[PATCH 1/6] iio: imu: adis16480: Use the default data ready pin configuration

[Stefan Popa <stefan.popa@analog.com>]

The FNCTIO_CTRL register, Bits[3:0] provide three configuration options
for the data ready function: on/off, polarity, and DIOx line. The
factory default assigns DIO2 as a positive polarity, data ready signal.

The adis16480_enable_irq() function, overwrites this configuration when
it enables/disables the data ready pin by only setting BIT[3].
As a result, the data ready signal becomes DIO1 pin which is assigned as
negative polarity.

This patch reads the FNCTIO_CTRL register and creates a mask, such that
only data ready enable (BIT[3]) will be modified when
adis16480_enable_irq function is called.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
---
 drivers/iio/imu/adis16480.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c
index a27fe20..d222188 100644
--- a/drivers/iio/imu/adis16480.c
+++ b/drivers/iio/imu/adis16480.c
@@ -9,6 +9,7 @@
  *
  */
 
+#include <linux/bitfield.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
@@ -107,6 +108,10 @@
 #define ADIS16480_FIR_COEF_C(x)			ADIS16480_FIR_COEF(0x09, (x))
 #define ADIS16480_FIR_COEF_D(x)			ADIS16480_FIR_COEF(0x0B, (x))
 
+/* ADIS16480_REG_FNCTIO_CTRL */
+#define ADIS16480_DRDY_EN_MSK		BIT(3)
+#define ADIS16480_DRDY_EN(x)		FIELD_PREP(ADIS16480_DRDY_EN_MSK, x)
+
 struct adis16480_chip_info {
 	unsigned int num_channels;
 	const struct iio_chan_spec *channels;
@@ -741,8 +746,17 @@ 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);
+	uint16_t val;
+	int ret;
+
+	ret = adis_read_reg_16(adis, ADIS16480_REG_FNCTIO_CTRL, &val);
+	if (ret < 0)
+		return ret;
+
+	val &= ~ADIS16480_DRDY_EN_MSK;
+	val |= ADIS16480_DRDY_EN(enable);
+
+	return adis_write_reg_16(adis, ADIS16480_REG_FNCTIO_CTRL, val);
 }
 
 static int adis16480_initial_setup(struct iio_dev *indio_dev)
-- 
2.7.4