On Wed, 2010-11-24 at 11:07 -0500, Jeremy Moles wrote: > Hello everyone! I have a piece of hardware here using a vanilla 2.6.34 > kernel (though I can easily change kernels if needed) that has attached > to it internally a USB touchscreen device. The relevant DMESG info is > below, and this is printed out whenever the module 'usbhid' is loaded. > > -------------------------------------------------------------------- > > usbcore: registered new interface driver hiddev > input: Fujitsu Component USB Touch Panel > as /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.0/input/input9 > generic-usb 0003:0430:0501.0002: input: USB HID v1.00 Mouse [Fujitsu > Component USB Touch Panel] on usb-0000:00:1a.0-2/input0 > usbcore: registered new interface driver usbhid > usbhid: USB HID core driver > > -------------------------------------------------------------------- > > For a long time now, we have been successfully configuring these > machines using the device node created when this driver is loaded, often > something like /dev/input/event5 (with a UDEV rule to make the name more > sensible). In X, we've been using the "evtouch" driver with this device > node, to great effect. > > However, I am doing a bit of research and experimentation, and what I > would like to do is write some custom driver code to interface with this > device, instead of letting usbhid manage it. My question is, where is > the best place to start? > > - Since usbhid already recognizes and binds to this device, what code > can I begin studying to see exactly how it's detecting this and > formatting input? > > - Once usbhid attaches to this device, is the device in some kind of > lock? Is it possible to simply inject additional features or formatting > functions, possibly via quirks? (I don't quite understand how to do > anything with quirks other than blacklist a device). > > - If I want to write a full driver for the device, what source file > would be best to start from? I've tried hacking usbtouchscreen.c and > hid-ntrig.c for the last few days to try and get them to bind to the > device, but neither attempt has seen any success. My hid-ntrig change > refuses to successfully call hid_parse(), and my usbtouchscreen change > continually returns some error code in the IRQ callback. I hope this isn't bad etiquette to self-bump my owns posts... I was just curious if anyone might have any advice. I've continued to hack around, and I'm certainly gaining more knowledge, but not quite there yet. Is there a good primer anywhere, or does have any skeleton code they use, for writing input drivers in Linux? The code is already there in usbhid.ko for this particular device, so I know it's just a matter of piecing it together, adding my modifications, and making them play nice. :) -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
