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

[Arnd Bergmann]

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.

        Arnd