Re: [RFC] Changes to the driver model class code.

From: John Lenz
Date: Tue Mar 15 2005 - 14:55:17 EST


On 03/15/05 13:08:47, Dominik Brodowski wrote:
On Tue, Mar 15, 2005 at 09:08:34AM -0800, Greg KH wrote:
> Then I moved the USB host controller code to use this new interface.
> That was a bit more complex as it used the struct class and struct
> class_device code directly. As you can see by the patch, the result is
> pretty much identical, and actually a bit smaller in the end.
>
> So I'll be slowly converting the kernel over to using this new
> interface, and when finished, I can get rid of the old class apis (or
> actually, just make them static) so that no one can implement them
> improperly again...
>
> Comments?

Also, it seems to me that you view the class subsystem to be too closely
related to /dev entries -- and for these /dev entries class_simple was
introduced, IIRC. However, /dev is not the reason the class subsystem was
introduced for -- instead, it describes _types_ of devices which want to
share (userspace and in-kernel) interfaces.

Exactly. I hope you take a close look at drivers/video/backlight/backlight.c and drivers/video/backlight/lcd.c and how it uses the class device. Neither does not create anything in /dev. The model and design that is used in the backlight.c and lcd.c code is also being used in some (currently out of tree) new code I am working on. Either continue to support the current class API or provide a design and API that works with backlight.c

John

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