[PATCH v2 13/14] iio: accel: adxl345: add coupling detection for activity/inactivity

[Lothar Rubusch <l.rubusch@gmail.com>]

Add coupling activity/inactivity detection by the AC/DC bit. This is an
addititional enhancement for the detection of activity states and
completes the activity / inactivity feature of the ADXL345.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 77 ++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 7de869fac799..411ae7bf6b97 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -36,7 +36,9 @@
 #define ADXL345_REG_TAP_AXIS_MSK	GENMASK(2, 0)
 #define ADXL345_REG_TAP_SUPPRESS_MSK	BIT(3)
 #define ADXL345_REG_ACT_AXIS_MSK	GENMASK(6, 4)
+#define ADXL345_REG_ACT_ACDC_MSK	BIT(7)
 #define ADXL345_REG_INACT_AXIS_MSK	GENMASK(2, 0)
+#define ADXL345_REG_INACT_ACDC_MSK	BIT(3)
 #define ADXL345_POWER_CTL_INACT_MSK	(ADXL345_POWER_CTL_AUTO_SLEEP | ADXL345_POWER_CTL_LINK)
 
 enum adxl345_axis {
@@ -86,6 +88,11 @@ static const unsigned int adxl345_act_thresh_reg[2] = {
 	[ADXL345_INACTIVITY] = ADXL345_REG_THRESH_INACT,
 };
 
+static const unsigned int adxl345_act_acdc_msk[2] = {
+	[ADXL345_ACTIVITY] = ADXL345_REG_ACT_ACDC_MSK,
+	[ADXL345_INACTIVITY] = ADXL345_REG_INACT_ACDC_MSK,
+};
+
 static const unsigned int adxl345_act_axis_msk[2] = {
 	[ADXL345_ACTIVITY] = ADXL345_REG_ACT_AXIS_MSK,
 	[ADXL345_INACTIVITY] = ADXL345_REG_INACT_AXIS_MSK,
@@ -178,9 +185,11 @@ struct adxl345_state {
 	enum adxl345_range range;
 
 	u32 act_axis_ctrl;
+	bool act_ac;
 	u8 act_threshold;
 
 	u32 inact_axis_ctrl;
+	bool inact_ac;
 	u8 inact_threshold;
 	u8 inact_time_s;
 
@@ -237,6 +246,18 @@ static struct iio_event_spec adxl345_events[] = {
 			BIT(IIO_EV_INFO_VALUE) |
 			BIT(IIO_EV_INFO_PERIOD),
 	},
+	{
+		/* activity, activity - ac bit */
+		.type = IIO_EV_TYPE_MAG_REFERENCED,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		/* activity, inactivity - ac bit */
+		.type = IIO_EV_TYPE_MAG_REFERENCED,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE),
+	},
 };
 
 #define ADXL345_CHANNEL(index, reg, axis) {					\
@@ -334,6 +355,35 @@ static int adxl345_write_act_axis(struct adxl345_state *st,
 	return 0;
 }
 
+static int adxl345_is_act_inact_ac(struct adxl345_state *st,
+				   enum adxl345_activity_type type, bool *ac)
+{
+	if (type == ADXL345_ACTIVITY)
+		*ac = st->act_ac;
+	else
+		*ac = st->inact_ac;
+
+	return 0;
+}
+
+static int adxl345_set_act_inact_ac(struct adxl345_state *st,
+				    enum adxl345_activity_type type, bool ac)
+{
+	int ret;
+
+	ret = regmap_update_bits(st->regmap, ADXL345_REG_ACT_INACT_CTRL,
+				 adxl345_act_acdc_msk[type], ac);
+	if (ret)
+		return ret;
+
+	if (type == ADXL345_ACTIVITY)
+		st->act_ac = ac;
+	else
+		st->inact_ac = ac;
+
+	return 0;
+}
+
 static int adxl345_is_act_inact_en(struct adxl345_state *st,
 				   enum adxl345_activity_type type, bool *en)
 {
@@ -959,6 +1009,21 @@ static int adxl345_read_event_config(struct iio_dev *indio_dev,
 		if (ret)
 			return ret;
 		return int_en;
+	case IIO_EV_TYPE_MAG_REFERENCED:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			ret = adxl345_is_act_inact_ac(st, ADXL345_ACTIVITY, &int_en);
+			if (ret)
+				return ret;
+			return int_en;
+		case IIO_EV_DIR_FALLING:
+			ret = adxl345_is_act_inact_ac(st, ADXL345_INACTIVITY, &int_en);
+			if (ret)
+				return ret;
+			return int_en;
+		default:
+			return -EINVAL;
+		}
 	default:
 		return -EINVAL;
 	}
@@ -1008,6 +1073,16 @@ static int adxl345_write_event_config(struct iio_dev *indio_dev,
 		}
 	case IIO_EV_TYPE_MAG:
 		return adxl345_set_ff_en(st, state);
+	case IIO_EV_TYPE_MAG_REFERENCED:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			return adxl345_set_act_inact_ac(st, ADXL345_ACTIVITY, state);
+		case IIO_EV_DIR_FALLING:
+			return adxl345_set_act_inact_ac(st, ADXL345_INACTIVITY, state);
+		default:
+			return -EINVAL;
+		}
+
 	default:
 		return -EINVAL;
 	}
@@ -1619,6 +1694,8 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 	 */
 	st->act_axis_ctrl = ADXL345_REG_ACT_AXIS_MSK;
 	st->inact_axis_ctrl = ADXL345_REG_INACT_AXIS_MSK;
+	st->inact_ac = 0;			/*    0 [dc]              */
+	st->act_ac = 0;
 	st->int_map = 0x00;			/* reset interrupts */
 
 	/* Init with reasonable values */
-- 
2.39.5