linux-kernel - Re: [PATCH v8 6/7] iio: accel: kionix-kx022a: Add a function to retrieve number of bytes in buffer

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Message-ID: <ZOdFyKHBc6BcOgZw@smile.fi.intel.com>
Date:   Thu, 24 Aug 2023 14:58:00 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Mehdi Djait <mehdi.djait.k@...il.com>
Cc:     jic23@...nel.org, mazziesaccount@...il.com,
        krzysztof.kozlowski+dt@...aro.org, robh+dt@...nel.org,
        lars@...afoo.de, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v8 6/7] iio: accel: kionix-kx022a: Add a function to
 retrieve number of bytes in buffer

On Wed, Aug 23, 2023 at 11:16:40PM +0200, Mehdi Djait wrote:
> Since Kionix accelerometers use various numbers of bits to report data, a
> device-specific function is required.
> Implement the function as a callback in the device-specific chip_info structure

...

> +	int ret, fifo_bytes;
> +
> +	ret = regmap_read(data->regmap, KX022A_REG_BUF_STATUS_1, &fifo_bytes);
> +	if (ret) {
> +		dev_err(data->dev, "Error reading buffer status\n");
> +		return ret;
> +	}
> +
> +	if (fifo_bytes == KX022A_FIFO_FULL_VALUE)
> +		return KX022A_FIFO_MAX_BYTES;
> +
> +	return fifo_bytes;

This will be called each time ->get_fifo_bytes() called.
Do you expect the fifo_bytes to be changed over times?
Shouldn't we simply cache the value?

...

> +	fifo_bytes = data->chip_info->get_fifo_bytes(data);

>  

Now this blank line becomes redundant.

>  	if (fifo_bytes % KX022A_FIFO_SAMPLES_SIZE_BYTES)
>  		dev_warn(data->dev, "Bad FIFO alignment. Data may be corrupt\n");


-- 
With Best Regards,
Andy Shevchenko