Re: [PATCH] mmc: sdhci-of-dwcmshc: Use logical OR instead of bitwise OR in dwcmshc_probe()

[Ulf Hansson <ulf.hansson@linaro.org>]

On Fri, 17 Nov 2023 at 02:46, Nathan Chancellor <nathan@kernel.org> wrote:
>
> Clang warns (or errors with CONFIG_WERROR=y):
>
>   drivers/mmc/host/sdhci-of-dwcmshc.c:873:7: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
>     873 |                 if ((device_property_read_bool(dev, "mmc-ddr-1_8v")) |
>         |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>     874 |                     (device_property_read_bool(dev, "mmc-hs200-1_8v")) |
>         |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>         |                                                                        ||
>     875 |                     (device_property_read_bool(dev, "mmc-hs400-1_8v")))
>         |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   drivers/mmc/host/sdhci-of-dwcmshc.c:873:7: note: cast one or both operands to int to silence this warning
>   drivers/mmc/host/sdhci-of-dwcmshc.c:873:7: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
>     873 |                 if ((device_property_read_bool(dev, "mmc-ddr-1_8v")) |
>         |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>         |                                                                      ||
>     874 |                     (device_property_read_bool(dev, "mmc-hs200-1_8v")) |
>         |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   drivers/mmc/host/sdhci-of-dwcmshc.c:873:7: note: cast one or both operands to int to silence this warning
>   2 errors generated.
>
> There is little reason for this if statement to use bitwise ORs, as the
> short circuiting of logical OR does not need to be avoided in this
> context; it would be wasteful to call device_property_read_bool() three
> times if the first two calls returned true. Switch to logical OR to fix
> the warning.
>
> While in the area, the parentheses around the calls to
> device_property_read_bool() are not necessary and make the if statement
> harder to read, so remove them.
>
> Closes: https://github.com/ClangBuiltLinux/linux/issues/1960
> Fixes: aff35fbc7830 ("mmc: sdhci-of-dwcmshc: Add support for T-Head TH1520")
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/sdhci-of-dwcmshc.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
> index 0eb72544c09e..a1f57af6acfb 100644
> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
> @@ -870,9 +870,9 @@ static int dwcmshc_probe(struct platform_device *pdev)
>         if (pltfm_data == &sdhci_dwcmshc_th1520_pdata) {
>                 priv->delay_line = PHY_SDCLKDL_DC_DEFAULT;
>
> -               if ((device_property_read_bool(dev, "mmc-ddr-1_8v")) |
> -                   (device_property_read_bool(dev, "mmc-hs200-1_8v")) |
> -                   (device_property_read_bool(dev, "mmc-hs400-1_8v")))
> +               if (device_property_read_bool(dev, "mmc-ddr-1_8v") ||
> +                   device_property_read_bool(dev, "mmc-hs200-1_8v") ||
> +                   device_property_read_bool(dev, "mmc-hs400-1_8v"))
>                         priv->flags |= FLAG_IO_FIXED_1V8;
>                 else
>                         priv->flags &= ~FLAG_IO_FIXED_1V8;
>
> ---
> base-commit: 3f00051234f02d0d9d1f63b9a334d0fd4c65b6ca
> change-id: 20231116-sdhci-of-dwcmshc-fix-wbitwise-instead-of-logical-bf8fed73b5bb
>
> Best regards,
> --
> Nathan Chancellor <nathan@kernel.org>
>