linux-kernel - Re: [PATCH v2 06/18] media: i2c: max9271: Check max9271

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Message-ID: <dc98a803-1559-e93c-3270-a55a0ca52849@ideasonboard.com>
Date:   Mon, 15 Mar 2021 15:46:07 +0000
From:   Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To:     Jacopo Mondi <jacopo+renesas@...ndi.org>,
        laurent.pinchart+renesas@...asonboard.com,
        niklas.soderlund+renesas@...natech.se, geert@...ux-m68k.org
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 06/18] media: i2c: max9271: Check max9271_write()
 return

Hi Jacopo,

On 15/03/2021 13:15, Jacopo Mondi wrote:
> Check the return value of the max9271_write() function in the
> max9271 library driver.
> 
> While at it, modify an existing condition to be made identical
> to other checks.

Excellent, much better to catch write errors early.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>


> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
> ---
>  drivers/media/i2c/max9271.c | 30 +++++++++++++++++++++++-------
>  1 file changed, 23 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/i2c/max9271.c b/drivers/media/i2c/max9271.c
> index c495582dcff6..2c7dc7fb9846 100644
> --- a/drivers/media/i2c/max9271.c
> +++ b/drivers/media/i2c/max9271.c
> @@ -106,7 +106,10 @@ int max9271_set_serial_link(struct max9271_device *dev, bool enable)
>  	 * Short delays here appear to show bit-errors in the writes following.
>  	 * Therefore a conservative delay seems best here.
>  	 */
> -	max9271_write(dev, 0x04, val);
> +	ret = max9271_write(dev, 0x04, val);
> +	if (ret < 0)
> +		return ret;
> +
>  	usleep_range(5000, 8000);
>  
>  	return 0;
> @@ -118,7 +121,7 @@ int max9271_configure_i2c(struct max9271_device *dev, u8 i2c_config)
>  	int ret;
>  
>  	ret = max9271_write(dev, 0x0d, i2c_config);
> -	if (ret)
> +	if (ret < 0)
>  		return ret;
>  
>  	/* The delay required after an I2C bus configuration change is not
> @@ -143,7 +146,10 @@ int max9271_set_high_threshold(struct max9271_device *dev, bool enable)
>  	 * Enable or disable reverse channel high threshold to increase
>  	 * immunity to power supply noise.
>  	 */
> -	max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0));
> +	ret = max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0));
> +	if (ret < 0)
> +		return ret;
> +
>  	usleep_range(2000, 2500);
>  
>  	return 0;
> @@ -152,6 +158,8 @@ EXPORT_SYMBOL_GPL(max9271_set_high_threshold);
>  
>  int max9271_configure_gmsl_link(struct max9271_device *dev)
>  {
> +	int ret;
> +
>  	/*
>  	 * Configure the GMSL link:
>  	 *
> @@ -162,16 +170,24 @@ int max9271_configure_gmsl_link(struct max9271_device *dev)
>  	 *
>  	 * TODO: Make the GMSL link configuration parametric.
>  	 */
> -	max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN |
> -		      MAX9271_EDC_1BIT_PARITY);
> +	ret = max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN |
> +			    MAX9271_EDC_1BIT_PARITY);
> +	if (ret < 0)
> +		return ret;
> +
>  	usleep_range(5000, 8000);
>  
>  	/*
>  	 * Adjust spread spectrum to +4% and auto-detect pixel clock
>  	 * and serial link rate.
>  	 */
> -	max9271_write(dev, 0x02, MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES |
> -		      MAX9271_PCLK_AUTODETECT | MAX9271_SERIAL_AUTODETECT);
> +	ret = max9271_write(dev, 0x02,
> +			    MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES |
> +			    MAX9271_PCLK_AUTODETECT |
> +			    MAX9271_SERIAL_AUTODETECT);
> +	if (ret < 0)
> +		return ret;
> +
>  	usleep_range(5000, 8000);
>  
>  	return 0;
>