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From: Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH v2 1/3] mfd: add support for Diolan DLN-2 devices
Date: Wed, 3 Sep 2014 17:37:07 +0200
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To: Octavian Purdila <octavian.purdila-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Alexandre Courbot <gnurou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lkml <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Laurentiu Palcu <laurentiu.palcu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
List-Id: linux-gpio@vger.kernel.org

On Wed, Sep 03, 2014 at 04:39:48PM +0300, Octavian Purdila wrote:
> On Tue, Sep 2, 2014 at 6:23 PM, Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:

> > That should be possible using the regmap bus read and write operations.
> 
> I took a closer look on the regmap bus read/write operations and I
> think they are not fit for what we need in the driver. The driver uses
> a request/response model which, IMHO, does not fit well with a
> register read/write API. Yes, maybe we can emulate it, but why do
> that?
> 
> >> (Also creating a regmap class for a particular device seems over
> >> engineering since nobody else is going to use it)
> >
> > Possibly, but it would allow subdrivers to be implemented using a
> > standard interface and also provide register caching for free.
> 
> Using a standard interface is nice, but I think that using the right
> interface type is more important. This hardware does not use registers
> but a messages to communicate with the OS.

You might be right, and as I mentioned, I haven't looked that closely at
the protocol yet. I'll take a look at your updated I/O interface and how
you use it.

Johan