[RFC] WIP: add usb keyboard driver

[Sascha Hauer]

On Thu, Sep 10, 2015 at 06:51:33PM +0300, Peter Mamonov wrote:
> On Thu, 10 Sep 2015 09:38:15 +0200
> Sascha Hauer <s.hauer at pengutronix.de> wrote:
> 
> > Excellent! This makes the framebuffer console support complete :)
> 
> I'm sorry to dissapoint you, but this implementation of the usb
> keyboard driver seems to be wrong. The driver employs the get_report
> request to poll the keyboard state via the control endpoint, however
> the "Device Class Definition for Human Interface Devices (HID)" states
> the following:
> "This request is not intended to be used for polling the device state
> on a regular basis. [...] The Interrupt In pipe should be used for
> recurring Input reports."
> 
> I guess this is the source of the problems with some keyboards: 2 of 4
> keyboards I've tested changed their state only on key down, but not
> on key up.

Yes, same here. The first keyboard I tested ended up with this
behaviour, the second worked.

> 
> So, according the standard, we need to poll a keyboard via interrupt
> endpoint. However, current implementation of EHCI driver doesn't support
> interrupt transactions: submit_int_msg() in ehci-hcd.c is a stub. I'll
> try to implement it.

U-Boot has an implementation for it, should be possible to adopt the
corresponding code.

Sascha

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