[v5 00/14] Add support for Bosch BNO055 IMU

[v5 00/14] Add support for Bosch BNO055 IMU

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

This series (tries to) add support for Bosch BNO055 IMU to Linux IIO
subsystem. It is made up several patches:

  1/14 to 6/14: add some IIO modifiers, and their documentation, to the IIO
                core layer, in order to being able to expose the linear
                acceleration and Euler angles among standard attributes.
                Also update the IIO event monitor tool

  7/14: fix binary attributes didn't work with IIO

  8/14 to 11/14: add the core IIO BNO055 driver and documentation for sysfs
                 attributes and DT bindings

  12/14: adds serdev BNO055 driver to actually use the IMU via serial line

  13/14: adds I2C BNO055 driver to actually use the IMU via I2C wiring

  14/14: add a documentation file that describe the bno055 driver and
         specifically the calibration

Differences wrt v4:
- be more tolerant wrt unrecognized chip IDs
- rename 'serial_number' attribute in 'serialnumber'
- fix missing NULL variable initialization
- use sign_extend32() instead of s16 casting where appropriate
- fix quaternion unit
- minor stuff (e.g. comments..)
- reduce (slightly) locking in serdev driver
- rework tracepoint support (e.g. remove dedicated config option)

Differences wrt other BNO055 drivers:

  Previously at least another driver for the very same chip has been posted
  to the Linux ML [0], but it has been never merged, and it seems no one
  cared of it since quite a long time.

  This driver differs from the above driver on the following aspects:

  - This driver supports also serial access (to be reliable, reset pin is
    required to be wired)

  - The above driver tried to support all IMU HW modes by allowing to
    choose one in the DT, and adapting IIO attributes accordingly. This
    driver does not rely on DT for this, instead settings are done via
    sysfs attributes.  All IIO attributes are always exposed; more on this
    later on. This driver however supports only a subset of the
    HW-supported modes.

  - This driver has some support for managing the IMU calibration

Supported operation modes:

  - AMG (accelerometer, magnetometer and gyroscope) mode, which provides
    raw (uncalibrated) measurements from the said sensors, and allows for
    setting some parameters about them (e.g. filter cut-off frequency, max
    sensor ranges, etc).

  - Fusion mode, which still provides AMG measures, while it also provides
    other data calculated by the IMU (e.g. rotation angles, linear
    acceleration, etc). In this mode user has no freedom to set any sensor
    parameter, since the HW locks them. Autocalibration and correction is
    performed by the IMU.

  IIO attributes exposing sensors parameters are always present, but in
  fusion modes the available values are constrained to just the one used by
  the HW. This is reflected in the '*_available' IIO attributes.

  Trying to set a not-supported value always falls back to the closest
  supported one, which in this case is just the one in use by the HW.

  IIO attributes for unavailable measurements (e.g. Euler angles in AMG
  mode) can't be read (return -EBUSY, or refuse to enable buffer).

IMU calibration:

  The IMU supports for two sets of calibration parameters:

  - SIC matrix. user-provided; this driver doesn't currently support it

  - Offset and radius parameters. The IMU automatically finds out them when
    it is running in fusion mode; supported by this driver.

  The driver provides access to autocalibration flags (i.e. you can known
  if the IMU has successfully autocalibrated) and to calibration data blob.
  The user can save this blob in a "firmware" file (i.e. in /lib/firmware)
  that the driver looks for at probe time. If found, then the IMU is
  initialized with this calibration data. This saves the user from
  performing the calibration procedure every time (which consist of moving
  the IMU in various way).

  The driver looks for calibration data file using two different names:
  first a file whose name is suffixed with the IMU unique ID is searched
  for; this is useful when there is more than one IMU instance. If this
  file is not found, then a "generic" calibration file is searched for
  (which can be used when only one IMU is present, without struggling with
  fancy names, that changes on each device).

  In AMG mode the IIO 'offset' attributes provide access to the offsets
  from calibration data (if any), so that the user can apply them to the
  accel, angvel and magn IIO attributes. In fusion mode they are not needed
  and read as zero.


Access protocols and serdev module:

  The serial protocol is quite simple, but there are tricks to make it
  really works. Those tricks and workarounds are documented in the driver
  source file.

  The core BNO055 driver tries to group readings in burst when appropriate,
  in order to optimize triggered buffer operation. The threshold for
  splitting a burst (i.e. max number of unused bytes in the middle of a
  burst that will be throw away) is provided to the core driver by the
  lowlevel access driver (either serdev or I2C) at probe time.

[0] https://www.spinics.net/lists/linux-iio/msg25508.html

Andrea Merello (14):
  iio: add modifiers for linear acceleration
  iio: document linear acceleration modifiers
  iio: event_monitor: add linear acceleration modifiers
  iio: add modifers for pitch, yaw, roll
  iio: document pitch, yaw, roll modifiers
  iio: event_monitor: add pitch, yaw and roll modifiers
  iio: add support for binary attributes
  iio: imu: add Bosch Sensortec BNO055 core driver
  iio: document bno055 private sysfs attributes
  iio: document "serialnumber" sysfs attribute
  dt-bindings: iio/imu: Add Bosch BNO055
  iio: imu: add BNO055 serdev driver
  iio: imu: add BNO055 I2C driver
  docs: iio: add documentation for BNO055 driver

 Documentation/ABI/testing/sysfs-bus-iio       |   25 +
 .../ABI/testing/sysfs-bus-iio-bno055          |   81 +
 .../bindings/iio/imu/bosch,bno055.yaml        |   59 +
 Documentation/iio/bno055.rst                  |   50 +
 Documentation/iio/index.rst                   |    2 +
 drivers/iio/imu/Kconfig                       |    1 +
 drivers/iio/imu/Makefile                      |    1 +
 drivers/iio/imu/bno055/Kconfig                |   25 +
 drivers/iio/imu/bno055/Makefile               |   10 +
 drivers/iio/imu/bno055/bno055.c               | 1710 +++++++++++++++++
 drivers/iio/imu/bno055/bno055.h               |   12 +
 drivers/iio/imu/bno055/bno055_i2c.c           |   57 +
 drivers/iio/imu/bno055/bno055_ser_core.c      |  560 ++++++
 drivers/iio/imu/bno055/bno055_ser_trace.h     |  104 +
 drivers/iio/industrialio-core.c               |   10 +-
 include/uapi/linux/iio/types.h                |    7 +-
 tools/iio/iio_event_monitor.c                 |    6 +
 17 files changed, 2718 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-bno055
 create mode 100644 Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml
 create mode 100644 Documentation/iio/bno055.rst
 create mode 100644 drivers/iio/imu/bno055/Kconfig
 create mode 100644 drivers/iio/imu/bno055/Makefile
 create mode 100644 drivers/iio/imu/bno055/bno055.c
 create mode 100644 drivers/iio/imu/bno055/bno055.h
 create mode 100644 drivers/iio/imu/bno055/bno055_i2c.c
 create mode 100644 drivers/iio/imu/bno055/bno055_ser_core.c
 create mode 100644 drivers/iio/imu/bno055/bno055_ser_trace.h

--
2.17.1

[v5 01/14] iio: add modifiers for linear acceleration

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add IIO_MOD_LINEAR_X, IIO_MOD_LINEAR_Y and IIO_MOD_LINEAR_Z modifiers to te
IIO core, which is preparatory for adding the Bosch BNO055 IMU driver.

Bosch BNO055 IMU can report raw accelerations (among x, y and z axis) as
well as the so called "linear accelerations" (again, among x, y and z axis)
which is basically the acceleration after subtracting gravity and for which
those new modifiers are for.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 drivers/iio/industrialio-core.c | 3 +++
 include/uapi/linux/iio/types.h  | 4 +++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 2f48e9a97274..d087b2607cc9 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -134,6 +134,9 @@ static const char * const iio_modifier_names[] = {
 	[IIO_MOD_ETHANOL] = "ethanol",
 	[IIO_MOD_H2] = "h2",
 	[IIO_MOD_O2] = "o2",
+	[IIO_MOD_LINEAR_X] = "linear_x",
+	[IIO_MOD_LINEAR_Y] = "linear_y",
+	[IIO_MOD_LINEAR_Z] = "linear_z",
 };
 
 /* relies on pairs of these shared then separate */
diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
index 472cead10d8d..0993f6b697fc 100644
--- a/include/uapi/linux/iio/types.h
+++ b/include/uapi/linux/iio/types.h
@@ -95,6 +95,9 @@ enum iio_modifier {
 	IIO_MOD_ETHANOL,
 	IIO_MOD_H2,
 	IIO_MOD_O2,
+	IIO_MOD_LINEAR_X,
+	IIO_MOD_LINEAR_Y,
+	IIO_MOD_LINEAR_Z,
 };
 
 enum iio_event_type {
@@ -115,4 +118,3 @@ enum iio_event_direction {
 };
 
 #endif /* _UAPI_IIO_TYPES_H_ */
-
-- 
2.17.1

[v5 02/14] iio: document linear acceleration modifiers

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Introduce ABI documentation for new IIO modifiers used for reporting
"linear acceleration" measures.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 Documentation/ABI/testing/sysfs-bus-iio | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index d4ccc68fdcf0..aadddd43bf22 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -233,6 +233,15 @@ Description:
 		Has all of the equivalent parameters as per voltageY. Units
 		after application of scale and offset are m/s^2.
 
+What:		/sys/bus/iio/devices/iio:deviceX/in_accel_linear_x_raw
+What:		/sys/bus/iio/devices/iio:deviceX/in_accel_linear_y_raw
+What:		/sys/bus/iio/devices/iio:deviceX/in_accel_linear_z_raw
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		As per in_accel_X_raw attributes, but minus the
+		acceleration due to gravity.
+
 What:		/sys/bus/iio/devices/iio:deviceX/in_gravity_x_raw
 What:		/sys/bus/iio/devices/iio:deviceX/in_gravity_y_raw
 What:		/sys/bus/iio/devices/iio:deviceX/in_gravity_z_raw
-- 
2.17.1

[v5 03/14] iio: event_monitor: add linear acceleration modifiers

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Following the introduction of IIO linear acceleration modifiers, update the
event_monitor tool accordingly.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 tools/iio/iio_event_monitor.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/iio/iio_event_monitor.c b/tools/iio/iio_event_monitor.c
index 2f4581658859..1fee44abb836 100644
--- a/tools/iio/iio_event_monitor.c
+++ b/tools/iio/iio_event_monitor.c
@@ -122,6 +122,9 @@ static const char * const iio_modifier_names[] = {
 	[IIO_MOD_PM4] = "pm4",
 	[IIO_MOD_PM10] = "pm10",
 	[IIO_MOD_O2] = "o2",
+	[IIO_MOD_LINEAR_X] = "linear_x",
+	[IIO_MOD_LINEAR_Y] = "linear_y",
+	[IIO_MOD_LINEAR_Z] = "linear_z",
 };
 
 static bool event_is_known(struct iio_event_data *event)
-- 
2.17.1

[v5 04/14] iio: add modifers for pitch, yaw, roll

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add modifiers for reporting rotations as euler angles (i.e. yaw, pitch and
roll).

