linux驱动之platform

linux驱动之platform

平台驱动注册

#define platform_driver_register(drv) \
	__platform_driver_register(drv, THIS_MODULE)

int __platform_driver_register(struct platform_driver *drv,
				struct module *owner)
{
   
	//THIS_MODULE代表模块自身
	drv->driver.owner = owner;
	//平台总线
	drv->driver.bus = &platform_bus_type;
	if (drv->probe)
		drv->driver.probe = platform_drv_probe;
	if (drv->remove)
		drv->driver.remove = platform_drv_remove;
	if (drv->shutdown)
		drv->driver.shutdown = platform_drv_shutdown;

	return driver_register(&drv->driver);
}

struct platform_driver {
   
	//device和driver匹配成功后调用，用于初始化
	int (*probe)(struct platform_device *);
	//driver卸载时调用
	int (*remove)(struct platform_device *);
	//系统关机时调用
	void (*shutdown)(struct platform_device *);
	//系统挂起时调用
	int (*suspend)(struct platform_device *, pm_message_t state);
	//系统挂起恢复时调用
	int (*resume)(struct platform_device *);
	struct device_driver driver;
	//id_table->name和设备树的compatible进行字符匹配
	const struct platform_device_id *id_table;
	//是否延迟匹配
	bool prevent_deferred_probe;
};
struct platform_device_id {
   
	char name[PLATFORM_NAME_SIZE];
	kernel_ulong_t driver_data;
};
struct bus_type platform_bus_type = {
   
	.name		= "platform",
	.dev_groups	= platform_dev_groups,
	.match		= platform_match,
	.uevent		= platform_uevent,
	.pm		= &platform_dev_pm_ops,
};

static int platform_drv_probe(struct device *_dev)
{
   
	//使用container_of()获取drv和dev
	struct platform_driver *drv = to_platform_driver(_dev->driver);
	struct platform_device *dev = to_platform_device(_dev);
	int ret;
	//_dev->of_node是设备树节点
	//根据设备树信息设置时钟
	ret = of_clk_set_defaults(_dev->of_node, false);
	...
	ret = dev_pm_domain_attach(_dev, true);
	if (ret != -EPROBE_DEFER) {
   
		ret = drv->probe(dev);
		if (ret)
			dev_pm_domain_detach(_dev, true);
	}
	if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {
   
		...
	}
	return ret