From: Arnd Bergmann <arnd@arndb.de>
To: Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH 3/5] drivers/misc: rf/ad9361: AD9361 device driver for Radio phy
Date: Wed, 19 Jun 2013 16:58:04 +0200
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Cc: "Lars-Peter Clausen" <lars@metafoo.de>, akhil.goyal@freescale.com,
        linux-kernel@vger.kernel.org, pankaj.chauhan@freescale.com,
        "Getz, Robin" <robin.getz@analog.com>,
        "Hennerich, Michael" <Michael.Hennerich@analog.com>,
        "Lars-Peter Clausen" <lars-peter.clausen@analog.com>
References: <1371456566-4934-1-git-send-email-akhil.goyal@freescale.com> <51C1AAC4.3010605@metafoo.de> <20130619143042.GB8073@kroah.com>
In-Reply-To: <20130619143042.GB8073@kroah.com>
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On Wednesday 19 June 2013, Greg KH wrote:
> On Wed, Jun 19, 2013 at 02:57:40PM +0200, Lars-Peter Clausen wrote:
> > On 06/17/2013 10:09 AM, akhil.goyal@freescale.com wrote:
> > 
> > This is interesting. We at Analog Devices are currently also working on a
> > driver for this part. We are using the Linux Industrial IO (IIO) framework
> > though, since the AD9361 is more or less a multifunction device implementing
> > different functions already covered by the IIO framework, like ADCs, DACs,
> > clock chips and so on.
> 
> That's the "proper" api for this, not a bunch of chip-custom ioctls that
> aren't documented anywhere.

Depending on what functions there are in the device, it might actually be
better to make the chip itself an MFD device, and have sub-functions handled
by drivers/iio, drivers/clk, drivers/pwm etc. For the bigger picture I
definitely agree: it should use the existing subsystems whereever possible.
It may well be that a single IIO device is the right answer in this case,
but a new subsystem that covers the entire chip and adds a custom user
interface is almost certainly not.

	Arnd
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