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 drivers/iio/industrialio-core.c | 3 +++
 include/uapi/linux/iio/types.h  | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index d087b2607cc9..aa5f98d3b334 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -137,6 +137,9 @@ static const char * const iio_modifier_names[] = {
 	[IIO_MOD_LINEAR_X] = "linear_x",
 	[IIO_MOD_LINEAR_Y] = "linear_y",
 	[IIO_MOD_LINEAR_Z] = "linear_z",
+	[IIO_MOD_PITCH] = "pitch",
+	[IIO_MOD_YAW] = "yaw",
+	[IIO_MOD_ROLL] = "roll",
 };
 
 /* relies on pairs of these shared then separate */
diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
index 0993f6b697fc..4853701ba70d 100644
--- a/include/uapi/linux/iio/types.h
+++ b/include/uapi/linux/iio/types.h
@@ -98,6 +98,9 @@ enum iio_modifier {
 	IIO_MOD_LINEAR_X,
 	IIO_MOD_LINEAR_Y,
 	IIO_MOD_LINEAR_Z,
+	IIO_MOD_PITCH,
+	IIO_MOD_YAW,
+	IIO_MOD_ROLL,
 };
 
 enum iio_event_type {
-- 
2.17.1

[v5 05/14] iio: document pitch, yaw, roll modifiers

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Introduce ABI documentation for new modifiers used for reporting rotations
expressed as euler angles (i.e. yaw, pitch, roll).

It looks like we have some unit inconsistency along various IIO modifiers:
it seems that incli is in deg, angl is in radians and rot isn't documented,
but at least the adis16209 driver has rot in deg.

Here we use deg (so angl is the only one using radians).

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 Documentation/ABI/testing/sysfs-bus-iio | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index aadddd43bf22..2a6954ea1c71 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -2039,3 +2039,12 @@ Description:
 		Available range for the forced calibration value, expressed as:
 
 		- a range specified as "[min step max]"
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_rot_yaw_raw
+What:		/sys/bus/iio/devices/iio:deviceX/in_rot_pitch_raw
+What:		/sys/bus/iio/devices/iio:deviceX/in_rot_roll_raw
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Raw (unscaled) euler angles readings. Units after
+		application of scale are deg.
-- 
2.17.1

[v5 06/14] iio: event_monitor: add pitch, yaw and roll modifiers

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Following the introduction of pitch, yaw and roll IIO modifiers, update the
event_monitor tool accordingly.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 tools/iio/iio_event_monitor.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/iio/iio_event_monitor.c b/tools/iio/iio_event_monitor.c
index 1fee44abb836..ee3f78c47655 100644
--- a/tools/iio/iio_event_monitor.c
+++ b/tools/iio/iio_event_monitor.c
@@ -125,6 +125,9 @@ static const char * const iio_modifier_names[] = {
 	[IIO_MOD_LINEAR_X] = "linear_x",
 	[IIO_MOD_LINEAR_Y] = "linear_y",
 	[IIO_MOD_LINEAR_Z] = "linear_z",
+	[IIO_MOD_PITCH] = "pitch",
+	[IIO_MOD_YAW] = "yaw",
+	[IIO_MOD_ROLL] = "roll",
 };
 
 static bool event_is_known(struct iio_event_data *event)
-- 
2.17.1

[v5 07/14] iio: add support for binary attributes

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

When a IIO device is registered, the IIO core creates an attribute group on
its own, where it puts the channel attributes, and where it copies the
attributes in indio_dev->info->attrs.

Unfortunately it doesn't take care of binary attributes (i.e. it only
consider indio_dev->info->attrs->attrs, and it ignores
indio_dev->info->attrs->bin_attrs).

Fix this by making the IIO layer take care also of the binary attributes.

Note that while it is necessary to copy the non-binary attributes because
the IIO layer needs more room to add the channels attribute, it should be
enough to assign the bin_attrs pointer to the binary attributes pointed by
indio_dev->info->attrs->bin_attrs.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 drivers/iio/industrialio-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index aa5f98d3b334..aef30f0b9465 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1567,7 +1567,7 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 		ret = -ENOMEM;
 		goto error_clear_attrs;
 	}
-	/* Copy across original attributes */
+	/* Copy across original attributes, and point to original binary attributes */
 	if (indio_dev->info->attrs) {
 		memcpy(iio_dev_opaque->chan_attr_group.attrs,
 		       indio_dev->info->attrs->attrs,
@@ -1575,6 +1575,8 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 		       *attrcount_orig);
 		iio_dev_opaque->chan_attr_group.is_visible =
 			indio_dev->info->attrs->is_visible;
+		iio_dev_opaque->chan_attr_group.bin_attrs =
+			indio_dev->info->attrs->bin_attrs;
 	}
 	attrn = attrcount_orig;
 	/* Add all elements from the list. */
-- 
2.17.1

[v5 08/14] iio: imu: add Bosch Sensortec BNO055 core driver

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add the core driver for the BNO055 IMU from Bosch. This IMU can be
connected via both serial and I2C busses; separate patches will add support
for them.

The driver supports "AMG" (Accelerometer, Magnetometer, Gyroscope) mode,
that provides raw data from the said internal sensors, and a couple of
"fusion" modes (i.e. the IMU also do calculations in order to provide euler
angles, quaternions, linear acceleration and gravity measurements).

In fusion modes the AMG data is still available (with some calibration
refinements done by the IMU), but certain settings such as low pass filters
cut-off frequency and sensors ranges are fixed, while in AMG mode they can
be customized; this is why AMG mode can still be interesting.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 drivers/iio/imu/Kconfig         |    1 +
 drivers/iio/imu/Makefile        |    1 +
 drivers/iio/imu/bno055/Kconfig  |    4 +
 drivers/iio/imu/bno055/Makefile |    3 +
 drivers/iio/imu/bno055/bno055.c | 1710 +++++++++++++++++++++++++++++++
 drivers/iio/imu/bno055/bno055.h |   12 +
 6 files changed, 1731 insertions(+)
 create mode 100644 drivers/iio/imu/bno055/Kconfig
 create mode 100644 drivers/iio/imu/bno055/Makefile
 create mode 100644 drivers/iio/imu/bno055/bno055.c
 create mode 100644 drivers/iio/imu/bno055/bno055.h

diff --git a/drivers/iio/imu/Kconfig b/drivers/iio/imu/Kconfig
index 001ca2c3ff95..f1d7d4b5e222 100644
--- a/drivers/iio/imu/Kconfig
+++ b/drivers/iio/imu/Kconfig
@@ -52,6 +52,7 @@ config ADIS16480
 	  ADIS16485, ADIS16488 inertial sensors.
 
 source "drivers/iio/imu/bmi160/Kconfig"
+source "drivers/iio/imu/bno055/Kconfig"
 
 config FXOS8700
 	tristate
diff --git a/drivers/iio/imu/Makefile b/drivers/iio/imu/Makefile
index c82748096c77..6eb612034722 100644
--- a/drivers/iio/imu/Makefile
+++ b/drivers/iio/imu/Makefile
@@ -15,6 +15,7 @@ adis_lib-$(CONFIG_IIO_ADIS_LIB_BUFFER) += adis_buffer.o
 obj-$(CONFIG_IIO_ADIS_LIB) += adis_lib.o
 
