[PATCH v4 0/4] iio: accel: adxl345: Implement event scaling and ABI compliance

[PATCH v4 0/4] iio: accel: adxl345: Implement event scaling and ABI compliance

[Taha Ed-Dafili]

This series addresses ADXL345 driver non-compliance with the IIO ABI for
event thresholds.

Currently, the driver exposes raw values for thresholds
(e.g., tap, activity) without providing the necessary scale factor to
convert them to SI units (m/s^2), as mandated by the ABI.

This series implements `IIO_EV_INFO_SCALE` in the IIO core and applies it
to the ADXL345 driver, ensuring that userspace can correctly interpret
threshold values. It also cleans up existing documentation errors and
typos.

Changes in v4:
- Patch 3: Fix missing IIO_EV_INFO_SCALE handling for MAG/MAG_ADAPTIVE
  events by moving the check to the top of adxl345_read_event_value().
- Patch 3: Explicitly reject writes to IIO_EV_INFO_SCALE with -EINVAL.
- Patch 3: Fix bitmask ordering and whitespace alignment in event spec
  arrays.
- Patch 4: Update documentation table with the exact sysfs scale
  attributes generated by the IIO core.
- Patch 4: Sort the entire event attribute table alphabetically
  (David Lechner).

Changes in v3:
- Patch 1: Revert "axis" to "axes" in documentation.
- Patch 2: Reword commit message to "Implement support for".
- Patch 4: Remove repetitive scale values from every table row.
- Patch 4: Fix typo in commit message.

Changes in v2:
- Add core infrastructure for IIO_EV_INFO_SCALE.
- Implement event scaling (0.612915 m/s^2) for ADXL345.
- Fix technical math and decimal errors in documentation.
- Clean up grammar and pluralization in .rst file.

I would like to thank Jonathan Cameron for catching the missing MAG scale
handling via static analysis, David Lechner for the alphabetical and
bitmask ordering feedback, and Andy Shevchenko and Randy Dunlap for
catching the whitespace inconsistencies.

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    | 79 ++++++++++++++++++++------------
 drivers/iio/accel/adxl345_core.c | 37 ++++++++++-----
 drivers/iio/industrialio-event.c |  1 +
 include/linux/iio/types.h        |  1 +
 4 files changed, 78 insertions(+), 40 deletions(-)

-- 
2.47.3

[PATCH v4 1/4] docs: iio: adxl345: fix typos and grammar

[Taha Ed-Dafili]

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 <0rayn.dev@gmail.com>
---
 Documentation/iio/adxl345.rst | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/iio/adxl345.rst b/Documentation/iio/adxl345.rst
index bb19d64f67c3..3ca6a78feb5b 100644
--- a/Documentation/iio/adxl345.rst
+++ b/Documentation/iio/adxl345.rst
@@ -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
@@ -78,8 +78,8 @@ 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
-measurements are available.
+to FIFO bypass mode, where event detection is disabled and only individual
+X, Y, and Z axis measurements are available.
 
 The table below lists the ADXL345-related device files located in the
 device-specific path: ``/sys/bus/iio/devices/iio:deviceX/events``.
@@ -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
-- 
2.47.3

[PATCH v4 2/4] iio: core: Add IIO_EV_INFO_SCALE to event info

[Taha Ed-Dafili]

Implement support for IIO_EV_INFO_SCALE in the internal enum
iio_event_info to allow proper ABI compliance.

This allows drivers (like the ADXL345) to expose event scale
attributes using the standard IIO ABI rather than manual
device attributes.

Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
---
 drivers/iio/industrialio-event.c | 1 +
 include/linux/iio/types.h        | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
index 06295cfc2da8..5096baf233f0 100644
--- a/drivers/iio/industrialio-event.c
+++ b/drivers/iio/industrialio-event.c
@@ -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)
diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
index 34eebad12d2c..4e3099defc1d 100644
--- a/include/linux/iio/types.h
+++ b/include/linux/iio/types.h
@@ -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
-- 
2.47.3

[PATCH v4 3/4] iio: accel: adxl345: Implement event scaling for ABI compliance

[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.

Consequently, remove the obsolete comment in adxl345_read_event_value()
which stated that the scale factor is not applied.

Add explicit write rejection for IIO_EV_INFO_SCALE in
adxl345_write_event_value() returning -EINVAL.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 37 ++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 78e3f799ecc1..eac4ab052fa2 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -213,7 +213,8 @@ 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_VALUE),
+			BIT(IIO_EV_INFO_VALUE)	|
+			BIT(IIO_EV_INFO_SCALE),
 	},
 	{
 		/* activity, ac bit set */
@@ -221,22 +222,27 @@ 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_VALUE),
+			BIT(IIO_EV_INFO_VALUE)	|
+			BIT(IIO_EV_INFO_SCALE),
 	},
 	{
 		/* single tap */
 		.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_SCALE)		|
+			BIT(IIO_EV_INFO_RESET_TIMEOUT)  |
 			BIT(IIO_EV_INFO_TAP2_MIN_DELAY),
 	},
 };
@@ -275,6 +281,7 @@ static const struct iio_event_spec adxl345_fake_chan_events[] = {
 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
 		.mask_shared_by_type =
 			BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_SCALE) |
 			BIT(IIO_EV_INFO_PERIOD),
 	},
 	{
@@ -284,6 +291,7 @@ static const struct iio_event_spec adxl345_fake_chan_events[] = {
 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
 		.mask_shared_by_type =
 			BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_SCALE) |
 			BIT(IIO_EV_INFO_PERIOD),
 	},
 };
@@ -1341,6 +1349,16 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
 	unsigned int tap_threshold;
 	int ret;
 
