From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v2] misc: Driver for Silicon Labs Si570 and compatibles Date: Tue, 26 Apr 2011 16:00:23 +0200 Message-ID: <201104261600.23675.arnd@arndb.de> References: <1303248968-5069-1-git-send-email-guenter.roeck@ericsson.com> <20110421233415.GC2786@local> <1303501213.31666.27.camel@groeck-laptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1303501213.31666.27.camel@groeck-laptop> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: guenter.roeck-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org Cc: "Hans J. Koch" , Greg Kroah-Hartman , Andrew Morton , Jonathan Cameron , Randy Dunlap , "linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-i2c@vger.kernel.org On Friday 22 April 2011, Guenter Roeck wrote: > On Thu, 2011-04-21 at 19:34 -0400, Hans J. Koch wrote: > > I don't think the UIO framework is the right place for such a thing. If it's > > just this one driver that needs modification of a clock from userspace, then > > a sysfs attribute could be added to that driver. If there are several drivers > > that need this, then the clock framework should be extended. > > Agreed. Also, the desire to control the clock frequency through such a > driver (user mode or not) seems odd. Such an approach would be > inherently non-scalable (for my part I would have to support two drivers > already). Voltage regulators are not controlled through the drivers of > the chips they are providing power to either, but have an independent > existence. I think you are talking about different things here. What I think Hans was saying is that it should be in the specific UIO driver, not in the framework, which I can agree with. If we get a bunch of these, we can still make it generic at a later point, but that is not your problem. I think exporting the clock to kernel drivers as a struct clk is the most useful approach to allow reuse, and then you just have to interface to that from your existing UIO driver. Arnd