[PATCH v1] iio: potentiometer: mcp4131: fix double application of wiper shift

From: Lukas Schmid

Date: Mon Feb 02 2026 - 16:09:06 EST


The MCP4131 wiper address is shifted twice when preparing the SPI
command in mcp4131_write_raw().

The address is already shifted when assigned to the local variable
"address", but is then shifted again when written to data->buf[0].
This results in an incorrect command being sent to the device and
breaks wiper writes to the second channel.

Remove the second shift and use the pre-shifted address directly
when composing the SPI transfer.

Signed-off-by: Lukas Schmid <lukas.schmid@xxxxxxxxxx>
---
drivers/iio/potentiometer/mcp4131.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/potentiometer/mcp4131.c b/drivers/iio/potentiometer/mcp4131.c
index ad082827aad5..56c9111ef5e8 100644
--- a/drivers/iio/potentiometer/mcp4131.c
+++ b/drivers/iio/potentiometer/mcp4131.c
@@ -221,7 +221,7 @@ static int mcp4131_write_raw(struct iio_dev *indio_dev,

mutex_lock(&data->lock);

- data->buf[0] = address << MCP4131_WIPER_SHIFT;
+ data->buf[0] = address;
data->buf[0] |= MCP4131_WRITE | (val >> 8);
data->buf[1] = val & 0xFF; /* 8 bits here */

--
2.47.3