Re: [PATCH v2 1/3] iio: stx104: Unregister IIO device on remove callback

[Jonathan Cameron <jic23@kernel.org>]

On 19/07/16 17:25, William Breathitt Gray wrote:
> The devm_iio_device_register function should not be used if custom
> operations must be performed in the remove callback. This patch replaces
> the dem_iio_device_register call with a iio_device_register call and
> respective iio_device_unregister call in the remove callback.
> 
> Fixes: 765550e4d98d ("iio: stx104: Add GPIO support for the Apex Embedded Systems STX104")
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied to the fixes-togreg-post-rc1 branch (it's more convenient
right now than the fixes-togreg branch) and marked for stable.

These will go upstream in a few weeks after I'm back from travelling
and the merge windows has closed.

Thanks,

Jonathan
> ---
>  drivers/iio/dac/stx104.c | 38 +++++++++++++++++++++++++++++---------
>  1 file changed, 29 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/dac/stx104.c b/drivers/iio/dac/stx104.c
> index 792a971..bebbd00 100644
> --- a/drivers/iio/dac/stx104.c
> +++ b/drivers/iio/dac/stx104.c
> @@ -65,6 +65,16 @@ struct stx104_gpio {
>  	unsigned int out_state;
>  };
>  
> +/**
> + * struct stx104_dev - STX104 device private data structure
> + * @indio_dev:	IIO device
> + * @chip:	instance of the gpio_chip
> + */
> +struct stx104_dev {
> +	struct iio_dev *indio_dev;
> +	struct gpio_chip *chip;
> +};
> +
>  static int stx104_read_raw(struct iio_dev *indio_dev,
>  	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
>  {
> @@ -107,6 +117,7 @@ static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = {
>  static int stx104_gpio_get_direction(struct gpio_chip *chip,
>  	unsigned int offset)
>  {
> +	/* GPIO 0-3 are input only, while the rest are output only */
>  	if (offset < 4)
>  		return 1;
>  
> @@ -169,6 +180,7 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  	struct iio_dev *indio_dev;
>  	struct stx104_iio *priv;
>  	struct stx104_gpio *stx104gpio;
> +	struct stx104_dev *stx104dev;
>  	int err;
>  
>  	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
> @@ -179,6 +191,10 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  	if (!stx104gpio)
>  		return -ENOMEM;
>  
> +	stx104dev = devm_kzalloc(dev, sizeof(*stx104dev), GFP_KERNEL);
> +	if (!stx104dev)
> +		return -ENOMEM;
> +
>  	if (!devm_request_region(dev, base[id], STX104_EXTENT,
>  		dev_name(dev))) {
>  		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
> @@ -199,12 +215,6 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  	outw(0, base[id] + 4);
>  	outw(0, base[id] + 6);
>  
> -	err = devm_iio_device_register(dev, indio_dev);
> -	if (err) {
> -		dev_err(dev, "IIO device registering failed (%d)\n", err);
> -		return err;
> -	}
> -
>  	stx104gpio->chip.label = dev_name(dev);
>  	stx104gpio->chip.parent = dev;
>  	stx104gpio->chip.owner = THIS_MODULE;
> @@ -220,7 +230,9 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  
>  	spin_lock_init(&stx104gpio->lock);
>  
> -	dev_set_drvdata(dev, stx104gpio);
> +	stx104dev->indio_dev = indio_dev;
> +	stx104dev->chip = &stx104gpio->chip;
> +	dev_set_drvdata(dev, stx104dev);
>  
>  	err = gpiochip_add_data(&stx104gpio->chip, stx104gpio);
>  	if (err) {
> @@ -228,14 +240,22 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  		return err;
>  	}
>  
> +	err = iio_device_register(indio_dev);
> +	if (err) {
> +		dev_err(dev, "IIO device registering failed (%d)\n", err);
> +		gpiochip_remove(&stx104gpio->chip);
> +		return err;
> +	}
> +
>  	return 0;
>  }
>  
>  static int stx104_remove(struct device *dev, unsigned int id)
>  {
> -	struct stx104_gpio *const stx104gpio = dev_get_drvdata(dev);
> +	struct stx104_dev *const stx104dev = dev_get_drvdata(dev);
>  
> -	gpiochip_remove(&stx104gpio->chip);
> +	iio_device_unregister(stx104dev->indio_dev);
> +	gpiochip_remove(stx104dev->chip);
>  
>  	return 0;
>  }
>