 obj-y += bmi160/
+obj-y += bno055/
 
 obj-$(CONFIG_FXOS8700) += fxos8700_core.o
 obj-$(CONFIG_FXOS8700_I2C) += fxos8700_i2c.o
diff --git a/drivers/iio/imu/bno055/Kconfig b/drivers/iio/imu/bno055/Kconfig
new file mode 100644
index 000000000000..d0ab3221fba5
--- /dev/null
+++ b/drivers/iio/imu/bno055/Kconfig
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config BOSCH_BNO055_IIO
+	tristate
diff --git a/drivers/iio/imu/bno055/Makefile b/drivers/iio/imu/bno055/Makefile
new file mode 100644
index 000000000000..56cc4de60a7e
--- /dev/null
+++ b/drivers/iio/imu/bno055/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_BOSCH_BNO055_IIO) += bno055.o
diff --git a/drivers/iio/imu/bno055/bno055.c b/drivers/iio/imu/bno055/bno055.c
new file mode 100644
index 000000000000..4b79e1913b4c
--- /dev/null
+++ b/drivers/iio/imu/bno055/bno055.c
@@ -0,0 +1,1710 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IIO driver for Bosch BNO055 IMU
+ *
+ * Copyright (C) 2021-2022 Istituto Italiano di Tecnologia
+ * Electronic Design Laboratory
+ * Written by Andrea Merello <andrea.merello@iit.it>
+ *
+ * Portions of this driver are taken from the BNO055 driver patch
+ * from Vlad Dogaru which is Copyright (c) 2016, Intel Corporation.
+ *
+ * This driver is also based on BMI160 driver, which is:
+ *	Copyright (c) 2016, Intel Corporation.
+ *	Copyright (c) 2019, Martin Kelly.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/clk.h>
+#include <linux/bitfield.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/firmware.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/util_macros.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/sysfs.h>
+
+#include "bno055.h"
+
+#define BNO055_FW_NAME "bno055-caldata"
+#define BNO055_FW_EXT ".dat"
+#define BNO055_FW_UID_NAME BNO055_FW_NAME "-%*phN" BNO055_FW_EXT
+#define BNO055_FW_GENERIC_NAME (BNO055_FW_NAME BNO055_FW_EXT)
+
+/* common registers */
+#define BNO055_PAGESEL_REG		0x7
+
+/* page 0 registers */
+#define BNO055_CHIP_ID_REG		0x0
+#define BNO055_CHIP_ID_MAGIC 0xA0
+#define BNO055_SW_REV_LSB_REG		0x4
+#define BNO055_SW_REV_MSB_REG		0x5
+#define BNO055_ACC_DATA_X_LSB_REG	0x8
+#define BNO055_ACC_DATA_Y_LSB_REG	0xA
+#define BNO055_ACC_DATA_Z_LSB_REG	0xC
+#define BNO055_MAG_DATA_X_LSB_REG	0xE
+#define BNO055_MAG_DATA_Y_LSB_REG	0x10
+#define BNO055_MAG_DATA_Z_LSB_REG	0x12
+#define BNO055_GYR_DATA_X_LSB_REG	0x14
+#define BNO055_GYR_DATA_Y_LSB_REG	0x16
+#define BNO055_GYR_DATA_Z_LSB_REG	0x18
+#define BNO055_EUL_DATA_X_LSB_REG	0x1A
+#define BNO055_EUL_DATA_Y_LSB_REG	0x1C
+#define BNO055_EUL_DATA_Z_LSB_REG	0x1E
+#define BNO055_QUAT_DATA_W_LSB_REG	0x20
+#define BNO055_LIA_DATA_X_LSB_REG	0x28
+#define BNO055_LIA_DATA_Y_LSB_REG	0x2A
+#define BNO055_LIA_DATA_Z_LSB_REG	0x2C
+#define BNO055_GRAVITY_DATA_X_LSB_REG	0x2E
+#define BNO055_GRAVITY_DATA_Y_LSB_REG	0x30
+#define BNO055_GRAVITY_DATA_Z_LSB_REG	0x32
+#define BNO055_SCAN_CH_COUNT ((BNO055_GRAVITY_DATA_Z_LSB_REG - BNO055_ACC_DATA_X_LSB_REG) / 2)
+#define BNO055_TEMP_REG			0x34
+#define BNO055_CALIB_STAT_REG		0x35
+#define BNO055_CALIB_STAT_MASK GENMASK(1, 0)
+#define BNO055_CALIB_STAT_MAGN_SHIFT 0
+#define BNO055_CALIB_STAT_ACCEL_SHIFT 2
+#define BNO055_CALIB_STAT_GYRO_SHIFT 4
+#define BNO055_CALIB_STAT_SYS_SHIFT 6
+#define BNO055_SYS_ERR_REG		0x3A
+#define BNO055_POWER_MODE_REG		0x3E
+#define BNO055_POWER_MODE_NORMAL 0
+#define BNO055_SYS_TRIGGER_REG		0x3F
+#define BNO055_SYS_TRIGGER_RST_SYS BIT(5)
+#define BNO055_SYS_TRIGGER_CLK_SEL BIT(7)
+#define BNO055_OPR_MODE_REG		0x3D
+#define BNO055_OPR_MODE_CONFIG 0x0
+#define BNO055_OPR_MODE_AMG 0x7
+#define BNO055_OPR_MODE_FUSION_FMC_OFF 0xB
+#define BNO055_OPR_MODE_FUSION 0xC
+#define BNO055_UNIT_SEL_REG		0x3B
+/* Android orientation mode means: pitch value decreases turning clockwise */
+#define BNO055_UNIT_SEL_ANDROID BIT(7)
+#define BNO055_UNIT_SEL_GYR_RPS BIT(1)
+#define BNO055_CALDATA_START		0x55
+#define BNO055_CALDATA_END		0x6A
+#define BNO055_CALDATA_LEN 22
+
+/*
+ * The difference in address between the register that contains the
+ * value and the register that contains the offset.  This applies for
+ * accel, gyro and magn channels.
+ */
+#define BNO055_REG_OFFSET_ADDR		0x4D
+
+/* page 1 registers */
+#define BNO055_PG1(x) ((x) | 0x80)
+#define BNO055_ACC_CONFIG_REG		BNO055_PG1(0x8)
+#define BNO055_ACC_CONFIG_LPF_MASK GENMASK(4, 2)
+#define BNO055_ACC_CONFIG_RANGE_MASK GENMASK(1, 0)
+#define BNO055_MAG_CONFIG_REG		BNO055_PG1(0x9)
+#define BNO055_MAG_CONFIG_HIGHACCURACY 0x18
+#define BNO055_MAG_CONFIG_ODR_MASK GENMASK(2, 0)
+#define BNO055_GYR_CONFIG_REG		BNO055_PG1(0xA)
+#define BNO055_GYR_CONFIG_RANGE_MASK GENMASK(2, 0)
+#define BNO055_GYR_CONFIG_LPF_MASK GENMASK(5, 3)
+#define BNO055_GYR_AM_SET_REG		BNO055_PG1(0x1F)
+#define BNO055_UID_LOWER_REG		BNO055_PG1(0x50)
+#define BNO055_UID_HIGHER_REG		BNO055_PG1(0x5F)
+#define BNO055_UID_LEN 16
+
+struct bno055_sysfs_attr {
+	int *vals;
+	int len;
+	int *fusion_vals;
+	int *hw_xlate;
+	int type;
+};
+
+#define BNO055_ATTR_VALS(...)		\
+	.vals = (int[]){ __VA_ARGS__},	\
+	.len = ARRAY_SIZE(((int[]){__VA_ARGS__}))
+
+static struct bno055_sysfs_attr bno055_acc_lpf = {
+	BNO055_ATTR_VALS(7, 810000, 15, 630000,
+			 31, 250000, 62, 500000, 125, 0,
+			 250, 0, 500, 0, 1000, 0),
+	.fusion_vals = (int[]){62, 500000},
+	.type = IIO_VAL_INT_PLUS_MICRO
+};
+
+static struct bno055_sysfs_attr bno055_acc_range = {
+		     /* G:   2,    4,    8,    16 */
+	BNO055_ATTR_VALS(1962, 3924, 7848, 15696),
+	.fusion_vals = (int[]){3924}, /* 4G */
+	.type = IIO_VAL_INT
+};
+
+/*
+ * Theoretically the IMU should return data in a given (i.e. fixed) unit
+ * regardless the range setting. This happens for the accelerometer, but not for
+ * the gyroscope; the gyroscope range setting affects the scale.
+ * This is probably due to this[0] bug.
+ * For this reason we map the internal range setting onto the standard IIO scale
+ * attribute for gyro.
+ * Since the bug[0] may be fixed in future, we check for the IMU FW version and
+ * eventually warn the user.
+ * Currently we just don't care about "range" attributes for gyro.
+ *
+ * [0]  https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/BNO055-Wrong-sensitivity-resolution-in-datasheet/td-p/10266
+ */
+static struct bno055_sysfs_attr bno055_gyr_scale = {
+	/*
+	 * dps = hwval * (dps_range/2^15)
+	 * rps = hwval * (rps_range/2^15)
+	 *     = hwval * (dps_range/(2^15 * k))
+	 * where k is rad-to-deg factor
+	 */
+	BNO055_ATTR_VALS(125, 1877467, 250, 1877467,
+			 500, 1877467, 1000, 1877467,
+			 2000, 1877467),
+	.fusion_vals = (int[]){1, 900},
+	.hw_xlate = (int[]){4, 3, 2, 1, 0},
+	.type = IIO_VAL_FRACTIONAL
+};
+
+static struct bno055_sysfs_attr bno055_gyr_lpf = {
+	BNO055_ATTR_VALS(12, 23, 32, 47, 64, 116, 230, 523),
+	.fusion_vals = (int[]){32},
+	.hw_xlate = (int[]){5, 4, 7, 3, 6, 2, 1, 0},
+	.type = IIO_VAL_INT
+};
+
+static struct bno055_sysfs_attr bno055_mag_odr = {
+	BNO055_ATTR_VALS(2, 6, 8, 10, 15, 20, 25, 30),
+	.fusion_vals = (int[]){20},
+	.type = IIO_VAL_INT
+};
+
+struct bno055_priv {
+	struct regmap *regmap;
+	struct device *dev;
+	struct clk *clk;
+	int operation_mode;
+	int xfer_burst_break_thr;
+	struct mutex lock;
+	u8 uid[BNO055_UID_LEN];
+	struct gpio_desc *reset_gpio;
+	bool sw_reset;
+	struct {
+		__le16 chans[BNO055_SCAN_CH_COUNT];
+		s64 timestamp __aligned(8);
+	} buf;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *debugfs;
+#endif
+};
+
+static bool bno055_regmap_volatile(struct device *dev, unsigned int reg)
+{
+	/* data and status registers */
+	if (reg >= BNO055_ACC_DATA_X_LSB_REG && reg <= BNO055_SYS_ERR_REG)
+		return true;
+
+	/* when in fusion mode, config is updated by chip */
+	if (reg == BNO055_MAG_CONFIG_REG ||
+	    reg == BNO055_ACC_CONFIG_REG ||
+	    reg == BNO055_GYR_CONFIG_REG)
+		return true;
+
+	/* calibration data may be updated by the IMU */
+	if (reg >= BNO055_CALDATA_START && reg <= BNO055_CALDATA_END)
+		return true;
+
+	return false;
+}
+
+static bool bno055_regmap_readable(struct device *dev, unsigned int reg)
+{
+	/* unnamed PG0 reserved areas */
+	if ((reg < BNO055_PG1(0) && reg > BNO055_CALDATA_END) ||
+	    reg == 0x3C)
+		return false;
+
+	/* unnamed PG1 reserved areas */
+	if (reg > BNO055_PG1(BNO055_UID_HIGHER_REG) ||
+	    (reg < BNO055_PG1(BNO055_UID_LOWER_REG) && reg > BNO055_PG1(BNO055_GYR_AM_SET_REG)) ||
+	    reg == BNO055_PG1(0xE) ||
+	    (reg < BNO055_PG1(BNO055_PAGESEL_REG) && reg >= BNO055_PG1(0x0)))
+		return false;
+	return true;
+}
+
+static bool bno055_regmap_writeable(struct device *dev, unsigned int reg)
+{
+	/*
+	 * Unreadable registers are indeed reserved; there are no WO regs
+	 * (except for a single bit in SYS_TRIGGER register)
+	 */
+	if (!bno055_regmap_readable(dev, reg))
+		return false;
+
+	/* data and status registers */
+	if (reg >= BNO055_ACC_DATA_X_LSB_REG && reg <= BNO055_SYS_ERR_REG)
+		return false;
+
+	/* ID areas */
+	if (reg < BNO055_PAGESEL_REG ||
+	    (reg <= BNO055_UID_HIGHER_REG && reg >= BNO055_UID_LOWER_REG))
+		return false;
+
+	return true;
+}
+
+static const struct regmap_range_cfg bno055_regmap_ranges[] = {
+	{
+		.range_min = 0,
+		.range_max = 0x7f * 2,
+		.selector_reg = BNO055_PAGESEL_REG,
+		.selector_mask = GENMASK(7, 0),
+		.selector_shift = 0,
+		.window_start = 0,
+		.window_len = 0x80
+	},
+};
+
+const struct regmap_config bno055_regmap_config = {
+	.name = "bno055",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.ranges = bno055_regmap_ranges,
+	.num_ranges = 1,
+	.volatile_reg = bno055_regmap_volatile,
+	.max_register = 0x80 * 2,
+	.writeable_reg = bno055_regmap_writeable,
+	.readable_reg = bno055_regmap_readable,
+	.cache_type = REGCACHE_RBTREE,
+};
+EXPORT_SYMBOL_NS_GPL(bno055_regmap_config, IIO_BNO055);
+
+/* must be called in configuration mode */
+static int bno055_calibration_load(struct bno055_priv *priv, const u8 *data, int len)
+{
+	if (len != BNO055_CALDATA_LEN) {
+		dev_dbg(priv->dev, "Invalid calibration file size %d (expected %d)",
+			len, BNO055_CALDATA_LEN);
+		return -EINVAL;
+	}
+
+	dev_dbg(priv->dev, "loading cal data: %*ph", BNO055_CALDATA_LEN, data);
+	return regmap_bulk_write(priv->regmap, BNO055_CALDATA_START,
+				 data, BNO055_CALDATA_LEN);
+}
+
+static int bno055_operation_mode_do_set(struct bno055_priv *priv,
+					int operation_mode)
+{
+	int ret;
+
+	ret = regmap_write(priv->regmap, BNO055_OPR_MODE_REG,
+			   operation_mode);
+	if (ret)
+		return ret;
+
+	msleep(20);
+
+	return 0;
+}
+
+static int bno055_system_reset(struct bno055_priv *priv)
+{
+	int ret;
+
+	if (priv->reset_gpio) {
+		gpiod_set_value_cansleep(priv->reset_gpio, 0);
+		usleep_range(5000, 10000);
+		gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	} else {
+		if (!priv->sw_reset)
+			return 0;
+
+		ret = regmap_write(priv->regmap, BNO055_SYS_TRIGGER_REG,
+				   BNO055_SYS_TRIGGER_RST_SYS);
+		if (ret)
+			return ret;
+	}
+
+	regcache_drop_region(priv->regmap, 0x0, 0xff);
+	usleep_range(650000, 700000);
+
+	return 0;
+}
+
+static int bno055_init(struct bno055_priv *priv, const u8 *caldata, int len)
+{
+	int ret;
+
+	ret = bno055_operation_mode_do_set(priv, BNO055_OPR_MODE_CONFIG);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(priv->regmap, BNO055_POWER_MODE_REG,
+			   BNO055_POWER_MODE_NORMAL);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(priv->regmap, BNO055_SYS_TRIGGER_REG,
+			   priv->clk ? BNO055_SYS_TRIGGER_CLK_SEL : 0);
+	if (ret)
+		return ret;
+
+	/* use standard SI units */
+	ret = regmap_write(priv->regmap, BNO055_UNIT_SEL_REG,
+			   BNO055_UNIT_SEL_ANDROID | BNO055_UNIT_SEL_GYR_RPS);
+	if (ret)
+		return ret;
+
+	if (caldata) {
+		ret = bno055_calibration_load(priv, caldata, len);
+		if (ret)
+			dev_warn(priv->dev, "failed to load calibration data with error %d",
+				 ret);
+	}
+
+	return 0;
+}
+
+static ssize_t bno055_operation_mode_set(struct bno055_priv *priv,
