On Thu, Dec 13, 2018 at 4:13 PM Shawn Guo [off-list ref] wrote:

On Thu, Dec 13, 2018 at 04:02:34PM +0800, Olof Johansson wrote:
...

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diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index a47430b..8a9440a 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile

@@ -72,7 +72,7 @@ obj-$(CONFIG_ARCH_DAVINCI)            += davinci/
 obj-$(CONFIG_H8300)                    += h8300/
 obj-$(CONFIG_ARCH_HISI)                        += hisilicon/
 obj-y                                  += imgtec/
-obj-$(CONFIG_ARCH_MXC)                 += imx/
+obj-y                                  += imx/
 obj-y                                  += ingenic/
 obj-$(CONFIG_ARCH_K3)                  += keystone/
 obj-$(CONFIG_ARCH_KEYSTONE)            += keystone/

diff --git a/drivers/clk/imx/Kconfig b/drivers/clk/imx/Kconfig
new file mode 100644
index 0000000..37478ba
--- /dev/null
+++ b/drivers/clk/imx/Kconfig

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+# common clock support for NXP i.MX SoC family.
+config MXC_CLK
+       bool
+       def_bool (ARCH_MXC && !ARM64) || (ARCH_MXC && ARM64 && SOC_IMX8MQ)

Ok I looked closer, SOC_IMX8MQ is only being introduced now and has only
been in linux-next for a few days. Having such a config symbol is highly
unusual for arm64 code. Has that been accepted by arm-soc? I don't know
why it would be because we don't add SoC specific config options
anymore. I imagine it will be rejected and we'll need to have this new
MXC_CLK config be enabled in the defconfig instead of selected from the
arch layer.

Given all that, is there any damage if this is just a def_bool ARCH_MXC
right now? If it's enabled on the platforms that don't use it because
they have SCU, does it actually matter? Or we just get some code bloat?
If it's just some extra code, then even more reason to make a user
visible config option that can be selected in the configurations that
care to save some space.

On arm64 we generally add an ARCH_<family> and leave it at that. So,
ARCH_MXC would be suitable, but we shouldn't add more finegrained than
that.

Olof,

I'm just about to send pull request for i.MX8MQ support, which
introduced SOC_IMX8MQ option.  It sounds like we should rework the
patches to get SOC_IMX8MQ killed?

Yeah, I think the suggestions downthread are good approaches to avoid it.

Some platforms create SOC config options if they need it under
drivers/soc, but it will depend on your platform if you truly need it;
for most cases I think it'll just make dependencies more complicated.


-Olof

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