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Date: Tue, 14 Mar 2017 05:28:44 +0530
From: Aishwarya Pant <aishpant@gmail.com>
To: Lars-Peter Clausen <lars@metafoo.de>,
	Michael Hennerich <Michael.Hennerich@analog.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: outreachy-kernel@googlegroups.com
Subject: [PATCH] staging: iio: accel: replace mlock with driver private lock
Message-ID: <20170313235754.GA18423@aishwarya>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.5.24 (2015-08-30)

IIO subsystem is redefining iio_dev mlock to be used by IIO core only
for protecting device operating mode changes.

In the driver adis164201, a struct adis16201_state has been introduced
to store driver state information. Wherever iio_dev->mlock was used to
protect hardware state changes, it has been replaced by driver private
lock.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
---
 drivers/staging/iio/accel/adis16201.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/iio/accel/adis16201.c b/drivers/staging/iio/accel/adis16201.c
index d6c8658..6d84eae 100644
--- a/drivers/staging/iio/accel/adis16201.c
+++ b/drivers/staging/iio/accel/adis16201.c
@@ -150,6 +150,11 @@
 
 #define ADIS16201_ERROR_ACTIVE          BIT(14)
 
+struct adis16201_state {
+	struct adis adis; /* adis device */
+	struct mutex lock; /* protect state changes */
+};
+
 enum adis16201_scan {
 	ADIS16201_SCAN_ACC_X,
 	ADIS16201_SCAN_ACC_Y,
@@ -172,7 +177,7 @@ static int adis16201_read_raw(struct iio_dev *indio_dev,
 			      int *val, int *val2,
 			      long mask)
 {
-	struct adis *st = iio_priv(indio_dev);
+	struct adis16201_state *st = iio_priv(indio_dev);
 	int ret;
 	int bits;
 	u8 addr;
@@ -223,17 +228,17 @@ static int adis16201_read_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
-		mutex_lock(&indio_dev->mlock);
+		mutex_lock(&st->lock);
 		addr = adis16201_addresses[chan->scan_index];
-		ret = adis_read_reg_16(st, addr, &val16);
+		ret = adis_read_reg_16(&st->adis, addr, &val16);
 		if (ret) {
-			mutex_unlock(&indio_dev->mlock);
+			mutex_unlock(&st->lock);
 			return ret;
 		}
 		val16 &= (1 << bits) - 1;
 		val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
 		*val = val16;
-		mutex_unlock(&indio_dev->mlock);
+		mutex_unlock(&st->lock);
 		return IIO_VAL_INT;
 	}
 	return -EINVAL;
@@ -245,7 +250,7 @@ static int adis16201_write_raw(struct iio_dev *indio_dev,
 			       int val2,
 			       long mask)
 {
-	struct adis *st = iio_priv(indio_dev);
+	struct adis16201_state *st = iio_priv(indio_dev);
 	int bits;
 	s16 val16;
 	u8 addr;
@@ -264,7 +269,7 @@ static int adis16201_write_raw(struct iio_dev *indio_dev,
 		}
 		val16 = val & ((1 << bits) - 1);
 		addr = adis16201_addresses[chan->scan_index];
-		return adis_write_reg_16(st, addr, val16);
+		return adis_write_reg_16(&st->adis, addr, val16);
 	}
 	return -EINVAL;
 }
@@ -318,7 +323,7 @@ static const struct adis_data adis16201_data = {
 static int adis16201_probe(struct spi_device *spi)
 {
 	int ret;
-	struct adis *st;
+	struct adis16201_state *st;
 	struct iio_dev *indio_dev;
 
 	/* setup the industrialio driver allocated elements */
@@ -327,6 +332,7 @@ static int adis16201_probe(struct spi_device *spi)
 		return -ENOMEM;
 
 	st = iio_priv(indio_dev);
+	mutex_init(&st->lock);
 	/* this is only used for removal purposes */
 	spi_set_drvdata(spi, indio_dev);
 
@@ -338,15 +344,15 @@ static int adis16201_probe(struct spi_device *spi)
 	indio_dev->num_channels = ARRAY_SIZE(adis16201_channels);
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	ret = adis_init(st, indio_dev, spi, &adis16201_data);
+	ret = adis_init(&st->adis, indio_dev, spi, &adis16201_data);
 	if (ret)
 		return ret;
-	ret = adis_setup_buffer_and_trigger(st, indio_dev, NULL);
+	ret = adis_setup_buffer_and_trigger(&st->adis, indio_dev, NULL);
 	if (ret)
 		return ret;
 
 	/* Get the device into a sane initial state */
-	ret = adis_initial_startup(st);
+	ret = adis_initial_startup(&st->adis);
 	if (ret)
 		goto error_cleanup_buffer_trigger;
 
@@ -356,17 +362,17 @@ static int adis16201_probe(struct spi_device *spi)
 	return 0;
 
 error_cleanup_buffer_trigger:
-	adis_cleanup_buffer_and_trigger(st, indio_dev);
+	adis_cleanup_buffer_and_trigger(&st->adis, indio_dev);
 	return ret;
 }
 
 static int adis16201_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
-	struct adis *st = iio_priv(indio_dev);
+	struct adis16201_state *st = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
-	adis_cleanup_buffer_and_trigger(st, indio_dev);
+	adis_cleanup_buffer_and_trigger(&st->adis, indio_dev);
 
 	return 0;
 }
-- 
2.7.4