2019-06-27 22:16:21

by Nathan Huckleberry

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Subject: [PATCH] clk: mediatek: Fix -Wunused-const-variable

Clang produces the following warning

drivers/clk/mediatek/clk-mt8516.c:234:27: warning: unused variable
'ddrphycfg_parents' [-Wunused-const-variable] static const char * const
ddrphycfg_parents[] __initconst = {

This variable has never been used. Deleting it to cleanup the warning.

Cc: [email protected]
Link: https://github.com/ClangBuiltLinux/linux/issues/523
Signed-off-by: Nathan Huckleberry <[email protected]>
---
drivers/clk/mediatek/clk-mt8516.c | 5 -----
1 file changed, 5 deletions(-)

diff --git a/drivers/clk/mediatek/clk-mt8516.c b/drivers/clk/mediatek/clk-mt8516.c
index 26fe43cc9ea2..9d4261ecc760 100644
--- a/drivers/clk/mediatek/clk-mt8516.c
+++ b/drivers/clk/mediatek/clk-mt8516.c
@@ -231,11 +231,6 @@ static const char * const nfi1x_pad_parents[] __initconst = {
"nfi1x_ck"
};

-static const char * const ddrphycfg_parents[] __initconst = {
- "clk26m_ck",
- "mainpll_d16"
-};
-
static const char * const usb_78m_parents[] __initconst = {
"clk_null",
"clk26m_ck",
--
2.22.0.410.gd8fdbe21b5-goog


2019-06-27 23:07:36

by Nick Desaulniers

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Subject: Re: [PATCH] clk: mediatek: Fix -Wunused-const-variable

On Thu, Jun 27, 2019 at 3:15 PM 'Nathan Huckleberry' via Clang Built
Linux <[email protected]> wrote:
>
> Clang produces the following warning
>
> drivers/clk/mediatek/clk-mt8516.c:234:27: warning: unused variable
> 'ddrphycfg_parents' [-Wunused-const-variable] static const char * const
> ddrphycfg_parents[] __initconst = {
>
> This variable has never been used. Deleting it to cleanup the warning.

comparing this to `nfi1x_pad_parents`, it looks like this maybe should
be an entry in `top_muxes`, but there seem to be some magic constants
in those that I don't understand or know what we'd use for
`ddrphycfg_parents`.

Again, looking at `nfi1x_pad_parents` for reference, we see
`CLK_TOP_NFI1X_PAD_SEL` used with it and being defined in the device
tree bindings in include/dt-bindings/clock/mt8516-clk.h. I would
guess that `CLK_TOP_DDRPHYCFG_SEL` should be used in `top_muxes` with
`ddrphycfg_parents`.

`CLK_TOP_DDRPHYCFG_SEL` appears in:
drivers/clk/mediatek/clk-mt8135.c
drivers/clk/mediatek/clk-mt8173.c
drivers/clk/mediatek/clk-mt2701.c
drivers/clk/mediatek/clk-mt7629.c
drivers/clk/mediatek/clk-mt7622.c
but not the translation unit in question:
drivers/clk/mediatek/clk-mt8516.c

in most of the above (except clk-mt2701.c which simply has 1
additional field but otherwise matching values, and clk-mt8135.c which
has 2 different values), it's added to a similarly named and typed
`top_muxes` as:

MUX_GATE(CLK_TOP_DDRPHYCFG_SEL, "ddrphycfg_sel", ddrphycfg_parents,
0x040, 16, 1, 23),

even then `ddrphycfg_parents` shows up in the other translation units
in the same statement as `CLK_TOP_DDRPHYCFG_SEL`.

So questions to the maintainers I have:
1. Is the above `MUX_GATE` what should be added to `top_muxes` in
drivers/clk/mediatek/clk-mt8516.c?
2. If so, where? Is order of the array elements important.

If the answer to 1 is no, then we should take Nathan's patch.

>
> Cc: [email protected]
> Link: https://github.com/ClangBuiltLinux/linux/issues/523
> Signed-off-by: Nathan Huckleberry <[email protected]>
> ---
> drivers/clk/mediatek/clk-mt8516.c | 5 -----
> 1 file changed, 5 deletions(-)
>
> diff --git a/drivers/clk/mediatek/clk-mt8516.c b/drivers/clk/mediatek/clk-mt8516.c
> index 26fe43cc9ea2..9d4261ecc760 100644
> --- a/drivers/clk/mediatek/clk-mt8516.c
> +++ b/drivers/clk/mediatek/clk-mt8516.c
> @@ -231,11 +231,6 @@ static const char * const nfi1x_pad_parents[] __initconst = {
> "nfi1x_ck"
> };
>
> -static const char * const ddrphycfg_parents[] __initconst = {
> - "clk26m_ck",
> - "mainpll_d16"
> -};
> -


--
Thanks,
~Nick Desaulniers

2019-06-27 23:53:08

by Stephen Boyd

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Subject: Re: [PATCH] clk: mediatek: Fix -Wunused-const-variable

Quoting Nathan Huckleberry (2019-06-27 15:15:07)
> Clang produces the following warning
>
> drivers/clk/mediatek/clk-mt8516.c:234:27: warning: unused variable
> 'ddrphycfg_parents' [-Wunused-const-variable] static const char * const
> ddrphycfg_parents[] __initconst = {
>
> This variable has never been used. Deleting it to cleanup the warning.
>
> Cc: [email protected]
> Link: https://github.com/ClangBuiltLinux/linux/issues/523
> Signed-off-by: Nathan Huckleberry <[email protected]>

This patch has already been applied. It would be great if you could try
applying the patch to linux-next first before sending patches to make
sure they're still relevant.