[PATCH 04/15] iio: accel: adxl380: don't stay in standby on -EINVAL

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Josef Bacik <josef@toxicpanda.com>

adxl380_set_act_inact_threshold() puts the sensor into standby, writes the
threshold and switches the measurement on again.  A threshold above 8191 is
refused in between, and the sensor stays in standby: no samples and no
events until the next write that succeeds.

adxl380_set_range() has the same problem and a worse one.  It rescales both
thresholds for the new range.  If one no longer fits it returns -EINVAL
with the sensor in standby, the new range in the chip, the old one in
st->range and rescaled thresholds in the driver's state: from the next
successful write on the samples are reported with the wrong scale.

Switch the measurement on again if the threshold is refused.  In
adxl380_set_range() see whether the thresholds fit before anything is
changed.

Fixes: df36de13677a ("iio: accel: add ADXL380 driver")
Cc: stable <stable@kernel.org>
Cc: Ramona Gradinariu <ramona.gradinariu@analog.com>
Cc: Antoniu Miclaus <antoniu.miclaus@analog.com>
Cc: "Nuno Sá" <nuno.sa@analog.com>
Cc: Michael Hennerich <Michael.Hennerich@analog.com>
Cc: David Lechner <dlechner@baylibre.com>
Cc: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/iio/accel/adxl380.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/accel/adxl380.c b/drivers/iio/accel/adxl380.c
index 8518ee23e114..03b140303520 100644
--- a/drivers/iio/accel/adxl380.c
+++ b/drivers/iio/accel/adxl380.c
@@ -334,8 +334,11 @@ static int adxl380_set_act_inact_threshold(struct iio_dev *indio_dev,
 		return ret;
 
 	ret = adxl380_write_act_inact_threshold(st, act, th);
-	if (ret)
+	if (ret) {
+		/* Leave standby also if the value was refused */
+		adxl380_set_measure_en(st, true);
 		return ret;
+	}
 
 	return adxl380_set_measure_en(st, true);
 }
@@ -698,6 +701,12 @@ static int adxl380_set_range(struct adxl380_state *st, u8 range)
 
 	guard(mutex)(&st->lock);
 
+	/* The thresholds are rescaled: see that they fit before any change */
+	if (mult_frac(max(st->act_threshold, st->inact_threshold),
+		      adxl380_range_scale_factor_tbl[st->range],
+		      adxl380_range_scale_factor_tbl[range]) > ADXL380_THRESH_MAX)
+		return -EINVAL;
+
 	ret = adxl380_set_measure_en(st, false);
 	if (ret)
 		return ret;

-- 
2.56.0