Re: Nokia Internet Tablets

[Otto Solares <solca@guug.org>]

On Mon, Dec 22, 2008 at 02:50:45PM +0200, Jarkko Nikula wrote:
> On Mon, 22 Dec 2008 04:34:22 -0600
> "ext Otto Solares" <solca@guug.org> wrote:
> 
> > Hi all!
> > 
> > I want to resurrect missing support for the Nokia Internet Tablets
> > starting with the N8x0s for my NITdroid project, which uses just
> > standard Linux kernel APIs.
> > 
> > So first I would like to ask some very newbie questions:
> > 
> > -Is there any ongoing effort to support these devices in latest kernels
> >  at the same level as the latest Nokia production kernel (2.6.21-omap)?
> > 
> "make n800_defconfig" in linux-omap tree is a very good start.
> 
> > -I don't plan to suspend but just sleep while idling, is this a good
> >  approach to power management (pm)?
> > 
> > -I read about the pm branch, where can I pull it?
> > 
> Probably you read already this "N810 suspend" thread?
> 
> http://marc.info/?t=122937538800002&r=1&w=2
> 
> Short: N800 can do sleep_while_idle but GPS uart clock prevents it
> currently in N810 and PM branch may have solution to idle it.

Will try it.

> > -Does CONFIG_NO_HZ works for this devices?
> > 
> Was working at least some months ago with N800.
> 
> > -AFAIK the recent removals of the N800 sound driver was because it was
> >  not written for ALSA OMAP SoC API, right?
> > 
> That's correct. N810 audio is already supported with SND_OMAP_SOC_N810
> but N800 would require to have ASoC codec driver for TSC2301 and DAI
> link driver for EAC, at least for exact sample rates.
> 
> This is due TSC2301 which can be only slave so in order to get stardard
> sample rates, EAC or McBSP would require to use external master clock
> to them and EAC_AC_MCLK and McBSP2.CLKS are not routed into same pads
> like other four EAC and McBSP2 signals.
> 
> Most probably McBSP DAI & TSC2301 would work also if using internal 96
> MHz as a source clock to McBSP. Then sample rate would be e.g.
> 96 MHz / 32 / 32 = 46.875 kHz.

Excellent summary, that was what I need to know, I'll take a look.

> > If it is lack of time of the original developers, I would like to step
> > in, willing to try to complete this work as long as you are willing to
> > support me with answers to my newbie questions as this devices are in
> > plenty operation today but the Nokia kernel is getting really old and
> > it's a good thing if we can port all the drivers to standard Linux API.
> > 
> I welcome you to step in this porting effort! I help what I can :-)

What about my other questions? cpufreq and dvfs?

Thx for your support!

-otto