STM32MP157A上MFRC522驱动代码

以下是在STM32MP157A上MFRC522的驱动代码。需要注意的是，该代码是在Linux环境下运行的，因此需要使用Linux的GPIO库进行GPIO操作。

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/spi/spi.h>

// GPIO pins used for the MFRC522
#define MFRC522_RST_PIN 114
#define MFRC522_IRQ_PIN 115

// MFRC522 commands
#define MFRC522_CMD_IDLE 0x00
#define MFRC522_CMD_CALCCRC 0x03
#define MFRC522_CMD_TRANSMIT 0x04
#define MFRC522_CMD_RECEIVE 0x08
#define MFRC522_CMD_TRANSCEIVE 0x0C
#define MFRC522_CMD_AUTHENT 0x0E
#define MFRC522_CMD_SOFTRESET 0x0F

// MFRC522 registers
#define MFRC522_REG_COMMAND 0x01
#define MFRC522_REG_COMMIEN 0x02
#define MFRC522_REG_DIVIEN 0x03
#define MFRC522_REG_COMMIRQ 0x04
#define MFRC522_REG_DIVIRQ 0x05
#define MFRC522_REG_ERROR 0x06
#define MFRC522_REG_STATUS1 0x07
#define MFRC522_REG_STATUS2 0x08
#define MFRC522_REG_FIFO_DATA 0x09
#define MFRC522_REG_FIFO_LEVEL 0x0A
#define MFRC522_REG_WATERLEVEL 0x0B
#define MFRC522_REG_CONTROL 0x0C
#define MFRC522_REG_BITFRAMING 0x0D
#define MFRC522_REG_COLL 0x0E
#define MFRC522_REG_MODE 0x11
#define MFRC522_REG_TX_MODE 0x12
#define MFRC522_REG_RX_MODE 0x13
#define MFRC522_REG_TX_CONTROL 0x14
#define MFRC522_REG_TX_AUTO 0x15
#define MFRC522_REG_TX_SELL 0x16
#define MFRC522_REG_RX_SELL 0x17
#define MFRC522_REG_RX_THRESHOLD 0x18
#define MFRC522_REG_DEMOD 0x19
#define MFRC522_REG_MF_TX 0x1C
#define MFRC522_REG_MF_RX 0x1D
#define MFRC522_REG_SERIALSPEED 0x1F
#define MFRC522_REG_CRC_RESULT_MSB 0x21
#define MFRC522_REG_CRC_RESULT_LSB 0x22
#define MFRC522_REG_MOD_WIDTH 0x24
#define MFRC522_REG_RF_CFG 0x26
#define MFRC522_REG_GS_N 0x27
#define MFRC522_REG_CWGS_PREG 0x28
#define MFRC522_REG_MODGS_PREG 0x29
#define MFRC522_REG_T_MODE 0x2A
#define MFRC522_REG_T_PRESCALER 0x2B
#define MFRC522_REG_T_RELOAD_MSB 0x2C
#define MFRC522_REG_T_RELOAD_LSB 0x2D
#define MFRC522_REG_T_COUNTER_VALUE_MSB 0x2E
#define MFRC522_REG_T_COUNTER_VALUE_LSB 0x2F

struct mfrc522 {
    struct spi_device *spi;
    unsigned int irq_gpio;
    unsigned int rst_gpio;
};

static inline int mfrc522_send_command(struct mfrc522 *mfrc, u8 cmd, u8 *data, size_t len)
{
    int ret;
    u8 buffer[64];

    buffer[0] = cmd;
    if (len > 0) {
        memcpy(buffer + 1, data, len);
    }

    ret = spi_write(mfrc->spi, buffer, len + 1);
    if (ret < 0) {
        dev_err(&mfrc->spi->dev, "Error sending command %02x: %d\n", cmd, ret);
        return ret;
    }

    return 0;
}

static inline int mfrc522_receive_data(struct mfrc522 *mfrc, u8 *data, size_t len)
{
    int ret;
    u8 buffer[64];

    ret = spi_read(mfrc->spi, buffer, len);
    if (ret < 0) {
        dev_err(&mfrc->spi->dev, "Error receiving data: %d\n", ret);
        return ret;
    }

    memcpy(data, buffer, len);

    return 0;
}

static inline int mfrc522_reset(struct mfrc522 *mfrc)
{
    gpio_set_value(mfrc->rst_gpio, 0);
    udelay(100);
    gpio_set_value(mfrc->rst_gpio, 1);
    udelay(100);

    return 0;
}

static inline int mfrc522_init(struct mfrc522 *mfrc)
{
    int ret;
    u8 version;
    u8 buffer[25];

    // Reset the MFRC522
    mfrc522_reset(mfrc);

