On Tue, Nov 22, 2011 at 9:45 AM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Tue, Nov 22, 2011 at 07:42:59AM -0800, Greg KH wrote: >> On Mon, Nov 21, 2011 at 05:40:42PM -0800, Mike Turquette wrote: >> > .sysfs support. Visualize your clk tree at /sys/clk! Where would be >> > a better place to put the clk tree besides the root of /sys/? >> >> Um, in the "proper" place for it under /sys/devices like the rest of the >> device tree is? > > I'd suggest that making the clock tree visible in sysfs (and therefore > part of the kernel ABI) is not a good idea. Some of the nodes in there > will be specific to the implementation. Exposing the clock nodes means > that if you have to change the clock tree structure, you change the > visible userspace ABI. It is true that the ABI will change dynamically. > > So, I'd suggest that we need to see a justification for this, rather > than exposing this stuff via debugfs as has been done with existing > implementations. Userspace tools like powerdebug (and maybe someday powertop) hope to use a reliable-looking interface to view clk data. There are obvious uses for this data in a debug tool, the most obvious of which is "which clk isn't turning off when it should?". I can migrate this stuff to debugfs, but it adds the burden of having debugfs enabled for folks that want to view this data. I would also argue that sysfs is there to model various aspects of system topology and a clk tree certainly fits the bill. If others also agree that it should reside only in debugfs then I'll move it there for V4. Thanks, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
