Re: [PATCH v5 1/9] iio: adc: ad7606: remove frstdata check for serial mode

Jonathan Cameron
2024-09-07T14:51:47Z

On Sat, 7 Sep 2024 09:50:34 +0300
Alexandru Ardelean <aardelean@baylibre.com> wrote:

> From: Guillaume Stols <gstols@baylibre.com>
>
> The current implementation attempts to recover from an eventual glitch
> in the clock by checking frstdata state after reading the first
> channel's sample: If frstdata is low, it will reset the chip and
> return -EIO.
>
> This will only work in parallel mode, where frstdata pin is set low
> after the 2nd sample read starts.
>
> For the serial mode, according to the datasheet, "The FRSTDATA output
> returns to a logic low following the 16th SCLK falling edge.", thus
> after the Xth pulse, X being the number of bits in a sample, the check
> will always be true, and the driver will not work at all in serial
> mode if frstdata(optional) is defined in the devicetree as it will
> reset the chip, and return -EIO every time read_sample is called.
>
> Hence, this check must be removed for serial mode.
>
> Fixes: b9618c0cacd7 ("staging: IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4")
> Signed-off-by: Guillaume Stols <gstols@baylibre.com>
> Reviewed-by: Nuno Sa <nuno.sa@analog.com>
> Link: https://patch.msgid.link/20240702-cleanup-ad7606-v3-1-18d5ea18770e@baylibre.com
> Cc: <Stable@vger.kernel.org>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reference the fix patch in your cover letter, but don't include it in the series.

I'll just get confused when I pick this up.