linux-kernel - Re: [PATCH 1/2] iio: accel: bma220: convert probe to device-managed functions

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Date:   Sat, 17 Jul 2021 19:13:11 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <aardelean@...iqon.com>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] iio: accel: bma220: convert probe to device-managed
 functions

On Sun, 4 Jul 2021 18:08:17 +0100
Jonathan Cameron <jic23@...nel.org> wrote:

> On Fri, 25 Jun 2021 17:01:36 +0300
> Alexandru Ardelean <aardelean@...iqon.com> wrote:
> 
> > This change converts the driver to use devm_iio_triggered_buffer_setup()
> > and devm_iio_device_register() for initializing and registering the IIO
> > device.
> > 
> > The bma220_deinit() is converted into a callback for a
> > devm_add_action_or_reset() hook, so that the device is put in stand-by when
> > the driver gets uninitialized.
> > The return value of the bma220_deinit() function isn't used as it does not
> > add any value. On the error path of the probe function, this can just
> > override the actual error with -EBUSY, or can even return 0 (no error), on
> > the error path.
> > 
> > Signed-off-by: Alexandru Ardelean <aardelean@...iqon.com>  
> Hmm. That return on the error path issue in probe is almost worth a backported
> fix, but meh, it's been there for ages so unless anyone shouts, let us assume
> it never bit anyone.
> 
> Otherwise, this looks fine.  I'm not going to comment on all the similar
> devm patches you have on list unless I have something I want changed.
> I'll pick them all up in a week or two once we are well into the new cycle.
> 
> thanks,
> 
> Jonathan

Both applied to the togreg branch of iio.git and pushed out as testing for
0-day to poke at them and see if we missed anything.

Thanks,

Jonathan

> 
> > ---
> >  drivers/iio/accel/bma220_spi.c | 44 +++++++++-------------------------
> >  1 file changed, 11 insertions(+), 33 deletions(-)
> > 
> > diff --git a/drivers/iio/accel/bma220_spi.c b/drivers/iio/accel/bma220_spi.c
> > index 0622c7936499..0095931a11f8 100644
> > --- a/drivers/iio/accel/bma220_spi.c
> > +++ b/drivers/iio/accel/bma220_spi.c
> > @@ -218,20 +218,14 @@ static int bma220_init(struct spi_device *spi)
> >  	return 0;
> >  }
> >  
> > -static int bma220_deinit(struct spi_device *spi)
> > +static void bma220_deinit(void *spi)
> >  {
> >  	int ret;
> >  
> >  	/* Make sure the chip is powered off */
> >  	ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
> >  	if (ret == BMA220_SUSPEND_SLEEP)
> > -		ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
> > -	if (ret < 0)
> > -		return ret;
> > -	if (ret == BMA220_SUSPEND_SLEEP)
> > -		return -EBUSY;
> > -
> > -	return 0;
> > +		bma220_read_reg(spi, BMA220_REG_SUSPEND);
> >  }
> >  
> >  static int bma220_probe(struct spi_device *spi)
> > @@ -262,34 +256,19 @@ static int bma220_probe(struct spi_device *spi)
> >  	if (ret)
> >  		return ret;
> >  
> > -	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
> > -					 bma220_trigger_handler, NULL);
> > -	if (ret < 0) {
> > -		dev_err(&spi->dev, "iio triggered buffer setup failed\n");
> > -		goto err_suspend;
> > -	}
> > +	ret = devm_add_action_or_reset(&spi->dev, bma220_deinit, spi);
> > +	if (ret)
> > +		return ret;
> >  
> > -	ret = iio_device_register(indio_dev);
> > +	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
> > +					      iio_pollfunc_store_time,
> > +					      bma220_trigger_handler, NULL);
> >  	if (ret < 0) {
> > -		dev_err(&spi->dev, "iio_device_register failed\n");
> > -		iio_triggered_buffer_cleanup(indio_dev);
> > -		goto err_suspend;
> > +		dev_err(&spi->dev, "iio triggered buffer setup failed\n");
> > +		return ret;
> >  	}
> >  
> > -	return 0;
> > -
> > -err_suspend:
> > -	return bma220_deinit(spi);
> > -}
> > -
> > -static int bma220_remove(struct spi_device *spi)
> > -{
> > -	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > -
> > -	iio_device_unregister(indio_dev);
> > -	iio_triggered_buffer_cleanup(indio_dev);
> > -
> > -	return bma220_deinit(spi);
> > +	return devm_iio_device_register(&spi->dev, indio_dev);
> >  }
> >  
> >  static __maybe_unused int bma220_suspend(struct device *dev)
> > @@ -326,7 +305,6 @@ static struct spi_driver bma220_driver = {
> >  		.acpi_match_table = bma220_acpi_id,
> >  	},
> >  	.probe =            bma220_probe,
> > -	.remove =           bma220_remove,
> >  	.id_table =         bma220_spi_id,
> >  };
> >  module_spi_driver(bma220_driver);  
>