sensor: adxl345: Fix decoder for non-streaming mode

ubieda · kartben · commit 283b5197e6ee · 2025-01-20T20:56:19.000+01:00
The following fixes have been applied to this decoder:
- The Q-scale factor was fixed, both for full-scale and non
full-scale modes.
- The data-type decoded is struct sensor_three_axis_data, as
it should for read/decode API.

Signed-off-by: Luis Ubieda &lt;luisf@croxel.com&gt;
diff --git a/drivers/sensor/adi/adxl345/adxl345.c b/drivers/sensor/adi/adxl345/adxl345.c
@@ -281,6 +281,7 @@ int adxl345_read_sample(const struct device *dev,
 {
 	int16_t raw_x, raw_y, raw_z;
 	uint8_t axis_data[6], status1;
+	struct adxl345_dev_data *data = dev->data;
 
 	if (!IS_ENABLED(CONFIG_ADXL345_TRIGGER)) {
 		do {
@@ -303,6 +304,9 @@ int adxl345_read_sample(const struct device *dev,
 	sample->y = raw_y;
 	sample->z = raw_z;
 
+	sample->selected_range = data->selected_range;
+	sample->is_full_res = data->is_full_res;
+
 	return 0;
 }
 
diff --git a/drivers/sensor/adi/adxl345/adxl345.h b/drivers/sensor/adi/adxl345/adxl345.h
@@ -205,6 +205,7 @@ struct adxl345_sample {
 	uint8_t res: 7;
 #endif /* CONFIG_ADXL345_STREAM */
 	uint8_t selected_range;
+	bool is_full_res;
 	int16_t x;
 	int16_t y;
 	int16_t z;
diff --git a/drivers/sensor/adi/adxl345/adxl345_decoder.c b/drivers/sensor/adi/adxl345/adxl345_decoder.c
@@ -6,17 +6,42 @@
 
 #include "adxl345.h"
 
-#ifdef CONFIG_ADXL345_STREAM
+/** The q-scale factor will always be the same, as the nominal LSB/g
+ * changes at the same rate the selected shift parameter per range:
+ *
+ * - At 2G: 256 LSB/g, 10-bits resolution.
+ * - At 4g: 128 LSB/g, 10-bits resolution.
+ * - At 8g: 64 LSB/g, 10-bits resolution.
+ * - At 16g 32 LSB/g, 10-bits resolution.
+ */
+static const uint32_t qscale_factor_no_full_res[] = {
+	/* (1.0 / Resolution-LSB-per-g * (2^31 / 2^5) * SENSOR_G / 1000000 */
+	[ADXL345_RANGE_2G] = UINT32_C(2570754),
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^6) * SENSOR_G / 1000000  */
+	[ADXL345_RANGE_4G] = UINT32_C(2570754),
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^7) ) * SENSOR_G / 1000000 */
+	[ADXL345_RANGE_8G] = UINT32_C(2570754),
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^8) ) * SENSOR_G / 1000000 */
+	[ADXL345_RANGE_16G] = UINT32_C(2570754),
+};
 
-#define SENSOR_SCALING_FACTOR (SENSOR_G / (16 * 1000 / 100))
 
-static const uint32_t accel_period_ns[] = {
-	[ADXL345_ODR_12HZ] = UINT32_C(1000000000) / 12,
-	[ADXL345_ODR_25HZ] = UINT32_C(1000000000) / 25,
-	[ADXL345_ODR_50HZ] = UINT32_C(1000000000) / 50,
-	[ADXL345_ODR_100HZ] = UINT32_C(1000000000) / 100,
-	[ADXL345_ODR_200HZ] = UINT32_C(1000000000) / 200,
-	[ADXL345_ODR_400HZ] = UINT32_C(1000000000) / 400,
+/** Sensitivities based on Range:
+ *
+ * - At 2G: 256 LSB/g, 10-bits resolution.
+ * - At 4g: 256 LSB/g, 11-bits resolution.
+ * - At 8g: 256 LSB/g, 12-bits resolution.
+ * - At 16g 256 LSB/g, 13-bits resolution.
+ */
+static const uint32_t qscale_factor_full_res[] = {
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^5) * SENSOR_G / 1000000 */
+	[ADXL345_RANGE_2G] = UINT32_C(2570754),
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^6) * SENSOR_G / 1000000  */
+	[ADXL345_RANGE_4G] = UINT32_C(1285377),
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^7) ) * SENSOR_G / 1000000 */
+	[ADXL345_RANGE_8G] = UINT32_C(642688),
+	/* (1.0 / Resolution-LSB-per-g) * (2^31 / 2^8) ) * SENSOR_G / 1000000 */
+	[ADXL345_RANGE_16G] = UINT32_C(321344),
 };
 
 static const uint32_t range_to_shift[] = {
@@ -26,30 +51,6 @@ static const uint32_t range_to_shift[] = {
 	[ADXL345_RANGE_16G] = 8,
 };
 
