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* [PATCH v5] staging: Use buf_lock instead of mlock and Refactor code
@ 2017-03-19 12:50 simran singhal
  2017-03-19 17:14 ` [Outreachy kernel] " Gargi Sharma
  2017-03-21 14:31 ` kbuild test robot
  0 siblings, 2 replies; 7+ messages in thread
From: simran singhal @ 2017-03-19 12:50 UTC (permalink / raw)
  To: lars
  Cc: Michael.Hennerich, jic23, Hartmut Knaack, Peter Meerwald-Stadler,
	Greg Kroah-Hartman, linux-iio, devel, linux-kernel,
	outreachy-kernel

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.

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

 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().
    

 drivers/staging/iio/gyro/adis16060_core.c | 42 ++++++++++++-------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/iio/gyro/adis16060_core.c b/drivers/staging/iio/gyro/adis16060_core.c
index c9d46e7..0f12492 100644
--- a/drivers/staging/iio/gyro/adis16060_core.c
+++ b/drivers/staging/iio/gyro/adis16060_core.c
@@ -40,25 +40,20 @@ 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) {
+		mutex_unlock(&st->buf_lock);
+		return ret;
+	}
 
 	ret = spi_read(st->us_r, st->buf, 3);
 
@@ -69,8 +64,8 @@ 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 +78,19 @@ 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);
+		mutex_lock(&st->buf_lock);
+		ret = adis16060_spi_write_than_read(indio_dev,
+						    chan->address, &tval);
 		if (ret < 0)
-			goto out_unlock;
+			mutex_unlock(&st->buf_lock);
+			return ret;
 
-		ret = adis16060_spi_read(indio_dev, &tval);
-		if (ret < 0)
-			goto out_unlock;
-
-		mutex_unlock(&indio_dev->mlock);
+		mutex_unlock(&st->buf_lock);
 		*val = tval;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
@@ -110,10 +104,6 @@ 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



^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-03-21 19:33 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-19 12:50 [PATCH v5] staging: Use buf_lock instead of mlock and Refactor code simran singhal
2017-03-19 17:14 ` [Outreachy kernel] " Gargi Sharma
2017-03-19 20:43   ` Jonathan Cameron
2017-03-19 21:15     ` SIMRAN SINGHAL
2017-03-21 14:31 ` kbuild test robot
2017-03-21 15:05   ` SIMRAN SINGHAL
2017-03-21 19:32     ` Jonathan Cameron

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