Re: [PATCH 1/7] pwm: Add pwm core driver

[Felipe Balbi]

On Tue, Sep 28, 2010 at 08:06:11AM -0500, Samuel Ortiz wrote:
> On Tue, Sep 28, 2010 at 06:23:24PM +0530, Hemanth V wrote:
> > ----- Original Message ----- From: "Arun Murthy"
> > <arun.murthy@xxxxxxxxxxxxxx>
> >
> >
> > >The existing pwm based led and backlight driver makes use of the
> > >pwm(include/linux/pwm.h). So all the board specific pwm drivers will
> > >be exposing the same set of function name as in include/linux/pwm.h.
> > >As a result build fails in case of multi soc environments where each soc
> > >has a pwm device in it.
> >
> > This seems very specific to ST environment,
> No it's not. It's an issue Arun has hit while enabling one of the ST MFD chip,
> but he's tackling a generic issue.
>
> > looking at the driver list from
> > ( [PATCH 4/7] pwm: Align existing pwm drivers with pwm-core ) it seems
> > most multi SOC environments might support PWM in either one of the SOC.
> >
> > arch/arm/plat-mxc/pwm.c
> > arch/arm/plat-pxa/pwm.c
> > arch/arm/plat-samsung/pwm.c
> > arch/mips/jz4740/pwm.c
> > drivers/mfd/twl6030-pwm.c
> >
> > Unless people have examples of other SOCs which might use this,
> > the better approach might be to go for a custom driver rather than changing
> > the framework.
> I wouldn't call the current pwm code a framework. It's a bunch of header
> definitions that happens to work in the specific case of 1 pwm per
> sub architecture.
> What Arun is proposing is an actual framework. And it seems to be clean and
> simple enough.

FWIW, I agree with you Sam. Sooner or later, this will hit other SoCs.

--
balbi
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