+					 int operation_mode)
+{
+	u8 caldata[BNO055_CALDATA_LEN];
+	int ret;
+
+	mutex_lock(&priv->lock);
+
+	ret = bno055_operation_mode_do_set(priv, BNO055_OPR_MODE_CONFIG);
+	if (ret)
+		goto exit;
+
+	if (operation_mode == BNO055_OPR_MODE_FUSION ||
+	    operation_mode == BNO055_OPR_MODE_FUSION_FMC_OFF) {
+		/* for entering fusion mode, reset the chip to clear the algo state */
+		ret = regmap_bulk_read(priv->regmap, BNO055_CALDATA_START, caldata,
+				       BNO055_CALDATA_LEN);
+		if (ret)
+			goto exit;
+
+		ret = bno055_system_reset(priv);
+		if (ret)
+			goto exit;
+
+		ret = bno055_init(priv, caldata, BNO055_CALDATA_LEN);
+		if (ret)
+			goto exit;
+	}
+
+	ret = bno055_operation_mode_do_set(priv, operation_mode);
+	if (ret)
+		goto exit;
+
+	priv->operation_mode = operation_mode;
+
+exit:
+	mutex_unlock(&priv->lock);
+	return ret;
+}
+
+static void bno055_uninit(void *arg)
+{
+	struct bno055_priv *priv = arg;
+
+	/* stop the IMU */
+	bno055_operation_mode_do_set(priv, BNO055_OPR_MODE_CONFIG);
+}
+
+#define BNO055_CHANNEL(_type, _axis, _index, _address, _sep, _sh, _avail) {	\
+	.address = _address,							\
+	.type = _type,								\
+	.modified = 1,								\
+	.channel2 = IIO_MOD_##_axis,						\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | (_sep),			\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | (_sh),		\
+	.info_mask_shared_by_type_available = _avail,				\
+	.scan_index = _index,							\
+	.scan_type = {								\
+		.sign = 's',							\
+		.realbits = 16,							\
+		.storagebits = 16,						\
+		.endianness = IIO_LE,						\
+		.repeat = IIO_MOD_##_axis == IIO_MOD_QUATERNION ? 4 : 0		\
+	},									\
+}
+
+/* scan indexes follow DATA register order */
+enum bno055_scan_axis {
+	BNO055_SCAN_ACCEL_X,
+	BNO055_SCAN_ACCEL_Y,
+	BNO055_SCAN_ACCEL_Z,
+	BNO055_SCAN_MAGN_X,
+	BNO055_SCAN_MAGN_Y,
+	BNO055_SCAN_MAGN_Z,
+	BNO055_SCAN_GYRO_X,
+	BNO055_SCAN_GYRO_Y,
+	BNO055_SCAN_GYRO_Z,
+	BNO055_SCAN_YAW,
+	BNO055_SCAN_ROLL,
+	BNO055_SCAN_PITCH,
+	BNO055_SCAN_QUATERNION,
+	BNO055_SCAN_LIA_X,
+	BNO055_SCAN_LIA_Y,
+	BNO055_SCAN_LIA_Z,
+	BNO055_SCAN_GRAVITY_X,
+	BNO055_SCAN_GRAVITY_Y,
+	BNO055_SCAN_GRAVITY_Z,
+	BNO055_SCAN_TIMESTAMP,
+	_BNO055_SCAN_MAX
+};
+
+static const struct iio_chan_spec bno055_channels[] = {
+	/* accelerometer */
+	BNO055_CHANNEL(IIO_ACCEL, X, BNO055_SCAN_ACCEL_X,
+		       BNO055_ACC_DATA_X_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)),
+	BNO055_CHANNEL(IIO_ACCEL, Y, BNO055_SCAN_ACCEL_Y,
+		       BNO055_ACC_DATA_Y_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)),
+	BNO055_CHANNEL(IIO_ACCEL, Z, BNO055_SCAN_ACCEL_Z,
+		       BNO055_ACC_DATA_Z_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)),
+	/* gyroscope */
+	BNO055_CHANNEL(IIO_ANGL_VEL, X, BNO055_SCAN_GYRO_X,
+		       BNO055_GYR_DATA_X_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |
+		       BIT(IIO_CHAN_INFO_SCALE)),
+	BNO055_CHANNEL(IIO_ANGL_VEL, Y, BNO055_SCAN_GYRO_Y,
+		       BNO055_GYR_DATA_Y_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |
+		       BIT(IIO_CHAN_INFO_SCALE)),
+	BNO055_CHANNEL(IIO_ANGL_VEL, Z, BNO055_SCAN_GYRO_Z,
+		       BNO055_GYR_DATA_Z_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+		       BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |
+		       BIT(IIO_CHAN_INFO_SCALE)),
+	/* magnetometer */
+	BNO055_CHANNEL(IIO_MAGN, X, BNO055_SCAN_MAGN_X,
+		       BNO055_MAG_DATA_X_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_SAMP_FREQ), BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	BNO055_CHANNEL(IIO_MAGN, Y, BNO055_SCAN_MAGN_Y,
+		       BNO055_MAG_DATA_Y_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_SAMP_FREQ), BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	BNO055_CHANNEL(IIO_MAGN, Z, BNO055_SCAN_MAGN_Z,
+		       BNO055_MAG_DATA_Z_LSB_REG, BIT(IIO_CHAN_INFO_OFFSET),
+		       BIT(IIO_CHAN_INFO_SAMP_FREQ), BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	/* euler angle */
+	BNO055_CHANNEL(IIO_ROT, YAW, BNO055_SCAN_YAW,
+		       BNO055_EUL_DATA_X_LSB_REG, 0, 0, 0),
+	BNO055_CHANNEL(IIO_ROT, ROLL, BNO055_SCAN_ROLL,
+		       BNO055_EUL_DATA_Y_LSB_REG, 0, 0, 0),
+	BNO055_CHANNEL(IIO_ROT, PITCH, BNO055_SCAN_PITCH,
+		       BNO055_EUL_DATA_Z_LSB_REG, 0, 0, 0),
+	/* quaternion */
+	BNO055_CHANNEL(IIO_ROT, QUATERNION, BNO055_SCAN_QUATERNION,
+		       BNO055_QUAT_DATA_W_LSB_REG, 0, 0, 0),
+
+	/* linear acceleration */
+	BNO055_CHANNEL(IIO_ACCEL, LINEAR_X, BNO055_SCAN_LIA_X,
+		       BNO055_LIA_DATA_X_LSB_REG, 0, 0, 0),
+	BNO055_CHANNEL(IIO_ACCEL, LINEAR_Y, BNO055_SCAN_LIA_Y,
+		       BNO055_LIA_DATA_Y_LSB_REG, 0, 0, 0),
+	BNO055_CHANNEL(IIO_ACCEL, LINEAR_Z, BNO055_SCAN_LIA_Z,
+		       BNO055_LIA_DATA_Z_LSB_REG, 0, 0, 0),
+
+	/* gravity vector */
+	BNO055_CHANNEL(IIO_GRAVITY, X, BNO055_SCAN_GRAVITY_X,
+		       BNO055_GRAVITY_DATA_X_LSB_REG, 0, 0, 0),
+	BNO055_CHANNEL(IIO_GRAVITY, Y, BNO055_SCAN_GRAVITY_Y,
+		       BNO055_GRAVITY_DATA_Y_LSB_REG, 0, 0, 0),
+	BNO055_CHANNEL(IIO_GRAVITY, Z, BNO055_SCAN_GRAVITY_Z,
+		       BNO055_GRAVITY_DATA_Z_LSB_REG, 0, 0, 0),
+
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(BNO055_SCAN_TIMESTAMP),
+};
+
+static int bno055_get_regmask(struct bno055_priv *priv, int *val, int *val2,
+			      int reg, int mask, struct bno055_sysfs_attr *attr)
+{
+	const int shift = __ffs(mask);
+	int hwval, idx;
+	int ret;
+	int i;
+
+	ret = regmap_read(priv->regmap, reg, &hwval);
+	if (ret)
+		return ret;
+
+	idx = (hwval & mask) >> shift;
+	if (attr->hw_xlate)
+		for (i = 0; i < attr->len; i++)
+			if (attr->hw_xlate[i] == idx) {
+				idx = i;
+				break;
+			}
+	if (attr->type == IIO_VAL_INT) {
+		*val = attr->vals[idx];
+	} else { /* IIO_VAL_INT_PLUS_MICRO or IIO_VAL_FRACTIONAL */
+		*val = attr->vals[idx * 2];
+		*val2 = attr->vals[idx * 2 + 1];
+	}
+
+	return attr->type;
+}
+
+static int bno055_set_regmask(struct bno055_priv *priv, int val, int val2,
+			      int reg, int mask, struct bno055_sysfs_attr *attr)
+{
+	const int shift = __ffs(mask);
+	int best_delta;
+	int req_val;
+	int tbl_val;
+	bool first;
+	int delta;
+	int hwval;
+	int ret;
+	int len;
+	int i;
+
+	/*
+	 * The closest value the HW supports is only one in fusion mode,
+	 * and it is autoselected, so don't do anything, just return OK,
+	 * as the closest possible value has been (virtually) selected
+	 */
+	if (priv->operation_mode != BNO055_OPR_MODE_AMG)
+		return 0;
+
+	len = attr->len;
+
+	/*
+	 * We always get a request in INT_PLUS_MICRO, but we
+	 * take care of the micro part only when we really have
+	 * non-integer tables. This prevents 32-bit overflow with
+	 * larger integers contained in integer tables.
+	 */
+	req_val = val;
+	if (attr->type != IIO_VAL_INT) {
+		if (val > 2147)
+			val = 2147;
+		len /= 2;
+		req_val = val * 1000000 + val2;
+	}
+
+	first = true;
+	for (i = 0; i < len; i++) {
+		switch (attr->type) {
+		case IIO_VAL_INT:
+			tbl_val = attr->vals[i];
+			break;
+		case IIO_VAL_INT_PLUS_MICRO:
+			WARN_ON(attr->vals[i * 2] > 2147);
+			tbl_val = attr->vals[i * 2] * 1000000 +
+				attr->vals[i * 2 + 1];
+			break;
+		case IIO_VAL_FRACTIONAL:
+			WARN_ON(attr->vals[i * 2] > 4294);
+			tbl_val = attr->vals[i * 2] * 1000000 /
+				attr->vals[i * 2 + 1];
+			break;
+		default:
+			return -EINVAL;
+		}
+		delta = abs(tbl_val - req_val);
+		if (first || delta < best_delta) {
+			best_delta = delta;
+			hwval = i;
+			first = false;
+		}
+	}
+
+	if (attr->hw_xlate)
+		hwval = attr->hw_xlate[hwval];
+
+	ret = bno055_operation_mode_do_set(priv, BNO055_OPR_MODE_CONFIG);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(priv->regmap, reg, mask, hwval << shift);
+	if (ret)
+		return ret;
+
+	return bno055_operation_mode_do_set(priv, BNO055_OPR_MODE_AMG);
+}
+
+static int bno055_read_simple_chan(struct iio_dev *indio_dev,
+				   struct iio_chan_spec const *chan,
+				   int *val, int *val2, long mask)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	__le16 raw_val;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = regmap_bulk_read(priv->regmap, chan->address,
+				       &raw_val, sizeof(raw_val));
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(le16_to_cpu(raw_val), 15);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_OFFSET:
+		if (priv->operation_mode != BNO055_OPR_MODE_AMG) {
+			*val = 0;
+		} else {
+			ret = regmap_bulk_read(priv->regmap,
+					       chan->address +
+					       BNO055_REG_OFFSET_ADDR,
+					       &raw_val, sizeof(raw_val));
+			if (ret < 0)
+				return ret;
+			/*
+			 * IMU reports sensor offests; IIO wants correction
+			 * offset, thus we need the 'minus' here.
+			 */
+			*val = -sign_extend32(le16_to_cpu(raw_val), 15);
+		}
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 1;
+		switch (chan->type) {
+		case IIO_GRAVITY:
+			/* Table 3-35: 1 m/s^2 = 100 LSB */
+		case IIO_ACCEL:
+			/* Table 3-17: 1 m/s^2 = 100 LSB */
+			*val2 = 100;
+			break;
+		case IIO_MAGN:
+			/*
+			 * Table 3-19: 1 uT = 16 LSB.  But we need
+			 * Gauss: 1G = 0.1 uT.
+			 */
+			*val2 = 160;
+			break;
+		case IIO_ANGL_VEL:
+			/*
+			 * Table 3-22: 1 Rps = 900 LSB
+			 * .. but this is not exactly true. See comment at the
+			 * beginning of this file.
+			 */
+			if (priv->operation_mode != BNO055_OPR_MODE_AMG) {
+				*val = bno055_gyr_scale.fusion_vals[0];
+				*val2 = bno055_gyr_scale.fusion_vals[1];
+				return IIO_VAL_FRACTIONAL;
+			}
+
+			return bno055_get_regmask(priv, val, val2,
+						  BNO055_GYR_CONFIG_REG,
+						  BNO055_GYR_CONFIG_RANGE_MASK,
+						  &bno055_gyr_scale);
+			break;
+		case IIO_ROT:
+			/* Table 3-28: 1 degree = 16 LSB */
+			*val2 = 16;
+			break;
+		default:
+			return -EINVAL;
+		}
+		return IIO_VAL_FRACTIONAL;
+
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (chan->type != IIO_MAGN)
+			return -EINVAL;
+		else
+			return bno055_get_regmask(priv, val, val2,
+						  BNO055_MAG_CONFIG_REG,
+						  BNO055_MAG_CONFIG_ODR_MASK,
+						  &bno055_mag_odr);
+
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			return bno055_get_regmask(priv, val, val2,
+						  BNO055_GYR_CONFIG_REG,
+						  BNO055_GYR_CONFIG_LPF_MASK,
+						  &bno055_gyr_lpf);
+		case IIO_ACCEL:
+			return bno055_get_regmask(priv, val, val2,
+						  BNO055_ACC_CONFIG_REG,
+						  BNO055_ACC_CONFIG_LPF_MASK,
+						  &bno055_acc_lpf);
+		default:
+			return -EINVAL;
+		}
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bno055_sysfs_attr_avail(struct bno055_priv *priv, struct bno055_sysfs_attr *attr,
+				   const int **vals, int *length)
+{
+	if (priv->operation_mode != BNO055_OPR_MODE_AMG) {
+		/* locked when fusion enabled */
+		*vals = attr->fusion_vals;
+		if (attr->type == IIO_VAL_INT)
+			*length = 1;
+		else
+			*length = 2; /* IIO_VAL_INT_PLUS_MICRO or IIO_VAL_FRACTIONAL*/
+	} else {
+		*vals = attr->vals;
+		*length = attr->len;
+	}
+
+	return attr->type;
+}
+
+static int bno055_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     const int **vals, int *type, int *length,
+			     long mask)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			*type = bno055_sysfs_attr_avail(priv, &bno055_gyr_scale,
+							vals, length);
+			return IIO_AVAIL_LIST;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			*type = bno055_sysfs_attr_avail(priv, &bno055_gyr_lpf,
+							vals, length);
+			return IIO_AVAIL_LIST;
+		case IIO_ACCEL:
+			*type = bno055_sysfs_attr_avail(priv, &bno055_acc_lpf,
+							vals, length);
+			return IIO_AVAIL_LIST;
+		default:
+			return -EINVAL;
+		}
+
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		switch (chan->type) {
+		case IIO_MAGN:
+			*type = bno055_sysfs_attr_avail(priv, &bno055_mag_odr,
+							vals, length);
+			return IIO_AVAIL_LIST;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bno055_read_temp_chan(struct iio_dev *indio_dev, int *val)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	unsigned int raw_val;
