qmk_firmware/drivers/gpio/mcp23018.c

// Copyright 2022 zvecr<git@zvecr.com>
// SPDX-License-Identifier: GPL-2.0-or-later

#include "mcp23018.h"
#include "i2c_master.h"
#include "wait.h"
#include "debug.h"

#define SLAVE_TO_ADDR(n) (n << 1)
#define TIMEOUT 100

enum {
    CMD_IODIRA = 0x00, // i/o direction register
    CMD_IODIRB = 0x01,
    CMD_GPPUA  = 0x0C, // GPIO pull-up resistor register
    CMD_GPPUB  = 0x0D,
    CMD_GPIOA  = 0x12, // general purpose i/o port register (write modifies OLAT)
    CMD_GPIOB  = 0x13,
};

bool mcp23018_init(uint8_t slave_addr) {
    static uint8_t s_init = 0;
    uint8_t        addr   = SLAVE_TO_ADDR(slave_addr);
    if (0 == s_init) {
        i2c_init();
        wait_ms(100);

        // probe that the expander is actually connected by reading from it
        uint8_t data = 0;
        if (I2C_STATUS_SUCCESS == i2c_readReg(addr, 0, &data, sizeof(data), 150)) {
            s_init = 1;
        }
    }
    return (s_init > 0);
}

bool mcp23018_set_config(uint8_t slave_addr, mcp23018_port_t port, uint8_t conf) {
    uint8_t addr         = SLAVE_TO_ADDR(slave_addr);
    uint8_t cmdDirection = port ? CMD_IODIRB : CMD_IODIRA;
    uint8_t cmdPullup    = port ? CMD_GPPUB : CMD_GPPUA;

    i2c_status_t ret = i2c_writeReg(addr, cmdDirection, &conf, sizeof(conf), TIMEOUT);
    if (ret != I2C_STATUS_SUCCESS) {
        dprintf("mcp23018_set_config::directionFAILED::%u\n", ret);
        return false;
    }

    ret = i2c_writeReg(addr, cmdPullup, &conf, sizeof(conf), TIMEOUT);
    if (ret != I2C_STATUS_SUCCESS) {
        dprintf("mcp23018_set_config::pullupFAILED::%u\n", ret);
        return false;
    }

    return true;
}

bool mcp23018_set_output(uint8_t slave_addr, mcp23018_port_t port, uint8_t conf) {
    uint8_t addr = SLAVE_TO_ADDR(slave_addr);
    uint8_t cmd  = port ? CMD_GPIOB : CMD_GPIOA;

    i2c_status_t ret = i2c_writeReg(addr, cmd, &conf, sizeof(conf), TIMEOUT);
    if (ret != I2C_STATUS_SUCCESS) {
        dprintf("mcp23018_set_output::FAILED::%u\n", ret);
        return false;
    }

    return true;
}

bool mcp23018_set_output_all(uint8_t slave_addr, uint8_t confA, uint8_t confB) {
    uint8_t addr    = SLAVE_TO_ADDR(slave_addr);
    uint8_t conf[2] = {confA, confB};

    i2c_status_t ret = i2c_writeReg(addr, CMD_GPIOA, &conf[0], sizeof(conf), TIMEOUT);
    if (ret != I2C_STATUS_SUCCESS) {
        dprintf("mcp23018_set_output::FAILED::%u\n", ret);
        return false;
    }

    return true;
}

bool mcp23018_readPins(uint8_t slave_addr, mcp23018_port_t port, uint8_t* out) {
    uint8_t addr = SLAVE_TO_ADDR(slave_addr);
    uint8_t cmd  = port ? CMD_GPIOB : CMD_GPIOA;

    i2c_status_t ret = i2c_readReg(addr, cmd, out, sizeof(uint8_t), TIMEOUT);
    if (ret != I2C_STATUS_SUCCESS) {
        dprintf("mcp23018_readPins::FAILED::%u\n", ret);
        return false;
    }

    return true;
}

bool mcp23018_readPins_all(uint8_t slave_addr, uint16_t* out) {
    uint8_t addr = SLAVE_TO_ADDR(slave_addr);

    typedef union {
        uint8_t  u8[2];
        uint16_t u16;
    } data16;

    data16 data = {.u16 = 0};

    i2c_status_t ret = i2c_readReg(addr, CMD_GPIOA, &data.u8[0], sizeof(data), TIMEOUT);
    if (ret != I2C_STATUS_SUCCESS) {
        dprintf("mcp23018_readPins::FAILED::%u\n", ret);
        return false;
    }

    *out = data.u16;
    return true;
}