Re: [PATCH v3 1/8] iio: adc: stm32-adc: fix channel sampling time init

From: Jonathan Cameron <jic23@kernel.org>
To: Olivier Moysan <olivier.moysan@foss.st.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>, <nuno.sa@analog.com>,
	Paul Cercueil <paul@crapouillou.net>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Wan Jiabing <wanjiabing@vivo.com>,
	Yannick Brosseau <yannick.brosseau@gmail.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>
Subject: Re: [PATCH v3 1/8] iio: adc: stm32-adc: fix channel sampling time init
Date: Sun, 9 Oct 2022 13:42:52 +0100	[thread overview]
Message-ID: <20221009134252.2b636e0a@jic23-huawei> (raw)
In-Reply-To: <20221005161424.4537-2-olivier.moysan@foss.st.com>

On Wed, 5 Oct 2022 18:14:17 +0200
Olivier Moysan <olivier.moysan@foss.st.com> wrote:

> Fix channel init for ADC generic channel bindings.
> In generic channel initialization, stm32_adc_smpr_init() is called
> to initialize channel sampling time. The "st,min-sample-time-ns"
> property is an optional property. If it is not defined,
> stm32_adc_smpr_init() is currently skipped.
> However stm32_adc_smpr_init() must always be called,
> to force a minimum sampling time for the internal channels,
> as the minimum sampling time is known.
> Make stm32_adc_smpr_init() call unconditional.

Hi Olivier.  Andy commented on this in v2... 

Line lengths in patch description are rather random and no where near the typical
72-75 chars.  Should look more like:

Fix channel init for ADC generic channel bindings. In generic channel
initialization, stm32_adc_smpr_init() is called > to initialize channel
sampling time. The "st,min-sample-time-ns" property is an optional
property. If it is not defined, stm32_adc_smpr_init() is currently
skipped. However stm32_adc_smpr_init() must always be called, to force a
minimum sampling time for the internal channels, as the minimum sampling
time is known. Make stm32_adc_smpr_init() call unconditional.

Fine to have multiple paragraphs, but within each one, don't wrap too early.

> 
> Fixes: 796e5d0b1e9b ("iio: adc: stm32-adc: use generic binding for sample-time")
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
> ---
>  drivers/iio/adc/stm32-adc.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 6256977eb7f7..3cda529f081d 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -2086,18 +2086,19 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
>  		stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
>  					vin[1], scan_index, differential);
>  
> +		val = 0;
>  		ret = fwnode_property_read_u32(child, "st,min-sample-time-ns", &val);
>  		/* st,min-sample-time-ns is optional */
> -		if (!ret) {
> -			stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
> -			if (differential)
> -				stm32_adc_smpr_init(adc, vin[1], val);
> -		} else if (ret != -EINVAL) {
> +		if (ret && ret != -EINVAL) {
>  			dev_err(&indio_dev->dev, "Invalid st,min-sample-time-ns property %d\n",
>  				ret);
>  			goto err;
>  		}
>  
> +		stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
> +		if (differential)
> +			stm32_adc_smpr_init(adc, vin[1], val);
> +
>  		scan_index++;
>  	}
>  

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