Re: [PATCH V3 04/10] clk: imx: Support building SCU clock driver as module

[Arnd Bergmann]

On Mon, Jun 29, 2020 at 2:53 PM Anson Huang <anson.huang@xxxxxxx> wrote:
> > Subject: Re: [PATCH V3 04/10] clk: imx: Support building SCU clock driver as
> > module
> >
> > On Mon, Jun 29, 2020 at 8:06 AM Anson Huang <Anson.Huang@xxxxxxx>
> > wrote:
> >
> > > --- a/drivers/clk/imx/Makefile
> > > +++ b/drivers/clk/imx/Makefile
> > > @@ -21,9 +21,9 @@ obj-$(CONFIG_MXC_CLK) += \
> > >         clk-sscg-pll.o \
> > >         clk-pll14xx.o
> > >
> > > -obj-$(CONFIG_MXC_CLK_SCU) += \
> > > -       clk-scu.o \
> > > -       clk-lpcg-scu.o
> > > +mxc-clk-scu-objs += clk-lpcg-scu.o
> > > +mxc-clk-scu-objs += clk-scu.o
> > > +obj-$(CONFIG_MXC_CLK_SCU) += mxc-clk-scu.o
> >
> > It looks like the two modules are tightly connected, one is useless without the
> > other. How about linking them into a combined module and dropping the
> > export statement?
> >
>
> From HW perspective, the SCU clock driver and LPCG SCU clock driver are different,
> SCU clock driver is for those clocks controlled by system controller (M4 which runs a firmware),
> while LPCG SCU clock is for those clock gates inside module, which means AP core can
> control it directly via register access, no need to via SCU API.

Sorry, I misread the patch in multiple ways. First of all, you already put
clk-scu.o and clk-lpcg-scu.o files into a combined loadable module, and
I had only looked at clk-scu.c.

What I actually meant here was to link clk-scu.o together with clk-imx8qxp.o
(and possibly future chip-specific files) into a loadable module and drop
the export.

> So, I think it is NOT that tightly connected, it is because they are both for i.MX8 SoCs with SCU
> inside, so they are put together in the Makefile.
>
> If the export statement is acceptable, I think it is better to just keep it, make sense?

There is nothing wrong with the export as such, this was just an
idea to simplify the logic.

      Arnd