-/* (1 / sensitivity) * (pow(2,31) / pow(2,shift)) * (unit_scaler) */
-static const uint32_t qscale_factor_no_full_res[] = {
-	/* (1.0 / ADXL362_ACCEL_2G_LSB_PER_G) * (2^31 / 2^5) * SENSOR_G / 1000000 */
-	[ADXL345_RANGE_2G] = UINT32_C(2569011),
-	/* (1.0 / ADXL362_ACCEL_4G_LSB_PER_G) * (2^31 / 2^6) * SENSOR_G / 1000000  */
-	[ADXL345_RANGE_4G] = UINT32_C(642253),
-	/* (1.0 / ADXL362_ACCEL_8G_LSB_PER_G) * (2^31 / 2^7) ) * SENSOR_G / 1000000 */
-	[ADXL345_RANGE_8G] = UINT32_C(160563),
-	/* (1.0 / ADXL362_ACCEL_8G_LSB_PER_G) * (2^31 / 2^8) ) * SENSOR_G / 1000000 */
-	[ADXL345_RANGE_16G] = UINT32_C(40141),
-};
-
-/* (1 / sensitivity) * (pow(2,31) / pow(2,shift)) * (unit_scaler) */
-static const uint32_t qscale_factor_full_res[] = {
-	/* (1.0 / ADXL362_ACCEL_2G_LSB_PER_G) * (2^31 / 2^5) * SENSOR_G / 1000000 */
-	[ADXL345_RANGE_2G] = UINT32_C(2569011),
-	/* (1.0 / ADXL362_ACCEL_4G_LSB_PER_G) * (2^31 / 2^6) * SENSOR_G / 1000000  */
-	[ADXL345_RANGE_4G] = UINT32_C(1284506),
-	/* (1.0 / ADXL362_ACCEL_8G_LSB_PER_G) * (2^31 / 2^7) ) * SENSOR_G / 1000000 */
-	[ADXL345_RANGE_8G] = UINT32_C(642253),
-	/* (1.0 / ADXL362_ACCEL_8G_LSB_PER_G) * (2^31 / 2^8) ) * SENSOR_G / 1000000 */
-	[ADXL345_RANGE_16G] = UINT32_C(321126),
-};
-
 static inline void adxl345_accel_convert_q31(q31_t *out, int16_t sample, int32_t range,
 					uint8_t is_full_res)
 {
@@ -76,15 +77,28 @@ static inline void adxl345_accel_convert_q31(q31_t *out, int16_t sample, int32_t
 			}
 			break;
 		}
+		*out = sample * qscale_factor_full_res[range];
 	} else {
 		if (sample & BIT(9)) {
 			sample |= ADXL345_COMPLEMENT;
 		}
+		*out = sample * qscale_factor_no_full_res[range];
 	}
-
-	*out = sample * qscale_factor_no_full_res[range];
 }
 
+#ifdef CONFIG_ADXL345_STREAM
+
+#define SENSOR_SCALING_FACTOR (SENSOR_G / (16 * 1000 / 100))
+
+static const uint32_t accel_period_ns[] = {
+	[ADXL345_ODR_12HZ] = UINT32_C(1000000000) / 12,
+	[ADXL345_ODR_25HZ] = UINT32_C(1000000000) / 25,
+	[ADXL345_ODR_50HZ] = UINT32_C(1000000000) / 50,
+	[ADXL345_ODR_100HZ] = UINT32_C(1000000000) / 100,
+	[ADXL345_ODR_200HZ] = UINT32_C(1000000000) / 200,
+	[ADXL345_ODR_400HZ] = UINT32_C(1000000000) / 400,
+};
+
 static int adxl345_decode_stream(const uint8_t *buffer, struct sensor_chan_spec chan_spec,
 				 uint32_t *fit, uint16_t max_count, void *data_out)
 {
@@ -208,25 +222,33 @@ static int adxl345_decode_sample(const struct adxl345_sample *data,
 				 struct sensor_chan_spec chan_spec, uint32_t *fit,
 				 uint16_t max_count, void *data_out)
 {
-	struct sensor_value *out = (struct sensor_value *)data_out;
+	struct sensor_three_axis_data *out = (struct sensor_three_axis_data *)data_out;
+
+	memset(out, 0, sizeof(struct sensor_three_axis_data));
+	out->header.base_timestamp_ns = k_ticks_to_ns_floor64(k_uptime_ticks());
+	out->header.reading_count = 1;
+	out->shift = range_to_shift[data->selected_range];
 
 	if (*fit > 0) {
 		return -ENOTSUP;
 	}
 
 	switch (chan_spec.chan_type) {
 	case SENSOR_CHAN_ACCEL_XYZ:
-		adxl345_accel_convert(out++, data->x);
-		adxl345_accel_convert(out++, data->y);
-		adxl345_accel_convert(out, data->z);
+		adxl345_accel_convert_q31(&out->readings->x, data->x, data->selected_range,
+					  data->is_full_res);
+		adxl345_accel_convert_q31(&out->readings->y, data->y, data->selected_range,
+					  data->is_full_res);
+		adxl345_accel_convert_q31(&out->readings->z, data->z, data->selected_range,
+					  data->is_full_res);
 		break;
 	default:
 		return -ENOTSUP;
 	}
 
 	*fit = 1;
 
-	return 0;
+	return 1;
 }
 
 static int adxl345_decoder_decode(const uint8_t *buffer, struct sensor_chan_spec chan_spec,

Original file line number	Diff line number	Diff line change
`@@ -281,6 +281,7 @@ int adxl345_read_sample(const struct device *dev,`
`281`	`281`	`{`
`282`	`282`	`int16_t raw_x, raw_y, raw_z;`
`283`	`283`	`uint8_t axis_data[6], status1;`
	`284`	`+ struct adxl345_dev_data *data = dev->data;`
`284`	`285`
`285`	`286`	`if (!IS_ENABLED(CONFIG_ADXL345_TRIGGER)) {`
`286`	`287`	`do {`
`@@ -303,6 +304,9 @@ int adxl345_read_sample(const struct device *dev,`
`303`	`304`	`sample->y = raw_y;`
`304`	`305`	`sample->z = raw_z;`
`305`	`306`
	`307`	`+ sample->selected_range = data->selected_range;`
	`308`	`+ sample->is_full_res = data->is_full_res;`
	`309`	`+`
`306`	`310`	`return 0;`
`307`	`311`	`}`
`308`	`312`