Subject: Re: CPM2 USB host driver

From: Arnd Bergmann <[email-masked]>
Date: Fri, 30 Nov 2007 23:32:20 +0100

(Cc:'ing linux-usb-devel)

On Friday 30 November 2007, Anton Vorontsov wrote:
> As for FHCI driver, it's not that big (6100 lines host patch + 3516
> lines usbgadget patch), but since usb subsystem changed: you have to
> know all the changes (or to look them up) and blindly follow them. Or
> start from scratch with FHCI/cpm2usb as the reference, thus evolve
> into Linux USB expert one day.

6100 lines means it's still the second-largest hcd driver in the kernel,
only drivers/usb/host/u132-hcd.c has even more.

> Today, I think I would choose the second option. Definitely more
> fun, and most probably quicker to progress. Though, I repeat,
> I didn't look into cpm2usb project.

My experience with other drivers moved into the kernel is that you
end up rewriting it completely anyway. I can also recommend starting
from scratch, and taking one of the in-kernel drivers as an example.
Maybe Greg or David can give you a suggestion which one of them
serves as the best example for a new host driver.

	Arnd <><