[PATCH v4 02/12] iio: dac: ad5446: Use DMA safe buffer for transfers

["Nuno Sá via B4 Relay" <devnull+nuno.sa.analog.com@kernel.org>]

From: Nuno Sá <nuno.sa@analog.com>

Make sure to use DMA safe buffer. While for i2c we could be fine without
them, we need it for spi anyways.

As we now have DMA safe buffers, use i2c_master_send_dmasafe().

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/dac/ad5446.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/dac/ad5446.c b/drivers/iio/dac/ad5446.c
index ad304b0fec08..de5e4e0e397e 100644
--- a/drivers/iio/dac/ad5446.c
+++ b/drivers/iio/dac/ad5446.c
@@ -47,6 +47,10 @@ struct ad5446_state {
 	unsigned			pwr_down_mode;
 	unsigned			pwr_down;
 	struct mutex			lock;
+	union {
+		__be16 d16;
+		u8 d24[3];
+	} __aligned(IIO_DMA_MINALIGN);
 };
 
 /**
@@ -265,19 +269,18 @@ static int ad5446_probe(struct device *dev, const char *name,
 static int ad5446_write(struct ad5446_state *st, unsigned val)
 {
 	struct spi_device *spi = to_spi_device(st->dev);
-	__be16 data = cpu_to_be16(val);
+	st->d16 = cpu_to_be16(val);
 
-	return spi_write(spi, &data, sizeof(data));
+	return spi_write(spi, &st->d16, sizeof(st->d16));
 }
 
 static int ad5660_write(struct ad5446_state *st, unsigned val)
 {
 	struct spi_device *spi = to_spi_device(st->dev);
-	uint8_t data[3];
 
-	put_unaligned_be24(val, &data[0]);
+	put_unaligned_be24(val, &st->d24[0]);
 
-	return spi_write(spi, data, sizeof(data));
+	return spi_write(spi, st->d24, sizeof(st->d24));
 }
 
 /*
@@ -489,13 +492,13 @@ static inline void ad5446_spi_unregister_driver(void) { }
 static int ad5622_write(struct ad5446_state *st, unsigned val)
 {
 	struct i2c_client *client = to_i2c_client(st->dev);
-	__be16 data = cpu_to_be16(val);
+	st->d16 = cpu_to_be16(val);
 	int ret;
 
-	ret = i2c_master_send(client, (char *)&data, sizeof(data));
+	ret = i2c_master_send_dmasafe(client, (char *)&st->d16, sizeof(st->d16));
 	if (ret < 0)
 		return ret;
-	if (ret != sizeof(data))
+	if (ret != sizeof(st->d16))
 		return -EIO;
 
 	return 0;

-- 
2.51.0