Re: PXA2xx/3xx AC97 Driver(s)

Re: PXA2xx/3xx AC97 Driver(s)

[Mark Brown]

On Mon, Mar 24, 2008 at 12:38:00PM +0000, Oliver Ford wrote:

> Is there any work currently under way on an AC97 driver for the PXA3xx?

There is PXA3xx AC97 support present in the ASoC tree:

   git://opensource.wolfsonmicro.com/linux-2.6-asoc

It's under the asoc-v2-dev branch at the minute and is probably only
done for the ASoC AC97 driver, I'd need to check.  The main reason it's
only there is that it depends on the ARM architecture changes that you
identified (which are also applied on the asoc-v2-dev branch) and it
makes life easier to manage the cross-tree changes in only one tree.

All the ARM architecture changes have been submitted and marked as
applied in the patch system so should hopefully appear in Linus' kernel
early in the 2.6.26 cycle.  Once this has happened I will submit the
AC97 driver PXA3xx support.

> I want to get the touch screen working on my iPAQ 214, which uses the 
> PXA310. It's a WM97xx chip on the AC97 interface. I'm not really too 

I know that there are a number of users currently using the tree for
that use case so the asoc-v2-dev branch should hopefully work for you.
If you run into trouble please let me know.

> include/asm-arm/arch-pxa/pxa3xx-regs.h). Does the pxa310 require
> anything special like this or should just setting the cold-reset in
> the AC97 GCR work?

It also doesn't support the use of interrupts during reset operations,
requiring another special case, but I think that's about it.

> The Wolfson Microelectronics open-source page indicates that work is on 
> going with the 3xx driver but there doesn't seem to be anything more 
> than the pxa2xx driver in their source tree. Does anyone know how active 
> / close to producing anything this is?

Like I say, it's there.  The changes are fairly straightforward and
should be easy to backport to whatever kernel you need - if you need
help identifying what needs merging over please just ask.

> More generally, I'm a little confused as to why there is both the 
> standard (sound/arm/pxa2xx-ac97.c) and SoC (sound/soc/pxa/pxa2xx-ac97) 
> driver. Is one of these obsolete now or are they both still in 
> development? If guessing, I'd say the SoC driver is now the one to use 

The SoC driver is generally preferable, though it requires a bit more
work to use (since you have to write a platform driver to use it).  Both
are still maintained.  SoC offers better power management and support
for a wider range of board configurations, especially those that also
have non-AC97 interfaces (such as the I2S interface on the WM97xx
parts).

> but am not sure. Compiling either gives the warning "'pxa_set_cken' is 
> deprecated". I suspect calling this won't work for the pxa310 since it's 

This is also fixed in the patches currently queued in the ARM tree -
the drivers have been converted to use the clk_() API.

> clocks are different, but given that I'm booting linux from windows 
> (which will leave the clock on) and don't particularly care about 
> suspend/resume, should not being able to switch it off be a problem?

The cken calls should actually work fine.

Re: PXA2xx/3xx AC97 Driver(s)

[Russell King - ARM Linux]

On Mon, Mar 24, 2008 at 01:42:32PM +0000, Mark Brown wrote:
> On Mon, Mar 24, 2008 at 12:38:00PM +0000, Oliver Ford wrote:
> > but am not sure. Compiling either gives the warning "'pxa_set_cken' is 
> > deprecated". I suspect calling this won't work for the pxa310 since it's 
> 
> This is also fixed in the patches currently queued in the ARM tree -
> the drivers have been converted to use the clk_() API.
> 
> > clocks are different, but given that I'm booting linux from windows 
> > (which will leave the clock on) and don't particularly care about 
> > suspend/resume, should not being able to switch it off be a problem?
> 
> The cken calls should actually work fine.

The pxa_set_cken() will not do the right thing for PXA3xx CPUs, which is
why that interface is deprecated.  If you're building for PXA3 CPUs and
you get warnings about pxa_set_cken() that's a sure sign that something's
wrong.

Re: PXA2xx/3xx AC97 Driver(s)

[Mark Brown]

On Mon, Mar 24, 2008 at 01:57:03PM +0000, Russell King - ARM Linux wrote:

> The pxa_set_cken() will not do the right thing for PXA3xx CPUs, which is
> why that interface is deprecated.  If you're building for PXA3 CPUs and
> you get warnings about pxa_set_cken() that's a sure sign that something's
> wrong.

OK, fair enough - in any case, the cken() calls are removed in one of
the patches you have pending so they'll be gone before the PXA3xx
support is merged.

