iio: accel: adxl380: Avoid reading more entries than present in FIFO

The interrupt handler reads FIFO entries in batches of N samples, where N
is the number of scan elements that have been enabled. However, the sensor
fills the FIFO one sample at a time, even when more than one channel is
enabled. Therefore,the number of entries reported by the FIFO status
registers may not be a multiple of N; if this number is not a multiple, the
number of entries read from the FIFO may exceed the number of entries
actually present.

To fix the above issue, round down the number of FIFO entries read from the
status registers so that it is always a multiple of N.

Fixes: df36de13677a ("iio: accel: add ADXL380 driver")
Signed-off-by: Francesco Lavra <flavra@baylibre.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/accel/adxl380.c b/drivers/iio/accel/adxl380.c
index ba550142866a3c49aa91a0fa6e56a3924496ef32..a77c2323d1aa48744f854cd537b4bf72ed2ccbad 100644 (file)
--- a/drivers/iio/accel/adxl380.c
+++ b/drivers/iio/accel/adxl380.c
@@ -966,6 +966,7 @@ static irqreturn_t adxl380_irq_handler(int irq, void  *p)
        if (ret)
                return IRQ_HANDLED;
 
+       fifo_entries = rounddown(fifo_entries, st->fifo_set_size);
        for (i = 0; i < fifo_entries; i += st->fifo_set_size) {
                ret = regmap_noinc_read(st->regmap, ADXL380_FIFO_DATA,
                                        &st->fifo_buf[i],