linux-kernel - Re: [PATCH] clk: mediatek: fix cppcheck error for uninitialized variable

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Date: Tue, 2 Jan 2024 10:41:45 +0100
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
To: mturquette@...libre.com, sboyd@...nel.org, matthias.bgg@...il.com,
 kishan.dudhatra@...iconsignals.io
Cc: Chen-Yu Tsai <wenst@...omium.org>, Tom Rix <trix@...hat.com>,
 linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH] clk: mediatek: fix cppcheck error for uninitialized
 variable

Il 25/12/23 16:28,  ha scritto:
> From: Kishan Dudhatra <kishan.dudhatra@...iconsignals.io>
> 
> cppcheck reports below warning
> 
> clk/mediatek/clk-fhctl.c:206:27:
> error: Uninitialized variable: pll_postdiv [uninitvar]
> if (postdiv && postdiv < pll_postdiv)
> 
> This is due to uninitialization of variable pll_postdiv,
> which is now initialized as part of this patch.
> 
> Signed-off-by: Kishan Dudhatra <kishan.dudhatra@...iconsignals.io>

This is a false positive... the pll_postdiv variable is *always* used
and *only if* postdiv > 0.

P.S.: There was some problem with your email, as the From entry is empty.

Regards,
Angelo

> 
> diff --git a/drivers/clk/mediatek/clk-fhctl.c b/drivers/clk/mediatek/clk-fhctl.c
> index 33b6ad8fdc2e..b0e71e4fd938 100644
> --- a/drivers/clk/mediatek/clk-fhctl.c
> +++ b/drivers/clk/mediatek/clk-fhctl.c
> @@ -186,7 +186,7 @@ static int fhctl_hopping(struct mtk_fh *fh, unsigned int new_dds,
>   	struct fh_pll_regs *regs = &fh->regs;
>   	struct mtk_clk_pll *pll = &fh->clk_pll;
>   	spinlock_t *lock = fh->lock;
> -	unsigned int pll_postdiv;
> +	unsigned int pll_postdiv = 0;
>   	unsigned long flags = 0;
>   	int ret;
>