Re: PXA2xx/3xx AC97 Driver(s)

[Oliver Ford]

Mark Brown wrote:
> There is PXA3xx AC97 support present in the ASoC tree:
>
>    git://opensource.wolfsonmicro.com/linux-2.6-asoc
>
> It's under the asoc-v2-dev branch at the minute
>
After a few hours of learning what git is and how to find and fetch that
branch I've got it.
I'm now using the whole kernel from there and have applied my patches
for the Ipaq214 to it. The Pxa2xx driver (with 3xx support) happily
talks down the AC97 bus now. The sound isn't working yet as I've still
got to set up the platform definition file properly.

> All the ARM architecture changes have been submitted and marked as
> applied in the patch system so should hopefully appear in Linus' kernel
> early in the 2.6.26 cycle.  Once this has happened I will submit the
> AC97 driver PXA3xx support.
>   
The machine no longer reboots out of linux though. I assume there were
some changes in 2.6.25-rc4 mainline that aren't in the asoc-v2-dev yet.
I will wait for the pxa3xx stuff to be merged into the mainline for
this. What version of the mainline kernel is the latest asoc-v2-dev
branch based on. (I'm still a little hazy on the git stuff I'm afraid).
>> I want to get the touch screen working on my iPAQ 214, which uses the 
>> PXA310. It's a WM97xx chip on the AC97 interface. I'm not really too 
>>     
>
> I know that there are a number of users currently using the tree for
> that use case so the asoc-v2-dev branch should hopefully work for you.
> If you run into trouble please let me know.
>   
The WM97xx touchscreen driver only appears to be in the linux-2.6-touch
repository (dev branch, iirc), rather than  linux-2.6-asoc where the
pxa3xx support is. Since I want both the wm97xx touchscreen and pxa3xx
support, is there a simple way I can get the necessary changes in one
applied to the other?

Thanks,

Oliver



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Re: PXA2xx/3xx AC97 Driver(s)

[Mark Brown]

On Wed, Mar 26, 2008 at 01:52:39PM +0000, Oliver Ford wrote:

> The machine no longer reboots out of linux though. I assume there were
> some changes in 2.6.25-rc4 mainline that aren't in the asoc-v2-dev yet.
> I will wait for the pxa3xx stuff to be merged into the mainline for
> this. What version of the mainline kernel is the latest asoc-v2-dev
> branch based on. (I'm still a little hazy on the git stuff I'm afraid).

The last version that was merged in appears to be 2.6.25-rc2 (say 'git
log' then search for 'Merge.*v2\.6').  For production use I would
recommend going with ASoC v1 at the moment.  The PXA3xx support should
be straightforward to backport (I wouldn't be suprised if the patches
introducing it could just applied against mainline but I've not actually
tried yet).

> > I know that there are a number of users currently using the tree for
> > that use case so the asoc-v2-dev branch should hopefully work for you.
> > If you run into trouble please let me know.

> The WM97xx touchscreen driver only appears to be in the linux-2.6-touch
> repository (dev branch, iirc), rather than  linux-2.6-asoc where the
> pxa3xx support is. Since I want both the wm97xx touchscreen and pxa3xx
> support, is there a simple way I can get the necessary changes in one
> applied to the other?

You can track both multiple git trees using the remotes feature of
git - see git-remote(1) for usage information.  For example, this:

	git remote add wolfson-touch \
		git://opensource.wolfsonmicro.com/linux-2.6-touch

will tell git to track the Wolfson touch drivers using the name
'wolfson-touch'.  If you do that and then say:

	git remote update
	git merge wolfson-touch/dev

it will fetch the current state of all remote trees it knows about and
then merge the current dev branch of the Wolfson touch drivers git into
your current working copy.

The touchscreen drivers and git usage are both rather off-topic for
either list, though - probably best to follow up off-list or on
linux-input.

Re: PXA2xx/3xx AC97 Driver(s)

[Mark Brown]

On Mon, Mar 24, 2008 at 01:42:32PM +0000, Mark Brown wrote:
> On Mon, Mar 24, 2008 at 12:38:00PM +0000, Oliver Ford wrote:

> > Is there any work currently under way on an AC97 driver for the PXA3xx?

> There is PXA3xx AC97 support present in the ASoC tree:

>    git://opensource.wolfsonmicro.com/linux-2.6-asoc

> It's under the asoc-v2-dev branch at the minute and is probably only
> done for the ASoC AC97 driver, I'd need to check.  The main reason it's

I have now merged the PXA3xx AC97 support into ASoC v1 and the non-ASoC
PXA AC97 driver.  Both drivers onto the dev branch of the above git
tree.  As I mentioned previously the intention is that they be merged
into the mainline during the 2.6.26 cycle.