Re: [PATCH 0/4] bq27x00 updates

[Anton Vorontsov <avorontsov@ru.mvista.com>]

On Sun, Oct 19, 2008 at 01:23:43AM +0300, Felipe Balbi wrote:
> On Sun, Oct 19, 2008 at 01:16:43AM +0400, Anton Vorontsov wrote:
> > On Sat, Oct 18, 2008 at 12:00:44AM +0300, Felipe Balbi wrote:
> > > The previous driver for bq27x00 batteries was a real
> > > ifdef mess. The following patches separate common code
> > > and create separate drivers for bq27200 and bq27000.
> > 
> > FYI (if you don't know already): Rodolfo Giometti already
> > cleaned up bq27200 part of that driver and submitted it few
> > months ago.
> 
> Didn't know that. Good to know by the way. In any case I think Copyright
> Texas Instruments should be kept as is and not like Rodolfo wrote:
> 
> "Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc."
> 
> since he's not really writing new driver from scratch but only cleaning
> up an existing one that still sits in linux-omap tree.

Sure, I'll happily apply a patch that you think would correct
copyright/authorship entries. But please preserve Rodolfo's credits
too, since he spent some time cleaning up your (or TI's) code.

> In any case, that's what you get when you don't push your drivers upstream,
> right ?? :-p

Right. ;-)

> Hopefully TI will start pushing their code upstream and this kind of
> issue will vanish.
> 
> > http://lkml.org/lkml/2008/6/18/154
> > 
> > It will appear in the 2.6.28 kernel. For now it lives here:
> > 
> > http://git.infradead.org/battery-2.6.git?a=commitdiff;h=b996ad0e9fb15ca4acc60bcd0380912117a45d13
> > 
> > So I'd be happy if you could just rework it to support
> > bq27000 (w1) interface as well.
> 
> Sure, but I'll only take a look at that after it falls into mainline.

I hope this will be soon.

> And btw, I don't have access to bq27000, only bq27200, so don't know if
> I'm gonna be the best person to put down that code since I can only
> build test.

IMHO build-tested driver is better than nothing. Others could
fix up any issues later, when they'll have the hardware. But it's
just my opinion... (Other's opinion could be: "untested code
is broken code" ;-)

> > > The code looks much cleaner, but we had to keep a global
> > > static pointer to hold the i2c_client (bq27200) or the
> > > w1 device (bq27000).
> > 
> > Yeah, this is not great...
> 
> What I was trying to do, actually, is to provide a generic structure for
> bq27200 and bq27000 and another device specific which would hold the
> bus-related hooks (basically a pointer to i2c_client or a pointer to
> the w1 dev).
> 
> Turned out that would be way too complicated for such a simple driver.
> 
> > Can you consider this idea
> > http://kerneltrap.org/mailarchive/linux-kernel/2008/6/23/2198444
> > ?
> > 
> > It shows only i2c part, but the idea should be clear:
> > there should be w1 and i2c drivers, both would create bq27x00
> > platform devices, then the platform driver would not depend on
> > any hw interface.
> 
> That looks good, but please don't add new stuff to drivers/i2c/chips.

I won't. I won't work on this driver at all. :-) it was just a
patch to show the idea. I didn't even sign off on it. Feel free
to use the idea in your patches. ;-)

> That directory is schedule to vanish asap.

Ok, in the end I think driver/power/ placement would be fine for
i2c part of this driver...

> Also, I think bq27x00.h
> should not site in include/linux since it's not really related to the
> kernel as a whole.

Good point.

> Sure you need the access method, but that structure is initialized by
> bq27200.c or bq27000.c; better would be to move bq27200.c into
> drivers/power and make bq27x00.h sit inside drivers/power as well.
> 
> Also, this line is wrong:
> 
> +	di->bus = platform_get_drvdata(pdev);
> 
> di->bus will get initialized by di again. The correct would be:
> 
> di->bus = pdev->dev.platform_data;
> 
> another point is that I suppose that goto idr_try_again should have a
> max_tries hook to prevent that code from looping unconditionally if we
> can't get new IDR (for some reason).

Good catches.


Thanks,

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2