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

[Matti Vaittinen]

On 8/24/23 14:58, Andy Shevchenko wrote:
> 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?

I think this value tells how many samples there currently is in the 
FIFO. Caching it does not sound meaningful unless I am missing something.

Yours,
	-- Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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