iio: imu: inv_mpu6050: fix lock issues by using our own mutex

There are several locks issues when using buffer and direct polling
data at the same time. Use our own mutex for managing locking and
block simultaneous use of buffer and direct polling by using
iio_device_{claim/release}_direct_mode. This makes chip_config
enable bit obsolete, so delete it.

Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 84 insertions, 63 deletions

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index 96dabbd2f004..9b4bbeea3d4f 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -187,7 +187,6 @@ int inv_mpu6050_set_power_itg(struct inv_mpu6050_state *st, bool power_on)
 	int result = 0;
 
 	if (power_on) {
-		/* Already under indio-dev->mlock mutex */
 		if (!st->powerup_count)
 			result = regmap_write(st->map, st->reg->pwr_mgmt_1, 0);
 		if (!result)
@@ -298,50 +297,37 @@ inv_mpu6050_read_raw(struct iio_dev *indio_dev,
 		int result;
 
 		ret = IIO_VAL_INT;
-		result = 0;
-		mutex_lock(&indio_dev->mlock);
-		if (!st->chip_config.enable) {
-			result = inv_mpu6050_set_power_itg(st, true);
-			if (result)
-				goto error_read_raw;
-		}
-		/* when enable is on, power is already on */
+		mutex_lock(&st->lock);
+		result = iio_device_claim_direct_mode(indio_dev);
+		if (result)
+			goto error_read_raw_unlock;
+		result = inv_mpu6050_set_power_itg(st, true);
+		if (result)
+			goto error_read_raw_release;
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
-			if (!st->chip_config.gyro_fifo_enable ||
-			    !st->chip_config.enable) {
-				result = inv_mpu6050_switch_engine(st, true,
-						INV_MPU6050_BIT_PWR_GYRO_STBY);
-				if (result)
-					goto error_read_raw;
-			}
+			result = inv_mpu6050_switch_engine(st, true,
+					INV_MPU6050_BIT_PWR_GYRO_STBY);
+			if (result)
+				goto error_read_raw_power_off;
 			ret = inv_mpu6050_sensor_show(st, st->reg->raw_gyro,
 						      chan->channel2, val);
-			if (!st->chip_config.gyro_fifo_enable ||
-			    !st->chip_config.enable) {
-				result = inv_mpu6050_switch_engine(st, false,
-						INV_MPU6050_BIT_PWR_GYRO_STBY);
-				if (result)
-					goto error_read_raw;
-			}
+			result = inv_mpu6050_switch_engine(st, false,
+					INV_MPU6050_BIT_PWR_GYRO_STBY);
+			if (result)
+				goto error_read_raw_power_off;
 			break;
 		case IIO_ACCEL:
-			if (!st->chip_config.accl_fifo_enable ||
-			    !st->chip_config.enable) {
-				result = inv_mpu6050_switch_engine(st, true,
-						INV_MPU6050_BIT_PWR_ACCL_STBY);
-				if (result)
-					goto error_read_raw;
-			}
+			result = inv_mpu6050_switch_engine(st, true,
+					INV_MPU6050_BIT_PWR_ACCL_STBY);
+			if (result)
+				goto error_read_raw_power_off;
 			ret = inv_mpu6050_sensor_show(st, st->reg->raw_accl,
 						      chan->channel2, val);
-			if (!st->chip_config.accl_fifo_enable ||
-			    !st->chip_config.enable) {
-				result = inv_mpu6050_switch_engine(st, false,
-						INV_MPU6050_BIT_PWR_ACCL_STBY);
-				if (result)
-					goto error_read_raw;
-			}
+			result = inv_mpu6050_switch_engine(st, false,
+					INV_MPU6050_BIT_PWR_ACCL_STBY);
+			if (result)
+				goto error_read_raw_power_off;
 			break;
 		case IIO_TEMP:
 			/* wait for stablization */
@@ -353,10 +339,12 @@ inv_mpu6050_read_raw(struct iio_dev *indio_dev,
 			ret = -EINVAL;
 			break;
 		}
-error_read_raw:
-		if (!st->chip_config.enable)
-			result |= inv_mpu6050_set_power_itg(st, false);
-		mutex_unlock(&indio_dev->mlock);
+error_read_raw_power_off:
+		result |= inv_mpu6050_set_power_itg(st, false);
+error_read_raw_release:
+		iio_device_release_direct_mode(indio_dev);
+error_read_raw_unlock:
+		mutex_unlock(&st->lock);
 		if (result)
 			return result;
 
@@ -365,13 +353,17 @@ error_read_raw:
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
+			mutex_lock(&st->lock);
 			*val  = 0;
 			*val2 = gyro_scale_6050[st->chip_config.fsr];
+			mutex_unlock(&st->lock);
 
 			return IIO_VAL_INT_PLUS_NANO;
 		case IIO_ACCEL:
+			mutex_lock(&st->lock);
 			*val = 0;
 			*val2 = accel_scale[st->chip_config.accl_fs];
+			mutex_unlock(&st->lock);
 
 			return IIO_VAL_INT_PLUS_MICRO;
 		case IIO_TEMP:
@@ -394,12 +386,16 @@ error_read_raw:
 	case IIO_CHAN_INFO_CALIBBIAS:
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
+			mutex_lock(&st->lock);
 			ret = inv_mpu6050_sensor_show(st, st->reg->gyro_offset,
 						chan->channel2, val);
+			mutex_unlock(&st->lock);
 			return IIO_VAL_INT;
 		case IIO_ACCEL:
+			mutex_lock(&st->lock);
 			ret = inv_mpu6050_sensor_show(st, st->reg->accl_offset,
 						chan->channel2, val);
+			mutex_unlock(&st->lock);
 			return IIO_VAL_INT;
 
