[PATCH] iio: adis16480: fix FNCTIO_CTRL corruption when enabling IRQ

[Vlad Banea]

Enabling the IRQ should leave all other settings in the FNCTIO_CTRL
register untouched: read the whole register, toggle just the enable bit,
before writing it back.
---
 drivers/iio/imu/adis16480.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c
index b94bfd3..8473859 100644
--- a/drivers/iio/imu/adis16480.c
+++ b/drivers/iio/imu/adis16480.c
@@ -738,8 +738,19 @@ static int adis16480_stop_device(struct iio_dev *indio_dev)
 
 static int adis16480_enable_irq(struct adis *adis, bool enable)
 {
-	return adis_write_reg_16(adis, ADIS16480_REG_FNCTIO_CTRL,
-		enable ? BIT(3) : 0);
+	u16 fnctio_ctrl;
+	int ret;
+
+	ret = adis_read_reg_16(adis, ADIS16480_REG_FNCTIO_CTRL, &fnctio_ctrl);
+	if (ret < 0)
+		return ret;
+
+	if (enable)
+		fnctio_ctrl |= BIT(3);
+	else
+		fnctio_ctrl &= ~BIT(3);
+
+	return adis_write_reg_16(adis, ADIS16480_REG_FNCTIO_CTRL, fnctio_ctrl);
 }
 
 static int adis16480_initial_setup(struct iio_dev *indio_dev)
-- 
2.7.1