR(&pin_map_dict_obj) },
    #if PIN_DEBUG
    { MP_ROM_QSTR(MP_QSTR_debug),   MP_ROM_PTR(&pin_debug_obj) },
    #endif

    // class attributes
    { MP_ROM_QSTR(MP_QSTR_board),   MP_ROM_PTR(&pin_board_pins_obj_type) },
    { MP_ROM_QSTR(MP_QSTR_cpu),     MP_ROM_PTR(&pin_cpu_pins_obj_type) },

    // class constants
    { MP_ROM_QSTR(MP_QSTR_IN),        MP_ROM_INT(NRF_GPIO_PIN_DIR_INPUT) },
    { MP_ROM_QSTR(MP_QSTR_OUT),       MP_ROM_INT(NRF_GPIO_PIN_DIR_OUTPUT) },
/*
    { MP_ROM_QSTR(MP_QSTR_OPEN_DRAIN),     MP_ROM_INT(GPIO_MODE_OUTPUT_OD) },
    { MP_ROM_QSTR(MP_QSTR_ALT),            MP_ROM_INT(GPIO_MODE_AF_PP) },
    { MP_ROM_QSTR(MP_QSTR_ALT_OPEN_DRAIN), MP_ROM_INT(GPIO_MODE_AF_OD) },
    { MP_ROM_QSTR(MP_QSTR_ANALOG),         MP_ROM_INT(GPIO_MODE_ANALOG) },
*/
    { MP_ROM_QSTR(MP_QSTR_PULL_DISABLED), MP_ROM_INT(NRF_GPIO_PIN_NOPULL) },
    { MP_ROM_QSTR(MP_QSTR_PULL_UP),       MP_ROM_INT(NRF_GPIO_PIN_PULLUP) },
    { MP_ROM_QSTR(MP_QSTR_PULL_DOWN),     MP_ROM_INT(NRF_GPIO_PIN_PULLDOWN) },

    // IRQ triggers, can be or'd together
    { MP_ROM_QSTR(MP_QSTR_IRQ_RISING),    MP_ROM_INT(NRF_GPIOTE_POLARITY_LOTOHI) },
    { MP_ROM_QSTR(MP_QSTR_IRQ_FALLING),   MP_ROM_INT(NRF_GPIOTE_POLARITY_HITOLO) },
/*
    // legacy class constants
    { MP_ROM_QSTR(MP_QSTR_OUT_PP),    MP_ROM_INT(GPIO_MODE_OUTPUT_PP) },
    { MP_ROM_QSTR(MP_QSTR_OUT_OD),    MP_ROM_INT(GPIO_MODE_OUTPUT_OD) },
    { MP_ROM_QSTR(MP_QSTR_AF_PP),     MP_ROM_INT(GPIO_MODE_AF_PP) },
    { MP_ROM_QSTR(MP_QSTR_AF_OD),     MP_ROM_INT(GPIO_MODE_AF_OD) },
    { MP_ROM_QSTR(MP_QSTR_PULL_NONE), MP_ROM_INT(GPIO_NOPULL) },
*/
    #include "genhdr/pins_af_const.h"
};

static MP_DEFINE_CONST_DICT(pin_locals_dict, pin_locals_dict_table);

MP_DEFINE_CONST_OBJ_TYPE(
    pin_type,
    MP_QSTR_Pin,
    MP_TYPE_FLAG_NONE,
    make_new, pin_make_new,
    print, pin_print,
    call, pin_call,
    locals_dict, &pin_locals_dict
    );

/// \moduleref machine
/// \class PinAF - Pin Alternate Functions
///
/// A Pin represents a physical pin on the microcprocessor. Each pin
/// can have a variety of functions (GPIO, I2C SDA, etc). Each PinAF
/// object represents a particular function for a pin.
///
/// Usage Model:
///
///     x3 = machine.Pin.board.X3
///     x3_af = x3.af_list()
///
/// x3_af will now contain an array of PinAF objects which are available on
/// pin X3.
///
/// For the pyboard, x3_af would contain:
///     [Pin.AF1_TIM2, Pin.AF2_TIM5, Pin.AF3_TIM9, Pin.AF7_USART2]
///
/// Normally, each peripheral would configure the af automatically, but sometimes
/// the same function is available on multiple pins, and having more control
/// is desired.
///
/// To configure X3 to expose TIM2_CH3, you could use:
///    pin = machine.Pin(machine.Pin.board.X3, mode=machine.Pin.AF_PP, af=machine.Pin.AF1_TIM2)
/// or:
///    pin = machine.Pin(machine.Pin.board.X3, mode=machine.Pin.AF_PP, af=1)

/// \method __str__()
/// Return a string describing the alternate function.
static void pin_af_obj_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    pin_af_obj_t *self = self_in;
    mp_printf(print, "Pin.%q", self->name);
}

/// \method index()
/// Return the alternate function index.
static mp_obj_t pin_af_index(mp_obj_t self_in) {
    pin_af_obj_t *af = self_in;
    return MP_OBJ_NEW_SMALL_INT(af->idx);
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_af_index_obj, pin_af_index);

/// \method name()
/// Return the name of the alternate function.
static mp_obj_t pin_af_name(mp_obj_t self_in) {
    pin_af_obj_t *af = self_in;
    return MP_OBJ_NEW_QSTR(af->name);
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_af_name_obj, pin_af_name);

/// \method reg()
/// Return the base register associated with the peripheral assigned to this
/// alternate function.
static mp_obj_t pin_af_reg(mp_obj_t self_in) {
    pin_af_obj_t *af = self_in;
    return MP_OBJ_NEW_SMALL_INT((mp_uint_t)af->reg);
}
static MP_DEFINE_CONST_FUN_OBJ_1(pin_af_reg_obj, pin_af_reg);

static const mp_rom_map_elem_t pin_af_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_index),   MP_ROM_PTR(&pin_af_index_obj) },
    { MP_ROM_QSTR(MP_QSTR_name),    MP_ROM_PTR(&pin_af_name_obj) },
    { MP_ROM_QSTR(MP_QSTR_reg),     MP_ROM_PTR(&pin_af_reg_obj) },
};
static MP_DEFINE_CONST_DICT(pin_af_locals_dict, pin_af_locals_dict_table);

MP_DEFINE_CONST_OBJ_TYPE(
    pin_af_type,
    MP_QSTR_PinAF,
    MP_TYPE_FLAG_NONE,
    print, pin_af_obj_print,
    locals_dict, &pin_af_locals_dict
    );

MP_REGISTER_ROOT_POINTER(mp_obj_t pin_class_mapper);
MP_REGISTER_ROOT_POINTER(mp_obj_t pin_class_map_dict);
MP_REGISTER_ROOT_POINTER(mp_obj_t pin_irq_handlers[NUM_OF_PINS]);
