Linux Device Drivers Development

Where to declare platform devices?

Devices are registered along with their resources and data. In this old and deprecated method, they are declared in a separate module, or in the board init file in the arch/<arch>/mach-xxx/yyyy.c, which is arch/arm/mach-imx/mach-imx6q.c in our case, since we use a UDOO quad based on an i.MX6Q from NXP. The platform_device_register() function lets you do that:

static struct platform_device my_device = { 
        .name                   = "my_drv_name", 
        .id                     = 0, 
        .dev.platform_data      = &my_device_pdata, 
        .resource              = jz4740_udc_resources, 
        .num_resources         = ARRY_SIZE(jz4740_udc_resources), 
}; 
platform_device_register(&my_device); 
 

The name of the device is very important, and is used by the kernel to match the driver with the same name.