本文主要是介绍linux内核中的以太网phy芯片的驱动介绍：以lan8720和ip101作为对比，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
背景：
由于公司开发的新项目中设备需要联网，使用了MZ391的4G模块，并通过rmii接口和phy芯片ip101gr链接。
主控平台rv1108通过rmii接口和phy芯片lan8720相连接。
ip101gr和lan8720通过类似于以太网的双绞线：tx+，tx-，rx+，rx-，相连接。之所以mac和phy要分开，是因为mac属于数字电路部分，主要处理的信号是属于数字信号，将上层ip层等数据通过rmii接口发送给phy，或者将phy发送过来的数据在发送给上层等。phy属于模拟电路部分，主要处理魔力电路信号，就是将从rmii接收到的数据转换成可以通过网线传输的差分模拟信号，或者是将网线上接收到的差分模拟信号转换为可以通过rmii发送的数字信号。
硬件链接：https://blog.csdn.net/u010299133/article/details/87716700
驱动介绍（主要对比以下两个文件）：
dts文件加上mac的配置
lan8720a的驱动代码：drivers/net/phy/smsc.c
ip101gr的驱动代码：drivers/net/phy/icplus.c
在内核中需要sudo make menuconfig中选择好相应的驱动，在编译的时候能够编译进入内核。
当然如果想要phy芯片能够正常工作，还必须在menuconfig中选择好mac驱动，由于以太网传输数据量大，所以在芯片的mac和我们这里介绍的phy芯片之间都需要使用到dma：
驱动的注册和注销：
在内核加载完成后，会执行相应的驱动的插入函数中的phy驱动的注册。
其中比较重要的参数：phy_driver结构体
phy_id：the result of reading the UID register of this phy type，and them with the phy_id_mask。this driver only work for phys with id which match this field
name：the friendly name of the phy type
phy_id_mask：the defines the important bits of the phy_id
features：a list of feature（speed，duplex，etc） supported by the phy
flag：A bit field defining certain other feature this phy support
struct phy_driver {u32 phy_id;char *name;unsigned int phy_id_mask;u32 features;u32 flags;/** Called to initialize the PHY,* including after a reset*/int (*config_init)(struct phy_device *phydev);/** Called during discovery. Used to set* up device-specific structures, if any*/int (*probe)(struct phy_device *phydev);/* PHY Power Management */int (*suspend)(struct phy_device *phydev);int (*resume)(struct phy_device *phydev);/** Configures the advertisement and resets* autonegotiation if phydev->autoneg is on,* forces the speed to the current settings in phydev* if phydev->autoneg is off*/int (*config_aneg)(struct phy_device *phydev);/* Determines the negotiated speed and duplex */int (*read_status)(struct phy_device *phydev);/* Clears any pending interrupts */int (*ack_interrupt)(struct phy_device *phydev);/* Enables or disables interrupts */int (*config_intr)(struct phy_device *phydev);/** Checks if the PHY generated an interrupt.* For multi-PHY devices with shared PHY interrupt pin*/int (*did_interrupt)(struct phy_device *phydev);/* Clears up any memory if needed */void (*remove)(struct phy_device *phydev);/* Returns true if this is a suitable driver for the given* phydev. If NULL, matching is based on phy_id and* phy_id_mask.*/int (*match_phy_device)(struct phy_device *phydev);/* Handles ethtool queries for hardware time stamping. */int (*ts_info)(struct phy_device *phydev, struct ethtool_ts_info *ti);/* Handles SIOCSHWTSTAMP ioctl for hardware time stamping. */int (*hwtstamp)(struct phy_device *phydev, struct ifreq *ifr);/** Requests a Rx timestamp for 'skb'. If the skb is accepted,* the phy driver promises to deliver it using netif_rx() as* soon as a timestamp becomes available. One of the* PTP_CLASS_ values is passed in 'type'. The function must* return true if the skb is accepted for delivery.*/bool (*rxtstamp)(struct phy_device *dev, struct sk_buff *skb, int type);/** Requests a Tx timestamp for 'skb'. The phy driver promises* to deliver it using skb_complete_tx_timestamp() as soon as a* timestamp becomes available. One of the PTP_CLASS_ values* is passed in 'type'.*/void (*txtstamp)(struct phy_device *dev, struct sk_buff *skb, int type);/* Some devices (e.g. qnap TS-119P II) require PHY register changes to* enable Wake on LAN, so set_wol is provided to be called in the* ethernet driver's set_wol function. */int (*set_wol)(struct phy_device *dev, struct ethtool_wolinfo *wol);/* See set_wol, but for checking whether Wake on LAN is enabled. */void (*get_wol)(struct phy_device *dev, struct ethtool_wolinfo *wol);struct device_driver driver;
