[PATCH v5 6/8] iio: accel: adxl313: implement power-save on inactivity

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

Configure the link bit to associate activity and inactivity sensing,
allowing the sensor to reflect its internal power-saving state.
Additionally, enable the auto-sleep bit to transition the sensor into
auto-sleep mode during periods of inactivity, as outlined in the
datasheet.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl313.h      |  3 +++
 drivers/iio/accel/adxl313_core.c | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/iio/accel/adxl313.h b/drivers/iio/accel/adxl313.h
index d7e8cb44855b..75ef54b60f75 100644
--- a/drivers/iio/accel/adxl313.h
+++ b/drivers/iio/accel/adxl313.h
@@ -41,6 +41,9 @@
 #define ADXL313_RATE_BASE		6
 
 #define ADXL313_POWER_CTL_MSK		BIT(3)
+#define ADXL313_POWER_CTL_INACT_MSK	GENMASK(5, 4)
+#define ADXL313_POWER_CTL_LINK		BIT(5)
+#define ADXL313_POWER_CTL_AUTO_SLEEP	BIT(4)
 
 #define ADXL313_RANGE_MSK		GENMASK(1, 0)
 #define ADXL313_RANGE_MAX		3
diff --git a/drivers/iio/accel/adxl313_core.c b/drivers/iio/accel/adxl313_core.c
index 95f52c95682a..d8a263b2a6f6 100644
--- a/drivers/iio/accel/adxl313_core.c
+++ b/drivers/iio/accel/adxl313_core.c
@@ -396,6 +396,25 @@ static int adxl313_is_act_inact_en(struct adxl313_data *data,
 	return adxl313_act_int_reg[type] & regval;
 }
 
+static int adxl313_set_act_inact_linkbit(struct adxl313_data *data, bool en)
+{
+	int act_en, inact_en;
+
+	act_en = adxl313_is_act_inact_en(data, ADXL313_ACTIVITY);
+	if (act_en < 0)
+		return act_en;
+
+	inact_en = adxl313_is_act_inact_en(data, ADXL313_INACTIVITY);
+	if (inact_en < 0)
+		return inact_en;
+
+	en = en && act_en && inact_en;
+
+	return regmap_assign_bits(data->regmap, ADXL313_REG_POWER_CTL,
+				  (ADXL313_POWER_CTL_AUTO_SLEEP | ADXL313_POWER_CTL_LINK),
+				  en);
+}
+
 static int adxl313_set_act_inact_en(struct adxl313_data *data,
 				    enum adxl313_activity_type type,
 				    bool cmd_en)
@@ -426,6 +445,7 @@ static int adxl313_set_act_inact_en(struct adxl313_data *data,
 		}
 	}
 
+	/* Start modifying configuration registers */
 	ret = adxl313_set_measure_en(data, false);
 	if (ret)
 		return ret;
@@ -452,6 +472,11 @@ static int adxl313_set_act_inact_en(struct adxl313_data *data,
 	if (ret)
 		return ret;
 
+	/* Set link-bit and auto-sleep only when ACT and INACT are enabled */
+	ret = adxl313_set_act_inact_linkbit(data, cmd_en);
+	if (ret)
+		return ret;
+
 	return adxl313_set_measure_en(data, true);
 }
 
-- 
2.39.5