    // Read the MFRC522 version
    ret = mfrc522_send_command(mfrc, 0x00, NULL, 0);
    if (ret < 0) {
        return ret;
    }
    ret = mfrc522_receive_data(mfrc, &version, 1);
    if (ret < 0) {
        return ret;
    }
    dev_info(&mfrc->spi->dev, "MFRC522 version: %d\n", version);

    // Configure the MFRC522
    ret = mfrc522_send_command(mfrc, MFRC522_CMD_SOFTRESET, NULL, 0);
    if (ret < 0) {
        return ret;
    }
    mdelay(100);

    // Configure the timer
    buffer[0] = 0xA0;  // TPrescaler = 0xA0
    buffer[1] = 0x03;  // TReloadVal = 0x3E8
    ret = mfrc522_send_command(mfrc, MFRC522_REG_T_MODE, buffer, 2);
    if (ret < 0) {
        return ret;
    }

    // Configure the TX/RX registers
    buffer[0] = 0x40;  // 100% ASK modulation
    buffer[1] = 0x3F;  // Maximum RX waiting time
    buffer[2] = 0x03;  // Enable MIFARE Crypto1
    ret = mfrc522_send_command(mfrc, MFRC522_REG_TX_MODE, buffer, 3);
    if (ret < 0) {
        return ret;
    }
    buffer[0] = 0x08;  // Transceive FIFO level is 8
    ret = mfrc522_send_command(mfrc, MFRC522_REG_RX_MODE, buffer, 1);
    if (ret < 0) {
        return ret;
    }

    // Configure the ModWidthReg
    buffer[0] = 0x26;  // ModWidthReg = 0x26
    ret = mfrc522_send_command(mfrc, MFRC522_REG_MOD_WIDTH, buffer, 1);
    if (ret < 0) {
        return ret;
    }

    dev_info(&mfrc->spi->dev, "MFRC522 initialized\n");

    return 0;
}

static irqreturn_t mfrc522_irq_handler(int irq, void *dev_id)
{
    struct mfrc522 *mfrc = (struct mfrc522 *) dev_id;

    // TODO: handle the IRQ

    return IRQ_HANDLED;
}

static int mfrc522_probe(struct spi_device *spi)
{
    int ret;
    struct mfrc522 *mfrc;

    // Allocate memory for the MFRC522 device
    mfrc = devm_kzalloc(&spi->dev, sizeof(*mfrc), GFP_KERNEL);
    if (mfrc == NULL) {
        dev_err(&spi->dev, "Error allocating memory\n");
        return -ENOMEM;
    }

    // Save a reference to the SPI device
    mfrc->spi = spi;

    // Set up the GPIO pins
    mfrc->irq_gpio = MFRC522_IRQ_PIN;
    ret = devm_gpio_request(&spi->dev, mfrc->irq_gpio, "MFRC522 IRQ");
    if (ret < 0) {
        dev_err(&spi->dev, "Error requesting IRQ GPIO pin: %d\n", ret);
        return ret;
    }
    gpio_direction_input(mfrc->irq_gpio);

    mfrc->rst_gpio = MFRC522_RST_PIN;
    ret = devm_gpio_request(&spi->dev, mfrc->rst_gpio, "MFRC522 RST");
    if (ret < 0) {
        dev_err(&spi->dev, "Error requesting RST GPIO pin: %d\n", ret);
        return ret;
    }
    gpio_direction_output(mfrc->rst_gpio, 1);

    // Initialize the MFRC522
    ret = mfrc522_init(mfrc);
    if (ret < 0) {
        dev_err(&spi->dev, "Error initializing MFRC522: %d\n", ret);
        return ret;
    }

    // Register the IRQ handler
    ret = devm_request_irq(&spi->dev, gpio_to_irq(mfrc->irq_gpio), mfrc522_irq_handler,
                           IRQF_TRIGGER_FALLING, "MFRC522", mfrc);
    if (ret < 0) {
        dev_err(&spi->dev, "Error registering IRQ: %d\n", ret);
        return ret;
    }

    return 0;
}

static int mfrc522_remove(struct spi_device *spi)
{
    // TODO: cleanup

    return 0;
}

static const struct of_device_id mfrc522_of_match[] = {
    { .compatible = "mfrc522", },
    {},
};
MODULE_DEVICE_TABLE(of, mfrc522_of_match);

static struct spi_driver mfrc522_driver = {
    .driver = {
        .name = "mfrc522",
        .of_match_table = mfrc522_of_match,
    },
    .probe = mfrc522_probe,
    .remove = mfrc522_remove,
};

module_spi_driver(mfrc522_driver);

MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("MFRC522 driver for STM32MP157A");
MODULE_LICENSE("GPL");

需要注意的是，以上代码仅供参考，实际应用中可能需要进行更多的修改和优化。