[PATCH 2/2] iio: adc: ti-adc161s626: use DMA-safe memory for spi_read()

[David Lechner]

Add a DMA-safe buffer and use it for spi_read() instead of a stack
memory. All SPI buffers must be DMA-safe.

Since we only need up to 3 bytes, we just use a u8[] instead of __be16
and __be32 and change the conversion functions appropriately.

Fixes: 4d671b71beef ("iio: adc: ti-adc161s626: add support for TI 1-channel differential ADCs")
Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
---
 drivers/iio/adc/ti-adc161s626.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/iio/adc/ti-adc161s626.c b/drivers/iio/adc/ti-adc161s626.c
index 1d427548e0b3..6416d6a7ada0 100644
--- a/drivers/iio/adc/ti-adc161s626.c
+++ b/drivers/iio/adc/ti-adc161s626.c
@@ -70,6 +70,7 @@ struct ti_adc_data {
 
 	u8 read_size;
 	u8 shift;
+	u8 buf[3] __aligned(IIO_DMA_MINALIGN);
 };
 
 static int ti_adc_read_measurement(struct ti_adc_data *data,
@@ -78,26 +79,20 @@ static int ti_adc_read_measurement(struct ti_adc_data *data,
 	int ret;
 
 	switch (data->read_size) {
-	case 2: {
-		__be16 buf;
-
-		ret = spi_read(data->spi, (void *) &buf, 2);
+	case 2:
+		ret = spi_read(data->spi, data->buf, 2);
 		if (ret)
 			return ret;
 
-		*val = be16_to_cpu(buf);
+		*val = get_unaligned_be16(data->buf);
 		break;
-	}
-	case 3: {
-		__be32 buf;
-
-		ret = spi_read(data->spi, (void *) &buf, 3);
+	case 3:
+		ret = spi_read(data->spi, data->buf, 3);
 		if (ret)
 			return ret;
 
-		*val = be32_to_cpu(buf) >> 8;
+		*val = get_unaligned_be24(data->buf);
 		break;
-	}
 	default:
 		return -EINVAL;
 	}

-- 
2.43.0