linux-kernel - Re: [PATCH] phy: intel: Eliminate unnecessary assignment in intel_cbphy_set

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Date:   Tue, 26 May 2020 11:12:58 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>
Subject: Re: [PATCH] phy: intel: Eliminate unnecessary assignment in intel_cbphy_set_mode

On Fri, May 22, 2020 at 8:51 PM Nathan Chancellor
<natechancellor@...il.com> wrote:
>
> Clang warns:
>
> drivers/phy/intel/phy-intel-combo.c:202:34: warning: implicit conversion
> from enumeration type 'enum intel_phy_mode' to different enumeration
> type 'enum intel_combo_mode' [-Wenum-conversion]
>         enum intel_combo_mode cb_mode = PHY_PCIE_MODE;
>                               ~~~~~~~   ^~~~~~~~~~~~~
> 1 warning generated.
>
> The correct enum to use would be PCIE0_PCIE1_MODE. However, eliminating
> this assignment is a little better because the switch statement always

Indeed, the switch is exhaustive.  Might be a risk if new enumeration
values are added to the enum, though.

Probably should just initialize it to PCIE0_PCIE1_MODE, then you can
simplify the PHY_PCIE_MODE case a little (replace ternary with
if+assignment).

> assigns a new value to cb_mode, which also takes care of the warning.
>
> Fixes: ac0a95a3ea78 ("phy: intel: Add driver support for ComboPhy")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1034
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> ---
>  drivers/phy/intel/phy-intel-combo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/phy/intel/phy-intel-combo.c b/drivers/phy/intel/phy-intel-combo.c
> index c2a35be4cdfb..4bc1276ecf23 100644
> --- a/drivers/phy/intel/phy-intel-combo.c
> +++ b/drivers/phy/intel/phy-intel-combo.c
> @@ -199,9 +199,9 @@ static int intel_cbphy_pcie_dis_pad_refclk(struct intel_cbphy_iphy *iphy)
>
>  static int intel_cbphy_set_mode(struct intel_combo_phy *cbphy)
>  {
> -       enum intel_combo_mode cb_mode = PHY_PCIE_MODE;
>         enum aggregated_mode aggr = cbphy->aggr_mode;
>         struct device *dev = cbphy->dev;
> +       enum intel_combo_mode cb_mode;
>         enum intel_phy_mode mode;
>         int ret;
>
>
> base-commit: c11d28ab4a691736e30b49813fb801847bd44e83
> --

-- 
Thanks,
~Nick Desaulniers