linux-kernel - MFD: core assumes that all children are platform devices

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Message-Id: <2F9D884C-6B95-4F81-8445-8056676B28D8@sonatest.com>
Date:	Mon, 28 Nov 2011 11:23:00 -0500
From:	Jean-François Dagenais <dagenaisj@...atest.com>
To:	Samuel Ortiz <sameo@...ux.intel.com>
Cc:	open list <linux-kernel@...r.kernel.org>
Subject: MFD: core assumes that all children are platform devices

Hi,

I have a pci driver that registers with UIO for it's operations. As a consequence, the pci device
instance has a child device of class uio.

My driver also declares a ds1wm instance that has it's register interface at an offset in BAR0
of the pci device, as an MFD cell.

When I call mfd_remove_devices, MFD proceeds to enumerate ALL the parent device's chilren
and assumes that they are MFD cells, and thus platform_device, which is not true in my case.
(...uio is a child of the parent pci device)

I had (luckily or unluckily) not seen signs of this broken assumption on certain setups I have
used, but in my current setup, this page-faults every time now.

This is a major thing and I have not found the assumption documented anywhere.

I could first declare a new child device on my pci device and then declare it as the parent to
the mfd cells...

Or, is there a way for the mfd-core, as it's doing the "for each child device", to recognize
non-MFD-cell children and skip them?

/jfd--
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