};.config_aneg = genphy_config_aneg,
/*** genphy_config_aneg - restart auto-negotiation or write BMCR* @phydev: target phy_device struct** Description: If auto-negotiation is enabled, we configure the* advertising, and then restart auto-negotiation. If it is not* enabled, then we write the BMCR.*/
int genphy_config_aneg(struct phy_device *phydev)
{int result;if (AUTONEG_ENABLE != phydev->autoneg)return genphy_setup_forced(phydev);result = genphy_config_advert(phydev);if (result < 0) /* error */return result;if (result == 0) {/* Advertisement hasn't changed, but maybe aneg was never on to* begin with? Or maybe phy was isolated? */int ctl = phy_read(phydev, MII_BMCR);if (ctl < 0)return ctl;if (!(ctl & BMCR_ANENABLE) || (ctl & BMCR_ISOLATE))result = 1; /* do restart aneg */}/* Only restart aneg if we are advertising something different* than we were before. */if (result > 0)result = genphy_restart_aneg(phydev);return result;
}
EXPORT_SYMBOL(genphy_config_aneg);.read_status = lan87xx_read_status,
static int lan87xx_read_status(struct phy_device *phydev)
{int err = genphy_read_status(phydev);if (!phydev->link) {/* Disable EDPD to wake up PHY */int rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);if (rc < 0)return rc;rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,rc & ~MII_LAN83C185_EDPWRDOWN);if (rc < 0)return rc;/* Sleep 64 ms to allow ~5 link test pulses to be sent */msleep(64);/* Re-enable EDPD */rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);if (rc < 0)return rc;rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,rc | MII_LAN83C185_EDPWRDOWN);if (rc < 0)return rc;}return err;
}.config_init = smsc_phy_config_init,
static int smsc_phy_config_init(struct phy_device *phydev)
{int rc = phy_read(phydev, MII_LAN83C185_SPECIAL_MODES);if (rc < 0)return rc;/* If the SMSC PHY is in power down mode, then set it* in all capable mode before using it.*/if ((rc & MII_LAN83C185_MODE_MASK) == MII_LAN83C185_MODE_POWERDOWN) {int timeout = 50000;/* set "all capable" mode and reset the phy */rc |= MII_LAN83C185_MODE_ALL;phy_write(phydev, MII_LAN83C185_SPECIAL_MODES, rc);phy_write(phydev, MII_BMCR, BMCR_RESET);/* wait end of reset (max 500 ms) */do {udelay(10);if (timeout-- == 0)return -1;rc = phy_read(phydev, MII_BMCR);} while (rc & BMCR_RESET);}rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);if (rc < 0)return rc;/* Enable energy detect mode for this SMSC Transceivers */rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,rc | MII_LAN83C185_EDPWRDOWN);if (rc < 0)return rc;return smsc_phy_ack_interrupt (phydev);
}.ack_interrupt = smsc_phy_ack_interrupt,
static int smsc_phy_ack_interrupt(struct phy_device *phydev)
{int rc = phy_read (phydev, MII_LAN83C185_ISF);return rc < 0 ? rc : 0;
}.config_intr = smsc_phy_config_intr,
static int smsc_phy_config_intr(struct phy_device *phydev)
{int rc = phy_write (phydev, MII_LAN83C185_IM,((PHY_INTERRUPT_ENABLED == phydev->interrupts)? MII_LAN83C185_ISF_INT_PHYLIB_EVENTS: 0));return rc < 0 ? rc : 0;
}.suspend = genphy_suspend,
int genphy_suspend(struct phy_device *phydev)
{int value;mutex_lock(&phydev->lock);value = phy_read(phydev, MII_BMCR);phy_write(phydev, MII_BMCR, (value | BMCR_PDOWN));mutex_unlock(&phydev->lock);return 0;
}
EXPORT_SYMBOL(genphy_suspend);.resume = genphy_resume,
int genphy_resume(struct phy_device *phydev)
{int value;mutex_lock(&phydev->lock);value = phy_read(phydev, MII_BMCR);phy_write(phydev, MII_BMCR, (value & ~BMCR_PDOWN));mutex_unlock(&phydev->lock);return 0;