+	int ret;
+
+	ret = regmap_read(priv->regmap, BNO055_TEMP_REG, &raw_val);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Tables 3-36 and 3-37: one byte of priv, signed, 1 LSB = 1C.
+	 * ABI wants milliC.
+	 */
+	*val = raw_val * 1000;
+
+	return IIO_VAL_INT;
+}
+
+static int bno055_read_quaternion(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  int size, int *vals, int *val_len,
+				  long mask)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	__le16 raw_vals[4];
+	int i, ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (size < 4)
+			return -EINVAL;
+		ret = regmap_bulk_read(priv->regmap,
+				       BNO055_QUAT_DATA_W_LSB_REG,
+				       raw_vals, sizeof(raw_vals));
+		if (ret < 0)
+			return ret;
+		for (i = 0; i < 4; i++)
+			vals[i] = sign_extend32(le16_to_cpu(raw_vals[i]), 15);
+		*val_len = 4;
+		return IIO_VAL_INT_MULTIPLE;
+	case IIO_CHAN_INFO_SCALE:
+		/* Table 3-31: 1 quaternion = 2^14 LSB */
+		if (size < 2)
+			return -EINVAL;
+		vals[0] = 1;
+		vals[1] = 14;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		return -EINVAL;
+	}
+}
+
+static bool bno055_is_chan_readable(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+
+	if (priv->operation_mode != BNO055_OPR_MODE_AMG)
+		return true;
+
+	switch (chan->type) {
+	case IIO_GRAVITY:
+	case IIO_ROT:
+		return false;
+	case IIO_ACCEL:
+		if (chan->channel2 == IIO_MOD_LINEAR_X ||
+		    chan->channel2 == IIO_MOD_LINEAR_Y ||
+		    chan->channel2 == IIO_MOD_LINEAR_Z)
+			return false;
+		return true;
+	default:
+		return true;
+	}
+}
+
+static int _bno055_read_raw_multi(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  int size, int *vals, int *val_len,
+				  long mask)
+{
+	if (!bno055_is_chan_readable(indio_dev, chan))
+		return -EBUSY;
+
+	switch (chan->type) {
+	case IIO_MAGN:
+	case IIO_ACCEL:
+	case IIO_ANGL_VEL:
+	case IIO_GRAVITY:
+		if (size < 2)
+			return -EINVAL;
+		*val_len = 2;
+		return bno055_read_simple_chan(indio_dev, chan,
+					       &vals[0], &vals[1],
+					       mask);
+	case IIO_TEMP:
+		*val_len = 1;
+		return bno055_read_temp_chan(indio_dev, &vals[0]);
+	case IIO_ROT:
+		/*
+		 * Rotation is exposed as either a quaternion or three
+		 * Euler angles.
+		 */
+		if (chan->channel2 == IIO_MOD_QUATERNION)
+			return bno055_read_quaternion(indio_dev, chan,
+						      size, vals,
+						      val_len, mask);
+		if (size < 2)
+			return -EINVAL;
+		*val_len = 2;
+		return bno055_read_simple_chan(indio_dev, chan,
+					       &vals[0], &vals[1],
+					       mask);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bno055_read_raw_multi(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int size, int *vals, int *val_len,
+				 long mask)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&priv->lock);
+	ret = _bno055_read_raw_multi(indio_dev, chan, size,
+				     vals, val_len, mask);
+	mutex_unlock(&priv->lock);
+	return ret;
+}
+
+static int _bno055_write_raw(struct iio_dev *iio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct bno055_priv *priv = iio_priv(iio_dev);
+
+	switch (chan->type) {
+	case IIO_MAGN:
+		switch (mask) {
+		case IIO_CHAN_INFO_SAMP_FREQ:
+			return bno055_set_regmask(priv, val, val2,
+						  BNO055_MAG_CONFIG_REG,
+						  BNO055_MAG_CONFIG_ODR_MASK,
+						  &bno055_mag_odr);
+		default:
+			return -EINVAL;
+		}
+	case IIO_ACCEL:
+		switch (mask) {
+		case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+			return bno055_set_regmask(priv, val, val2,
+						  BNO055_ACC_CONFIG_REG,
+						  BNO055_ACC_CONFIG_LPF_MASK,
+						  &bno055_acc_lpf);
+
+		default:
+			return -EINVAL;
+		}
+	case IIO_ANGL_VEL:
+		switch (mask) {
+		case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+			return bno055_set_regmask(priv, val, val2,
+						  BNO055_GYR_CONFIG_REG,
+						  BNO055_GYR_CONFIG_LPF_MASK,
+						  &bno055_gyr_lpf);
+		case IIO_CHAN_INFO_SCALE:
+			return bno055_set_regmask(priv, val, val2,
+						  BNO055_GYR_CONFIG_REG,
+						  BNO055_GYR_CONFIG_RANGE_MASK,
+						  &bno055_gyr_scale);
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bno055_write_raw(struct iio_dev *iio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long mask)
+{
+	struct bno055_priv *priv = iio_priv(iio_dev);
+	int ret;
+
+	mutex_lock(&priv->lock);
+	ret = _bno055_write_raw(iio_dev, chan, val, val2, mask);
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static ssize_t in_accel_range_raw_available_show(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+	int len = 0;
+	int i;
+
+	if (priv->operation_mode != BNO055_OPR_MODE_AMG)
+		return sysfs_emit(buf, "%d\n", bno055_acc_range.fusion_vals[0]);
+
+	for (i = 0; i < bno055_acc_range.len; i++)
+		len += sysfs_emit_at(buf, len, "%d%c", bno055_acc_range.vals[i],
+				     (i == bno055_acc_range.len - 1) ? '\n' : ' ');
+	return len;
+}
+
+static ssize_t bno055_fusion_enable_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+
+	return sysfs_emit(buf, "%d\n",
+			  priv->operation_mode != BNO055_OPR_MODE_AMG);
+}
+
+static ssize_t bno055_fusion_enable_store(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	int ret = 0;
+
+	if (indio_dev->active_scan_mask &&
+	    !bitmap_empty(indio_dev->active_scan_mask, _BNO055_SCAN_MAX))
+		return -EBUSY;
+
+	if (sysfs_streq(buf, "0")) {
+		ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_AMG);
+	} else {
+		/*
+		 * Coming from AMG means the FMC was off, just switch to fusion
+		 * but don't change anything that doesn't belong to us (i.e let
+		 * FMC stay off.
+		 * Coming from any other fusion mode means we don't need to do
+		 * anything.
+		 */
+		if (priv->operation_mode == BNO055_OPR_MODE_AMG)
+			ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_FUSION_FMC_OFF);
+	}
+	if (ret)
+		return ret;
+	return len;
+}
+
+static ssize_t bno055_fmc_enable_show(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+
+	return sysfs_emit(buf, "%d\n",
+			  priv->operation_mode == BNO055_OPR_MODE_FUSION);
+}
+
+static ssize_t bno055_fmc_enable_store(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	if (indio_dev->active_scan_mask &&
+	    !bitmap_empty(indio_dev->active_scan_mask, _BNO055_SCAN_MAX))
+		return -EBUSY;
+
+	if (sysfs_streq(buf, "0")) {
+		if (priv->operation_mode == BNO055_OPR_MODE_FUSION) {
+			ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_FUSION_FMC_OFF);
+			if (ret)
+				return ret;
+		}
+	} else {
+		if (priv->operation_mode == BNO055_OPR_MODE_AMG)
+			return -EINVAL;
+
+		if (priv->operation_mode != BNO055_OPR_MODE_FUSION) {
+			ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_FUSION);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return len;
+}
+
+static ssize_t bno055_in_accel_range_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+	int val;
+	int ret;
+
+	ret = bno055_get_regmask(priv, &val, NULL,
+				 BNO055_ACC_CONFIG_REG,
+				 BNO055_ACC_CONFIG_RANGE_MASK,
+				 &bno055_acc_range);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", val);
+}
+
+static ssize_t bno055_in_accel_range_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t len)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&priv->lock);
+	ret = bno055_set_regmask(priv, val, 0,
+				 BNO055_ACC_CONFIG_REG,
+				 BNO055_ACC_CONFIG_RANGE_MASK,
+				 &bno055_acc_range);
+	mutex_unlock(&priv->lock);
+
+	return ret ?: len;
+}
+
+static ssize_t bno055_get_calib_status(struct device *dev, char *buf, int which)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+	int calib;
+	int ret;
+	int val;
+
+	if (priv->operation_mode == BNO055_OPR_MODE_AMG ||
+	    (priv->operation_mode == BNO055_OPR_MODE_FUSION_FMC_OFF &&
+	     which == BNO055_CALIB_STAT_MAGN_SHIFT)) {
+		calib = 0;
+	} else {
+		mutex_lock(&priv->lock);
+		ret = regmap_read(priv->regmap, BNO055_CALIB_STAT_REG, &val);
+		mutex_unlock(&priv->lock);
+
+		if (ret)
+			return -EIO;
+
+		calib = ((val >> which) & BNO055_CALIB_STAT_MASK) + 1;
+	}
+
+	return sysfs_emit(buf, "%d\n", calib);
+}
+
+static ssize_t serialnumber_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(dev));
+
+	return sysfs_emit(buf, "%*ph\n", BNO055_UID_LEN, priv->uid);
+}
+
+static ssize_t calibration_data_read(struct file *filp, struct kobject *kobj,
+				     struct bin_attribute *bin_attr, char *buf,
+				     loff_t pos, size_t count)
+{
+	struct bno055_priv *priv = iio_priv(dev_to_iio_dev(kobj_to_dev(kobj)));
+	u8 data[BNO055_CALDATA_LEN];
+	int ret;
+
+	/*
+	 * Calibration data is volatile; reading it in chunks will possibly
+	 * results in inconsistent data. We require the user to read the whole
+	 * blob in a single chunk
+	 */
+	if (count < BNO055_CALDATA_LEN || pos != 0)
+		return -EINVAL;
+
+	mutex_lock(&priv->lock);
+	ret = bno055_operation_mode_do_set(priv, BNO055_OPR_MODE_CONFIG);
+	if (ret)
+		goto unlock;
+
+	ret = regmap_bulk_read(priv->regmap, BNO055_CALDATA_START, data,
+			       BNO055_CALDATA_LEN);
+	if (ret)
+		goto unlock;
+
+	ret = bno055_operation_mode_do_set(priv, priv->operation_mode);
+	if (ret)
+		goto unlock;
+
+	memcpy(buf, data, BNO055_CALDATA_LEN);
+
+	ret = BNO055_CALDATA_LEN;
+unlock:
+	mutex_unlock(&priv->lock);
+	return ret;
+}
+
+static ssize_t sys_calibration_auto_status_show(struct device *dev,
+						struct device_attribute *a,
+						char *buf)
+{
+	return bno055_get_calib_status(dev, buf, BNO055_CALIB_STAT_SYS_SHIFT);
+}
+
+static ssize_t in_accel_calibration_auto_status_show(struct device *dev,
+						     struct device_attribute *a,
+						     char *buf)
+{
+	return bno055_get_calib_status(dev, buf, BNO055_CALIB_STAT_ACCEL_SHIFT);
+}
+
+static ssize_t in_gyro_calibration_auto_status_show(struct device *dev,
+						    struct device_attribute *a,
+						    char *buf)
+{
+	return bno055_get_calib_status(dev, buf, BNO055_CALIB_STAT_GYRO_SHIFT);
+}
+
+static ssize_t in_magn_calibration_auto_status_show(struct device *dev,
+						    struct device_attribute *a,
+						    char *buf)
+{
+	return bno055_get_calib_status(dev, buf, BNO055_CALIB_STAT_MAGN_SHIFT);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int bno055_debugfs_reg_access(struct iio_dev *iio_dev, unsigned int reg,
+				     unsigned int writeval, unsigned int *readval)
+{
+	struct bno055_priv *priv = iio_priv(iio_dev);
+
+	if (readval)
+		return regmap_read(priv->regmap, reg, readval);
+	else
+		return regmap_write(priv->regmap, reg, writeval);
+}
+
+static ssize_t bno055_show_fw_version(struct file *file, char __user *userbuf,
+				      size_t count, loff_t *ppos)
+{
+	struct bno055_priv *priv = file->private_data;
+	int rev, ver;
+	char *buf;
+	int ret;
+
+	ret = regmap_read(priv->regmap, BNO055_SW_REV_LSB_REG, &rev);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(priv->regmap, BNO055_SW_REV_MSB_REG, &ver);
+	if (ret)
+		return ret;
+
+	buf = kasprintf(GFP_KERNEL, "ver: 0x%x, rev: 0x%x\n", ver, rev);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
+	kfree(buf);
+
+	return ret;
+}
+
+static const struct file_operations bno055_fw_version_ops = {
+	.open = simple_open,
+	.read = bno055_show_fw_version,
+	.llseek = default_llseek,
+	.owner = THIS_MODULE,
+};
+
+static void bno055_debugfs_remove(void *debugfs)
+{
+	debugfs_remove((struct dentry *)debugfs);
+}
+
+static void bno055_debugfs_init(struct iio_dev *iio_dev)
+{
+	struct bno055_priv *priv = iio_priv(iio_dev);
+
+	priv->debugfs = debugfs_create_file("firmware_version", 0400,
+					    iio_get_debugfs_dentry(iio_dev),
+					    priv, &bno055_fw_version_ops);
+
+	devm_add_action_or_reset(priv->dev, bno055_debugfs_remove, priv->debugfs);
+}
+#else
+static void bno055_debugfs_init(struct iio_dev *iio_dev)
+{
+}
+
+int bno055_debugfs_reg_access(struct iio_dev *iio_dev, unsigned int reg,
+			      unsigned int writeval, unsigned int *readval)
+{
+	return 0;
+}
+#endif
+
+static IIO_DEVICE_ATTR(fusion_enable, 0644,
