Re: [PATCH v2] iio: light: ltr501: claim direct mode during raw writes

[Jonathan Cameron]

On 16/10/16 06:02, Alison Schofield wrote:
> Driver was checking for direct mode but not locking it.  Use
> claim/release helper functions to guarantee the device stays
> in direct mode during all raw write operations.
> 
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
> ---
> Changes in v2:
>   Replaced 'goto release' statements with breaks.
>   The release helper function remains in the same place as in version
>   one of patch, but now break statements control the flow rather than
>   jumping out with goto's.
>   
>   I may have 'break'd more than needed at tail end of nested switch.
>   Tried to follow official c language definition.  
> 
I'd have done it exactly the same

Applied to the togreg branch of iio.git.  Again, Peter, if you have
a chance to look at this that would be great.  If not then not to worry!

Jonathan
> 
>  drivers/iio/light/ltr501.c | 81 +++++++++++++++++++++++++++++-----------------
>  1 file changed, 51 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 3afc53a..8f9d5cf 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -729,8 +729,9 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
>  	int i, ret, freq_val, freq_val2;
>  	struct ltr501_chip_info *info = data->chip_info;
>  
> -	if (iio_buffer_enabled(indio_dev))
> -		return -EBUSY;
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_SCALE:
> @@ -739,85 +740,105 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
>  			i = ltr501_get_gain_index(info->als_gain,
>  						  info->als_gain_tbl_size,
>  						  val, val2);
> -			if (i < 0)
> -				return -EINVAL;
> +			if (i < 0) {
> +				ret = -EINVAL;
> +				break;
> +			}
>  
>  			data->als_contr &= ~info->als_gain_mask;
>  			data->als_contr |= i << info->als_gain_shift;
>  
> -			return regmap_write(data->regmap, LTR501_ALS_CONTR,
> -					    data->als_contr);
> +			ret = regmap_write(data->regmap, LTR501_ALS_CONTR,
> +					   data->als_contr);
> +			break;
>  		case IIO_PROXIMITY:
>  			i = ltr501_get_gain_index(info->ps_gain,
>  						  info->ps_gain_tbl_size,
>  						  val, val2);
> -			if (i < 0)
> -				return -EINVAL;
> +			if (i < 0) {
> +				ret = -EINVAL;
> +				break;
> +			}
>  			data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
>  			data->ps_contr |= i << LTR501_CONTR_PS_GAIN_SHIFT;
>  
> -			return regmap_write(data->regmap, LTR501_PS_CONTR,
> -					    data->ps_contr);
> +			ret = regmap_write(data->regmap, LTR501_PS_CONTR,
> +					   data->ps_contr);
> +			break;
>  		default:
> -			return -EINVAL;
> +			ret = -EINVAL;
> +			break;
>  		}
> +		break;
> +
>  	case IIO_CHAN_INFO_INT_TIME:
>  		switch (chan->type) {
>  		case IIO_INTENSITY:
> -			if (val != 0)
> -				return -EINVAL;
> +			if (val != 0) {
> +				ret = -EINVAL;
> +				break;
> +			}
>  			mutex_lock(&data->lock_als);
> -			i = ltr501_set_it_time(data, val2);
> +			ret = ltr501_set_it_time(data, val2);
>  			mutex_unlock(&data->lock_als);
> -			return i;
> +			break;
>  		default:
> -			return -EINVAL;
> +			ret = -EINVAL;
> +			break;
>  		}
> +		break;
> +
>  	case IIO_CHAN_INFO_SAMP_FREQ:
>  		switch (chan->type) {
>  		case IIO_INTENSITY:
>  			ret = ltr501_als_read_samp_freq(data, &freq_val,
>  							&freq_val2);
>  			if (ret < 0)
> -				return ret;
> +				break;
>  
>  			ret = ltr501_als_write_samp_freq(data, val, val2);
>  			if (ret < 0)
> -				return ret;
> +				break;
>  
>  			/* update persistence count when changing frequency */
>  			ret = ltr501_write_intr_prst(data, chan->type,
>  						     0, data->als_period);
>  
>  			if (ret < 0)
> -				return ltr501_als_write_samp_freq(data,
> -								  freq_val,
> -								  freq_val2);
> -			return ret;
> +				ret = ltr501_als_write_samp_freq(data, freq_val,
> +								 freq_val2);
> +			break;
>  		case IIO_PROXIMITY:
>  			ret = ltr501_ps_read_samp_freq(data, &freq_val,
>  						       &freq_val2);
>  			if (ret < 0)
> -				return ret;
> +				break;
>  
>  			ret = ltr501_ps_write_samp_freq(data, val, val2);
>  			if (ret < 0)
> -				return ret;
> +				break;
>  
>  			/* update persistence count when changing frequency */
>  			ret = ltr501_write_intr_prst(data, chan->type,
>  						     0, data->ps_period);
>  
>  			if (ret < 0)
> -				return ltr501_ps_write_samp_freq(data,
> -								 freq_val,
> -								 freq_val2);
> -			return ret;
> +				ret = ltr501_ps_write_samp_freq(data, freq_val,
> +								freq_val2);
> +			break;
>  		default:
> -			return -EINVAL;
> +			ret = -EINVAL;
> +			break;
>  		}
> +		break;
> +
> +	default:
> +		ret = -EINVAL;
> +		break;
>  	}
> -	return -EINVAL;
> +
> +	iio_device_release_direct_mode(indio_dev);
> +	return ret;
>  }
>  
>  static int ltr501_read_thresh(struct iio_dev *indio_dev,
>