Re: [PATCH v2 5/7] ASoC: qdsp6: Add depends on OF

[Srinivas Kandagatla]

On 18/06/18 21:53, Rob Herring wrote:
> On Mon, Jun 18, 2018 at 2:08 PM, Niklas Cassel <niklas.cassel@xxxxxxxxxx> wrote:
> > On Mon, Jun 18, 2018 at 08:48:32AM -0600, Rob Herring wrote:
> > > On Mon, Jun 18, 2018 at 6:39 AM, Niklas Cassel <niklas.cassel@xxxxxxxxxx> wrote:
> > > > On Mon, Jun 18, 2018 at 12:06:42PM +0100, Mark Brown wrote:
> > > > > On Thu, Jun 14, 2018 at 01:11:36PM +0200, Niklas Cassel wrote:
> > > > > > of_platform_device_destroy is only defined when building
> > > > > > with CONFIG_OF=y. Add a depends on OF.
> > > > >
> > > > > Is it sensible that of_platform_device_destroy() is only defined when
> > > > > building with CONFIG_OF=y?
> > > >
> > > > I'm redirecting that question to the device tree maintainers.
> > > >
> > > > There are a few of_* functions in include/linux/of_platform.h
> > > > that are only defined when CONFIG_OF=y:
> > > >
> > > > of_platform_device_create()
> > > > of_platform_device_destroy()
> > > > of_platform_bus_probe()
> > > > of_device_alloc()
> > > >
> > > > Rob, Frank, do you want me to create static inline dummy versions of these?
> > >
> > > No, because generally you should not be using these functions
> > > directly. Yes, there are some users, but if you look at the tree,
> > > there are few or isolated (PowerPC) users. Using
> > > of_platform_populate/of_platform_depopulate is preferred.
> >
> > of_platform_device_destroy() is also used by sound/soc/qcom/qdsp6/*
> > which is why I suggested this patch:
> > https://marc.info/?l=alsa-devel&m=152932497413567
> > that adds "depends on OF" for SND_SOC_QDSP6 in sound/soc/qcom/Kconfig.
> >
> > Or do you think that a better solution would be to modify
> > sound/soc/qcom/qdsp6/* so that it instead uses
> > of_platform_populate()/of_platform_depopulate()?
>
> Yes, that is preferred. However, that won't work here because the
> child nodes don't have compatible strings. Maybe we should add them as
> this all just went in. That would also allow DT based module
> autoloading to work (which I don't think would currently). Really, as
> is, of_platform_device_create isn't needed here and you could just use
> platform_device_register_simple instead. The child driver would have
> to get the DT node pointer from the parent device instead.
compatible was the reason why I started using 
of_platform_device_{create,destroy} apis. As you said we could also do 
it with simple platform device too.

I think adding compatible seems to be better option here along with 
of_platform_populate()/of_platform_depopulate(), I will try this!

thanks,
srini

> But if you want to add empty functions for just
> of_platform_device_{create,destroy}, I guess that is fine.
>
> Rob