// 读操作u8 readb(constvolatilevoid __iomem *addr);  // 8位u16 readw(constvolatilevoid __iomem *addr); // 16位u32 readl(constvolatilevoid __iomem *addr); // 32位// 写操作voidwriteb(u8 value, volatilevoid __iomem *addr);voidwritew(u16 value, volatilevoid __iomem *addr);voidwritel(u32 value, volatilevoid __iomem *addr);

// 启用设备中断 (设置寄存器的第 0 位)void enable_interrupts(struct device *dev){    u8 ctrl_reg;    // 1. 读取当前控制寄存器值    ctrl_reg = readb(dev->regs + CONTROL_REG_OFFSET);    // 2. 设置中断使能位 (BIT0)    ctrl_reg |= 0x01;    // 3. 写回控制寄存器    writeb(ctrl_reg, dev->regs + CONTROL_REG_OFFSET);}// 发送命令到设备void send_device_command(struct device *dev, u8 cmd){    // 直接写入命令寄存器    writeb(cmd, dev->regs + COMMAND_REG_OFFSET);}

// 读取设备状态寄存器u16 get_device_status(struct device *dev){    // 直接读取16位状态寄存器    return readw(dev->regs + STATUS_REG_OFFSET);}// 从数据寄存器读取温度值intread_temperature(struct device *dev){    u16 raw_value;    // 1. 启动温度转换    writeb(START_CONV_CMD, dev->regs + COMMAND_REG);    // 2. 等待转换完成    while (!(readw(dev->regs + STATUS_REG) & CONV_COMPLETE_BIT))        udelay(10);    // 3. 读取16位温度值    raw_value = readw(dev->regs + DATA_REG);    return convert_raw_temp(raw_value);}

u16 val = readw(addr);u16 host_val = le16_to_cpu(val); // 小端设备转主机序

// 安全修改特定位u8 reg = readb(ctrl_reg);reg |= BIT(3);    // 设置第3位reg &= ~BIT(5);   // 清除第5位writeb(reg, ctrl_reg);

// 单次读写inti2c_master_send(struct i2c_client *client, constchar *buf, int count);inti2c_master_recv(struct i2c_client *client, char *buf, int count);// SMBus封装（推荐）s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 reg);s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 reg, u8 value);s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 reg);

s32 i2c_smbus_read_byte_data(conststruct i2c_client *client, u8 command){ union i2c_smbus_data data; int status; status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, I2C_SMBUS_READ, command, I2C_SMBUS_BYTE_DATA, &data); return (status < 0) ? status : data.byte;}EXPORT_SYMBOL(i2c_smbus_read_byte_data);

// 读取温度传感器(地址0x48)的温度寄存器(命令码0x00)struct i2c_client *client = ...; u8 temp_reg = 0x00;int temperature = i2c_smbus_read_byte_data(client, temp_reg);if (temperature < 0) {    dev_err(&client->dev, "读取失败: %d\n", temperature);} else {    dev_info(&client->dev, "当前温度: %d°C\n", temperature);}

s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,      u8 value){ union i2c_smbus_data data; data.byte = value; return i2c_smbus_xfer(client->adapter, client->addr, client->flags,      I2C_SMBUS_WRITE, command,      I2C_SMBUS_BYTE_DATA, &data);}EXPORT_SYMBOL(i2c_smbus_write_byte_data);

staticinlineintspi_write(struct spi_device *spi, constvoid *buf, size_t len){ struct spi_transfer t = {  //描述单个 SPI 传输操作的结构体 .tx_buf = buf, // 发送数据缓冲区 .len = len, // 发送数据长度 }; struct spi_message m; spi_message_init(&m); // 初始化 SPI 消息 spi_message_add_tail(&t, &m); // 将传输加入消息队列 return spi_sync(spi, &m); //阻塞式函数，会等待整个传输完成 0 表示成功，负数表示错误码       //实际驱动中应检查 spi_sync() 的错误码,根据错误码判断问题。}

staticinlineintspi_read(struct spi_device *spi, void *buf, size_t len){ struct spi_transfer t = { .rx_buf = buf, .len = len, }; struct spi_message m; spi_message_init(&m); spi_message_add_tail(&t, &m); return spi_sync(spi, &m);}

staticinlineintspi_write_and_read(struct spi_device *spi, constvoid *tx_buf, void *rx_buf, size_t len){        struct spi_transfer     t = {                        .tx_buf         = tx_buf,                        .rx_buf         = rx_buf,                        .len            = len,                };        struct spi_message      m;        spi_message_init(&m);        spi_message_add_tail(&t, &m);        return spi_sync(spi, &m);}

// 初始化Regmapstruct regmap_config config = {.reg_bits = 8, // 寄存器地址位数.val_bits = 16, // 寄存器值位数};

struct regmap *regmap = devm_regmap_init_i2c(client, &config); // I2C设备// 读写寄存器intregmap_write(struct regmap *map, unsignedint reg, unsignedint val);intregmap_read(struct regmap *map, unsignedint reg, unsignedint *val);

/** * regmap_write(): Write a value to a single register * * @map: Register map to write to * @reg: Register to write to * @val: Value to be written * * A value of zero will be returned on success, a negative errno will * be returned in error cases. */int regmap_write(struct regmap *map, unsigned int reg, unsigned int val){ int ret; if (reg % map->reg_stride) return -EINVAL; map->lock(map->lock_arg); ret = _regmap_write(map, reg, val); map->unlock(map->lock_arg); return ret;}EXPORT_SYMBOL_GPL(regmap_write);

/** * regmap_read(): Read a value from a single register * * @map: Register map to write to * @reg: Register to be read from * @val: Pointer to store read value * * A value of zero will be returned on success, a negative errno will * be returned in error cases. */int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val){ int ret; if (reg % map->reg_stride) return -EINVAL; map->lock(map->lock_arg); ret = _regmap_read(map, reg, val); map->unlock(map->lock_arg); return ret;}EXPORT_SYMBOL_GPL(regmap_read);