RE: [PATCH V3 04/10] clk: imx: Support building SCU clock driver as module
From: Anson Huang
Date: Mon Jun 29 2020 - 17:12:51 EST
Hi, Arnd
> Subject: Re: [PATCH V3 04/10] clk: imx: Support building SCU clock driver as
> module
>
> On Mon, Jun 29, 2020 at 4:52 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 2:53 PM Anson Huang
> <anson.huang@xxxxxxx> wrote:
> > >
> > > 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.
> >
> > Sorry, could you please advise more details about how to do it in Makefile?
> > I tried below but it looks like NOT working. multiple definition of
> module_init() error reported.
> >
> > obj-$(CONFIG_MXC_CLK_SCU) := clk-imx.o clk-imx-y += clk-scu.o
> > clk-lpcg-scu.o
> > clk-imx-$(CONFIG_CLK_IMX8QXP) += clk-imx8qxp.o clk-imx8qxp-lpcg.o
>
> Right, you can't have multiple module_init() in a module, so what I suggested
> earlier won't work any more as soon as you add a second chip that uses the
> clk-scu driver, and then you have to use separate modules, or some hack that
> calls the init functions one at a time, which is probably worse.
>
> If it's only imx8qxp, you can do it like this:
>
> obj-$(CONFIG_MXC_CLK_SCU) := clk-imx-scu.o clk-imx-lpcg.o
> clk-imx-scu-y += clk-scu.o clk-imx8qxp.o
> clk-imx-lpcq-scu-y += clk-lpcg-scu.o clk-imx8qxp-lpcg.o
>
> If you already know that the scu driver is going to be used in future chips, then
> just stay with what you have now, using a separate module per file, exporting
> the symbols as needed.
>
Thanks, and yes, I know that scu clk driver will be used for future i.MX8X chips with
SCU inside, the current i.MX8QXP clock driver can NOT cover all i.MX8X chips, so
I will stay with the exporting symbols.
Thanks,
Anson