From: Marcelo Schmitt Date: Tue, 15 Apr 2025 12:21:10 +0000 (-0300) Subject: iio: adc: ad4000: Avoid potential double data word read X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=ce45446e520c85db022f8bcd7f0334b042ff3571;p=linux-2.6-microblaze.git iio: adc: ad4000: Avoid potential double data word read Currently, SPI-Engine offload module always sends 32-bit data elements to DMA engine. Appropriately, when set for SPI offloading, the IIO driver uses 32 storagebits for IIO ADC channel buffer elements. However, setting SPI transfer length according to storagebits (32-bits in case of offload) can lead to unnecessarily long transfers for ADCs that are 16-bit or less precision. Adjust AD4000 single-shot read to run transfers of 2 bytes when that is enough to get all ADC data bits. Fixes: 59b51edf717b ("iio: adc: ad4000: Add support for SPI offload") Suggested-by: David Lechner Signed-off-by: Marcelo Schmitt Reviewed-by: David Lechner Link: https://patch.msgid.link/8f765cfd6e93fad4e755dd95d709b7bea2a388e2.1744718916.git.marcelo.schmitt@analog.com Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/adc/ad4000.c b/drivers/iio/adc/ad4000.c index 93ecaf401f27..5609a7845b6f 100644 --- a/drivers/iio/adc/ad4000.c +++ b/drivers/iio/adc/ad4000.c @@ -942,7 +942,7 @@ static int ad4000_prepare_3wire_mode_message(struct ad4000_state *st, xfers[0].cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; xfers[1].rx_buf = &st->scan.data; - xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits); + xfers[1].len = chan->scan_type.realbits > 16 ? 4 : 2; /* * If the device is set up for SPI offloading, IIO channel scan_type is