鸿蒙系统 I2C 通信代码阅读理解

HdfDriverEntry驱动入口数据结构：

struct HdfDriverEntry {
    int moduleVersion;
    int32_t (*Bind)(struct HdfDeviceObject *device);
    int32_t (*I2cManagerInit)(struct HdfDeviceObject *device);
    void (*Release)(struct HdfDeviceObject *device);
    char *moduleName;
};

内核层驱动入口：g_i2cManagerEntry：

struct HdfDriverEntry g_i2cManagerEntry = {

.moduleVersion = 1,

.Bind = I2cManagerBind,

.Init = I2cManagerInit,

.Release = I2cManagerRelease,

.moduleName = "HDF_PLATFORM_I2C_MANAGER",

};

内核层驱动入口，会维护一个静态全局的 i2c 管理器 g_i2cManager ，数据结构为 I2cManager：

struct I2cManager {
    struct IDeviceIoService service;
    struct HdfDeviceObject *device;
    struct I2cCntlr *cntlrs[I2C_BUS_MAX];
    struct OsalMutex lock;
};

static struct I2cManager *g_i2cManager = NULL;

内核层驱动的 bind 函数，会将输入的 device 指针，绑定到 i2c 管理器 g_i2cManager 上面。

struct i2c_adapter ：

根据 struct device dev 地址，加上 offset，可以获取到 struct i2c_adapter 的地址。

struct i2c_adapter {
	struct module *owner;
	unsigned int class;		  /* classes to allow probing for */
	const struct i2c_algorithm *algo; /* the algorithm to access the bus */
	void *algo_data;

	/* data fields that are valid for all devices	*/
	const struct i2c_lock_operations *lock_ops;
	struct rt_mutex bus_lock;
	struct rt_mutex mux_lock;

	int timeout;			/* in jiffies */
	int retries;
	struct device dev;		/* the adapter device */
	unsigned long locked_flags;	/* owned by the I2C core */
#define I2C_ALF_IS_SUSPENDED		0
#define I2C_ALF_SUSPEND_REPORTED	1

	int nr;
	char name[48];
	struct completion dev_released;

	struct mutex userspace_clients_lock;
	struct list_head userspace_clients;

	struct i2c_bus_recovery_info *bus_recovery_info;
	const struct i2c_adapter_quirks *quirks;

	struct irq_domain *host_notify_domain;
};