 		default:
@@ -475,18 +471,17 @@ static int inv_mpu6050_write_raw(struct iio_dev *indio_dev,
 	struct inv_mpu6050_state  *st = iio_priv(indio_dev);
 	int result;
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&st->lock);
 	/*
 	 * we should only update scale when the chip is disabled, i.e.
 	 * not running
 	 */
-	if (st->chip_config.enable) {
-		result = -EBUSY;
-		goto error_write_raw;
-	}
+	result = iio_device_claim_direct_mode(indio_dev);
+	if (result)
+		goto error_write_raw_unlock;
 	result = inv_mpu6050_set_power_itg(st, true);
 	if (result)
-		goto error_write_raw;
+		goto error_write_raw_release;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
@@ -522,9 +517,11 @@ static int inv_mpu6050_write_raw(struct iio_dev *indio_dev,
 		break;
 	}
 
-error_write_raw:
 	result |= inv_mpu6050_set_power_itg(st, false);
-	mutex_unlock(&indio_dev->mlock);
+error_write_raw_release:
+	iio_device_release_direct_mode(indio_dev);
+error_write_raw_unlock:
+	mutex_unlock(&st->lock);
 
 	return result;
 }
@@ -578,31 +575,35 @@ inv_mpu6050_fifo_rate_store(struct device *dev, struct device_attribute *attr,
 	if (fifo_rate < INV_MPU6050_MIN_FIFO_RATE ||
 	    fifo_rate > INV_MPU6050_MAX_FIFO_RATE)
 		return -EINVAL;
-	if (fifo_rate == st->chip_config.fifo_rate)
-		return count;
 
-	mutex_lock(&indio_dev->mlock);
-	if (st->chip_config.enable) {
-		result = -EBUSY;
-		goto fifo_rate_fail;
+	mutex_lock(&st->lock);
+	if (fifo_rate == st->chip_config.fifo_rate) {
+		result = 0;
+		goto fifo_rate_fail_unlock;
 	}
+	result = iio_device_claim_direct_mode(indio_dev);
+	if (result)
+		goto fifo_rate_fail_unlock;
 	result = inv_mpu6050_set_power_itg(st, true);
 	if (result)
-		goto fifo_rate_fail;
+		goto fifo_rate_fail_release;
 
 	d = INV_MPU6050_ONE_K_HZ / fifo_rate - 1;
 	result = regmap_write(st->map, st->reg->sample_rate_div, d);
 	if (result)
-		goto fifo_rate_fail;
+		goto fifo_rate_fail_power_off;
 	st->chip_config.fifo_rate = fifo_rate;
 
 	result = inv_mpu6050_set_lpf(st, fifo_rate);
 	if (result)
-		goto fifo_rate_fail;
+		goto fifo_rate_fail_power_off;
 
-fifo_rate_fail:
+fifo_rate_fail_power_off:
 	result |= inv_mpu6050_set_power_itg(st, false);
-	mutex_unlock(&indio_dev->mlock);
+fifo_rate_fail_release:
+	iio_device_release_direct_mode(indio_dev);
+fifo_rate_fail_unlock:
+	mutex_unlock(&st->lock);
 	if (result)
 		return result;
 
@@ -617,8 +618,13 @@ inv_fifo_rate_show(struct device *dev, struct device_attribute *attr,
 		   char *buf)
 {
 	struct inv_mpu6050_state *st = iio_priv(dev_to_iio_dev(dev));
+	unsigned fifo_rate;
+
+	mutex_lock(&st->lock);
+	fifo_rate = st->chip_config.fifo_rate;
+	mutex_unlock(&st->lock);
 
-	return sprintf(buf, "%d\n", st->chip_config.fifo_rate);
+	return scnprintf(buf, PAGE_SIZE, "%u\n", fifo_rate);
 }
 
 /**
@@ -836,6 +842,7 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
 		return -ENODEV;
 	}
 	st = iio_priv(indio_dev);
+	mutex_init(&st->lock);
 	st->chip_type = chip_type;
 	st->powerup_count = 0;
 	st->irq = irq;
@@ -929,12 +936,26 @@ EXPORT_SYMBOL_GPL(inv_mpu_core_remove);
 
 static int inv_mpu_resume(struct device *dev)
 {
-	return inv_mpu6050_set_power_itg(iio_priv(dev_get_drvdata(dev)), true);
+	struct inv_mpu6050_state *st = iio_priv(dev_get_drvdata(dev));
+	int result;
+
+	mutex_lock(&st->lock);
+	result = inv_mpu6050_set_power_itg(st, true);
+	mutex_unlock(&st->lock);
+
+	return result;
 }
 
 static int inv_mpu_suspend(struct device *dev)
 {
-	return inv_mpu6050_set_power_itg(iio_priv(dev_get_drvdata(dev)), false);
+	struct inv_mpu6050_state *st = iio_priv(dev_get_drvdata(dev));
+	int result;
+
+	mutex_lock(&st->lock);
+	result = inv_mpu6050_set_power_itg(st, false);
+	mutex_unlock(&st->lock);
+
+	return result;
 }
 #endif /* CONFIG_PM_SLEEP */