接前一篇文章：Linux网络驱动之Fixed-Link（7）
本文内容参考：
linux phy fixed-link-CSDN博客
fixed-link 网口驱动设备树-CSDN博客
GMAC网卡Fixed-Link模式 - StepForwards - 博客园
RTL8367RB的国产P2P替代方案用JL6107-PC的可行性及实现方法-CSDN博客
linux phy处理流程一:探测phy设备_phy link过程-CSDN博客
设备树 fixed-link 使用说明-CSDN博客
Linux 网络驱动-MAC、PHY层驱动框架(三)_ethernet-phy-ieee802.3-c22-CSDN博客
特此致谢！
三、深入了解
4. Linux内核中Fixed-Link的相关内容
（2）PHY驱动（driver）匹配
上一回继续讲解of_phy_get_and_connect函数，讲到了of_phy_connect函数，本回开始解析该函数。为了便于理解和回顾，再次贴出of_phy_get_and_connect函数代码，在drivers/net/mdio/of_mdio.c中，如下：
/** * of_phy_get_and_connect * - Get phy node and connect to the phy described in the device tree * @dev: pointer to net_device claiming the phy * @np: Pointer to device tree node for the net_device claiming the phy * @hndlr: Link state callback for the network device * * If successful, returns a pointer to the phy_device with the embedded * struct device refcount incremented by one, or NULL on failure. The * refcount must be dropped by calling phy_disconnect() or phy_detach(). */ struct phy_device *of_phy_get_and_connect(struct net_device *dev, struct device_node *np, void (*hndlr)(struct net_device *)) { phy_interface_t iface; struct device_node *phy_np; struct phy_device *phy; int ret; ret = of_get_phy_mode(np, &iface); if (ret) return NULL; if (of_phy_is_fixed_link(np)) { ret = of_phy_register_fixed_link(np); if (ret < 0) { netdev_err(dev, "broken fixed-link specification\n"); return NULL; } phy_np = of_node_get(np); } else { phy_np = of_parse_phandle(np, "phy-handle", 0); if (!phy_np) return NULL; } phy = of_phy_connect(dev, phy_np, hndlr, 0, iface); of_node_put(phy_np); return phy; } EXPORT_SYMBOL(of_phy_get_and_connect);前文书讲过，通过of_phy_register_fixed_link函数（最终是通过fixed_phy_register函数）完成了PHY设备（struct phy_device）设备的注册。接下来就要调用of_phy_connect函数来匹配PHY驱动（struct phy_driver）。当前正是讲到这个of_phy_connect函数。
of_phy_connect函数。其也在drivers/net/mdio/of_mdio.c中，代码如下：
/** * of_phy_connect - Connect to the phy described in the device tree * @dev: pointer to net_device claiming the phy * @phy_np: Pointer to device tree node for the PHY * @hndlr: Link state callback for the network device * @flags: flags to pass to the PHY * @iface: PHY data interface type * * If successful, returns a pointer to the phy_device with the embedded * struct device refcount incremented by one, or NULL on failure. The * refcount must be dropped by calling phy_disconnect() or phy_detach(). */ struct phy_device *of_phy_connect(struct net_device *dev, struct device_node *phy_np, void (*hndlr)(struct net_device *), u32 flags, phy_interface_t iface) { struct phy_device *phy = of_phy_find_device(phy_np); int ret; if (!phy) return NULL; phy->dev_flags |= flags; ret = phy_connect_direct(dev, phy, hndlr, iface); /* refcount is held by phy_connect_direct() on success */ put_device(&phy->mdio.dev); return ret ? NULL : phy; } EXPORT_SYMBOL(of_phy_connect);先来看一下of_phy_connect函数的注释。
of_phy_connect函数的作用是，获取phy节点并连接到设备树中描述的phy。
参数说明：
- dev：指向声称拥有phy的net_device的指针
- phy_np：指向PHY设备树节点的指针
- hndlr：网络设备的链路状态回调
- flags：传递给PHY的标志
- iface：PHY数据接口类型
返回值：
如果成功，返回一个指向phy_device的指针，其中嵌入的结构设备refcount递增1；否则返回NULL。
必须通过调用phy_disconnect()或phy_detach()来删除引用计数。
下一回开始解析函数具体内容。
