iio: imu: st_lsm6dsx: track hw FIFO buffering with fifo_mask

Track hw FIFO state introducing fifo_mask since now the accel sensor
can be enabled during suspend/resume in order to trigger the wake-up
enabling the FIFO in st_lsm6dsx_resume even if it was disabled before
the suspend.  Hence we must separately track the fifo state.

Fixes: 4c997dfa69 ("iio: imu: st_lsm6dsx: add wakeup-source option")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h

@@ -349,9 +349,9 @@ struct st_lsm6dsx_sensor {
  * @fifo_lock: Mutex to prevent concurrent access to the hw FIFO.
  * @conf_lock: Mutex to prevent concurrent FIFO configuration update.
  * @page_lock: Mutex to prevent concurrent memory page configuration.
- * @fifo_mode: FIFO operating mode supported by the device.
  * @suspend_mask: Suspended sensor bitmask.
  * @enable_mask: Enabled sensor bitmask.
+ * @fifo_mask: Enabled hw FIFO bitmask.
  * @ts_gain: Hw timestamp rate after internal calibration.
  * @ts_sip: Total number of timestamp samples in a given pattern.
  * @sip: Total number of samples (acc/gyro/ts) in a given pattern.
@@ -371,9 +371,9 @@ struct st_lsm6dsx_hw {
 	struct mutex conf_lock;
 	struct mutex page_lock;
 
-	enum st_lsm6dsx_fifo_mode fifo_mode;
 	u8 suspend_mask;
 	u8 enable_mask;
+	u8 fifo_mask;
 	s64 ts_gain;
 	u8 ts_sip;
 	u8 sip;

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c

@@ -187,17 +187,10 @@ int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
 			     enum st_lsm6dsx_fifo_mode fifo_mode)
 {
 	unsigned int data;
-	int err;
 
 	data = FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, fifo_mode);
-	err = st_lsm6dsx_update_bits_locked(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
+	return st_lsm6dsx_update_bits_locked(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
-					    ST_LSM6DSX_FIFO_MODE_MASK, data);
+					     ST_LSM6DSX_FIFO_MODE_MASK, data);
-	if (err < 0)
-		return err;
-
-	hw->fifo_mode = fifo_mode;
-
-	return 0;
 }
 
 static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor,
@@ -619,11 +612,17 @@ int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
 int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
 {
 	struct st_lsm6dsx_hw *hw = sensor->hw;
+	u8 fifo_mask;
 	int err;
 
 	mutex_lock(&hw->conf_lock);
 
-	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) {
+	if (enable)
+		fifo_mask = hw->fifo_mask | BIT(sensor->id);
+	else
+		fifo_mask = hw->fifo_mask & ~BIT(sensor->id);
+
+	if (hw->fifo_mask) {
 		err = st_lsm6dsx_flush_fifo(hw);
 		if (err < 0)
 			goto out;
@@ -653,15 +652,19 @@ int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
 	if (err < 0)
 		goto out;
 
-	if (hw->enable_mask) {
+	if (fifo_mask) {
 		/* reset hw ts counter */
 		err = st_lsm6dsx_reset_hw_ts(hw);
 		if (err < 0)
 			goto out;
 
 		err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
+		if (err < 0)
+			goto out;
 	}
 
+	hw->fifo_mask = fifo_mask;
+
 out:
 	mutex_unlock(&hw->conf_lock);
 

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c

@@ -2300,7 +2300,7 @@ static int __maybe_unused st_lsm6dsx_suspend(struct device *dev)
 		hw->suspend_mask |= BIT(sensor->id);
 	}
 
-	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS)
+	if (hw->fifo_mask)
 		err = st_lsm6dsx_flush_fifo(hw);
 
 	return err;
@@ -2336,7 +2336,7 @@ static int __maybe_unused st_lsm6dsx_resume(struct device *dev)
 		hw->suspend_mask &= ~BIT(sensor->id);
 	}
 
-	if (hw->enable_mask)
+	if (hw->fifo_mask)
 		err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
 
 	return err;