在Linux中获取指向struct设备的指针的更干净的方法是哪种? [英] Which is the cleaner way to get a pointer to a struct device in linux?

问题描述

我需要获取一个指向在Linux中注册的特定设备的指针.简而言之，此设备代表一个mii_bus对象.问题在于该设备似乎不属于总线(其dev->bus为NULL)，因此我无法使用例如功能bus_for_each_dev.但是，该设备已由开放固件层注册，并且我可以在/sys/bus/of_platform中看到相对的of_device(这是我感兴趣的设备的父级).我的设备也在class中注册，因此我可以在/sys/class/mdio_bus中找到它.现在的问题:

i'd need to obtain a pointer to a particular device registered in linux. Briefly, this device represents a mii_bus object. The problem is that this device seems doesn't belong to a bus (its dev->bus is NULL) so i can't use for example the function bus_for_each_dev. The device is however registered by the Open Firmware layer and i can see the relative of_device (which is the parent of the device i'm interested in) in /sys/bus/of_platform. My device is also registered in a class so i can find it in /sys/class/mdio_bus. Now the questions:

1. 是否可以使用指向of_device的指针来获取指针，该指针是我们想要的设备的父级?

1. It's possible to obtain the pointer using the pointer to the of_device that is the parent of the device we want?

如何仅使用名称获取指向已实例化的类的指针?如果可能，我可以遍历该类的设备.

How can i get a pointer to an already instantiated class by using only the name?If it was possible i could iterate over the devices of that class.

任何其他建议将非常有用！谢谢大家.

Any other advice would be very useful! Thank you all.

推荐答案

我找到了方法.我简要地解释一下，也许它可能有用.我们可以使用的方法是device_find_child.该方法将指向实现比较逻辑的函数的指针作为第三个参数.如果以特定设备作为第一个参数调用时函数返回的值不为零，则device_find_child将返回该指针.

I found the way. I explain it briefly, maybe it could be useful. The method we could use is device_find_child. The method takes as third parameter a pointer to a function that implements the comparison logic. If the function returns not zero when called with a particular device as first parameter, device_find_child will return that pointer.

#include <linux/device.h>
#include <linux/of_platform.h>

static int custom_match_dev(struct device *dev, void *data)
{
  /* this function implements the comaparison logic. Return not zero if device
     pointed by dev is the device you are searching for.
   */
}

static struct device *find_dev()
{
  struct device *ofdev = bus_find_device_by_name(&of_platform_bus_type,
                                                 NULL, "OF_device_name");
  if (ofdev)
  {
    /* of device is the parent of device we are interested in */

    struct device *real_dev = device_find_child(ofdev,
                                                NULL, /* passed in the second param to custom_match_dev */
                                                custom_match_dev);
    if (real_dev)
      return real_dev;
  }
  return NULL;
}

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