On 22/03/17 16:20, simran singhal wrote:
> The IIO subsystem is redefining iio_dev->mlock to be used by
> the IIO core only for protecting device operating mode changes.
> ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.
>
> In this driver, mlock was being used to protect hardware state changes.
>
> In the driver, buf_lock protects both the adis16060_spi_write() and
> adis16060_spi_read() functions and both are always called in
> pair. First write, then read. Refactor the code to have
> one single function adis16060_spi_write_than_read() and remove
> the use of mlock as adis16060_read_raw() does not require an
> iio_dev->mlock for reads.
I'll slightly modify this description. The key thing is
that after the above change to have a unified read then write
there is no longer any need for mlock to protect these
read, update, write cycles.
>
> Signed-off-by: simran singhal <singhalsimr...@gmail.com>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
I slightly modified the title as well. It's useful to be a little
more specific than staging, so I added iio: after that.
Thanks,
Jonathan
> ---
>
> v8:
> -change subject
> -change commit message
> v7:
> -Change subject
> -Remove lock from read_raw instead from
> function adis16060_spi_write_than_read().
> v6:
> -Change commit message
> -Remove nested lock
> v5:
> -Rename val in adis16060_spi_write_than_read() to conf.
> -Rename val2 in adis16060_spi_write_than_read() to val.
> -Corrected Checkpatch issues.
> -Removed goto from adis16060_read_raw().
> v4:
> -Refactored code
> -change commit subject
> -change commit message
> v3:
> -Removed new lock to reuse the existing lock
> v2:
> -Fixed compilation error
>
> drivers/staging/iio/gyro/adis16060_core.c | 33
> ++++++++-----------------------
> 1 file changed, 8 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/staging/iio/gyro/adis16060_core.c
> b/drivers/staging/iio/gyro/adis16060_core.c
> index c9d46e7..e96fce5 100644
> --- a/drivers/staging/iio/gyro/adis16060_core.c
> +++ b/drivers/staging/iio/gyro/adis16060_core.c
> @@ -40,25 +40,18 @@ struct adis16060_state {
>
> static struct iio_dev *adis16060_iio_dev;
>
> -static int adis16060_spi_write(struct iio_dev *indio_dev, u8 val)
> +static int adis16060_spi_write_than_read(struct iio_dev *indio_dev,
> + u8 conf, u16 *val)
> {
> int ret;
> struct adis16060_state *st = iio_priv(indio_dev);
>
> mutex_lock(&st->buf_lock);
> - st->buf[2] = val; /* The last 8 bits clocked in are latched */
> + st->buf[2] = conf; /* The last 8 bits clocked in are latched */
> ret = spi_write(st->us_w, st->buf, 3);
> - mutex_unlock(&st->buf_lock);
> -
> - return ret;
> -}
> -
> -static int adis16060_spi_read(struct iio_dev *indio_dev, u16 *val)
> -{
> - int ret;
> - struct adis16060_state *st = iio_priv(indio_dev);
>
> - mutex_lock(&st->buf_lock);
> + if (ret < 0)
> + return ret;
>
> ret = spi_read(st->us_r, st->buf, 3);
>
> @@ -86,17 +79,11 @@ static int adis16060_read_raw(struct iio_dev *indio_dev,
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> - /* Take the iio_dev status lock */
> - mutex_lock(&indio_dev->mlock);
> - ret = adis16060_spi_write(indio_dev, chan->address);
> + ret = adis16060_spi_write_than_read(indio_dev,
> + chan->address, &tval);
> if (ret < 0)
> - goto out_unlock;
> + return ret;
>
> - ret = adis16060_spi_read(indio_dev, &tval);
> - if (ret < 0)
> - goto out_unlock;
> -
> - mutex_unlock(&indio_dev->mlock);
> *val = tval;
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_OFFSET:
> @@ -110,10 +97,6 @@ static int adis16060_read_raw(struct iio_dev *indio_dev,
> }
>
> return -EINVAL;
> -
> -out_unlock:
> - mutex_unlock(&indio_dev->mlock);
> - return ret;
> }
>
> static const struct iio_info adis16060_info = {
>
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