help with writing a usb mouse driver

help with writing a usb mouse driver

[Jeffrey Lim]

Note: pls cc me in any replies as i'm not subscribed to the list.

hi guys, i've been trying to write a usb mouse driver for a custom
mouse, but i'm getting stuck.

I previously started out with trying to hack usbmouse.c, but
apparently after a wild goose chase, it seems that that is not the
recommended path to take. It supposedly conflicts with the hid driver,
though in what way i do not know. (If somebody could enlighten me on
this, pls do. Documentation/input/input.txt does not really explain
why).

So now it almost seems as if the only code i have for analysis and as
a sample is the hid code (hid-core.c, hid-input.c, i assume). But the
problem for me is that this code is too complex for me, and really
doesn't offer the easiest way to get started on this project. I'm not
too sure usb-skeleton.c does it either, because it doesn't have the
code for interfacing with the input layer.

While i could take some pointers for interfacing with the input layer
from usbmouse.c, i really don't see how I could differentiate what
code to take, cos heck, that thing doesnt even work (conflicts with
hid), and I don't even know why! (That thing looks pretty ok to me).

Could somebody give me some pointers on how to go about starting my
project, and where I might perhaps be able to get my hands on some
code that i can work with?

I'm using kernel 2.4.20.

Thanks,
-jf

Re: help with writing a usb mouse driver

[Greg KH]

On Sat, Nov 27, 2004 at 11:39:37PM +0800, Jeffrey Lim wrote:
> Note: pls cc me in any replies as i'm not subscribed to the list.
> 
> hi guys, i've been trying to write a usb mouse driver for a custom
> mouse, but i'm getting stuck.
> 
> I previously started out with trying to hack usbmouse.c, but
> apparently after a wild goose chase, it seems that that is not the
> recommended path to take. It supposedly conflicts with the hid driver,
> though in what way i do not know. (If somebody could enlighten me on
> this, pls do. Documentation/input/input.txt does not really explain
> why).

The Kconfig documentation for that driver should explain why.
usbmouse.c is for USB Boot Protocol Mice only.  Only if you understand
what this protocol is, should you use that driver.  Everyone else should
use the hid driver.

> So now it almost seems as if the only code i have for analysis and as
> a sample is the hid code (hid-core.c, hid-input.c, i assume). But the
> problem for me is that this code is too complex for me, and really
> doesn't offer the easiest way to get started on this project. I'm not
> too sure usb-skeleton.c does it either, because it doesn't have the
> code for interfacing with the input layer.

What kind of usb mouse do you have?  Is it a HID mouse?  Or some custom
protocol?

Also, this should be discussed on the linux-usb-devel mailing list,
there are more Linux usb developers there than on linux-kernel.

> I'm using kernel 2.4.20.

Ick, why?  What's wrong with the latest 2.4 or 2.6 kernel?

thanks,

greg k-h