Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] clk: vc5: Initialize src in vc5_mux_set_parent()
To:     Stephen Boyd <sboyd@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>
Cc:     linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
        Marek Vasut <marek.vasut+renesas@gmail.com>,
        Alexey Firago <alexey_firago@mentor.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        linux-renesas-soc@vger.kernel.org
References: <20181214214959.162744-1-sboyd@kernel.org>
From:   Marek Vasut <marek.vasut@gmail.com>
Message-ID: <c1065c2f-3e7e-e2c4-a9f5-e672e86beb43@gmail.com>
Date:   Fri, 14 Dec 2018 23:29:30 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.8.0
MIME-Version: 1.0
In-Reply-To: <20181214214959.162744-1-sboyd@kernel.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 12/14/2018 10:49 PM, Stephen Boyd wrote:
> It seems that it may be possible to get to the regmap update call
> without ever initializing this variable, so just set it to 0 to be safe.
> 
> Cc: Marek Vasut <marek.vasut+renesas@gmail.com>
> Cc: Alexey Firago <alexey_firago@mentor.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: linux-renesas-soc@vger.kernel.org
> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
> ---
>  drivers/clk/clk-versaclock5.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
> index 5b393e711e94..026f76276933 100644
> --- a/drivers/clk/clk-versaclock5.c
> +++ b/drivers/clk/clk-versaclock5.c
> @@ -246,7 +246,7 @@ static int vc5_mux_set_parent(struct clk_hw *hw, u8 index)
>  	struct vc5_driver_data *vc5 =
>  		container_of(hw, struct vc5_driver_data, clk_mux);
>  	const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL | VC5_PRIM_SRC_SHDN_EN_CLKIN;
> -	u8 src;
> +	u8 src = 0;
>  
>  	if ((index > 1) || !vc5->clk_mux_ins)
>  		return -EINVAL;

Can you rather change the else { } branch in that function such that it does

 if (vc5->clk_mux)ins == ...)
  ...
 else if (...)
  ...
+ else
+  return -EINVAL;

The last bit would assure the function would fail in case the
clk_mux_ins == 0, which can happen if someone builds a setup without any
clock into connected to the VC5 (which would not work hardware-vise).

-- 
Best regards,
Marek Vasut