+Linus W
On Mon, Jan 18, 2021 at 2:30 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> On Mon, Jan 18, 2021 at 8:33 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> >
> > After converting am335x to probe devices with simple-pm-bus I noticed
> > that we are not passing auxdata for of_platform_populate() like we do
> > with simple-bus.
> >
> > While device tree using SoCs should no longer need platform data, there
> > are still quite a few drivers that still need it as can be seen with
> > git grep OF_DEV_AUXDATA. We want to have simple-pm-bus be usable as a
> > replacement for simple-bus also for cases where OF_DEV_AUXDATA is still
> > needed.
> >
> > Let's fix the issue by passing auxdata as platform data to simple-pm-bus.
> > That way the SoCs needing this can pass the auxdata with OF_DEV_AUXDATA.
> > And let's pass the auxdata for omaps to fix the issue for am335x.
> >
> > As an alternative solution, adding simple-pm-bus handling directly to
> > drivers/of/platform.c was considered, but we would still need simple-pm-bus
> > device driver. So passing auxdata as platform data seems like the simplest
> > solution.
> >
> > Fixes: 5a230524f879 ("ARM: dts: Use simple-pm-bus for genpd for am3 l4_wkup")
> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> > ---
> > Changes since v1: Updated description, added devicetree list to Cc
>
> This looks fine to me for now
>
> Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
>
> But I think we should take the time to discuss how to phase out auxdata
> over time. There are still a number of users, but it's not that many in the
> end. For some of them I see a clear solution, for other ones I do not:
Thanks for summarizing.
> lpc32xx: Used only for pl080 DMA data with the old method, needs to
> be converted to use the proper DT binding that was added a few years
> ago.
>
> kirkwood: I don't see what this does at all, as there is no pdata, and
> there is no clkdev lookup for "mvebu-audio"
Probably nothing. I reached that conclusion on u300 too. Clocks got
added in DT and someone forgot to remove auxdata. Granted, it's pretty
non-obvious what the purpose is if there is no platform_data.
>
> orion: similar to kirkwood, these seem to have been added for
> clkdev lookup, but the orion_clkdev_init() function seems to
> not be called for the orion5x_dt variant.
>
> omap2: I'll leave these for Tony to comment
>
> spear3xx: pl022 and pl080 should just use the normal DT
> binding, see lpc32xx.
>
> u300: platform is scheduled for removal
>
> integrator_ap: pl010_set_mctrl() needs a callback to
> integrator_uart_set_mctrl(). I see no good alternative, but
> a workaround might be to call into syscon directly from the
> driver on versatile machines. For all I can tell, pl010 is only
> used on versatile and ep93xx, so that would not harm a
> commonly used driver.
That was my conclusion.
> versatile/integrator_cp: similar problem but for mmci, which is
> used more widely. Used for card detection, which could
> theoretically be implemented with a fake gpio driver, but that
> might be excessive.
>
> mips/pic32: used for setting up DMA for sdhci, could be done
> in a platform-specific sdhci front-end.
>
> arm-cci: used to pass cci address after ioremap(), avoiding
> this would revert e9c112c94b01 ("perf/arm-cci: Untangle
> global cci_ctrl_base").
Create a regmap and then secondary drivers needing register access can
lookup the regmap? Or just ioremap it twice... I'll take a closer look
at this one.
Rob
