linux-kernel - Re: [PATCH] i2c: imx: Remove a useless test in 'i2c_imx_init_recovery

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Date:   Mon, 7 Aug 2017 08:36:17 +0200
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     wsa@...-dreams.de, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH] i2c: imx: Remove a useless test in
 'i2c_imx_init_recovery_info()'

On Mon, Aug 07, 2017 at 01:49:53AM +0200, Christophe JAILLET wrote:
> 'devm_pinctrl_get()' never returns NULL, so this test can be simplified.

That's wrong. If CONFIG_PINCTRL is disabled devm_pinctrl_get returns
NULL. But I think this shouldn't be considered an error, so your change
is right, just the commit log is not.

> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 54a47b40546f..7e84662fe1c0 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -997,7 +997,7 @@ static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
>  	struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
>  
>  	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
> -	if (!i2c_imx->pinctrl || IS_ERR(i2c_imx->pinctrl)) {
> +	if (IS_ERR(i2c_imx->pinctrl)) {
>  		dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
>  		return PTR_ERR(i2c_imx->pinctrl);
>  	}

Side note: I'm not sure, this construct is valid. IIRC PTR_ERR should
only be called for values x where IS_ERR(x) is true. Here it is at least
surprising that an message hints to a problem but the return code is 0.

@Julia: I'm sure coccinelle can find more of those?!

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |