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iio: accel: adxl345: Add event scaling and doc fixes

PATCH Superseded Taha Ed-Dafili 4 participants 13 messages Feb 1 – Feb 7

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Documentation IIO Analog Devices IIO drivers

v2 of 6 Superseded Latest is v6 →

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Taha Ed-Dafili

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#0 lore raw

v2 cover iio: accel: adxl345: Add event scaling and doc fixes

This series addresses ADXL345 driver non-compliance with the IIO ABI for event thresholds, following feedback from Jonathan Cameron on v1.

Core Changes: During development, I noticed IIO_EV_INFO_SCALE was missing from the internal IIO core. I've added this constant to the iio_event_info enum to allow proper ABI compliance. I would appreciate a sanity check on this infrastructure change.

Testing: This series is compile-tested only, as I do not have access to physical hardware. Implementation is based on the ADXL345 datasheet.

Changes since v1:
- Added core infrastructure for IIO_EV_INFO_SCALE.
- Implemented event scaling (0.612915 m/s2) for ADXL345.
- Fixed technical math/decimal errors in existing documentation.
- Cleaned up grammar and pluralization issues in .rst file.

Many thanks to Jonathan Cameron for the detailed guidance on v1.

Taha Ed-Dafili (4):
docs: iio: adxl345: fix typos and grammar
iio: core: Add IIO_EV_INFO_SCALE to event info
iio: accel: adxl345: Implement event scaling for ABI compliance
docs: iio: adxl345: update math and examples for scaling

 Documentation/iio/adxl345.rst    | 63 +++++++++++++++++++-------------
 drivers/iio/accel/adxl345_core.c | 28 +++++++++++---
 drivers/iio/industrialio-event.c |  1 +
 include/linux/iio/types.h        |  1 +
 4 files changed, 62 insertions(+), 31 deletions(-)
Signature · 1 line
2.47.3
author
#1 lore raw

PATCH v2 1/4 docs: iio: adxl345: fix typos and grammar

Correct several grammatical errors, typos, and pluralization issues throughout the ADXL345 documentation. Key changes include:
- Changing 'generic' to 'general-purpose'
- Correcting 'axis' to 'axes' in multiple tables and descriptions
- Improving phrasing in the device attributes section
- Fixing 'latent' to 'latency' in usage examples

Signed-off-by Taha Ed-Dafili <[email protected]>
---
 Documentation/iio/adxl345.rst | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)
Documentation/iio/adxl345.rst +11 -11
index bb19d64f67c3..41d209a4dccf 100644
@@ -12,16 +12,16 @@ This driver supports Analog Device's ADXL345/375 on SPI/I2C bus.
 * `ADXL345 <https://www.analog.com/ADXL345>`_
 * `ADXL375 <https://www.analog.com/ADXL375>`_
 
-The ADXL345 is a generic purpose low power, 3-axis accelerometer with selectable
+The ADXL345 is a general-purpose, low-power, 3-axis accelerometer with selectable
 measurement ranges. The ADXL345 supports the ±2 g, ±4 g, ±8 g, and ±16 g ranges.
 
 2. Device Attributes
 ====================
 
-Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``,
+Each IIO device has a device folder under ``/sys/bus/iio/devices/iio:deviceX``,
 where X is the IIO index of the device. Under these folders reside a set of
 device files, depending on the characteristics and features of the hardware
-device in questions. These files are consistently generalized and documented in
+device in question. These files are consistently generalized and documented in
 the IIO ABI documentation.
 
 The following table shows the ADXL345 related device files, found in the

@@ -42,7 +42,7 @@ specific device folder path ``/sys/bus/iio/devices/iio:deviceX``.
 +-------------------------------------------+----------------------------------------------------------+
 | in_accel_x_raw                            | Raw X-axis accelerometer channel value.                  |
 +-------------------------------------------+----------------------------------------------------------+
-| in_accel_y_calibbias                      | y-axis acceleration offset correction                    |
+| in_accel_y_calibbias                      | Y-axis acceleration offset correction                    |
 +-------------------------------------------+----------------------------------------------------------+
 | in_accel_y_raw                            | Raw Y-axis accelerometer channel value.                  |
 +-------------------------------------------+----------------------------------------------------------+

@@ -68,7 +68,7 @@ present, simply assume its value is 0.
 +-------------------------------------+---------------------------+
 | Channel type                        | Measurement unit          |
 +-------------------------------------+---------------------------+
-| Acceleration on X, Y, and Z axis    | Meters per second squared |
+| Acceleration on X, Y, and Z axes    | Meters per second squared |
 +-------------------------------------+---------------------------+
 
 Sensor Events

@@ -78,7 +78,7 @@ Specific IIO events are triggered by their corresponding interrupts. The sensor
 driver supports either none or a single active interrupt (INT) line, selectable
 from the two available options: INT1 or INT2. The active INT line should be
 specified in the device tree. If no INT line is configured, the sensor defaults
-to FIFO bypass mode, where event detection is disabled and only X, Y, and Z axis
+to FIFO bypass mode, where event detection is disabled and only X, Y, and Z axes
 measurements are available.
 
 The table below lists the ADXL345-related device files located in the

@@ -90,11 +90,11 @@ listed.
 +---------------------------------------------+---------------------------------------------+
 | Event handle                                | Description                                 |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_gesture_doubletap_en               | Enable double tap detection on all axis     |
+| in_accel_gesture_doubletap_en               | Enable double tap detection on all axes     |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_gesture_doubletap_reset_timeout    | Double tap window in [us]                   |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_gesture_doubletap_tap2_min_delay   | Double tap latent in [us]                   |
+| in_accel_gesture_doubletap_tap2_min_delay   | Double tap latency in [us]                  |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_gesture_singletap_timeout          | Single tap duration in [us]                 |
 +---------------------------------------------+---------------------------------------------+

@@ -118,9 +118,9 @@ listed.
 +---------------------------------------------+---------------------------------------------+
 | in_accel_x_gesture_singletap_en             | Enable single tap detection on X axis       |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_x&y&z_mag_falling_en               | Enable inactivity detection on all axis     |
+| in_accel_x&y&z_mag_falling_en               | Enable inactivity detection on all axes     |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_x&y&z_mag_adaptive_falling_en      | Enable AC coupled inactivity on all axis    |
+| in_accel_x&y&z_mag_adaptive_falling_en      | Enable AC coupled inactivity on all axes    |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_y_gesture_singletap_en             | Enable single tap detection on Y axis       |
 +---------------------------------------------+---------------------------------------------+

@@ -330,7 +330,7 @@ Configure one or several events:
         ## doubletap, window [us]
         root:/sys/bus/iio/devices/iio:device0> echo 0.025 > ./events/in_accel_gesture_doubletap_reset_timeout
 
-        ## doubletap, latent [us]
+        ## doubletap, latency [us]
         root:/sys/bus/iio/devices/iio:device0> echo 0.025 > ./events/in_accel_gesture_doubletap_tap2_min_delay
 
         ## AC coupled activity, enable
Signature · 1 line
2.47.3
reviewer
#2 lore raw

Re: [PATCH v2 1/4] docs: iio: adxl345: fix typos and grammar

Hi,
I have one little nit here:

Documentation/iio/adxl345.rst Specific IIO events are triggered by their corresponding interrupts. The sensor · line 81

Quoted 6 lines · Taha Ed-Dafili
Documentation/iio/adxl345.rst +1 -1
@@ -78,7 +78,7 @@ Specific IIO events are triggered by their corresponding interrupts. The sensor
 driver supports either none or a single active interrupt (INT) line, selectable
 from the two available options: INT1 or INT2. The active INT line should be
 specified in the device tree. If no INT line is configured, the sensor defaults
-to FIFO bypass mode, where event detection is disabled and only X, Y, and Z axis
+to FIFO bypass mode, where event detection is disabled and only X, Y, and Z axes

As an adjective, I think that "axis" is still correct here.

Quoted 1 line
Documentation/iio/adxl345.rst +0 -0
 measurements are available.
Signature · 1 line
~Randy
author
#3 lore raw

Re: [PATCH v2 1/4] docs: iio: adxl345: fix typos and grammar

Thanks for the catch, Randy.

That makes sense; I'll revert that change in v3.

Best, Taha

author
#4 lore raw

PATCH v2 2/4 iio: core: Add IIO_EV_INFO_SCALE to event info

In reply to Taha Ed-Dafili

While implementing event scaling for the ADXL345 to match the IIO ABI documentation, I noticed that IIO_EV_INFO_SCALE was missing from the internal enum iio_event_info.

