[PATCH v9 07/11] 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. 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.

Activity, ODR configuration together with the range setting prepare the
activity/inactivity hysteresis setup, implemented in a follow up patch.
Thus parts of this patch prepare switch/case setups for the follow up
patches.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 205 ++++++++++++++++++++++++++++++-
 1 file changed, 202 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 2c4f045c741c..04b9f155872f 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -36,11 +36,16 @@
 #define ADXL345_REG_TAP_AXIS_MSK	GENMASK(2, 0)
 #define ADXL345_REG_TAP_SUPPRESS_MSK	BIT(3)
 #define ADXL345_REG_TAP_SUPPRESS	BIT(3)
+#define ADXL345_REG_ACT_AXIS_MSK	GENMASK(6, 4)
 
 #define ADXL345_TAP_Z_EN		BIT(0)
 #define ADXL345_TAP_Y_EN		BIT(1)
 #define ADXL345_TAP_X_EN		BIT(2)
 
+#define ADXL345_ACT_Z_EN		BIT(4)
+#define ADXL345_ACT_Y_EN		BIT(5)
+#define ADXL345_ACT_X_EN		BIT(6)
+
 /* single/double tap */
 enum adxl345_tap_type {
 	ADXL345_SINGLE_TAP,
@@ -64,6 +69,19 @@ 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,
+};
+
 enum adxl345_odr {
 	ADXL345_ODR_0P10HZ = 0,
 	ADXL345_ODR_0P20HZ,
@@ -144,6 +162,13 @@ struct adxl345_state {
 };
 
 static struct iio_event_spec adxl345_events[] = {
+	{
+		/* activity */
+		.type = IIO_EV_TYPE_MAG,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_VALUE),
+	},
 	{
 		/* single tap */
 		.type = IIO_EV_TYPE_GESTURE,
@@ -237,6 +262,90 @@ static int adxl345_set_measure_en(struct adxl345_state *st, bool en)
 				  ADXL345_POWER_CTL_MEASURE, en);
 }
 
+/* act/inact */
+
+static int adxl345_is_act_inact_en(struct adxl345_state *st,
+				   enum adxl345_activity_type type)
+{
+	unsigned int regval;
+	u32 axis_ctrl;
+	bool en;
+	int ret;
+
+	ret = regmap_read(st->regmap, ADXL345_REG_ACT_INACT_CTRL, &axis_ctrl);
+	if (ret)
+		return ret;
+
+	switch (type) {
+	case ADXL345_ACTIVITY:
+		en = FIELD_GET(ADXL345_ACT_X_EN, axis_ctrl) |
+			FIELD_GET(ADXL345_ACT_Y_EN, axis_ctrl) |
+			FIELD_GET(ADXL345_ACT_Z_EN, axis_ctrl);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (!en)
+		return en;
+
+	/* Check if corresponding interrupts are enabled */
+	ret = regmap_read(st->regmap, ADXL345_REG_INT_ENABLE, &regval);
+	if (ret)
+		return ret;
+
+	return adxl345_act_int_reg[type] & regval;
+}
+
+static int adxl345_set_act_inact_en(struct adxl345_state *st,
+				    enum adxl345_activity_type type,
+				    bool cmd_en)
+{
+	bool en;
+	unsigned int threshold;
+	u32 axis_ctrl;
+	int ret;
+
+	if (type == ADXL345_ACTIVITY) {
+		axis_ctrl = ADXL345_ACT_X_EN | ADXL345_ACT_Y_EN |
+				ADXL345_ACT_Z_EN;
+	} else {
+		axis_ctrl = 0x00;
+	}
+
+	/* Start configuring the sensor registers */
+	ret = adxl345_set_measure_en(st, false);
+	if (ret)
+		return ret;
+
+	ret = regmap_assign_bits(st->regmap, ADXL345_REG_ACT_INACT_CTRL,
+				 axis_ctrl, cmd_en);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->regmap, adxl345_act_thresh_reg[type], &threshold);
+	if (ret)
+		return ret;
+
+	en = false;
+
+	switch (type) {
+	case ADXL345_ACTIVITY:
+		en = FIELD_GET(ADXL345_REG_ACT_AXIS_MSK, axis_ctrl) &&
+			threshold;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = regmap_assign_bits(st->regmap, ADXL345_REG_INT_ENABLE,
+				 adxl345_act_int_reg[type], cmd_en && en);
+	if (ret)
+		return ret;
+
+	return adxl345_set_measure_en(st, true);
+}
+
 /* tap */
 
