Subject: RE: [E3-hacking] E3 u-boot & Linux

From: Cliff Lawson <[email-masked]>
Date: Thu, 23 Feb 2006 12:08:48 -0000

Lads, I can't help thinking you may be reinventing the wheel a bit here.

> -----Original Message-----
> From: Jonathan McDowell [mailto:[email-masked]]
> 
> Not supported yet:
> 
> * LCD (Mark Underwood is working on it, there's code in the Amstrad
>   source)

There's already a /dev/fb driver for the LCD in the kernel - is there
some argument against using that? I've got the LCD setup in (4x0):4:4:4
mode,
not 5:6:5 mode by the way as the R, G and B are limited to 4 bits each
5:6:5 isn't 5:6:5 anyway! In fact bit patterns 1110 and 1111 for each of
R, G and B are the same colour so rather than 4096 colours there are 3375 
(i.e. 15*15*15, not 16*16*16)

> * modem UART (I don't think this should be hard to get going; 
> Smart SMC
>   at 0xeb000000 on irq 66 according to dmesg on 2.4)

There's already a serial port driver mapped to the modem in the kernel

> * sound (no idea; there's omap sound code in the tree, but does the E3
>   use this?)

just insmod our ams_beep_mod.o device driver (its in the initrd) and it 
hooks the kd_mksound vector in drivers\char\vt.c so that when vt_ioctl() 
is called with KDMKTONE (such as for a console "beep") it invokes the
routine in 
ams_beep_mod.o which, in turn, uses the PWT generator in the OMAP but, 
as you'll read in the OMAP datasheet this can only generate 48 frequencies 
(12 notes in 4 ocatves) so my code matches the given Hz value to the closest

that can be played and plays that one.

> * keyboard (this is separate from the keypad and is PS/2 based I
>   believe)

I went to some length when doing the matrix and PS/2 drivers to make sure
they returned sensible (Linux friendly) keycodes so after insmodding 
ams_keyb_mod.o you should just find that both matrix and PS/2 generate
"sensible" characters to the terminal. I even arranged for PS/2 stop to
generate the mush more useful [TAB] character.

> * camera (some code in the 2.6 OMAP tree already, source in 
> the Amstrad
>   tree too)

Yup it's supported by v4l2

Cliff

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---

From: Jonathan McDowell <[email-masked]>
Date: Thu, 23 Feb 2006 16:47:33 +0000

> Lads, I can't help thinking you may be reinventing the wheel a bit

Probably true, but the other option is to end up running an ancient
2.4.18 based kernel. Aside from the numerous security issues that have
been fixed since then there are quite simply some things that can't be
added modularly to a kernel that we don't have proper source for. IPv6,
for example, is something that's of use to me but impossible without a
kernel recompile.

J.

-- 
 [   There are always at least two ways to program the same thing.    ]