Add the constant and the "scale" sysfs string to allow drivers to expose these attributes correctly.

Signed-off-by Taha Ed-Dafili <[email protected]>
---
 drivers/iio/industrialio-event.c | 1 +
 include/linux/iio/types.h        | 1 +
 2 files changed, 2 insertions(+)
drivers/iio/industrialio-event.c +1 -0
index 06295cfc2da8..5096baf233f0 100644
@@ -256,6 +256,7 @@ static const char * const iio_ev_info_text[] = {
 	[IIO_EV_INFO_TAP2_MIN_DELAY] = "tap2_min_delay",
 	[IIO_EV_INFO_RUNNING_PERIOD] = "runningperiod",
 	[IIO_EV_INFO_RUNNING_COUNT] = "runningcount",
+	[IIO_EV_INFO_SCALE] = "scale",
 };
 
 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
include/linux/iio/types.h +1 -0
index 34eebad12d2c..4e3099defc1d 100644
@@ -21,6 +21,7 @@ enum iio_event_info {
 	IIO_EV_INFO_TAP2_MIN_DELAY,
 	IIO_EV_INFO_RUNNING_PERIOD,
 	IIO_EV_INFO_RUNNING_COUNT,
+	IIO_EV_INFO_SCALE,
 };
 
 #define IIO_VAL_INT 1
Signature · 1 line
2.47.3
reviewer
#5 lore raw

Re: [PATCH v2 2/4] iio: core: Add IIO_EV_INFO_SCALE to event info

Quoted 6 lines · Taha Ed-Dafili

While implementing event scaling for the ADXL345 to match the IIO ABI documentation, I noticed that IIO_EV_INFO_SCALE was missing from the internal enum iio_event_info.

Add the constant and the "scale" sysfs string to allow drivers to expose these attributes correctly.

I think this could be worded better. The enum member isn't really "missing". Are there actually any users of these attributes that have implemented it manually? Or is this something just in the docs but not actually ever used? I didn't look very hard, but I didn't find any drivers with these attributes.

Quoted 31 lines
Signed-off-by Taha Ed-Dafili <[email protected]>
---
 drivers/iio/industrialio-event.c | 1 +
 include/linux/iio/types.h        | 1 +
 2 files changed, 2 insertions(+)
drivers/iio/industrialio-event.c +1 -0
index 06295cfc2da8..5096baf233f0 100644
@@ -256,6 +256,7 @@ static const char * const iio_ev_info_text[] = {
 	[IIO_EV_INFO_TAP2_MIN_DELAY] = "tap2_min_delay",
 	[IIO_EV_INFO_RUNNING_PERIOD] = "runningperiod",
 	[IIO_EV_INFO_RUNNING_COUNT] = "runningcount",
+	[IIO_EV_INFO_SCALE] = "scale",
 };
 
 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
include/linux/iio/types.h +1 -0
index 34eebad12d2c..4e3099defc1d 100644
@@ -21,6 +21,7 @@ enum iio_event_info {
 	IIO_EV_INFO_TAP2_MIN_DELAY,
 	IIO_EV_INFO_RUNNING_PERIOD,
 	IIO_EV_INFO_RUNNING_COUNT,
+	IIO_EV_INFO_SCALE,
 };
 
 #define IIO_VAL_INT 1
author
#6 lore raw

Re: [PATCH v2 2/4] iio: core: Add IIO_EV_INFO_SCALE to event info

Hi David,

Thanks for the feedback. You're right—"missing" was poor wording; I’ll rephrase to "implement support in the core" for v3 to reflect that this is an infrastructure addition.

Regarding existing users, the current lack of IIO_EV_INFO_SCALE in the core forces developers into manual workarounds to stay ABI-compliant. For instance, in drivers/iio/accel/mma8452.c, the developer used IIO_CONST_ATTR_NAMED to create a manual in_accel_scale and linked it via .event_attrs. This approach is static and bypasses the standard event_spec infrastructure.

My goal with adding IIO_EV_INFO_SCALE is to provide a standard path to report these scales dynamically through read_event_value(), ensuring ABI compliance without manual sysfs boilerplate.

Does this core infrastructure approach seem like the right architectural path, or would you prefer I stick to a driver-level attribute for the ADXL345? Regardless of the path chosen, I will address your other comments in the next version: I'll fix the "in scale" typo and add the new scale entries to the adxl345 documentation table.

