Hi Andy, On Friday 11 March 2011, Andy Green wrote: > > platform_data is a well established way in Linux to pass configuration > data up to on-board assets from a machine file like mach-xyz.c. It's > also supported to pass platform_data up to devices that are probed > asynchronously from busses like i2c as well, which is very handy. > > However AFAIK it's not possible to bind platform_data to probed USB > devices as it stands. > > There are now boards which have on-board USB assets, for example OMAP4 > Panda which has a USB <-> Ethernet bridge wired up permanently. It'd be > convenient to also be able to pass optional platform_data to these > devices when they are asynchronously probed. Sorry, but I think it's a bad idea to use platform data for this. USB is a bus that we can reasonably probe, while we use platform_data only for stuff that we can by definition not probe at all. > The particular use that suggested this is on Panda, it would be ideal to > be able to set a flag in the usb device's platform data that forces it > to be named eth%d since it's a hardwired asset on the board with an RJ45 > socket. I understand the problem, but IMHO there really needs to be a better solution for this. As far as I understand, the underlying problem is that USB ethernet devices with a proper MAC address get a different device name from devices with a generated random MAC address, and the people that designed this board were trying to save a few cents by not allocating a MAC address for the ethernet device [1], right? I believe we should fix this particular problem locally, instead of coming up with generic infrastructure for broken hardware. One relatively easy solution would be to allow passing a MAC address to this particular device driver as a module parameter, and generating a fixed MAC address in the regular vendor space when installing the boot loader. That would also solve the problem that a DHCP server currently assigns a new IP address to a panda board at every boot. Arnd --- [1] https://bugs.launchpad.net/linux-linaro/+bug/622429 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
