[PATCH v2 4/6] iio: bmi160: Protect data transmission with mutex

[Marcin Niestroj <m.niestroj@xxxxxxxxxxxxxxxx>]

There are currently two possible cases for data transmission with the
sensor: read/write by iio sysfs and read in trigger interrupt
handler. Hence we need to protect data transmission using regmap_*
functions with mutex.

Signed-off-by: Marcin Niestroj <m.niestroj@xxxxxxxxxxxxxxxx>
---
Patch introduced in v2

 drivers/iio/imu/bmi160/bmi160_core.c | 39 +++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/imu/bmi160/bmi160_core.c b/drivers/iio/imu/bmi160/bmi160_core.c
index e0251b8..095533c 100644
--- a/drivers/iio/imu/bmi160/bmi160_core.c
+++ b/drivers/iio/imu/bmi160/bmi160_core.c
@@ -2,6 +2,7 @@
  * BMI160 - Bosch IMU (accel, gyro plus external magnetometer)
  *
  * Copyright (c) 2016, Intel Corporation.
+ * Copyright (c) 2016, Grinn
  *
  * This file is subject to the terms and conditions of version 2 of
  * the GNU General Public License.  See the file COPYING in the main
@@ -112,6 +113,7 @@ enum bmi160_sensor_type {
 
 struct bmi160_data {
 	struct regmap *regmap;
+	struct mutex mutex;
 };
 
 const struct regmap_config bmi160_regmap_config = {
@@ -285,7 +287,9 @@ int bmi160_set_mode(struct bmi160_data *data, enum bmi160_sensor_type t,
 	else
 		cmd = bmi160_regs[t].pmu_cmd_suspend;
 
+	mutex_lock(&data->mutex);
 	ret = regmap_write(data->regmap, BMI160_REG_CMD, cmd);
+	mutex_unlock(&data->mutex);
 	if (ret < 0)
 		return ret;
 
@@ -298,6 +302,7 @@ static
 int bmi160_set_scale(struct bmi160_data *data, enum bmi160_sensor_type t,
 		     int uscale)
 {
+	int ret;
 	int i;
 
 	for (i = 0; i < bmi160_scale_table[t].num; i++)
@@ -307,8 +312,12 @@ int bmi160_set_scale(struct bmi160_data *data, enum bmi160_sensor_type t,
 	if (i == bmi160_scale_table[t].num)
 		return -EINVAL;
 
-	return regmap_write(data->regmap, bmi160_regs[t].range,
-			    bmi160_scale_table[t].tbl[i].bits);
+	mutex_lock(&data->mutex);
+	ret = regmap_write(data->regmap, bmi160_regs[t].range,
+			   bmi160_scale_table[t].tbl[i].bits);
+	mutex_unlock(&data->mutex);
+
+	return ret;
 }
 
 static
@@ -317,7 +326,9 @@ int bmi160_get_scale(struct bmi160_data *data, enum bmi160_sensor_type t,
 {
 	int i, ret, val;
 
+	mutex_lock(&data->mutex);
 	ret = regmap_read(data->regmap, bmi160_regs[t].range, &val);
+	mutex_unlock(&data->mutex);
 	if (ret < 0)
 		return ret;
 
@@ -340,7 +351,9 @@ static int bmi160_get_data(struct bmi160_data *data, int chan_type,
 
 	reg = bmi160_regs[t].data + (axis - IIO_MOD_X) * sizeof(__le16);
 
+	mutex_lock(&data->mutex);
 	ret = regmap_bulk_read(data->regmap, reg, &sample, sizeof(__le16));
+	mutex_unlock(&data->mutex);
 	if (ret < 0)
 		return ret;
 
@@ -353,6 +366,7 @@ static
 int bmi160_set_odr(struct bmi160_data *data, enum bmi160_sensor_type t,
 		   int odr, int uodr)
 {
+	int ret;
 	int i;
 
 	for (i = 0; i < bmi160_odr_table[t].num; i++)
@@ -363,10 +377,14 @@ int bmi160_set_odr(struct bmi160_data *data, enum bmi160_sensor_type t,
 	if (i >= bmi160_odr_table[t].num)
 		return -EINVAL;
 
-	return regmap_update_bits(data->regmap,
-				  bmi160_regs[t].config,
-				  bmi160_regs[t].config_odr_mask,
-				  bmi160_odr_table[t].tbl[i].bits);
+	mutex_lock(&data->mutex);
+	ret = regmap_update_bits(data->regmap,
+				 bmi160_regs[t].config,
+				 bmi160_regs[t].config_odr_mask,
+				 bmi160_odr_table[t].tbl[i].bits);
+	mutex_unlock(&data->mutex);
+
+	return ret;
 }
 
 static int bmi160_get_odr(struct bmi160_data *data, enum bmi160_sensor_type t,
@@ -374,7 +392,9 @@ static int bmi160_get_odr(struct bmi160_data *data, enum bmi160_sensor_type t,
 {
 	int i, val, ret;
 
+	mutex_lock(&data->mutex);
 	ret = regmap_read(data->regmap, bmi160_regs[t].config, &val);
+	mutex_unlock(&data->mutex);
 	if (ret < 0)
 		return ret;
 
@@ -402,14 +422,18 @@ static irqreturn_t bmi160_trigger_handler(int irq, void *p)
 	int i, ret, j = 0, base = BMI160_REG_DATA_MAGN_XOUT_L;
 	__le16 sample;
 
+	mutex_lock(&data->mutex);
 	for_each_set_bit(i, indio_dev->active_scan_mask,
 			 indio_dev->masklength) {
 		ret = regmap_bulk_read(data->regmap, base + i * sizeof(__le16),
 				       &sample, sizeof(__le16));
-		if (ret < 0)
+		if (ret < 0) {
+			mutex_unlock(&data->mutex);
 			goto done;
+		}
 		buf[j++] = sample;
 	}
+	mutex_unlock(&data->mutex);
 
 	iio_push_to_buffers_with_timestamp(indio_dev, buf,
 					   iio_get_time_ns(indio_dev));
@@ -575,6 +599,7 @@ int bmi160_core_probe(struct device *dev, struct regmap *regmap,
 	data = iio_priv(indio_dev);
 	dev_set_drvdata(dev, indio_dev);
 	data->regmap = regmap;
+	mutex_init(&data->mutex);
 
 	ret = bmi160_chip_init(data, use_spi);
 	if (ret < 0)
-- 
2.10.2

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