Re: [patch 0/8] Nesting class_device patches that actually work

[Vojtech Pavlik <vojtech@suse.cz>]

On Fri, Oct 14, 2005 at 02:14:23PM +0200, Kay Sievers wrote:

> Sorry, my previous drawing wasn't correct for the input devices.
> 
> Here is a new picture of the:
>   - all classes are unique and flat and will stay the same,
>     even when the hierarchy of the devices changes
>   - all hierarchy is _only_ in /sys/devices
>   - virtual and physical devices are both in /sys/devices
> proposal.

I like the layout.

I'm not completely sure whether mouse0 and event0 are the same class,
because they have different APIs and protocols. And I believe that class
is exactly that - a collection of devices where you can use the same API
to access them. A possibility would be to do it like this:

> /sys
> |-- class
> |   |-- mouse
> |   |   |-- mice -> ../../devices/mice
> |   |   |-- mouse0 -> ../../devices/platform/i8042/serio0/input0/mouse0
> |   |---event
> |   |   `-- event0 -> ../../devices/platform/i8042/serio0/input0/event0
> |   |-- input
> |   |   `-- input0 -> ../../devices/platform/i8042/serio0/input0
> |   `-- tty
> |       `-- console -> ../../devices/console

It might be too much work to create a new class in each of the
handlers, it'd be similar to harddrives and partititions having
different classes.

> /sys
> |-- class
> |   |-- input
> |   |   |-- mice -> ../../devices/mice
> |   |   |-- mouse0 -> ../../devices/platform/i8042/serio0/input0/mouse0
> |   |   `-- event0 -> ../../devices/platform/i8042/serio0/input0/event0
> |   |-- input_device
> |   |   `-- input0 -> ../../devices/platform/i8042/serio0/input0
> |
> |-- devices
> |   |-- platform
> |   |   `-- i8042
> |   |       `-- serio0
> |   |            `-- input0
> |   |                 |-- event0
> |   |                 |   `-- dev
> |   |                 |-- mouse0
> |   |                 |   `-- dev
> |   |                 |-- bind_mode
> |   |                 |-- description
> |   |                 |-- id
> |   |                 |   |-- extra
> |   |                 |   |-- id
> |   |                 |   |-- proto
> |   |                 |   `-- type
> |   |                 |-- modalias
> |   |                 |-- protocol
> |   |                 |-- rate
> |   |                 |-- resetafter
> |   |                 `-- resolution
> |   |-- mice
> |   |   `-- dev
 
Having 'mice' at top level is not very nice. It's a logical consequence
of the system, and as such probably correct, though.

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR