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Subject[PATCH v7] staging: adis16060_core: Replace mlock with buf_lock and refactor code
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. Replace it with buf_lock in the devices global data.

As buf_lock protects both the adis16060_spi_write() and
adis16060_spi_read() functions and both are always called in
pair. First write, then read. Thus, refactor the code to have
one single function adis16060_spi_write_than_read() which is
protected by the existing buf_lock.

Removed nested locks as the function adis16060_read_raw call
a lock on &st->buf_lock and then calls the function
adis16060_spi_write which again tries to get hold
of the same lock.

The locks in adis16060_read_raw are dropped and now have a
single safe function adis16060_spi_write_than_read
with the locks inside it being called.

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
---

v7:
-Change subject
-Remove lock from read_raw instead of from
function adis16060_spi_write_than_read().

drivers/staging/iio/gyro/adis16060_core.c | 38 +++++++++----------------------
1 file changed, 11 insertions(+), 27 deletions(-)

diff --git a/drivers/staging/iio/gyro/adis16060_core.c b/drivers/staging/iio/gyro/adis16060_core.c
index c9d46e7..193587c 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);

@@ -69,8 +62,8 @@ static int adis16060_spi_read(struct iio_dev *indio_dev, u16 *val)
*/
if (!ret)
*val = ((st->buf[0] & 0x3) << 12) |
- (st->buf[1] << 4) |
- ((st->buf[2] >> 4) & 0xF);
+ (st->buf[1] << 4) |
+ ((st->buf[2] >> 4) & 0xF);
mutex_unlock(&st->buf_lock);

return ret;
@@ -83,20 +76,15 @@ static int adis16060_read_raw(struct iio_dev *indio_dev,
{
u16 tval = 0;
int ret;
+ struct adis16060_state *st = iio_priv(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 +98,6 @@ 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 = {
--
2.7.4
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