iio: dac: ad5446: Use DMA safe buffer for transfers

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>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/dac/ad5446.c b/drivers/iio/dac/ad5446.c
index ad304b0fec08352d51c3ef25c53897c03b10ab56..ce19e20dd38eb12cb15b5f254d3f9602bd8a8577 100644 (file)
--- a/drivers/iio/dac/ad5446.c
+++ b/drivers/iio/dac/ad5446.c
@@ -37,6 +37,8 @@
  * @pwr_down_mode:     power down mode (1k, 100k or tristate)
  * @pwr_down:          true if the device is in power down
  * @lock:              lock to protect the data buffer during write ops
+ * @d16:               16bit DMA safe buffer
+ * @d24:               24bit DMA safe buffer
  */
 
 struct ad5446_state {
@@ -47,6 +49,10 @@ 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 +271,18 @@ 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);
 
-       return spi_write(spi, data, sizeof(data));
+       return spi_write(spi, st->d24, sizeof(st->d24));
 }
 
 /*
@@ -489,13 +494,13 @@ 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;