Thanks,
Taha

reviewer
#7 lore raw

Re: [PATCH v2 2/4] iio: core: Add IIO_EV_INFO_SCALE to event info

Quoted 6 lines · Taha Ed-Dafili

Hi David,

Thanks for the feedback. You're right—"missing" was poor wording; I’ll rephrase to "implement support in the core" for v3 to reflect that this is an infrastructure addition.

Quoted 6 lines

Regarding existing users, the current lack of IIO_EV_INFO_SCALE in the core forces developers into manual workarounds to stay ABI-compliant. For instance, in drivers/iio/accel/mma8452.c, the developer used IIO_CONST_ATTR_NAMED to create a manual in_accel_scale and linked it via .event_attrs. This approach is static and bypasses the standard event_spec infrastructure.

OK, so it looks like there is just one existing user of any events/*_scale attribute then. That would explain why there isn't a IIO_EV_INFO_SCALE. It just isn't very common.

Quoted 10 lines

My goal with adding IIO_EV_INFO_SCALE is to provide a standard path to report these scales dynamically through read_event_value(), ensuring ABI compliance without manual sysfs boilerplate.

Does this core infrastructure approach seem like the right architectural path, or would you prefer I stick to a driver-level attribute for the ADXL345? Regardless of the path chosen, I will address your other comments in the next version: I'll fix the "in scale" typo and add the new scale entries to the adxl345 documentation table.

If we think there will be more users of this and we want to make it more discoverable, then adding IIO_EV_INFO_SCALE seems useful.

I would wait until Jonathan weighs in with his opinion before taking action though.

Quoted 3 lines

Thanks,
Taha

maintainer
#8 lore raw

Re: [PATCH v2 2/4] iio: core: Add IIO_EV_INFO_SCALE to event info

Quoted 29 lines · On Mon, 2 Feb 2026 09:31:45 -0600 David Lechner <[email protected]> wrote:
Quoted 6 lines · Taha Ed-Dafili

Hi David,

Thanks for the feedback. You're right—"missing" was poor wording; I’ll rephrase to "implement support in the core" for v3 to reflect that this is an infrastructure addition.

Quoted 6 lines

Regarding existing users, the current lack of IIO_EV_INFO_SCALE in the core forces developers into manual workarounds to stay ABI-compliant. For instance, in drivers/iio/accel/mma8452.c, the developer used IIO_CONST_ATTR_NAMED to create a manual in_accel_scale and linked it via .event_attrs. This approach is static and bypasses the standard event_spec infrastructure.

OK, so it looks like there is just one existing user of any events/*_scale attribute then. That would explain why there isn't a IIO_EV_INFO_SCALE. It just isn't very common.

Quoted 10 lines

My goal with adding IIO_EV_INFO_SCALE is to provide a standard path to report these scales dynamically through read_event_value(), ensuring ABI compliance without manual sysfs boilerplate.

Does this core infrastructure approach seem like the right architectural path, or would you prefer I stick to a driver-level attribute for the ADXL345? Regardless of the path chosen, I will address your other comments in the next version: I'll fix the "in scale" typo and add the new scale entries to the adxl345 documentation table.

Quoted 5 lines

If we think there will be more users of this and we want to make it more discoverable, then adding IIO_EV_INFO_SCALE seems useful.

I would wait until Jonathan weighs in with his opinion before taking action though.

I agree. Makes sense to add this.

Jonathan

Quoted 5 lines
Quoted 4 lines

Thanks,
Taha

author
#9 lore raw

PATCH v2 3/4 iio: accel: adxl345: Implement event scaling for ABI compliance

In reply to Taha Ed-Dafili

The ADXL345 uses a fixed threshold resolution of 62.5 mg/LSB for event-related registers. Previously, the driver reported raw values without a scale factor.

Implement IIO_EV_INFO_SCALE for all event types to provide the conversion factor (0.612915 m/s^2) as required by the IIO ABI.

