Hello Word Device Tree Based device driver

1. I created a custom device in my device tree:

   my_device@ffdf0000 {
       compatible = "my_driver";
       reg = <0xffdf0000 0x1000> 
       /* 
        * reg = address of device and size 
        * (Minimum is System's Pagesize = 0x1000 Byte in my case
        */
   }
   

2. I wrote a Kernel stub for this Device:

   (Here I took kernel_src/drivers/uio/uio_pdrv_genirq.c and Hans J. Koch: Userspace I/O drivers in a realtime context (device driver tutorial) as basis.)

   This stub has following two structs:

   The of_device_id struct:

   static struct of_device_id my_match_table[] = {
        {
                .compatible = "my_driver",
        },
        {0}
   };
   MODULE_DEVICE_TABLE(of, my_match_table);
   

   and the driver struct itself:

   static struct platform_driver my_platform_driver = {
           .probe = my_probe,
           .remove = my_remove,
           .driver = {
                   .name = "my_driver",
                   .owner = THIS_MODULE,
                   .of_match_table = of_match_ptr(my_match_table),
           },
   };
   

3. Now I have access to the properties of the device tree in my probe function:

   static int my_probe(struct platform_device *dev)
   {
           struct uio_info *uioinfo;
           struct resource *r = &dev->resource[0];
           [...]
           uioinfo->name = dev->dev.of_node->name /* name from device tree: "my_device" */
           uioinfo->mem[0].addr = r->start; /* device address from device tree */
           uioinfo->mem[0].size = resource_size(r); /* size from device tree */
           [...]
   }
   

When there is a match in compatible with both the kernel stub's entry and the device tree, the probe function is called.