[PATCH v4 11/14] iio: accel: adxl345: add activity event feature

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

Make the sensor detect and issue interrupts at activity. Activity
events are configured by a threshold stored in regmap cache. Initialize
the activity threshold register to a reasonable default value in probe.
The value is taken from the older ADXL345 input driver, to provide a
similar behavior. Reset the activity/inactivity direction enabling
register in probe. Reset and initialization shall bring the sensor in a
defined initial state to prevent dangling settings when warm restarting
the sensor.

Activity, ODR configuration together with the range setting prepare the
activity/inactivity hystersesis setup, implemented in a follow up patch.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 222 ++++++++++++++++++++++++++++++-
 1 file changed, 219 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index de9202126f70..98a781987b63 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -35,6 +35,7 @@
 
 #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)
 
 enum adxl345_axis {
 	ADXL345_Z_EN = BIT(0),
@@ -67,6 +68,23 @@ static const unsigned int adxl345_tap_time_reg[] = {
 	[ADXL345_TAP_TIME_DUR] = ADXL345_REG_DUR,
 };
 
+/* activity/inactivity */
+enum adxl345_activity_type {
+	ADXL345_ACTIVITY,
+};
+
+static const unsigned int adxl345_act_int_reg[] = {
+	[ADXL345_ACTIVITY] = ADXL345_INT_ACTIVITY,
+};
+
+static const unsigned int adxl345_act_thresh_reg[] = {
+	[ADXL345_ACTIVITY] = ADXL345_REG_THRESH_ACT,
+};
+
+static const unsigned int adxl345_act_axis_msk[] = {
+	[ADXL345_ACTIVITY] = ADXL345_REG_ACT_AXIS_MSK,
+};
+
 enum adxl345_odr {
 	ADXL345_ODR_0P10HZ = 0,
 	ADXL345_ODR_0P20HZ,
@@ -157,6 +175,13 @@ struct adxl345_state {
 };
 
 static struct iio_event_spec adxl345_events[] = {
+	{
+		/* activity */
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
+	},
 	{
 		/* single tap */
 		.type = IIO_EV_TYPE_GESTURE,
@@ -259,6 +284,108 @@ static int adxl345_set_measure_en(struct adxl345_state *st, bool en)
 	return regmap_write(st->regmap, ADXL345_REG_POWER_CTL, val);
 }
 
+/* act/inact */
+
+static int adxl345_is_act_inact_en(struct adxl345_state *st,
+				   enum iio_modifier axis,
+				   enum adxl345_activity_type type, bool *en)
+{
+	unsigned int regval;
+	bool axis_en;
+	u32 axis_ctrl;
+	int act_shift;
+	int ret;
+
+	act_shift = (type == ADXL345_ACTIVITY) ? 4 : 0;
+
+	ret = regmap_read(st->regmap, ADXL345_REG_ACT_INACT_CTRL, &axis_ctrl);
+	if (ret)
+		return ret;
+
+	axis_ctrl = axis_ctrl >> act_shift;
+
+	switch (axis) {
+	case IIO_MOD_X:
+		axis_en = FIELD_GET(ADXL345_X_EN, axis_ctrl);
+		break;
+	case IIO_MOD_Y:
+		axis_en = FIELD_GET(ADXL345_Y_EN, axis_ctrl);
+		break;
+	case IIO_MOD_Z:
+		axis_en = FIELD_GET(ADXL345_Z_EN, axis_ctrl);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = regmap_read(st->regmap, ADXL345_REG_INT_ENABLE, &regval);
+	if (ret)
+		return ret;
+
+	*en = (adxl345_act_int_reg[type] & regval) > 0;
+
+	return 0;
+}
+
+static int adxl345_set_act_inact_en(struct adxl345_state *st,
+				    enum iio_modifier axis,
+				    enum adxl345_activity_type type,
+				    bool cmd_en)
+{
+	bool axis_en, en;
+	unsigned int threshold;
+	u32 axis_ctrl;
+	/*
+	 * Activity and inactivity share the same register for enabling
+	 * directions. Activity uses the four upper bits, where inactivity
+	 * detection uses the lower bits. In order to keep generic x, y
+	 * and z-axis type, it is shifted for initialization of activity.
+	 * NB: Activity and inactivitty axis enable bits are regmap cached.
+	 */
+	int act_shift = (type == ADXL345_ACTIVITY) ? 4 : 0;
+	int ret;
+
+	switch (axis) {
+	case IIO_MOD_X:
+		axis_ctrl = ADXL345_X_EN;
+		break;
+	case IIO_MOD_Y:
+		axis_ctrl = ADXL345_Y_EN;
+		break;
+	case IIO_MOD_Z:
+		axis_ctrl = ADXL345_Z_EN;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	axis_ctrl = axis_ctrl << act_shift;
+
+	if (cmd_en)
+		ret = regmap_set_bits(st->regmap,
+				      ADXL345_REG_ACT_INACT_CTRL, axis_ctrl);
+	else
+		ret = regmap_clear_bits(st->regmap,
+					ADXL345_REG_ACT_INACT_CTRL, axis_ctrl);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->regmap, adxl345_act_thresh_reg[type], &threshold);
+	if (ret)
+		return ret;
+
+	en = false;
+
+	if (type == ADXL345_ACTIVITY) {
+		axis_en = FIELD_GET(ADXL345_REG_ACT_AXIS_MSK, axis_ctrl) > 0;
+		en = axis_en && threshold > 0;
+	}
+
+	return regmap_update_bits(st->regmap, ADXL345_REG_INT_ENABLE,
+				  adxl345_act_int_reg[type],
+				  en ? adxl345_act_int_reg[type] : 0);
+}
+
 /* tap */
 
