linux driver probe 调用时机

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1、DTS树解析，创建platform 设备，调用platform_device_register ,驱动加载后会调用platform_driver_register,最终都会调用device_register,driver_register。

2、通过device_register,driver_register等关联起来。

（1）device_register

device_register->bus_probe_devce->device_attach->_device_attach->driver_probe_device->really_probe-> bus_probe或者driver_probe

针对设备去关联遍历每个驱动。

int device_attach(struct device *dev)413 { 414     int ret = 0;415 416     device_lock(dev);417     if (dev->driver) {418         if (klist_node_attached(&dev->p->knode_driver)) {419             ret = 1;420             goto out_unlock;421         }422         ret = device_bind_driver(dev);423         if (ret == 0)424             ret = 1;425         else {426             dev->driver = NULL;427             ret = 0;428         }429     } else {430         ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);431         pm_request_idle(dev);432     }433 out_unlock:434     device_unlock(dev);435     return ret;436 }

1 int driver_probe_device(struct device_driver *drv, struct device *dev)372 {373     int ret = 0;374 375     if (!device_is_registered(dev))376         return -ENODEV;377 378     pr_debug("bus: '%s': %s: matched device %s with driver %s\n",379          drv->bus->name, __func__, dev_name(dev), drv->name);380 381     pm_runtime_barrier(dev);382     ret = really_probe(dev, drv);383     pm_request_idle(dev);384 385     return ret;386 }

265 static int really_probe(struct device *dev, struct device_driver *drv)266 {267     int ret = 0;268 269     atomic_inc(&probe_count);270     pr_debug("bus: '%s': %s: probing driver %s with device %s\n",271          drv->bus->name, __func__, drv->name, dev_name(dev));272     WARN_ON(!list_empty(&dev->devres_head));273 274     dev->driver = drv;275 276     /* If using pinctrl, bind pins now before probing */277     ret = pinctrl_bind_pins(dev);278     if (ret)279         goto probe_failed;280 281     if (driver_sysfs_add(dev)) {282         printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",283             __func__, dev_name(dev));284         goto probe_failed;285     }286 287     if (dev->bus->probe) {288         ret = dev->bus->probe(dev);289         if (ret)290             goto probe_failed;291     } else if (drv->probe) {292         ret = drv->probe(dev);293         if (ret)294             goto probe_failed;295     }296 297     driver_bound(dev);

（2）driver_register

driver_register ->bus_add_driver->driver_attach->__driver_attach->driver_probe_device->really_probe ->bus_probe或者driver_probe

如果要使用driver_poble, device_driver的probe需要提前被设置好。

如果要使用bus_probe,需要封装好并调用具体设备驱动的probe.

9 static int __driver_attach(struct device *dev, void *data)440 {441     struct device_driver *drv = data;442 443     /*444      * Lock device and try to bind to it. We drop the error445      * here and always return 0, because we need to keep trying446      * to bind to devices and some drivers will return an error447      * simply if it didn't support the device.448      *449      * driver_probe_device() will spit a warning if there450      * is an error.451      */452 453     if (!driver_match_device(drv, dev))454         return 0;455 456     if (dev->parent)    /* Needed for USB */457         device_lock(dev->parent);458     device_lock(dev);459     if (!dev->driver)460         driver_probe_device(drv, dev);461     device_unlock(dev);462     if (dev->parent)463         device_unlock(dev->parent);464 465     return 0;466 }

265 static int really_probe(struct device *dev, struct device_driver *drv)266 {267     int ret = 0;268 269     atomic_inc(&probe_count);270     pr_debug("bus: '%s': %s: probing driver %s with device %s\n",271          drv->bus->name, __func__, drv->name, dev_name(dev));272     WARN_ON(!list_empty(&dev->devres_head));273 274     dev->driver = drv;275 276     /* If using pinctrl, bind pins now before probing */277     ret = pinctrl_bind_pins(dev);278     if (ret)279         goto probe_failed;280 281     if (driver_sysfs_add(dev)) {282         printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",283             __func__, dev_name(dev));284         goto probe_failed;285     }286 287     if (dev->bus->probe) {288         ret = dev->bus->probe(dev);289         if (ret)290             goto probe_failed;291     } else if (drv->probe) {292         ret = drv->probe(dev);293         if (ret)294             goto probe_failed;295     }296 297     driver_bound(dev);

3、platform,amba 设备等等通过对也会设置driver参数，最终回调到具体设备的probe。

bus probe 也会设置driver参数，最终回调到具体设备的probe。

总结，因此可分为

直接调用通过设置driver->probe 参数为具体设备驱动probe，从而可以调用到具体设备驱动的probe.

间接调用通过设置driver->probe参数为latform_probe或者amba_probe等等，,最终也回调到具体设备的probe.

通过bus->probe 调用具体设备的probe，如i2c设备驱动的probe，调用方法设置如下

9 struct bus_type i2c_bus_type = { 470     .name       = "i2c", 471     .match      = i2c_device_match, 472     .probe      = i2c_device_probe, 473     .remove     = i2c_device_remove, 474     .shutdown   = i2c_device_shutdown, 475     .pm     = &i2c_device_pm_ops, 476 };

 static int i2c_device_probe(struct device *dev) 260 { 261     struct i2c_client   *client = i2c_verify_client(dev); 262     struct i2c_driver   *driver; 263     int status; 264  265     if (!client) 266         return 0; 267  268     driver = to_i2c_driver(dev->driver); 269     if (!driver->probe || !driver->id_table) 270         return -ENODEV; 271  272     if (!device_can_wakeup(&client->dev)) 273         device_init_wakeup(&client->dev, 274                     client->flags & I2C_CLIENT_WAKE); 275     dev_dbg(dev, "probe\n"); 276  277     acpi_dev_pm_attach(&client->dev, true); 278     status <span style="color:#FF0000;">=driver->probe(client, i2c_match_id(driver->id_table, client));</span> 279     if (status)

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