+		       bno055_fusion_enable_show,
+		       bno055_fusion_enable_store, 0);
+
+static IIO_DEVICE_ATTR(in_magn_calibration_fast_enable, 0644,
+		       bno055_fmc_enable_show,
+		       bno055_fmc_enable_store, 0);
+
+static IIO_DEVICE_ATTR(in_accel_range_raw, 0644,
+		       bno055_in_accel_range_show,
+		       bno055_in_accel_range_store, 0);
+
+static IIO_DEVICE_ATTR_RO(in_accel_range_raw_available, 0);
+
+static IIO_DEVICE_ATTR_RO(sys_calibration_auto_status, 0);
+static IIO_DEVICE_ATTR_RO(in_accel_calibration_auto_status, 0);
+static IIO_DEVICE_ATTR_RO(in_gyro_calibration_auto_status, 0);
+static IIO_DEVICE_ATTR_RO(in_magn_calibration_auto_status, 0);
+
+static IIO_DEVICE_ATTR_RO(serialnumber, 0);
+
+static struct attribute *bno055_attrs[] = {
+	&iio_dev_attr_in_accel_range_raw_available.dev_attr.attr,
+	&iio_dev_attr_in_accel_range_raw.dev_attr.attr,
+	&iio_dev_attr_fusion_enable.dev_attr.attr,
+	&iio_dev_attr_in_magn_calibration_fast_enable.dev_attr.attr,
+	&iio_dev_attr_sys_calibration_auto_status.dev_attr.attr,
+	&iio_dev_attr_in_accel_calibration_auto_status.dev_attr.attr,
+	&iio_dev_attr_in_gyro_calibration_auto_status.dev_attr.attr,
+	&iio_dev_attr_in_magn_calibration_auto_status.dev_attr.attr,
+	&iio_dev_attr_serialnumber.dev_attr.attr,
+	NULL
+};
+
+static BIN_ATTR_RO(calibration_data, BNO055_CALDATA_LEN);
+
+static struct bin_attribute *bno055_bin_attrs[] = {
+	&bin_attr_calibration_data,
+	NULL
+};
+
+static const struct attribute_group bno055_attrs_group = {
+	.attrs = bno055_attrs,
+	.bin_attrs = bno055_bin_attrs,
+};
+
+static const struct iio_info bno055_info = {
+	.read_raw_multi = bno055_read_raw_multi,
+	.read_avail = bno055_read_avail,
+	.write_raw = bno055_write_raw,
+	.attrs = &bno055_attrs_group,
+	.debugfs_reg_access = bno055_debugfs_reg_access,
+};
+
+/*
+ * Reads len samples from the HW, stores them in buf starting from buf_idx,
+ * and applies mask to cull (skip) unneeded samples.
+ * Updates buf_idx incrementing with the number of stored samples.
+ * Samples from HW are transferred into buf, then in-place copy on buf is
+ * performed in order to cull samples that need to be skipped.
+ * This avoids copies of the first samples until we hit the 1st sample to skip,
+ * and also avoids having an extra bounce buffer.
+ * buf must be able to contain len elements in spite of how many samples we are
+ * going to cull.
+ */
+static int bno055_scan_xfer(struct bno055_priv *priv,
+			    int start_ch, int len, unsigned long mask,
+			    __le16 *buf, int *buf_idx)
+{
+	const int base = BNO055_ACC_DATA_X_LSB_REG;
+	bool quat_in_read = false;
+	int buf_base = *buf_idx;
+	__le16 *dst, *src;
+	int offs_fixup = 0;
+	int xfer_len = len;
+	int ret;
+	int i, n;
+
+	if (!mask)
+		return 0;
+
+	/*
+	 * All chans are made up 1 16-bit sample, except for quaternion that is
+	 * made up 4 16-bit values.
+	 * For us the quaternion CH is just like 4 regular CHs.
+	 * If our read starts past the quaternion make sure to adjust the
+	 * starting offset; if the quaternion is contained in our scan then make
+	 * sure to adjust the read len.
+	 */
+	if (start_ch > BNO055_SCAN_QUATERNION) {
+		start_ch += 3;
+	} else if ((start_ch <= BNO055_SCAN_QUATERNION) &&
+		 ((start_ch + len) > BNO055_SCAN_QUATERNION)) {
+		quat_in_read = true;
+		xfer_len += 3;
+	}
+
+	ret = regmap_bulk_read(priv->regmap,
+			       base + start_ch * sizeof(__le16),
+			       buf + buf_base,
+			       xfer_len * sizeof(__le16));
+	if (ret)
+		return ret;
+
+	for_each_set_bit(i, &mask, len) {
+		if (quat_in_read && ((start_ch + i) > BNO055_SCAN_QUATERNION))
+			offs_fixup = 3;
+
+		dst = buf + *buf_idx;
+		src = buf + buf_base + offs_fixup + i;
+
+		n = (start_ch + i == BNO055_SCAN_QUATERNION) ? 4 : 1;
+
+		if (dst != src)
+			memcpy(dst, src, n * sizeof(__le16));
+
+		*buf_idx += n;
+	}
+	return 0;
+}
+
+static irqreturn_t bno055_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *iio_dev = pf->indio_dev;
+	struct bno055_priv *priv = iio_priv(iio_dev);
+	int xfer_start, start, end, prev_end;
+	unsigned long mask;
+	int quat_extra_len;
+	bool first = true;
+	int buf_idx = 0;
+	bool thr_hit;
+	int ret;
+
+	mutex_lock(&priv->lock);
+
+	/*
+	 * Walk the bitmap and eventually perform several transfers.
+	 * Bitmap ones-fileds that are separated by gaps <= xfer_burst_break_thr
+	 * will be included in same transfer.
+	 * Every time the bitmap contains a gap wider than xfer_burst_break_thr
+	 * then we split the transfer, skipping the gap.
+	 */
+	for_each_set_bitrange(start, end, iio_dev->active_scan_mask,
+			      iio_dev->masklength) {
+		/*
+		 * First transfer will start from the beginnig of the first
+		 * ones-field in the bitmap
+		 */
+		if (first)
+			xfer_start = start;
+
+		/*
+		 * We found the next ones-field; check whether to include it in
+		 * the current transfer or not (i.e. let's perform the current
+		 * transfer and prepare for another one).
+		 */
+		if (!first) {
+			/*
+			 * In case the zeros-gap contains the quaternion bit,
+			 * then its length is actually 4 words instead of 1
+			 * (i.e. +3 wrt other channels).
+			 */
+			quat_extra_len = ((start > BNO055_SCAN_QUATERNION) &&
+					  (prev_end <= BNO055_SCAN_QUATERNION)) ? 3 : 0;
+
+			/* If the gap is wider than xfer_burst_break_thr then.. */
+			thr_hit = (start - prev_end + quat_extra_len) >
+				priv->xfer_burst_break_thr;
+
+			/*
+			 * .. transfer all the data up to the gap. Then set the
+			 * next transfer start index at right after the gap
+			 * (i.e. at the start of this ones-field).
+			 */
+			if (thr_hit) {
+				mask = *iio_dev->active_scan_mask >> xfer_start;
+				ret = bno055_scan_xfer(priv, xfer_start,
+						       prev_end - xfer_start,
+						       mask, priv->buf.chans, &buf_idx);
+				if (ret)
+					goto done;
+				xfer_start = start;
+			}
+		}
+		first = false;
+		prev_end = end;
+	}
+
+	/*
+	 * We finished walking the bitmap; no more gaps to check for. Just
+	 * perform the current transfer.
+	 */
+	mask = *iio_dev->active_scan_mask >> xfer_start;
+	ret = bno055_scan_xfer(priv, xfer_start,
+			       prev_end - xfer_start,
+			       mask, priv->buf.chans, &buf_idx);
+
+	iio_push_to_buffers_with_timestamp(iio_dev, &priv->buf, pf->timestamp);
+done:
+	mutex_unlock(&priv->lock);
+	iio_trigger_notify_done(iio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+static int bno055_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct bno055_priv *priv = iio_priv(indio_dev);
+	const unsigned long fusion_mask =
+		BIT(BNO055_SCAN_YAW) |
+		BIT(BNO055_SCAN_ROLL) |
+		BIT(BNO055_SCAN_PITCH) |
+		BIT(BNO055_SCAN_QUATERNION) |
+		BIT(BNO055_SCAN_LIA_X) |
+		BIT(BNO055_SCAN_LIA_Y) |
+		BIT(BNO055_SCAN_LIA_Z) |
+		BIT(BNO055_SCAN_GRAVITY_X) |
+		BIT(BNO055_SCAN_GRAVITY_Y) |
+		BIT(BNO055_SCAN_GRAVITY_Z);
+
+	if (priv->operation_mode == BNO055_OPR_MODE_AMG &&
+	    bitmap_intersects(indio_dev->active_scan_mask, &fusion_mask,
+			      _BNO055_SCAN_MAX))
+		return -EBUSY;
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops bno055_buffer_setup_ops = {
+	.preenable = bno055_buffer_preenable,
+};
+
+static void bno055_clk_disable(void *arg)
+{
+	clk_disable_unprepare((struct clk *)arg);
+}
+
+int bno055_probe(struct device *dev, struct regmap *regmap,
+		 int xfer_burst_break_thr, bool sw_reset)
+{
+	const struct firmware *caldata = NULL;
+	const u8 *caldata_data = NULL;
+	struct bno055_priv *priv;
+	struct iio_dev *iio_dev;
+	int caldata_size = 0;
+	char *fw_name_buf;
+	unsigned int val;
+	int rev, ver;
+	int ret;
+
+	iio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!iio_dev)
+		return -ENOMEM;
+
+	iio_dev->name = "bno055";
+	priv = iio_priv(iio_dev);
+	mutex_init(&priv->lock);
+	priv->regmap = regmap;
+	priv->dev = dev;
+	priv->xfer_burst_break_thr = xfer_burst_break_thr;
+	priv->sw_reset = sw_reset;
+
+	priv->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->reset_gpio), "Failed to get reset GPIO");
+
+	priv->clk = devm_clk_get_optional(dev, "clk");
+	if (IS_ERR(priv->clk))
+		return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get CLK");
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, bno055_clk_disable, priv->clk);
+	if (ret)
+		return ret;
+
+	if (priv->reset_gpio) {
+		usleep_range(5000, 10000);
+		gpiod_set_value_cansleep(priv->reset_gpio, 1);
+		usleep_range(650000, 750000);
+	} else {
+		if (!sw_reset)
+			dev_warn(dev, "No usable reset method; IMU may be unreliable");
+	}
+
+	ret = regmap_read(priv->regmap, BNO055_CHIP_ID_REG, &val);
+	if (ret)
+		return ret;
+
+	if (val != BNO055_CHIP_ID_MAGIC)
+		dev_warn(dev, "Unrecognized chip ID 0x%x", val);
+
+	/*
+	 * In case we haven't a HW reset pin, we can still reset the chip via
+	 * register write. This is probably nonsense in case we can't even
+	 * communicate with the chip or the chip isn't the one we expect (i.e.
+	 * we don't write to unknown chips), so we perform SW reset only after
+	 * chip magic ID check
+	 */
+	if (!priv->reset_gpio) {
+		ret = bno055_system_reset(priv);
+		if (ret)
+			return ret;
+	}
+
+	ret = regmap_read(priv->regmap, BNO055_SW_REV_LSB_REG, &rev);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(priv->regmap, BNO055_SW_REV_MSB_REG, &ver);
+	if (ret)
+		return ret;
+
+	/*
+	 * Seems that stock FW version conains a bug (see comment at the
+	 * beginning of this file) that causes the anglvel scale to be changed
+	 * depending by the chip range setting. We workaround this, but we don't
+	 * know what other FW version might do..
+	 */
+	if (ver != 0x3 || rev != 0x11)
+		dev_warn(dev, "Untested firmware version. Anglvel scale may not work as expected");
+
+	ret = regmap_bulk_read(priv->regmap, BNO055_UID_LOWER_REG,
+			       priv->uid, BNO055_UID_LEN);
+	if (ret)
+		return ret;
+
+	/* Sensor calibration data */
+	fw_name_buf = kasprintf(GFP_KERNEL,
+				BNO055_FW_UID_NAME,
+				BNO055_UID_LEN, priv->uid);
+	if (!fw_name_buf)
+		return -ENOMEM;
+
+	ret = request_firmware(&caldata, fw_name_buf, dev);
+	kfree(fw_name_buf);
+	if (ret)
+		ret = request_firmware(&caldata, BNO055_FW_GENERIC_NAME, dev);
+
+	if (ret)
+		dev_notice(dev, "Calibration file load failed. See instruction in kernel Documentation/iio/bno055.rst");
+
+	if (caldata) {
+		caldata_data = caldata->data;
+		caldata_size = caldata->size;
+	}
+	ret = bno055_init(priv, caldata_data, caldata_size);
+	if (caldata)
+		release_firmware(caldata);
+	if (ret)
+		return ret;
+
+	priv->operation_mode = BNO055_OPR_MODE_FUSION;
+	ret = bno055_operation_mode_do_set(priv, priv->operation_mode);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, bno055_uninit, priv);
+	if (ret)
+		return ret;
+
+	iio_dev->channels = bno055_channels;
+	iio_dev->num_channels = ARRAY_SIZE(bno055_channels);
+	iio_dev->info = &bno055_info;
+	iio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = devm_iio_triggered_buffer_setup(dev, iio_dev,
+					      iio_pollfunc_store_time,
+					      bno055_trigger_handler,
+					      &bno055_buffer_setup_ops);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_device_register(dev, iio_dev);
+	if (ret)
+		return ret;
+
+	bno055_debugfs_init(iio_dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(bno055_probe, IIO_BNO055);
+
+MODULE_AUTHOR("Andrea Merello <andrea.merello@iit.it>");
+MODULE_DESCRIPTION("Bosch BNO055 driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/iio/imu/bno055/bno055.h b/drivers/iio/imu/bno055/bno055.h
new file mode 100644
index 000000000000..2ccb373c61cd
--- /dev/null
+++ b/drivers/iio/imu/bno055/bno055.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __BNO055_H__
+#define __BNO055_H__
+
+#include <linux/regmap.h>
+
+struct device;
+int bno055_probe(struct device *dev, struct regmap *regmap,
+		 int xfer_burst_break_thr, bool sw_reset);
+extern const struct regmap_config bno055_regmap_config;
+
+#endif
-- 
2.17.1

