linux-kernel - Re: [PATCH] i2c: imx: make bus recovery through pinctrl optional

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Date:	Wed, 18 Nov 2015 08:24:37 +0100
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Li Yang <leoli@...escale.com>
Cc:	Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Gao Pan <b54642@...escale.com>
Subject: Re: [PATCH] i2c: imx: make bus recovery through pinctrl optional

Hello,

On Tue, Nov 17, 2015 at 06:02:59PM -0600, Li Yang wrote:
> Since commit 1c4b6c3bcf30 ("i2c: imx: implement bus recovery") the driver
> starts to use gpio/pinctrl to do i2c bus recovery.  But pinctrl is not
> always available for platforms using this driver such as ls1021a and
> ls1043a, and the device tree binding also mentioned this gpio based
> recovery mechanism as optional.  The patch make it really optional that
> the probe function won't bailout when pinctrl is not available and it
> won't try to register recovery functions if pinctrl is NULL when the
> PINCTRL is not enabled at all.
> 
> Signed-off-by: Li Yang <leoli@...escale.com>
> Cc: Gao Pan <b54642@...escale.com>
> ---
>  drivers/i2c/busses/i2c-imx.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 1e4d99d..7813153 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -1086,12 +1086,6 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
> -	if (IS_ERR(i2c_imx->pinctrl)) {
> -		ret = PTR_ERR(i2c_imx->pinctrl);
> -		goto clk_disable;
> -	}
> -
>  	/* Request IRQ */
>  	ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0,
>  				pdev->name, i2c_imx);
> @@ -1125,7 +1119,12 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  		goto clk_disable;
>  	}
>  
> -	i2c_imx_init_recovery_info(i2c_imx, pdev);
> +	/* optional bus recovery feature through pinctrl */
> +	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
> +	if (IS_ERR_OR_NULL(i2c_imx->pinctrl))
> +		dev_info(&pdev->dev, "can't get pinctrl, bus recovery feature disabled\n");
> +	else
> +		i2c_imx_init_recovery_info(i2c_imx, pdev);

I'm pretty sure this is wrong. If pinctrl isn't available
devm_pinctrl_get returns NULL? But AFAIK you must not ignore an error,
so the better thing to do is:

	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
	if (IS_ERR(i2c_imx->pinctrl)) {
		ret = PTR_ERR(i2c_imx->pinctrl);
		goto errorhandling;
	}

	if (i2c_imx->pinctrl)
		i2c_imx_init_recovery_info(i2c_imx, pdev);
	else
		dev_info(&pdev->dev, "can't get pinctrl, bus recovery feature disabled\n");


right?

Uwe Kleine-König

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