+	/*
+	 * The event threshold LSB is fixed at 62.5 mg/LSB
+	 * 0.0625 * 9.80665 = 0.612915625 m/s^2
+	 */
+	if (info == IIO_EV_INFO_SCALE) {
+		*val = 0;
+		*val2 = 612915;
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+
 	switch (type) {
 	case IIO_EV_TYPE_MAG:
 		return adxl345_read_mag_value(st, dir, info,
@@ -1355,12 +1373,6 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
 	case IIO_EV_TYPE_GESTURE:
 		switch (info) {
 		case IIO_EV_INFO_VALUE:
-			/*
-			 * The scale factor would be 62.5mg/LSB (i.e. 0xFF = 16g) but
-			 * not applied here. In context of this general purpose sensor,
-			 * what imports is rather signal intensity than the absolute
-			 * measured g value.
-			 */
 			ret = regmap_read(st->regmap, ADXL345_REG_THRESH_TAP,
 					  &tap_threshold);
 			if (ret)
@@ -1401,6 +1413,9 @@ static int adxl345_write_event_value(struct iio_dev *indio_dev,
 	if (ret)
 		return ret;
 
+	if (info == IIO_EV_INFO_SCALE)
+		return -EINVAL;
+
 	switch (type) {
 	case IIO_EV_TYPE_MAG:
 		ret = adxl345_write_mag_value(st, dir, info,
-- 
2.47.3

[PATCH v4 4/4] docs: iio: adxl345: update math and examples for scaling

[Taha Ed-Dafili]

Update the documentation to reflect the addition of event scaling
and correct existing technical errors in scale 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 the actual SI unit (m/s^2)
  values reported by the driver.
- Document the newly generated event scale attributes in the ABI table
  (e.g., in_accel_mag_rising_scale, in_accel_gesture_singletap_scale).
- Also sorted the existing table entries alphabetically as suggested
  by David Lechner.
- Add a sysfs example showing how to read and interpret the newly
  implemented event scale factor.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
---
 Documentation/iio/adxl345.rst | 57 ++++++++++++++++++++++++-----------
 1 file changed, 39 insertions(+), 18 deletions(-)

diff --git a/Documentation/iio/adxl345.rst b/Documentation/iio/adxl345.rst
index 3ca6a78feb5b..e830430e4870 100644
--- a/Documentation/iio/adxl345.rst
+++ b/Documentation/iio/adxl345.rst
@@ -13,7 +13,12 @@ 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
 ====================
@@ -94,33 +99,45 @@ listed.
 +---------------------------------------------+---------------------------------------------+
 | in_accel_gesture_doubletap_reset_timeout    | Double tap window in [us]                   |
 +---------------------------------------------+---------------------------------------------+
+| in_accel_gesture_doubletap_scale            | Double tap gesture threshold scale.         |
++---------------------------------------------+---------------------------------------------+
 | in_accel_gesture_doubletap_tap2_min_delay   | Double tap latency in [us]                  |
 +---------------------------------------------+---------------------------------------------+
+| in_accel_gesture_singletap_scale            | Single tap gesture threshold scale.         |
++---------------------------------------------+---------------------------------------------+
 | 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_accel_mag_falling_period                 | Inactivity time in seconds                  |
+| in_accel_mag_adaptive_falling_period        | AC coupled inactivity time in seconds       |
++---------------------------------------------+---------------------------------------------+
+| in_accel_mag_adaptive_falling_scale         | AC coupled inactivity threshold scale.      |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_falling_value                  | Inactivity threshold value in 62.5/LSB      |
+| in_accel_mag_adaptive_falling_value         | AC coupled inactivity threshold             |
 +---------------------------------------------+---------------------------------------------+
 | 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_rising_scale          | AC coupled activity threshold scale.        |
++---------------------------------------------+---------------------------------------------+
+| in_accel_mag_adaptive_rising_value          | AC coupled activity threshold               |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_adaptive_falling_value         | AC coupled inactivity threshold in 62.5/LSB |
+| in_accel_mag_falling_period                 | Inactivity time in seconds                  |
++---------------------------------------------+---------------------------------------------+
+| in_accel_mag_falling_scale                  | DC coupled inactivity threshold scale.      |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_mag_adaptive_rising_value          | AC coupled activity threshold in 62.5/LSB   |
+| in_accel_mag_falling_value                  | Inactivity threshold value                  |
 +---------------------------------------------+---------------------------------------------+
 | 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_scale                   | DC coupled activity threshold scale.        |
 +---------------------------------------------+---------------------------------------------+
-| in_accel_x_gesture_singletap_en             | Enable single tap detection on X axis       |
+| in_accel_mag_rising_value                   | Activity threshold value                    |
++---------------------------------------------+---------------------------------------------+
+| in_accel_x&y&z_mag_adaptive_falling_en      | Enable AC coupled inactivity on all axes    |
 +---------------------------------------------+---------------------------------------------+
 | 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 axes    |
+| in_accel_x_gesture_singletap_en             | Enable single tap detection on X axis       |
 +---------------------------------------------+---------------------------------------------+
 | in_accel_y_gesture_singletap_en             | Enable single tap detection on Y axis       |
 +---------------------------------------------+---------------------------------------------+
@@ -140,8 +157,8 @@ 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 +287,13 @@ 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 +329,14 @@ 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_doubletap_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]
-- 
2.47.3