[v5 09/14] iio: document bno055 private sysfs attributes

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add ABI documentation for bno055 driver private sysfs attributes.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 .../ABI/testing/sysfs-bus-iio-bno055          | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-bno055

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-bno055 b/Documentation/ABI/testing/sysfs-bus-iio-bno055
new file mode 100644
index 000000000000..22a5c6dc90dc
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-bno055
@@ -0,0 +1,81 @@
+What:		/sys/bus/iio/devices/iio:deviceX/in_accel_raw_range
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Raw (unscaled) range for acceleration readings. Unit after
+		application of scale is m/s^2. Note that this doesn't affects
+		the scale (which should be used when changing the maximum and
+		minimum readable value affects also the reading scaling factor).
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_anglvel_raw_range
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Range for angular velocity readings in radians per second. Note
+		that this does not affects the scale (which should be used when
+		changing the maximum and minimum readable value affects also the
+		reading scaling factor).
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_accel_raw_range_available
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		List of allowed values for in_accel_raw_range attribute
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_anglvel_raw_range_available
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		List of allowed values for in_anglvel_raw_range attribute
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_magn_calibration_fast_enable
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Can be 1 or 0. Enables/disables the "Fast Magnetometer
+		Calibration" HW function.
+
+What:		/sys/bus/iio/devices/iio:deviceX/fusion_enable
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Can be 1 or 0. Enables/disables the "sensor fusion" (a.k.a.
+		NDOF) HW function.
+
+What:		/sys/bus/iio/devices/iio:deviceX/calibration_data
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reports the binary calibration data blob for the IMU sensors.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_accel_calibration_auto_status
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reports the autocalibration status for the accelerometer sensor.
+		Can be 0 (calibration non even enabled) or 1 to 5 where the greater
+		the number, the better the calibration status.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_gyro_calibration_auto_status
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reports the autocalibration status for the gyroscope sensor.
+		Can be 0 (calibration non even enabled) or 1 to 5 where the greater
+		the number, the better the calibration status.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_magn_calibration_auto_status
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reports the autocalibration status for the magnetometer sensor.
+		Can be 0 (calibration non even enabled) or 1 to 5 where the greater
+		the number, the better the calibration status.
+
+What:		/sys/bus/iio/devices/iio:deviceX/sys_calibration_auto_status
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reports the status for the IMU overall autocalibration.
+		Can be 0 (calibration non even enabled) or 1 to 5 where the greater
+		the number, the better the calibration status.
-- 
2.17.1

