iio: dac: ad5360: Replace indio_dev->mlock with own device lock

As part of the general cleanup of indio_dev->mlock, this change replaces
it with a local lock on the device's state structure.
This also changes some internal functions to pass the pointer to the
state-struct vs a ref to indio_dev just to access the state-struct again.
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dac/ad5360.c

@@ -67,6 +67,7 @@ struct ad5360_chip_info {
  * @chip_info:		chip model specific constants, available modes etc
  * @vref_reg:		vref supply regulators
  * @ctrl:		control register cache
+ * @lock		lock to protect the data buffer during SPI ops
  * @data:		spi transfer buffers
  */
 
@@ -75,6 +76,7 @@ struct ad5360_state {
 	const struct ad5360_chip_info	*chip_info;
 	struct regulator_bulk_data	vref_reg[3];
 	unsigned int			ctrl;
+	struct mutex			lock;
 
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
@@ -205,10 +207,11 @@ static int ad5360_write(struct iio_dev *indio_dev, unsigned int cmd,
 	unsigned int addr, unsigned int val, unsigned int shift)
 {
 	int ret;
+	struct ad5360_state *st = iio_priv(indio_dev);
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&st->lock);
 	ret = ad5360_write_unlocked(indio_dev, cmd, addr, val, shift);
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&st->lock);
 
 	return ret;
 }
@@ -229,7 +232,7 @@ static int ad5360_read(struct iio_dev *indio_dev, unsigned int type,
 		},
 	};
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&st->lock);
 
 	st->data[0].d32 = cpu_to_be32(AD5360_CMD(AD5360_CMD_SPECIAL_FUNCTION) |
 		AD5360_ADDR(AD5360_REG_SF_READBACK) |
@@ -240,7 +243,7 @@ static int ad5360_read(struct iio_dev *indio_dev, unsigned int type,
 	if (ret >= 0)
 		ret = be32_to_cpu(st->data[1].d32) & 0xffff;
 
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&st->lock);
 
 	return ret;
 }
@@ -261,7 +264,7 @@ static int ad5360_update_ctrl(struct iio_dev *indio_dev, unsigned int set,
 	struct ad5360_state *st = iio_priv(indio_dev);
 	unsigned int ret;
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&st->lock);
 
 	st->ctrl |= set;
 	st->ctrl &= ~clr;
@@ -269,7 +272,7 @@ static int ad5360_update_ctrl(struct iio_dev *indio_dev, unsigned int set,
 	ret = ad5360_write_unlocked(indio_dev, AD5360_CMD_SPECIAL_FUNCTION,
 			AD5360_REG_SF_CTRL, st->ctrl, 0);
 
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&st->lock);
 
 	return ret;
 }
@@ -479,6 +482,8 @@ static int ad5360_probe(struct spi_device *spi)
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->num_channels = st->chip_info->num_channels;
 
+	mutex_init(&st->lock);
+
 	ret = ad5360_alloc_channels(indio_dev);
 	if (ret) {
 		dev_err(&spi->dev, "Failed to allocate channel spec: %d\n", ret);