linux-kernel - Re: [PATCH] iio: accel: mma8452: claim direct mode during write raw

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Date:   Sat, 15 Oct 2016 15:55:49 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alison Schofield <amsfield22@...il.com>
Cc:     knaack.h@....de, lars@...afoo.de, pmeerw@...erw.net,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: accel: mma8452: claim direct mode during write raw

On 11/10/16 20:32, 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 write raw operations.
> 
> Signed-off-by: Alison Schofield <amsfield22@...il.com>
Well you were consistent.  Forgot breaks that needed adding everywhere ;)

I fixed up and applied to the togreg branch of iio.git - initially
pushed out as testing for the autobuilders to play with it.

Please sanity check I didn't mess it up!

Thanks,

Jonathan
> ---
>  drivers/iio/accel/mma8452.c | 53 +++++++++++++++++++++++++++------------------
>  1 file changed, 32 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index 7951def..cbbc746 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -666,37 +666,43 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
>  	struct mma8452_data *data = iio_priv(indio_dev);
>  	int i, ret;
>  
> -	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_SAMP_FREQ:
>  		i = mma8452_get_samp_freq_index(data, val, val2);
> -		if (i < 0)
> -			return i;
> -
> +		if (i < 0) {
> +			ret = i;
> +			goto release;
> +		}
>  		data->ctrl_reg1 &= ~MMA8452_CTRL_DR_MASK;
>  		data->ctrl_reg1 |= i << MMA8452_CTRL_DR_SHIFT;
>  
> -		return mma8452_change_config(data, MMA8452_CTRL_REG1,
> -					     data->ctrl_reg1);
> +		ret = mma8452_change_config(data, MMA8452_CTRL_REG1,
> +					    data->ctrl_reg1);
break?
>  	case IIO_CHAN_INFO_SCALE:
>  		i = mma8452_get_scale_index(data, val, val2);
> -		if (i < 0)
> -			return i;
> +		if (i < 0) {
> +			ret = i;
> +			goto release;
> +		}
>  
>  		data->data_cfg &= ~MMA8452_DATA_CFG_FS_MASK;
>  		data->data_cfg |= i;
>  
> -		return mma8452_change_config(data, MMA8452_DATA_CFG,
> -					     data->data_cfg);
> +		ret = mma8452_change_config(data, MMA8452_DATA_CFG,
> +					    data->data_cfg);
break?
>  	case IIO_CHAN_INFO_CALIBBIAS:
> -		if (val < -128 || val > 127)
> -			return -EINVAL;
> +		if (val < -128 || val > 127) {
> +			ret = -EINVAL;
> +			goto release;
> +		}
>  
> -		return mma8452_change_config(data,
> -					     MMA8452_OFF_X + chan->scan_index,
> -					     val);
> +		ret = mma8452_change_config(data,
> +					    MMA8452_OFF_X + chan->scan_index,
> +					    val);
break?
>  
>  	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
>  		if (val == 0 && val2 == 0) {
> @@ -705,23 +711,28 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
>  			data->data_cfg |= MMA8452_DATA_CFG_HPF_MASK;
>  			ret = mma8452_set_hp_filter_frequency(data, val, val2);
>  			if (ret < 0)
> -				return ret;
> +				goto release;
>  		}
>  
> -		return mma8452_change_config(data, MMA8452_DATA_CFG,
> +		ret = mma8452_change_config(data, MMA8452_DATA_CFG,
>  					     data->data_cfg);
>  
break?
>  	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>  		ret = mma8452_get_odr_index(data);
>  
>  		for (i = 0; i < ARRAY_SIZE(mma8452_os_ratio); i++) {
> -			if (mma8452_os_ratio[i][ret] == val)
> -				return mma8452_set_power_mode(data, i);
> +			if (mma8452_os_ratio[i][ret] == val) {
> +				ret = mma8452_set_power_mode(data, i);
> +				goto release;
> +			}
>  		}
>  
>  	default:
> -		return -EINVAL;
> +		ret = -EINVAL;
>  	}
> +release:
> +	iio_device_release_direct_mode(indio_dev);
> +	return ret;
>  }
>  
>  static int mma8452_read_thresh(struct iio_dev *indio_dev,
>