Re: [PATCH v4 3/4] iio: accel: adxl345: Implement event scaling for ABI compliance

[David Lechner]

On 2/21/26 8:12 AM, Taha Ed-Dafili wrote:
> 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.
> 
> Consequently, remove the obsolete comment in adxl345_read_event_value()
> which stated that the scale factor is not applied.
> 
> Add explicit write rejection for IIO_EV_INFO_SCALE in
> adxl345_write_event_value() returning -EINVAL.
> 
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
> ---
>  drivers/iio/accel/adxl345_core.c | 37 ++++++++++++++++++++++----------
>  1 file changed, 26 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
> index 78e3f799ecc1..eac4ab052fa2 100644
> --- a/drivers/iio/accel/adxl345_core.c
> +++ b/drivers/iio/accel/adxl345_core.c
> @@ -213,7 +213,8 @@ 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_VALUE),
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE),
>  	},
>  	{
>  		/* activity, ac bit set */
> @@ -221,22 +222,27 @@ 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_VALUE),
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE),
>  	},
>  	{
>  		/* single tap */
>  		.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_SCALE)		|

I still question this one. Why do we have a IIO_EV_INFO_SCALE with no
IIO_EV_INFO_VALUE?

The docs say:

| in_accel_gesture_doubletap_scale | Double tap gesture threshold scale. |

But there is no attribute labeled "Double tap gesture threshold" that it
could be referring to.


> +			BIT(IIO_EV_INFO_RESET_TIMEOUT)  |
>  			BIT(IIO_EV_INFO_TAP2_MIN_DELAY),
>  	},
>  };ret = adxl345_write_mag_value(st, dir, info,

Re: [PATCH v4 4/4] docs: iio: adxl345: update math and examples for scaling

[David Lechner]

On 2/21/26 8:12 AM, Taha Ed-Dafili wrote:
> Update the documentation to reflect the addition of event scaling
> and correct existing technical errors in scale 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 the actual SI unit (m/s^2)
>   values reported by the driver.
> - Document the newly generated event scale attributes in the ABI table
>   (e.g., in_accel_mag_rising_scale, in_accel_gesture_singletap_scale).
> - Also sorted the existing table entries alphabetically as suggested
>   by David Lechner.

If we do a v5, it would be nice to do the sorting in PATCH 1/4 since
we are already doing tidying there. It would make it easier to see the
actual changes here.

> - Add a sysfs example showing how to read and interpret the newly
>   implemented event scale factor.
> 

Re: [PATCH v4 3/4] iio: accel: adxl345: Implement event scaling for ABI compliance

[Taha Ed-Dafili]

I did go over the datasheet and found the hardware uses a single
register for both tap thresholds, so I assume the VALUE was intentionally
omitted from DOUBLETAP to avoid duplicate sysfs attributes.

I mechanically added the scale attribute without realizing this. I will
drop BIT(IIO_EV_INFO_SCALE) for double tap and update the docs in v5.

I'll wait a couple of days for any other feedback before sending the
next version.

Re: [PATCH v4 3/4] iio: accel: adxl345: Implement event scaling for ABI compliance

[Jonathan Cameron]

On Sat, 21 Feb 2026 17:21:23 +0000
Taha Ed-Dafili <0rayn.dev@gmail.com> wrote:

> I did go over the datasheet and found the hardware uses a single
> register for both tap thresholds, so I assume the VALUE was intentionally
> omitted from DOUBLETAP to avoid duplicate sysfs attributes.
> 
> I mechanically added the scale attribute without realizing this. I will
> drop BIT(IIO_EV_INFO_SCALE) for double tap and update the docs in v5.

If the underlying register applies to two different events and it's not
possible to combine them using shared_by_ (which I don't think it is here)
then we should have attributes for both of them.

The IIO ABI always allows any write to any channel property including event
thresholds to change the value of a different one, so there is never a problem
with duplication like this

thanks,

Jonathan

> 
> I'll wait a couple of days for any other feedback before sending the
> next version.