Re: [V2 1/2] clk: imx6q: remove unsupported pll4_audio_div

[Eric Nelson]

> On March 11, 2019, 6:35 p.m. UTC, Stephen Boyd wrote:
>
> Quoting Eric Nelson (2019-03-11 08:59:56)
> > diff --git a/include/dt-bindings/clock/imx6qdl-clock.h b/include/dt-bindings/clock/imx6qdl-clock.h
> > index b3cef29..34bb14d 100644
> > --- a/include/dt-bindings/clock/imx6qdl-clock.h
> > +++ b/include/dt-bindings/clock/imx6qdl-clock.h
> > @@ -213,7 +213,15 @@
> >  #define IMX6QDL_CLK_CKO2                       200
> >  #define IMX6QDL_CLK_CKO                                201
> >  #define IMX6QDL_CLK_VDOA                       202
> > -#define IMX6QDL_CLK_PLL4_AUDIO_DIV             203
> > +
> > +/* The PLL4_AUDIO_DIV divider only appeared in
> > + * early versions of the reference manual.
> > + *
> > + * Renamed to _BROKEN to prevent inadvertent use,
> > + * but reserved the array slot to maintain DT binary
> > + * compatibility.
> > + */
> > +#define IMX6QDL_CLK_PLL4_AUDIO_DIV_BROKEN      203
>
> But it breaks the build. I don't get it. Just add a comment indicating
> it shouldn't be used? That breaks the cross-tree dependency chain and
> lets clk tree merge the clk driver part and arm-soc merge the dts part.
The device tree update also requires the update to clk-imx6q.c
for proper run-time operation, so I don't see how these two parts
can be separated.

I thought about leaving the PLL4_AUDIO_DIV clock in place but
turning it into a dummy (placeholder), but that might lead others
down the long path I traversed before I found out that my manual
was old and the clock didn't function.