platform_set_drvdata

           probe函數中定義的局部變量，如果我想在其他地方使用它怎麼辦呢？ 這就需要把它保存起來。內核提供了這個方法，使用函數platform_set_drvdata()可以將ndev保存成平臺總線設備的私有數據。以後再要使用它時只需調用platform_get_drvdata()就可以了。

#define platform_set_drvdata(_dev,data) dev_set_drvdata(&(_dev)->dev, (data))

/*   /drivers/base/dd.c  */

565 int dev_set_drvdata(struct device *dev, void *data)
566 {
567         int error;
568
569         if (!dev->p) {
570                 error = device_private_init(dev);
571                 if (error)
572                         return error;
573         }
574         dev->p->driver_data = data;
575         return 0;
576 }

/* /linux/device.h */

struct device {
    struct device       *parent;

    struct device_private   *p;

    struct kobject kobj;
    const char      *init_name; /* initial name of the device */
    struct device_type  *type;

    struct semaphore    sem;    /* semaphore to synchronize calls to
                     * its driver.
                     */

    struct bus_type *bus;       /* type of bus device is on */
    struct device_driver *driver;   /* which driver has allocated this
                       device */
    void        *platform_data; /* Platform specific data, device
                       core doesn't touch it */
    struct dev_pm_info  power;

#ifdef CONFIG_NUMA
    int     numa_node;  /* NUMA node this device is close to */
#endif
    u64     *dma_mask;  /* dma mask (if dma'able device) */
    u64     coherent_dma_mask;/* Like dma_mask, but for
                         alloc_coherent mappings as
                         not all hardware supports
                         64 bit addresses for consistent
                         allocations such descriptors. */

    struct device_dma_parameters *dma_parms;

    struct list_head    dma_pools;  /* dma pools (if dma'ble) */

    struct dma_coherent_mem *dma_mem; /* internal for coherent mem
                         override */
    /* arch specific additions */
    struct dev_archdata archdata;

    dev_t           devt;   /* dev_t, creates the sysfs "dev" */

    spinlock_t      devres_lock;
    struct list_head    devres_head;

    struct klist_node   knode_class;
    struct class        *class;
    const struct attribute_group **groups;  /* optional groups */

    void    (*release)(struct device *dev);
};

/* /drivers/base/base.h */

73 struct device_private {
74         struct klist klist_children;
75         struct klist_node knode_parent;
76         struct klist_node knode_driver;
77         struct klist_node knode_bus;
78         struct list_head deferred_probe;
79         void *driver_data;
80         struct device *device;
81 };

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