linux-kernel - Re: [PATCH RFC 6/6] iio: light: opt4060: Use cleanup.h for IIO locks

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Message-Id: <DEPLUDI44VU0.3CMJ0YOFXZOBR@gmail.com>
Date: Thu, 04 Dec 2025 12:23:10 -0500
From: "Kurt Borja" <kuurtb@...il.com>
To: "David Lechner" <dlechner@...libre.com>, "Kurt Borja"
 <kuurtb@...il.com>, "Andy Shevchenko" <andriy.shevchenko@...el.com>,
 "Lars-Peter Clausen" <lars@...afoo.de>, "Michael Hennerich"
 <Michael.Hennerich@...log.com>, "Jonathan Cameron" <jic23@...nel.org>,
 "Benson Leung" <bleung@...omium.org>, "Antoniu Miclaus"
 <antoniu.miclaus@...log.com>, "Gwendal Grignou" <gwendal@...omium.org>,
 "Shrikant Raskar" <raskar.shree97@...il.com>, "Per-Daniel Olsson"
 <perdaniel.olsson@...s.com>
Cc: Nuno Sá <nuno.sa@...log.com>, "Andy Shevchenko"
 <andy@...nel.org>, "Guenter Roeck" <groeck@...omium.org>, "Jonathan
 Cameron" <Jonathan.Cameron@...wei.com>, <linux-iio@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <chrome-platform@...ts.linux.dev>
Subject: Re: [PATCH RFC 6/6] iio: light: opt4060: Use cleanup.h for IIO
 locks

On Wed Dec 3, 2025 at 5:40 PM -05, David Lechner wrote:
> On 12/3/25 1:18 PM, Kurt Borja wrote:
>> Simplify and drop "hacky" busy-waiting code in
>> opt4060_set_driver_state() by using guard().
>> 
>> Signed-off-by: Kurt Borja <kuurtb@...il.com>
>> ---
>>  drivers/iio/light/opt4060.c | 52 +++++++++++++++------------------------------
>>  1 file changed, 17 insertions(+), 35 deletions(-)
>> 
>> diff --git a/drivers/iio/light/opt4060.c b/drivers/iio/light/opt4060.c
>> index 500899d7bd62..903963606143 100644
>> --- a/drivers/iio/light/opt4060.c
>> +++ b/drivers/iio/light/opt4060.c
>> @@ -22,6 +22,7 @@
>>  #include <linux/iio/trigger.h>
>>  #include <linux/iio/trigger_consumer.h>
>>  #include <linux/iio/triggered_buffer.h>
>> +#include <linux/cleanup.h>
>>  
>>  /* OPT4060 register set */
>>  #define OPT4060_RED_MSB				0x00
>> @@ -302,41 +303,22 @@ static int opt4060_set_driver_state(struct iio_dev *indio_dev,
>>  				    bool continuous_irq)
>>  {
>>  	struct opt4060_chip *chip = iio_priv(indio_dev);
>> -	int ret = 0;
>> -any_mode_retry:
>> -	if (!iio_device_claim_buffer(indio_dev)) {
>> -		/*
>> -		 * This one is a *bit* hacky. If we cannot claim buffer mode,
>> -		 * then try direct mode so that we make sure things cannot
>> -		 * concurrently change. And we just keep trying until we get one
>> -		 * of the modes...
>> -		 */
>> -		if (!iio_device_claim_direct(indio_dev))
>> -			goto any_mode_retry;
>> -		/*
>> -		 * This path means that we managed to claim direct mode. In
>> -		 * this case the buffer isn't enabled and it's okay to leave
>> -		 * continuous mode for sampling and/or irq.
>> -		 */
>> -		ret = opt4060_set_state_common(chip, continuous_sampling,
>> -					       continuous_irq);
>> -		iio_device_release_direct(indio_dev);
>> -		return ret;
>> -	} else {
>> -		/*
>> -		 * This path means that we managed to claim buffer mode. In
>> -		 * this case the buffer is enabled and irq and sampling must go
>> -		 * to or remain continuous, but only if the trigger is from this
>> -		 * device.
>> -		 */
>> -		if (!iio_trigger_validate_own_device(indio_dev->trig, indio_dev))
>> -			ret = opt4060_set_state_common(chip, true, true);
>> -		else
>> -			ret = opt4060_set_state_common(chip, continuous_sampling,
>> -						       continuous_irq);
>> -		iio_device_release_buffer(indio_dev);
>> -	}
>> -	return ret;
>> +
>> +	guard(iio_device_claim)(indio_dev);
>> +
>> +	/*
>> +	 * If we manage to claim buffer mode and we are using our own trigger,
>> +	 * IRQ and sampling must go to or remain continuous.
>> +	 */
>> +	if (iio_buffer_enabled(indio_dev) && iio_trigger_using_own(indio_dev))
>
> The commit message does not explain why this was changed from
> iio_trigger_validate_own_device() to iio_trigger_using_own(). I'm guessing
> that is why we also dropped the `!`?

Hmm I just assumed this functions were equivalent, but looking at the
code is not directly obvious.

I will look into it and mention this in the commit message.


-- 
 ~ Kurt