[PATCH 6.1 214/312] iio: adc: ti-adc161s626: use DMA-safe memory for spi_read()

Greg Kroah-Hartman
2026-04-08T18:16:04Z

From: David Lechner <dlechner@baylibre.com>

commit 768461517a28d80fe81ea4d5d03a90cd184ea6ad upstream.

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@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/adc/ti-adc161s626.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

--- a/drivers/iio/adc/ti-adc161s626.c
+++ b/drivers/iio/adc/ti-adc161s626.c
@@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/err.h>
#include <linux/spi/spi.h>
+#include <asm/unaligned.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/buffer.h>
@@ -70,6 +71,7 @@ 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 +80,20 @@ static int ti_adc_read_measurement(struc
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;
}