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Message-ID: <20170225145504.b66vvsi6hiilmaj2@ihha.localdomain>
Date: Sat, 25 Feb 2017 16:55:11 +0200
From: Sakari Ailus <sakari.ailus@....fi>
To: Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
Cc: Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>,
linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
devicetree@...r.kernel.org, CARLOS.PALMINHA@...opsys.com,
Arnd Bergmann <arnd@...db.de>,
"David S. Miller" <davem@...emloft.net>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Guenter Roeck <linux@...ck-us.net>,
Hans Verkuil <hans.verkuil@...co.com>,
Lars-Peter Clausen <lars@...afoo.de>,
Mark Rutland <mark.rutland@....com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Pali Rohár <pali.rohar@...il.com>,
Pavel Machek <pavel@....cz>,
Robert Jarzmik <robert.jarzmik@...e.fr>,
Rob Herring <robh+dt@...nel.org>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
Steve Longerbeam <slongerbeam@...il.com>
Subject: Re: [PATCH v9 1/2] Add OV5647 device tree documentation
On Sat, Feb 25, 2017 at 04:50:53PM +0200, Sakari Ailus wrote:
> Although, the driver could try to work on the actual obtained frequency.
> This is unlikely to work though, but it won't be very easy to figure out
> why the device isn't working. Having the frequency in DT accessible for the
> driver to check makes failing early with a clear error message possible.
The below point actually makes the above matter a non-issue: this driver
will contain a list of supported frequencies. A SMIA driver that I
typically work with, for instance, does not. So I think your suggestion of
having the CCF handle setting the frequency is a good one.
>
> >
> > So, the clock frequency set up is delegated to CCF, and when any other
> > than 25 MHz frequencies are got supported, that's only the matter of
> > driver updates, DTBs won't be touched.
>
> Indeed. The new supported frequencies in this case will be additional
> single values; there won't be ranges or such. The register lists the
> driver contains are more or less dependent on that frequency.
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@....fi XMPP: sailus@...iisi.org.uk
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