linux-kernel - Re: [PATCH 4/6] iio: imu: inv_icm42600: Simplify pm

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Message-ID: <20250713152810.4483c786@jic23-huawei>
Date: Sun, 13 Jul 2025 15:28:10 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Sean Nyekjaer <sean@...nix.com>
Cc: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@....com>, David Lechner
 <dlechner@...libre.com>, Nuno Sá <nuno.sa@...log.com>, Andy
 Shevchenko <andy@...nel.org>, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] iio: imu: inv_icm42600: Simplify pm_runtime setup

On Wed, 09 Jul 2025 14:35:12 +0200
Sean Nyekjaer <sean@...nix.com> wrote:

> Remove unnecessary pm_runtime_get_noresume() and pm_runtime_put()
> calls during probe. These are not required when the device is marked
> active via pm_runtime_set_active() before enabling pm_runtime with
> pm_runtime_enable().
> 
> Also remove the redundant pm_runtime_put_sync() call from the cleanup
> path, since the core is not incrementing the usage count beforehand.
> 
> This simplifies the PM setup and avoids manipulating the usage counter
> unnecessarily.

Could we switch directly to using devm_pm_runtime_enable() for this driver?

At first glance looks like this code is missing the disable of autosuspend
that should be there (which devm_pm_runtime_enable() will also handle).


> 
> Fixes: 31c24c1e93c3 ("iio: imu: inv_icm42600: add core of new inv_icm42600 driver")
> Signed-off-by: Sean Nyekjaer <sean@...nix.com>
> ---
>  drivers/iio/imu/inv_icm42600/inv_icm42600_core.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c
> index 55a29b1e2b11355598b0ede7af22857aed3ae134..1072bea11c73d09a9a0e6ea9d4a5c7a72248dca7 100644
> --- a/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c
> +++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c
> @@ -708,7 +708,6 @@ static void inv_icm42600_disable_pm(void *_data)
>  {
>  	struct device *dev = _data;
>  
> -	pm_runtime_put_sync(dev);
>  	pm_runtime_disable(dev);
>  }
>  
> @@ -806,11 +805,10 @@ int inv_icm42600_core_probe(struct regmap *regmap, int chip,
>  	ret = pm_runtime_set_active(dev);
>  	if (ret)
>  		return ret;
> -	pm_runtime_get_noresume(dev);
> +
>  	pm_runtime_enable(dev);
>  	pm_runtime_set_autosuspend_delay(dev, INV_ICM42600_SUSPEND_DELAY_MS);
>  	pm_runtime_use_autosuspend(dev);
> -	pm_runtime_put(dev);
>  
>  	return devm_add_action_or_reset(dev, inv_icm42600_disable_pm, dev);
>  }
>