Suggested-by Jonathan Cameron <[email protected]>
Signed-off-by Taha Ed-Dafili <[email protected]>
---
 drivers/iio/accel/adxl345_core.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)
drivers/iio/accel/adxl345_core.c +22 -6
index 78e3f799ecc1..dfe3169ffc5f 100644
@@ -212,7 +212,8 @@ static const struct iio_event_spec adxl345_events[] = {
 		.type = IIO_EV_TYPE_MAG,
 		.dir = IIO_EV_DIR_RISING,
 		.mask_shared_by_type =
-			BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_ENABLE)	|
+			BIT(IIO_EV_INFO_SCALE)	|
 			BIT(IIO_EV_INFO_VALUE),
 	},
 	{

@@ -221,6 +222,7 @@ static const struct iio_event_spec adxl345_events[] = {
 		.dir = IIO_EV_DIR_RISING,
 		.mask_shared_by_type =
 			BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_SCALE)	|
 			BIT(IIO_EV_INFO_VALUE),
 	},
 	{

@@ -228,15 +230,19 @@ static const struct iio_event_spec adxl345_events[] = {
 		.type = IIO_EV_TYPE_GESTURE,
 		.dir = IIO_EV_DIR_SINGLETAP,
 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
-		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE) |
+		.mask_shared_by_type =
+			BIT(IIO_EV_INFO_VALUE)	|
+			BIT(IIO_EV_INFO_SCALE)	|
 			BIT(IIO_EV_INFO_TIMEOUT),
 	},
 	{
 		/* double tap */
 		.type = IIO_EV_TYPE_GESTURE,
 		.dir = IIO_EV_DIR_DOUBLETAP,
-		.mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE) |
-			BIT(IIO_EV_INFO_RESET_TIMEOUT) |
+		.mask_shared_by_type =
+			BIT(IIO_EV_INFO_ENABLE)		|
+			BIT(IIO_EV_INFO_RESET_TIMEOUT)	|
+			BIT(IIO_EV_INFO_SCALE)		|
 			BIT(IIO_EV_INFO_TAP2_MIN_DELAY),
 	},
 };

@@ -274,7 +280,8 @@ static const struct iio_event_spec adxl345_fake_chan_events[] = {
 		.dir = IIO_EV_DIR_FALLING,
 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
 		.mask_shared_by_type =
-			BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_VALUE)	|
+			BIT(IIO_EV_INFO_SCALE)	|
 			BIT(IIO_EV_INFO_PERIOD),
 	},
 	{

@@ -283,7 +290,8 @@ static const struct iio_event_spec adxl345_fake_chan_events[] = {
 		.dir = IIO_EV_DIR_FALLING,
 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
 		.mask_shared_by_type =
-			BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_VALUE)	|
+			BIT(IIO_EV_INFO_SCALE)	|
 			BIT(IIO_EV_INFO_PERIOD),
 	},
 };

@@ -1367,6 +1375,14 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
 				return ret;
 			*val = sign_extend32(tap_threshold, 7);
 			return IIO_VAL_INT;
+		case IIO_EV_INFO_SCALE:
+			/*
+			 * The event threshold LSB is fixed at 62.5 mg/LSB
+			 * 0.0625 * 9.80665 = 0.612915625 m/s^2
+			 */
+			*val = 0;
+			*val2 = 612915;
+			return IIO_VAL_INT_PLUS_MICRO;
 		case IIO_EV_INFO_TIMEOUT:
 			*val = st->tap_duration_us;
 			*val2 = MICRO;
Signature · 1 line
2.47.3
author
#10 lore raw

PATCH v2 4/4 docs: iio: adxl345: update math and examples for scaling

In reply to Taha Ed-Dafili

Update the documentation to reflect the addition of event scaling and correct existing technical errors inscale values.

key changes:
- Fix the 62.5 g/LSB typo to 62.5 mg/LSB and add SI unit conversion.
- Correct decimal precision of in_accel_scale and in_accel_scale_available to match actual SI unit (m/s^2) values reported by the driver.
- Add sysfs example showing how to read and interpret the newly implemented event scale factor.

