Re: [PATCH v5 3/3] ARM: dts: igep00x0: add wl18xx bindings

[Tony Lindgren <tony@atomide.com>]

* Eliad Peller <eliad@wizery.com> [150310 10:01]:
> On Tue, Mar 10, 2015 at 6:18 PM, Tony Lindgren <tony@atomide.com> wrote:
> > * Eliad Peller <eliad@wizery.com> [150310 09:11]:
> >> On Tue, Mar 10, 2015 at 5:52 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> >> > On Tuesday 10 March 2015 16:31:33 Eliad Peller wrote:
> >> >> On Tue, Mar 10, 2015 at 4:11 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> >> >> > On Tuesday 10 March 2015 13:00:19 Eliad Peller wrote:
> >> >> >> On Tue, Mar 10, 2015 at 12:49 AM, Tony Lindgren <tony@atomide.com> wrote:
> >> >> >> >> > I was expecting you to remove all calls to legacy_init_wl12xx from this file,
> >> >> >> >> > including the ones for wl12xx aside from the wl18xx ones you removed, but
> >> >> >> >> > if that's enough to clean out the platform_data handling from the wlcore
> >> >> >> >> > driver, it's good enough as a start.
> >> >> >> >> not sure i'm following - can you elaborate?
> >> >> >> >>
> >> >> >> >> i'll summarize the way i see it. please correct me if i'm wrong.
> >> >> >> >>
> >> >> >> >> both wl18xx and wl12xx use the platform data to get the irq number.
> >> >> >> >> wl12xx (only) also needs some additional clock definitions to be
> >> >> >> >> passed. there's currently some issue with specifying some the of clock
> >> >> >> >> sources, so i preferred starting only with (the simpler) wl18xx
> >> >> >> >> bindings.
> >> >> >> >>
> >> >> >> >> for platforms with wl18xx, we can remove the pdata-quirk, as all the
> >> >> >> >> data (i.e. irq) can be passed by the new DT bindings.
> >> >> >> >> however, for platforms with wl12xx, we still need to pass the clock
> >> >> >> >> definitions (along with the irq), so we have to keep
> >> >> >> >> legacy_init_wl12xx for the time being (and that's also why we have to
> >> >> >> >> currently keep the platform_data handling in the wlcore driver)
> >> >> >> >>
> >> >> >> >> do you have something else in mind?
> >> >> >> >
> >> >> >> > I think what Arnd is saying is we've now removed all the wl12xx using
> >> >> >> > legacy platforms, so all of them can boot with just data from dts.
> >> >> >
> >> >> > Right, that was my idea.
> >> >> >
> >> >> >> I don't think that's the case (unless i'm missing something).
> >> >> >> e.g. there's still pdata-quirk for "compulab,omap3-sbc-t3730" which
> >> >> >> initializes wl12xx device.
> >> >> >
> >> >> > This one is just like the igep0030, as Tony was saying: the board
> >> >> > boots from device tree already, so now that we have a binding for
> >> >> > it, we can remove the wl12xx_set_platform_data() for it.
> >> >> >
> >> >> i think the wl12xx_set_platform_data() name created some confusion -
> >> >> it is used to pass platform data for both wl12xx and wl18xx devices.
> >> >> (this confusion is all around the wlcore driver as well, due to the
> >> >> code evolution)
> >> >>
> >> >> the binding i added is for wl18xx only (there is no wl12xx binding yet).
> >> >> the remaining boards, AFAICT, have wl12xx (rather than wl18xx) cards.
> >> >> so i don't see how we can remove these wl12xx_set_platform_data()
> >> >> calls before we have wl12xx bindings in-place as well.
> >> >
> >> > What is missing for that binding then? I keep getting confused here,
> >> > but I thought that they share the implementation that looks at the
> >> > platform data.
> >> >
> >> they both get the same wl12xx_platform_data struct, but only wl12xx
> >> cares about the clocks-related fields.
> >> the bindings i added parses only the irq.
> >>
> >> (Luca tried previously to upstream wl12xx DT support along with the
> >> required clock DT changes, but got some rejections, mainly wrt. clock
> >> stuff.
> >> e.g. http://thread.gmane.org/gmane.linux.kernel/1520752
> >> that's why i preferred starting with "easier" wl18xx bindings only)
> >
> > I believe we did not have clock bindings back then, now it's simple
> > to get the clock. If it's some internal clock to the wl12xx, then
> > that's a different story, it should be just hidden behind a compatible
> > flag then.
> >
> i'm really not familiar with the common clock framework, but there
> still doesn't seem to be a way to determine whether a clock is XTAL or
> not (which is what Luca's patch was about). should we use compatible
> flag in such case? i'm not sure it sounds right.
> 
> anyway, i'd really prefer, if possible, starting with the wl18xx
> bindings, and defer the wl12xx complications to later on.
> (i also need to find some wl12xx card in order to actually test the
> patches once i'll have them...)
> 
> we do have to make sure these wl18xx bindings are future-compatible
> with the wl12xx ones, but i think the current bindings are pretty much
> standard (and are actually a subset of the bindings needed by wl12xx),
> so it should be fine.

Well how about add just the parsing of the clock and assume it's always
WL12XX_REFCLOCK_38 for now as that's the only thing we're currently
using. Then we can add a property or compatible value if using something
else as needed.

Regards,

Tony