Messages in this thread | | | From | Aisheng Dong <> | Subject | RE: [PATCH V2 3/9] clk: imx: Support building SCU clock driver as module | Date | Wed, 24 Jun 2020 02:19:51 +0000 |
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> From: Stephen Boyd <sboyd@kernel.org> > Sent: Wednesday, June 24, 2020 8:58 AM > Subject: RE: [PATCH V2 3/9] clk: imx: Support building SCU clock driver as > module > > Quoting Aisheng Dong (2020-06-23 02:00:47) > > > From: Stephen Boyd <sboyd@kernel.org> > > > Sent: Tuesday, June 23, 2020 4:34 PM > > > Subject: RE: [PATCH V2 3/9] clk: imx: Support building SCU clock > > > driver as module > > > > > > Quoting Aisheng Dong (2020-06-22 20:42:19) > > > > > From: Stephen Boyd <sboyd@kernel.org> > > > > > Sent: Saturday, June 20, 2020 11:28 AM > > > > > Subject: RE: [PATCH V2 3/9] clk: imx: Support building SCU clock > > > > > driver as module > > > > > > > > > > Quoting Aisheng Dong (2020-06-17 18:58:51) > > > > > > > From: Anson Huang <anson.huang@nxp.com> > > > > > > > > > +obj-$(CONFIG_MXC_CLK_SCU) += mxc-clk-scu.o > > > > > > > > > > > > > > > > Like i.MX pinctrl, I'm not sure if it's really necessary > > > > > > > > to build core libraries as modules. Probably the simplest > > > > > > > > way is only building platform drivers part as module. And > > > > > > > > leave those core libraries > > > > > built in kernel. > > > > > > > > This may make the code a bit cleaner. > > > > > > > > > > > > > > > > > > > > > > Will discuss this with Linaro guys about it, previous > > > > > > > requirement I received is all SoC specific modules need to > > > > > > > be built as > > > module. > > > > > > > > > > > > > > > > > > > Okay. AFAIK it's not conflict. > > > > > > You still make drivers into modules. > > > > > > Only difference is for those common libraries part, we don't > > > > > > convert them into module Which is less meaningless. > > > > > > > > > > > > > > > > What is the benefit of making the core part of the SoC driver not a > module? > > > > > > > > Usually we could try to build it as module if it's not hard. > > > > > > > > One question is sometimes those core part are shared with some > > > > platforms > > > which can't built as module. > > > > For i.MX case, it's mainly patch 4: > > > > [V2,4/9] clk: imx: Support building i.MX common clock driver as > > > > module > > > > > > > > > > > > Those libraries are also used by i.MX6&7 which can't build as module. > > > > So we need an extra workaround patch to forcely 'select' it under > > > > arch/arm/mach-imx/Kconfig [V2,2/9] ARM: imx: Select MXC_CLK for > > > > ARCH_MXC Then the users can't configure it as module in order to > > > > not break build. > > > > > > > > If build-in those common libraries, the implementation could be a > > > > bit easier > > > and cleaner. > > > > So I'm not sure if we still have to build them as module. > > > > How would you suggest for such case? > > > > > > Stop using 'select MXC_CLK' when requiring the core library code? > > > Instead, make it a 'depends' and then that will make depending > > > modules (i.e. the SoC files) that want to be builtin force the core > > > module to be builtin too. Other modular configs that depend on the core will > still be modular. > > > > > > > It seems not work. > > Patch 4 already changes it to depend on ARCH_MXC which can only be 'Y'. > > [V2,4/9] clk: imx: Support building i.MX common clock driver as module > > diff --git a/drivers/clk/imx/Kconfig b/drivers/clk/imx/Kconfig index > > ded0643..678113b 100644 > > --- a/drivers/clk/imx/Kconfig > > +++ b/drivers/clk/imx/Kconfig > > @@ -1,8 +1,8 @@ > > # SPDX-License-Identifier: GPL-2.0 > > # common clock support for NXP i.MX SoC family. > > config MXC_CLK > > - bool > > - def_bool ARCH_MXC > > + tristate "IMX clock" > > + depends on ARCH_MXC > > > > But user can still set MXC_CLK to be m, either via make menuconfig or > defconfig. > > Isn't that what we want?
No, if user set MXC_CLK to m, the build will break for i.MX6&7.
> Why does ARCH_MXC being enabled mandate that it is > builtin? Is some architecture level code calling into the clk driver?
It's mainly because there's no Kconfig options for i.MX6 &7 clock drivers. It just reuses ARCH config CONFIG_SOC_XXX which can only be y. e.g. obj-$(CONFIG_SOC_IMX6Q) += clk-imx6q.o obj-$(CONFIG_SOC_IMX6SL) += clk-imx6sl.o obj-$(CONFIG_SOC_IMX7ULP) += clk-imx7ulp.o obj-$(CONFIG_SOC_VF610) += clk-vf610.o ..
If setting MXC_CLK to m, the platform clock drivers will fail to build due to miss to find symbols defined in the common clock library by CONFIG_MXC_CLK. So we have to avoid users to be able to config MXC_CLK to m for i.MX6&7. Only depends on ARCH_MXC mean user still can set it to m.
Regards Aisheng
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