Suggested-by Jonathan Cameron <[email protected]>
Signed-off-by Taha Ed-Dafili <[email protected]>
---
 Documentation/iio/adxl345.rst | 41 +++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 14 deletions(-)
Documentation/iio/adxl345.rst +27 -14
index 41d209a4dccf..2f51a2a4fbd0 100644
@@ -13,7 +13,11 @@ This driver supports Analog Device's ADXL345/375 on SPI/I2C bus.
 * `ADXL375 <https://www.analog.com/ADXL375>`_
 
 The ADXL345 is a general-purpose, low-power, 3-axis accelerometer with selectable
-measurement ranges. The ADXL345 supports the ±2 g, ±4 g, ±8 g, and ±16 g ranges.
+measurement ranges. The ADXL345 supports the following ranges:
+- ±2g  (approx. ±19.61 m/s^2)
+- ±4g  (approx. ±39.23 m/s^2)
+- ±8g  (approx. ±78.45 m/s^2)
+- ±16g (approx. ±156.91 m/s^2)
 
 2. Device Attributes
 ====================

@@ -98,23 +102,28 @@ listed.
 +---------------------------------------------+---------------------------------------------+
 | in_accel_gesture_singletap_timeout          | Single tap duration in [us]                 |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_gesture_singletap_value            | Single tap threshold value in 62.5/LSB      |
+| in_accel_gesture_singletap_value            | Single tap threshold value in               |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_falling_period                 | Inactivity time in seconds                  |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_falling_value                  | Inactivity threshold value in 62.5/LSB      |
+| in_accel_mag_falling_value                  | Inactivity threshold value in               |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_adaptive_rising_en             | Enable AC coupled activity on X axis        |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_adaptive_falling_period        | AC coupled inactivity time in seconds       |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_adaptive_falling_value         | AC coupled inactivity threshold in 62.5/LSB |
+| in_accel_mag_adaptive_falling_value         | AC coupled inactivity threshold in          |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_adaptive_rising_value          | AC coupled activity threshold in 62.5/LSB   |
+| in_accel_mag_adaptive_rising_value          | AC coupled activity threshold in            |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_rising_en                      | Enable activity detection on X axis         |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_rising_value                   | Activity threshold value in 62.5/LSB        |
+| in_accel_mag_rising_value                   | Activity threshold value in                 |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_x_gesture_singletap_en             | Enable single tap detection on X axis       |
 +---------------------------------------------+---------------------------------------------+

@@ -140,8 +149,8 @@ When changing the **g range** configuration, the driver attempts to estimate
 appropriate activity and inactivity thresholds by scaling the default values
 based on the ratio of the previous range to the new one. The resulting threshold
 will never be zero and will always fall between 1 and 255, corresponding to up
-to 62.5 g/LSB as specified in the datasheet. However, you can override these
-estimated thresholds by setting explicit values.
+to 62.5 mg/LSB (0.612915 m/s^2/LSB) as specified in the datasheet. However,
+you can override these estimated thresholds by setting explicit values.
 
 When **activity** and **inactivity** events are enabled, the driver
 automatically manages hysteresis behavior by setting the **link** and

@@ -270,13 +279,13 @@ Scale range configuration:
 .. code-block:: bash
 
         root:/sys/bus/iio/devices/iio:device0> cat ./in_accel_scale
-        0.478899
+        0.004789
         root:/sys/bus/iio/devices/iio:device0> cat ./in_accel_scale_available
-        0.478899 0.957798 1.915595 3.831190
+        0.004789 0.009578 0.019156 0.038312
 
-        root:/sys/bus/iio/devices/iio:device0> echo 1.915595 > ./in_accel_scale
+        root:/sys/bus/iio/devices/iio:device0> echo 0.019156 > ./in_accel_scale
         root:/sys/bus/iio/devices/iio:device0> cat ./in_accel_scale
-        1.915595
+        0.019156
 
 Set output data rate (ODR):
 

@@ -312,10 +321,14 @@ Configure one or several events:
 
         root:/sys/bus/iio/devices/iio:device0> echo 24 > ./buffer0/length
 
-        ## AC coupled activity, threshold [62.5/LSB]
+        ## Check the event scale factor (0.0625 * 9.80665)
+        root:/sys/bus/iio/devices/iio:device0> cat ./events/in_accel_gesture_scale
+        0.612915
+
+        ## AC coupled activity, threshold [0.612915 m/s^2/LSB]
         root:/sys/bus/iio/devices/iio:device0> echo 6 > ./events/in_accel_mag_adaptive_rising_value
 
-        ## AC coupled inactivity, threshold, [62.5/LSB]
+        ## AC coupled inactivity, threshold, [0.612915 m/s^2/LSB]
         root:/sys/bus/iio/devices/iio:device0> echo 4 > ./events/in_accel_mag_adaptive_falling_value
 
         ## AC coupled inactivity, time [s]
Signature · 1 line
2.47.3
reviewer
#11 lore raw

Re: [PATCH v2 4/4] docs: iio: adxl345: update math and examples for scaling

Quoted 2 lines · Taha Ed-Dafili

Update the documentation to reflect the addition of event scaling and correct existing technical errors inscale values.

s/inscale/in scale/

Quoted 56 lines

key changes:
- Fix the 62.5 g/LSB typo to 62.5 mg/LSB and add SI unit conversion.
- Correct decimal precision of in_accel_scale and in_accel_scale_available to match actual SI unit (m/s^2) values reported by the driver.
- Add sysfs example showing how to read and interpret the newly implemented event scale factor.

