linux-kernel - Re: [PATCH v1 08/13] iio: chemical: bme680: add power management

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Message-ID: <Zwl2SEmDqc-PTtqp@vamoirid-laptop>
Date: Fri, 11 Oct 2024 21:02:32 +0200
From: Vasileios Aoiridis <vassilisamir@...il.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: jic23@...nel.org, lars@...afoo.de, robh@...nel.org, krzk+dt@...nel.org,
	conor+dt@...nel.org, anshulusr@...il.com, gustavograzs@...il.com,
	linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 08/13] iio: chemical: bme680: add power management

On Fri, Oct 11, 2024 at 01:10:20PM +0300, Andy Shevchenko wrote:
> On Thu, Oct 10, 2024 at 11:00:25PM +0200, vamoirid wrote:
> > From: Vasileios Amoiridis <vassilisamir@...il.com>
> > 
> > Add runtime power management to the device. To facilitate this, add also
> > a struct dev * inside the bme680_data structure to have the device
> > accesible from the data structure.
> 
> ...
> 
> > --- a/drivers/iio/chemical/bme680.h
> > +++ b/drivers/iio/chemical/bme680.h
> > @@ -75,6 +75,7 @@
> >  #define BME680_CALIB_RANGE_3_LEN               5
> >  
> >  extern const struct regmap_config bme680_regmap_config;
> > +extern const struct dev_pm_ops bmp280_dev_pm_ops;
> 
> Is pm.h being included already in this header? Otherwise you need to add it.
>

No it is not, and indeed I need to add it. Probably because it was
included by some other file I didn't get an error from gcc?

> ...
> 
> >  	struct regmap *regmap;
> >  	struct bme680_calib bme680;
> >  	struct mutex lock; /* Protect multiple serial R/W ops to device. */
> > +	struct device *dev;
> 
> Is it the same that you may get wia regmap_get_device()?
> 

Yes it is the same. Maybe I can try and see if I can use the following

	regmap_get_device(data->regmap)

in the places where the pm functions are used in order to not declare a
new value inside the struct bme680_data. But in general, is this approach
prefered?

> >  	u8 oversampling_temp;
> >  	u8 oversampling_press;
> >  	u8 oversampling_humid;
> 
> ...
> 
> > +	/* Enable runtime PM */
> > +	pm_runtime_get_noresume(dev);
> > +	pm_runtime_set_active(dev);
> > +	pm_runtime_enable(dev);
> > +	pm_runtime_set_autosuspend_delay(dev, BME680_STARTUP_TIME_US * 100);
> > +	pm_runtime_use_autosuspend(dev);
> > +	pm_runtime_put(dev);
> 
> Can we use devm_pm_runtime_enable() for some of the above?
>

I will have to check its use, and I will let you know.

> > +	ret = devm_add_action_or_reset(dev, bme680_pm_disable, dev);
> > +	if (ret)
> > +		return ret;
> 
> ...
> 
> > +static int bme680_runtime_resume(struct device *dev)
> > +{
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct bme680_data *data = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	ret = regulator_bulk_enable(BME680_NUM_SUPPLIES, data->supplies);
> > +	if (ret)
> > +		return ret;
> > +
> > +	fsleep(BME680_STARTUP_TIME_US);
> > +
> > +	ret = bme680_chip_config(data);
> > +	if (ret)
> > +		return ret;
> 
> > +	ret = bme680_gas_config(data);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return 0;
> 
> 	return bme680_gas_config(...);
> 

Indeed, much cleaner, thanks!

> > +}
> 
> ...
> 
> > +EXPORT_RUNTIME_DEV_PM_OPS(bme680_dev_pm_ops, bme680_runtime_suspend,
> > +			  bme680_runtime_resume, NULL);
> 
> You also need pm.h for the macro IIRC.
> 

ACK.

> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

Cheers,
Vasilis