Re: [PATCH 01/12] drm/amdgpu: add amd_gnb_bus support

Felix Kuehling <felix.kuehling@xxxxxxx> · Fri, 7 Aug 2015 16:03:08 -0400



    On 15-08-07 02:24 PM, Mark Brown wrote:

    
      Like I say this just sounds like exactly the sort of thing we
      handle
      with an MFD, it's a very common pattern.
    
    
    OK, the MFD documentation in Documentation/devicetree/bindings/mfd/
    seemed to imply a dependency on a devicetree. It took me a moment to
    realize that's just the most common scenario.

    
    In our case we don't have a devicetree, we're talking about a PC
    platform. The GPU (GNB) is a PCIe device. Does the following sound
    like proper use of the MFD framework for our case?

    
      GPU driver gets initialized, detects a GPU with audio
        co-processor (ACP)

      
      GPU driver registers mfd_cell for the ACP device using
        mfd_add_hotplug_devices
      
        It's not really hot-plug, but the mem_base, irq_base,
          irq_domain parameters don't make sense for us

        
      Platform_data in the MFD cell contains audio driver-specific
        data, function pointers, etc. for the audio driver to use
      Audio driver binds to platform device created by
        mfd_add_hotplug_devices based on driver name

      
    Or do we have to convert our GPU device to be an MFD cell itself, a
    peer of the ACP cell?

    
    Thanks,

      Felix

    -- 
F e l i x   K u e h l i n g
SMTS Software Development Engineer | Vertical Workstation/Compute
1 Commerce Valley Dr. East, Markham, ON L3T 7X6 Canada
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