Suggested-by Jonathan Cameron <[email protected]>
Signed-off-by Taha Ed-Dafili <[email protected]>
---
 Documentation/iio/adxl345.rst | 41 +++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 14 deletions(-)
Documentation/iio/adxl345.rst +12 -5
index 41d209a4dccf..2f51a2a4fbd0 100644
@@ -13,7 +13,11 @@ This driver supports Analog Device's ADXL345/375 on SPI/I2C bus.
 * `ADXL375 <https://www.analog.com/ADXL375>`_
 
 The ADXL345 is a general-purpose, low-power, 3-axis accelerometer with selectable
-measurement ranges. The ADXL345 supports the ±2 g, ±4 g, ±8 g, and ±16 g ranges.
+measurement ranges. The ADXL345 supports the following ranges:
+- ±2g  (approx. ±19.61 m/s^2)
+- ±4g  (approx. ±39.23 m/s^2)
+- ±8g  (approx. ±78.45 m/s^2)
+- ±16g (approx. ±156.91 m/s^2)
 
 2. Device Attributes
 ====================

@@ -98,23 +102,28 @@ listed.
 +---------------------------------------------+---------------------------------------------+
 | in_accel_gesture_singletap_timeout          | Single tap duration in [us]                 |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_gesture_singletap_value            | Single tap threshold value in 62.5/LSB      |
+| in_accel_gesture_singletap_value            | Single tap threshold value in               |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_falling_period                 | Inactivity time in seconds                  |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_falling_value                  | Inactivity threshold value in 62.5/LSB      |
+| in_accel_mag_falling_value                  | Inactivity threshold value in               |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_adaptive_rising_en             | Enable AC coupled activity on X axis        |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_adaptive_falling_period        | AC coupled inactivity time in seconds       |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_adaptive_falling_value         | AC coupled inactivity threshold in 62.5/LSB |
+| in_accel_mag_adaptive_falling_value         | AC coupled inactivity threshold in          |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_adaptive_rising_value          | AC coupled activity threshold in 62.5/LSB   |
+| in_accel_mag_adaptive_rising_value          | AC coupled activity threshold in            |

Documentation/iio/adxl345.rst listed. · line 129

Quoted 10 lines
Documentation/iio/adxl345.rst +3 -1
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_mag_rising_en                      | Enable activity detection on X axis         |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_rising_value                   | Activity threshold value in 62.5/LSB        |
+| in_accel_mag_rising_value                   | Activity threshold value in                 |
+|                                             | 0.612915 m/s^2/LSB                          |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_x_gesture_singletap_en             | Enable single tap detection on X axis       |
 +---------------------------------------------+---------------------------------------------+

Why not also adding the new in_accel_*_scale attributes to the table?

maintainer
#12 lore raw

Re: [PATCH v2 4/4] docs: iio: adxl345: update math and examples for scaling

In reply to Taha Ed-Dafili
Quoted 2 lines · On Sun, 1 Feb 2026 13:33:13 -0500 Taha Ed-Dafili <[email protected]> wrote:

Update the documentation to reflect the addition of event scaling and correct existing technical errors inscale values.

Trivial but please wrap commit messages to 75 chars.

Quoted 11 lines

key changes:
- Fix the 62.5 g/LSB typo to 62.5 mg/LSB and add SI unit conversion.
- Correct decimal precision of in_accel_scale and in_accel_scale_available to match actual SI unit (m/s^2) values reported by the driver.
- Add sysfs example showing how to read and interpret the newly implemented event scale factor.

Suggested-by Jonathan Cameron <[email protected]>
Signed-off-by Taha Ed-Dafili <[email protected]>

As David suggested, better to just document the scale attribute and not add it to all the others.

Jonathan