 static int _adxl345_set_tap_int(struct adxl345_state *st,
@@ -634,6 +743,13 @@ static int adxl345_read_event_config(struct iio_dev *indio_dev,
 	int ret;
 
 	switch (type) {
+	case IIO_EV_TYPE_MAG:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			return adxl345_is_act_inact_en(st, ADXL345_ACTIVITY);
+		default:
+			return -EINVAL;
+		}
 	case IIO_EV_TYPE_GESTURE:
 		switch (dir) {
 		case IIO_EV_DIR_SINGLETAP:
@@ -665,6 +781,15 @@ 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_MAG:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			return adxl345_set_act_inact_en(st,
+							ADXL345_ACTIVITY,
+							state);
+		default:
+			return -EINVAL;
+		}
 	case IIO_EV_TYPE_GESTURE:
 		switch (dir) {
 		case IIO_EV_DIR_SINGLETAP:
@@ -687,10 +812,30 @@ 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;
 	int ret;
 
 	switch (type) {
+	case IIO_EV_TYPE_MAG:
+		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 = 62500 * act_threshold;
+				*val2 = MICRO;
+				return IIO_VAL_FRACTIONAL;
+			default:
+				return -EINVAL;
+			}
+		default:
+			return -EINVAL;
+		}
 	case IIO_EV_TYPE_GESTURE:
 		switch (info) {
 		case IIO_EV_INFO_VALUE:
@@ -739,6 +884,26 @@ static int adxl345_write_event_value(struct iio_dev *indio_dev,
 		return ret;
 
 	switch (type) {
+	case IIO_EV_TYPE_MAG:
+		switch (info) {
+		case IIO_EV_INFO_VALUE:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				val = DIV_ROUND_CLOSEST(val * MICRO + val2, 62500);
+				ret = regmap_write(st->regmap,
+						   adxl345_act_thresh_reg[ADXL345_ACTIVITY],
+						   val);
+				if (ret)
+					return ret;
+				break;
+			default:
+				return -EINVAL;
+			}
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
 	case IIO_EV_TYPE_GESTURE:
 		switch (info) {
 		case IIO_EV_INFO_VALUE:
@@ -980,7 +1145,8 @@ 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);
@@ -1007,6 +1173,16 @@ 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_MAG,
+							IIO_EV_DIR_RISING),
+				     ts);
+		if (ret)
+			return ret;
+	}
+
 	if (FIELD_GET(ADXL345_INT_WATERMARK, int_stat)) {
 		samples = adxl345_get_samples(st);
 		if (samples < 0)
@@ -1034,6 +1210,7 @@ static irqreturn_t adxl345_irq_handler(int irq, void *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;
@@ -1042,7 +1219,8 @@ 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;
@@ -1053,12 +1231,19 @@ static irqreturn_t adxl345_irq_handler(int irq, void *p)
 			tap_dir = IIO_MOD_Y;
 		else if (FIELD_GET(ADXL345_TAP_X_EN, regval))
 			tap_dir = IIO_MOD_X;
+
+		if (FIELD_GET(ADXL345_ACT_Z_EN, regval))
+			act_dir = IIO_MOD_Z;
+		else if (FIELD_GET(ADXL345_ACT_Y_EN, regval))
+			act_dir = IIO_MOD_Y;
+		else if (FIELD_GET(ADXL345_ACT_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))
@@ -1219,6 +1404,20 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 		if (ret)
 			return ret;
 
+		/*
+		 * Initialization with reasonable values to simplify operation
+		 * of the sensor. The default values are partly taken from the
+		 * older input driver for the ADXL345, and partly based on
+		 * recommendations in the datasheet.
+		 */
+		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