6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Lechner dlechner@baylibre.com
commit 632757312d7eb320b66ca60e0cfe098ec53cee08 upstream.
Add a special case to double the SPI offload trigger rate when all channels of a single-ended chip are enabled in a buffered read.
The single-ended chips in the AD738x family can only do simultaneous sampling of half their channels and have a multiplexer to allow reading the other half. To comply with the IIO definition of sampling_frequency, we need to trigger twice as often when the sequencer is enabled to so that both banks can be read in a single sample period.
Fixes: bbeaec81a03e ("iio: ad7380: add support for SPI offload") Signed-off-by: David Lechner dlechner@baylibre.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/ad7380.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/iio/adc/ad7380.c +++ b/drivers/iio/adc/ad7380.c @@ -1227,6 +1227,14 @@ static int ad7380_offload_buffer_postena if (ret) return ret;
+ /* + * When the sequencer is required to read all channels, we need to + * trigger twice per sample period in order to read one complete set + * of samples. + */ + if (st->seq) + config.periodic.frequency_hz *= 2; + ret = spi_offload_trigger_enable(st->offload, st->offload_trigger, &config); if (ret) spi_unoptimize_message(&st->offload_msg);