 static int _adxl345_set_tap_int(struct adxl345_state *st,
@@ -719,6 +846,18 @@ static int adxl345_read_event_config(struct iio_dev *indio_dev,
 	int ret = -EFAULT;
 
 	switch (type) {
+	case IIO_EV_TYPE_THRESH:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			ret = adxl345_is_act_inact_en(st, chan->channel2,
+						      ADXL345_ACTIVITY,
+						      &int_en);
+			if (ret)
+				return ret;
+			return int_en;
+		default:
+			return -EINVAL;
+		}
 	case IIO_EV_TYPE_GESTURE:
 		switch (dir) {
 		case IIO_EV_DIR_SINGLETAP:
@@ -755,6 +894,14 @@ static int adxl345_write_event_config(struct iio_dev *indio_dev,
 	struct adxl345_state *st = iio_priv(indio_dev);
 
 	switch (type) {
+	case IIO_EV_TYPE_THRESH:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			return adxl345_set_act_inact_en(st, chan->channel2,
+							ADXL345_ACTIVITY, state);
+		default:
+			return -EINVAL;
+		}
 	case IIO_EV_TYPE_GESTURE:
 		switch (dir) {
 		case IIO_EV_DIR_SINGLETAP:
@@ -779,11 +926,31 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
 				    int *val, int *val2)
 {
 	struct adxl345_state *st = iio_priv(indio_dev);
+	unsigned int act_threshold;
 	unsigned int tap_threshold;
 	unsigned int ff_threshold;
 	int ret;
 
 	switch (type) {
+	case IIO_EV_TYPE_THRESH:
+		switch (info) {
+		case IIO_EV_INFO_VALUE:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				ret = regmap_read(st->regmap,
+						  adxl345_act_thresh_reg[ADXL345_ACTIVITY],
+						  &act_threshold);
+				if (ret)
+					return ret;
+
+				*val = act_threshold;
+				return IIO_VAL_INT;
+			default:
+				return -EINVAL;
+			}
+		default:
+			return -EINVAL;
+		}
 	case IIO_EV_TYPE_GESTURE:
 		switch (info) {
 		case IIO_EV_INFO_VALUE:
@@ -850,6 +1017,23 @@ static int adxl345_write_event_value(struct iio_dev *indio_dev,
 		return ret;
 
 	switch (type) {
+	case IIO_EV_TYPE_THRESH:
+		switch (info) {
+		case IIO_EV_INFO_VALUE:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				ret = regmap_write(st->regmap,
+						   adxl345_act_thresh_reg[ADXL345_ACTIVITY],
+						   val);
+				break;
+			default:
+				ret = -EINVAL;
+			}
+			break;
+		default:
+			ret = -EINVAL;
+		}
+		break;
 	case IIO_EV_TYPE_GESTURE:
 		switch (info) {
 		case IIO_EV_INFO_VALUE:
@@ -1105,7 +1289,8 @@ static int adxl345_fifo_push(struct iio_dev *indio_dev,
 }
 