}
EXPORT_SYMBOL(genphy_resume);其中phy_write和phy_read分别如下:其中mdiobus_read和mdiobus_write位于drivers/net/phy/mdio_bus.c文件中，就是实现对phy芯片上的mdio和mdc的操作。
/*** phy_read - Convenience function for reading a given PHY register* @phydev: the phy_device struct* @regnum: register number to read** NOTE: MUST NOT be called from interrupt context,* because the bus read/write functions may wait for an interrupt* to conclude the operation.*/
static inline int phy_read(struct phy_device *phydev, u32 regnum)
{return mdiobus_read(phydev->bus, phydev->addr, regnum);
}/*** phy_write - Convenience function for writing a given PHY register* @phydev: the phy_device struct* @regnum: register number to write* @val: value to write to @regnum** NOTE: MUST NOT be called from interrupt context,* because the bus read/write functions may wait for an interrupt* to conclude the operation.*/
static inline int phy_write(struct phy_device *phydev, u32 regnum, u16 val)
{return mdiobus_write(phydev->bus, phydev->addr, regnum, val);
}
phy_device结构体：
/* phy_device: An instance of a PHY
*
* drv: Pointer to the driver for this PHY instance
* bus: Pointer to the bus this PHY is on
* dev: driver model device structure for this PHY
* phy_id: UID for this device found during discovery
* c45_ids: 802.3-c45 Device Identifers if is_c45.
* is_c45: Set to true if this phy uses clause 45 addressing.
* state: state of the PHY for management purposes
* dev_flags: Device-specific flags used by the PHY driver.
* addr: Bus address of PHY
* link_timeout: The number of timer firings to wait before the
* giving up on the current attempt at acquiring a link
* irq: IRQ number of the PHY's interrupt (-1 if none)
* phy_timer: The timer for handling the state machine
* phy_queue: A work_queue for the interrupt
* attached_dev: The attached enet driver's device instance ptr
* adjust_link: Callback for the enet controller to respond to
* changes in the link state.
* adjust_state: Callback for the enet driver to respond to
* changes in the state machine.
*
* speed, duplex, pause, supported, advertising, and
* autoneg are used like in mii_if_info
*
* interrupts currently only supports enabled or disabled,
* but could be changed in the future to support enabling
* and disabling specific interrupts
*
* Contains some infrastructure for polling and interrupt
* handling, as well as handling shifts in PHY hardware state
*/
struct phy_device {/* Information about the PHY type *//* And management functions */struct phy_driver *drv;struct mii_bus *bus;struct device dev;u32 phy_id;struct phy_c45_device_ids c45_ids;bool is_c45;enum phy_state state;u32 dev_flags;phy_interface_t interface;/* Bus address of the PHY (0-31) */int addr;/** forced speed & duplex (no autoneg)* partner speed & duplex & pause (autoneg)*/int speed;int duplex;int pause;int asym_pause;/* The most recently read link state */int link;/* Enabled Interrupts */u32 interrupts;/* Union of PHY and Attached devices' supported modes *//* See mii.h for more info */u32 supported;u32 advertising;int autoneg;int link_timeout;/** Interrupt number for this PHY* -1 means no interrupt*/int irq;/* private data pointer *//* For use by PHYs to maintain extra state */void *priv;/* Interrupt and Polling infrastructure */struct work_struct phy_queue;struct delayed_work state_queue;atomic_t irq_disable;struct mutex lock;struct net_device *attached_dev;void (*adjust_link)(struct net_device *dev);void (*adjust_state)(struct net_device *dev);
};
参考文献：
https://blog.csdn.net/jk198310/article/details/12909341
https://blog.csdn.net/helloyizhou/article/details/72675533
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