linux-kernel - Re: [PATCH v3 1/3] iio: temperature: mlx90632 Add runtime powermanagement modes

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Message-ID: <CAKv63utO6_vPtuCZKSa5MFFKbSYPQbrAGytiiqT+CZ402rO9fA@mail.gmail.com>
Date:   Thu, 15 Sep 2022 16:35:33 +0200
From:   Crt Mori <cmo@...exis.com>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH v3 1/3] iio: temperature: mlx90632 Add runtime
 powermanagement modes

> > +     pm_runtime_get_sync(dev);
> So, this isn't quite enough.
>
> Take a look at what devm_pm_runtime_enable()
> does as the documentation for
> pm_runtime_use_autosuspend()
>
> I'd suggest using devm_pm_runtime_enable() and
> an additional callback to turn the device on that
> is registered after devm_pm_runtime_enable()
> (so will maintain the ordering you have here).
>
>
>
I copied this from pressure/bmp280-core driver. I had devm_pm
originally, but was asked to replace it.

> > +     pm_runtime_put_noidle(dev);
> > +     pm_runtime_disable(dev);
> > +}
> > +
> >  static int mlx90632_probe(struct i2c_client *client,
> >                         const struct i2c_device_id *id)
> >  {
> > @@ -902,6 +1132,7 @@ static int mlx90632_probe(struct i2c_client *client,
> >       mlx90632->client = client;
> >       mlx90632->regmap = regmap;
> >       mlx90632->mtyp = MLX90632_MTYP_MEDICAL;
> > +     mlx90632->powerstatus = MLX90632_PWR_STATUS_HALT;
> >
> >       mutex_init(&mlx90632->lock);
> >       indio_dev->name = id->name;
> > @@ -961,16 +1192,25 @@ static int mlx90632_probe(struct i2c_client *client,
> >
> >       mlx90632->emissivity = 1000;
> >       mlx90632->object_ambient_temperature = 25000; /* 25 degrees milliCelsius */
> > +     mlx90632->interaction_ts = jiffies; /* Set initial value */
> >
> > -     pm_runtime_disable(&client->dev);
> > +     pm_runtime_get_noresume(&client->dev);
> >       ret = pm_runtime_set_active(&client->dev);
> >       if (ret < 0) {
> >               mlx90632_sleep(mlx90632);
> >               return ret;
> >       }
> > +
> >       pm_runtime_enable(&client->dev);
> >       pm_runtime_set_autosuspend_delay(&client->dev, MLX90632_SLEEP_DELAY_MS);
> >       pm_runtime_use_autosuspend(&client->dev);
> > +     pm_runtime_put_autosuspend(&client->dev);
> > +
> > +     ret = devm_add_action_or_reset(&client->dev, mlx90632_pm_disable, &client->dev);
>
> Having moved those over to devm you need to also have dropped the calls in remove()
> (I only noticed this whilst trying to fix the autosuspend issue above.)

So in remove, there should be no pm calls, because mlx90632_pm_disable
function handle all of it? I still keep the sleep call, so that it
also puts the sensor in lowest state, or I rather keep it only in
regulator_disable (which should also be called at removal)?

> > +     if (ret) {
> > +             mlx90632_sleep(mlx90632);
> > +             return ret;
> > +     }
> >
> >       return iio_device_register(indio_dev);
> >  }
>