 static int adxl345_push_event(struct iio_dev *indio_dev, int int_stat,
-			      enum iio_modifier tap_dir)
+			      enum iio_modifier tap_dir,
+			      enum iio_modifier act_dir)
 {
 	s64 ts = iio_get_time_ns(indio_dev);
 	struct adxl345_state *st = iio_priv(indio_dev);
@@ -1132,6 +1317,16 @@ static int adxl345_push_event(struct iio_dev *indio_dev, int int_stat,
 			return ret;
 	}
 
+	if (FIELD_GET(ADXL345_INT_ACTIVITY, int_stat)) {
+		ret = iio_push_event(indio_dev,
+				     IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, act_dir,
+							IIO_EV_TYPE_THRESH,
+							IIO_EV_DIR_RISING),
+				     ts);
+		if (ret)
+			return ret;
+	}
+
 	if (FIELD_GET(ADXL345_INT_FREE_FALL, int_stat)) {
 		ret = iio_push_event(indio_dev,
 				     IIO_MOD_EVENT_CODE(IIO_ACCEL, 0,
@@ -1164,10 +1359,12 @@ static int adxl345_push_event(struct iio_dev *indio_dev, int int_stat,
  */
 static irqreturn_t adxl345_irq_handler(int irq, void *p)
 {
+	const int act_shift = 4;
 	struct iio_dev *indio_dev = p;
 	struct adxl345_state *st = iio_priv(indio_dev);
 	unsigned int regval;
 	enum iio_modifier tap_dir = IIO_NO_MOD;
+	enum iio_modifier act_dir = IIO_NO_MOD;
 	u32 axis_ctrl;
 	int int_stat;
 	int ret;
@@ -1176,7 +1373,8 @@ static irqreturn_t adxl345_irq_handler(int irq, void *p)
 	if (ret)
 		return IRQ_NONE;
 
-	if (FIELD_GET(ADXL345_REG_TAP_AXIS_MSK, axis_ctrl)) {
+	if (FIELD_GET(ADXL345_REG_TAP_AXIS_MSK, axis_ctrl) ||
+	    FIELD_GET(ADXL345_REG_ACT_AXIS_MSK, axis_ctrl)) {
 		ret = regmap_read(st->regmap, ADXL345_REG_ACT_TAP_STATUS, &regval);
 		if (ret)
 			return IRQ_NONE;
@@ -1187,12 +1385,22 @@ static irqreturn_t adxl345_irq_handler(int irq, void *p)
 			tap_dir = IIO_MOD_Y;
 		else if (FIELD_GET(ADXL345_X_EN, regval))
 			tap_dir = IIO_MOD_X;
+
+		/* Activity direction is stored in the upper four bits */
+		regval >>= act_shift;
+
+		if (FIELD_GET(ADXL345_Z_EN, regval))
+			act_dir = IIO_MOD_Z;
+		else if (FIELD_GET(ADXL345_Y_EN, regval))
+			act_dir = IIO_MOD_Y;
+		else if (FIELD_GET(ADXL345_X_EN, regval))
+			act_dir = IIO_MOD_X;
 	}
 
 	if (regmap_read(st->regmap, ADXL345_REG_INT_SOURCE, &int_stat))
 		return IRQ_NONE;
 
-	if (adxl345_push_event(indio_dev, int_stat, tap_dir))
+	if (adxl345_push_event(indio_dev, int_stat, tap_dir, act_dir))
 		goto err;
 
 	if (FIELD_GET(ADXL345_INT_OVERRUN, int_stat))
@@ -1357,6 +1565,14 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 		if (ret)
 			return ret;
 
+		ret = regmap_write(st->regmap, ADXL345_REG_ACT_INACT_CTRL, 0);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(st->regmap, ADXL345_REG_THRESH_ACT, 6);
+		if (ret)
+			return ret;
+
 		ret = regmap_write(st->regmap, ADXL345_REG_THRESH_TAP, tap_threshold);
 		if (ret)
 			return ret;
-- 
2.39.5