[v5 10/14] iio: document "serialnumber" sysfs attribute

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add ABI documentation for the new "serialnumber" sysfs attribute. The
first user is the bno055 IIO driver.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 Documentation/ABI/testing/sysfs-bus-iio | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 2a6954ea1c71..eadf0326a56e 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -2048,3 +2048,10 @@ Contact:	linux-iio@vger.kernel.org
 Description:
 		Raw (unscaled) euler angles readings. Units after
 		application of scale are deg.
+
+What:		/sys/bus/iio/devices/iio:deviceX/serialnumber
+KernelVersion:	5.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		An example format is 16-bytes, 2-digits-per-byte, HEX-string
+		representing the sensor unique ID number.
-- 
2.17.1

[v5 11/14] dt-bindings: iio/imu: Add Bosch BNO055

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Introduce new documentation file for the Bosch BNO055 IMU.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../bindings/iio/imu/bosch,bno055.yaml        | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml

diff --git a/Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml b/Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml
new file mode 100644
index 000000000000..e0d06db161a9
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/imu/bosch,bno055.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bosch BNO055
+
+maintainers:
+  - Andrea Merello <andrea.merello@iit.it>
+
+description: |
+  Inertial Measurement Unit with Accelerometer, Gyroscope, Magnetometer and
+  internal MCU for sensor fusion
+  https://www.bosch-sensortec.com/products/smart-sensors/bno055/
+
+properties:
+  compatible:
+    enum:
+      - bosch,bno055
+
+  reg:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+required:
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    serial {
+      imu {
+        compatible = "bosch,bno055";
+        reset-gpios = <&gpio0 54 GPIO_ACTIVE_LOW>;
+        clocks = <&imu_clk>;
+      };
+    };
+
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      imu@28 {
+        compatible = "bosch,bno055";
+        reg = <0x28>;
+        reset-gpios = <&gpio0 54 GPIO_ACTIVE_LOW>;
+        clocks = <&imu_clk>;
+      };
+    };
-- 
2.17.1

[v5 12/14] iio: imu: add BNO055 serdev driver

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add a serdev driver for communicating to a BNO055 IMU via serial bus, and
enable the BNO055 core driver to work in this scenario.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 drivers/iio/imu/bno055/Kconfig            |  10 +
 drivers/iio/imu/bno055/Makefile           |   5 +
 drivers/iio/imu/bno055/bno055_ser_core.c  | 560 ++++++++++++++++++++++
 drivers/iio/imu/bno055/bno055_ser_trace.h | 104 ++++
 4 files changed, 679 insertions(+)
 create mode 100644 drivers/iio/imu/bno055/bno055_ser_core.c
 create mode 100644 drivers/iio/imu/bno055/bno055_ser_trace.h

diff --git a/drivers/iio/imu/bno055/Kconfig b/drivers/iio/imu/bno055/Kconfig
index d0ab3221fba5..d014b68cd43d 100644
--- a/drivers/iio/imu/bno055/Kconfig
+++ b/drivers/iio/imu/bno055/Kconfig
@@ -2,3 +2,13 @@
 
 config BOSCH_BNO055_IIO
 	tristate
+
+config BOSCH_BNO055_SERIAL
+	tristate "Bosch BNO055 attached via UART"
+	depends on SERIAL_DEV_BUS
+	select BOSCH_BNO055_IIO
+	help
+	  Enable this to support Bosch BNO055 IMUs attached via UART.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bno055_sl.
diff --git a/drivers/iio/imu/bno055/Makefile b/drivers/iio/imu/bno055/Makefile
index 56cc4de60a7e..212307ce9c08 100644
--- a/drivers/iio/imu/bno055/Makefile
+++ b/drivers/iio/imu/bno055/Makefile
@@ -1,3 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_BOSCH_BNO055_IIO) += bno055.o
+obj-$(CONFIG_BOSCH_BNO055_SERIAL) += bno055_ser.o
+bno055_ser-y := bno055_ser_core.o
+# define_trace.h needs to know how to find our header
+CFLAGS_bno055_ser_trace.o := -I$(src)
+bno055_ser-$(CONFIG_TRACING) += bno055_ser_trace.o
diff --git a/drivers/iio/imu/bno055/bno055_ser_core.c b/drivers/iio/imu/bno055/bno055_ser_core.c
new file mode 100644
index 000000000000..235131900260
--- /dev/null
+++ b/drivers/iio/imu/bno055/bno055_ser_core.c
@@ -0,0 +1,560 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Serial line interface for Bosh BNO055 IMU (via serdev).
+ * This file implements serial communication up to the register read/write
+ * level.
+ *
+ * Copyright (C) 2021-2022 Istituto Italiano di Tecnologia
+ * Electronic Design Laboratory
+ * Written by Andrea Merello <andrea.merello@iit.it>
+ *
+ * This driver is besed on
+ *	Plantower PMS7003 particulate matter sensor driver
+ *	Which is
+ *	Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/serdev.h>
+
+#include "bno055_ser_trace.h"
+#include "bno055.h"
+
+/*
+ * Register writes cmd have the following format
+ * +------+------+-----+-----+----- ... ----+
+ * | 0xAA | 0xOO | REG | LEN | payload[LEN] |
+ * +------+------+-----+-----+----- ... ----+
+ *
+ * Register write responses have the following format
+ * +------+----------+
+ * | 0xEE | ERROCODE |
+ * +------+----------+
+ *
+ * .. except when writing the SYS_RST bit (i.e. triggering a system reset); in
+ * case the IMU accepts the command, then it resets without responding. We don't
+ * handle this (yet) here (so we inform the common bno055 code not to perform
+ * sw resets - bno055 on serial bus basically requires the hw reset pin).
+ *
+ * Register read have the following format
+ * +------+------+-----+-----+
+ * | 0xAA | 0xO1 | REG | LEN |
+ * +------+------+-----+-----+
+ *
+ * Successful register read response have the following format
+ * +------+-----+----- ... ----+
+ * | 0xBB | LEN | payload[LEN] |
+ * +------+-----+----- ... ----+
+ *
+ * Failed register read response have the following format
+ * +------+--------+
+ * | 0xEE | ERRCODE|  (ERRCODE always > 1)
+ * +------+--------+
+ *
+ * Error codes are
+ * 01: OK
+ * 02: read/write FAIL
+ * 04: invalid address
+ * 05: write on RO
+ * 06: wrong start byte
+ * 07: bus overrun
+ * 08: len too high
+ * 09: len too low
+ * 10: bus RX byte timeout (timeout is 30mS)
+ *
+ *
+ * **WORKAROUND ALERT**
+ *
+ * Serial communication seems very fragile: the BNO055 buffer seems to overflow
+ * very easy; BNO055 seems able to sink few bytes, then it needs a brief pause.
+ * On the other hand, it is also picky on timeout: if there is a pause > 30mS in
+ * between two bytes then the transaction fails (IMU internal RX FSM resets).
+ *
+ * BNO055 has been seen also failing to process commands in case we send them
+ * too close each other (or if it is somehow busy?)
+ *
+ * In particular I saw these scenarios:
+ * 1) If we send 2 bytes per time, then the IMU never(?) overflows.
+ * 2) If we send 4 bytes per time (i.e. the full header), then the IMU could
+ *    overflow, but it seem to sink all 4 bytes, then it returns error.
+ * 3) If we send more than 4 bytes, the IMU could overflow, and I saw it sending
+ *    error after 4 bytes are sent; we have troubles in synchronizing again,
+ *    because we are still sending data, and the IMU interprets it as the 1st
+ *    byte of a new command.
+ *
+ * While we must avoid case 3, we could send 4 bytes per time and eventually
+ * retry in case of failure; this seemed convenient for reads (which requires
+ * TXing exactly 4 bytes), however it has been seen that, depending by the IMU
+ * settings (e.g. LPF), failures became less or more frequent; in certain IMU
+ * configurations they are very rare, but in certain others we keeps failing
+ * even after like 30 retries.
+ *
+ * So, we just split TXes in [2-bytes + delay] steps, and still keep an eye on
+ * the IMU response; in case it overflows (which is now unlikely), we retry.
+ */
+
+/*
+ * Read operation overhead:
+ *  4 bytes req + 2byte resp hdr.
+ *  6 bytes = 60 bit (considering 1start + 1stop bits).
+ *  60/115200 = ~520uS + about 2500mS dealay -> ~3mS
+ * In 3mS we could read back about 34 bytes that means 17 samples, this means
+ * that in case of scattered read in which the gap is 17 samples or less it is
+ * still convenient to go for a burst.
+ * We have to take into account also IMU response time - IMU seems to be often
+ * reasonably quick to respond, but sometimes it seems to be in some "critical
+ * section" in which it delays handling of serial protocol. Because of this we
+ * round-up to 22, which is the max number of samples, always bursting indeed.
+ */
+#define BNO055_SER_XFER_BURST_BREAK_THRESHOLD 22
+
+struct bno055_ser_priv {
+	enum {
+		CMD_NONE,
+		CMD_READ,
+		CMD_WRITE,
+	} expect_response;
+	int expected_data_len;
+	u8 *response_buf;
+
+	/**
+	 * enum cmd_status - represent the status of a command sent to the HW.
+	 * @STATUS_CRIT: The command failed: the serial communication failed.
+	 * @STATUS_OK:   The command executed successfully.
+	 * @STATUS_FAIL: The command failed: HW responded with an error.
+	 */
+	enum {
+		STATUS_CRIT = -1,
+		STATUS_OK = 0,
+		STATUS_FAIL = 1,
+	} cmd_status;
+
+	/*
+	 * Protects all the above fields, which are accessed in behalf of both
+	 * the serdev RX callback and the regmap side
+	 */
+	struct mutex lock;
+
+	/* Only accessed in serdev RX callback context*/
+	struct {
+		enum {
+			RX_IDLE,
+			RX_START,
+			RX_DATA,
+		} state;
+		int databuf_count;
+		int expected_len;
+		int type;
+	} rx;
+
+	/* Never accessed in behalf of serdev RX callback context */
+	bool cmd_stale;
+
+	struct completion cmd_complete;
+	struct serdev_device *serdev;
+};
+
+static int bno055_ser_send_chunk(struct bno055_ser_priv *priv, const u8 *data, int len)
+{
+	int ret;
+
+	trace_send_chunk(len, data);
+	ret = serdev_device_write(priv->serdev, data, len, msecs_to_jiffies(25));
+	if (ret < 0)
+		return ret;
+
+	if (ret < len)
+		return -EIO;
+
+	return 0;
+}
+
+/*
+ * Sends a read or write command.
+ * 'data' can be NULL (used in read case). 'len' parameter is always valid; in
+ * case 'data' is non-NULL then it must match 'data' size.
+ */
+static int bno055_ser_do_send_cmd(struct bno055_ser_priv *priv,
+				  bool read, int addr, int len, const u8 *data)
+{
+	u8 hdr[] = {0xAA, read, addr, len};
+	int chunk_len;
+	int ret;
+
+	ret = bno055_ser_send_chunk(priv, hdr, 2);
+	if (ret)
+		goto fail;
+	usleep_range(2000, 3000);
+	ret = bno055_ser_send_chunk(priv, hdr + 2, 2);
+	if (ret)
+		goto fail;
+
+	if (read)
+		return 0;
+
+	while (len) {
+		chunk_len = min(len, 2);
+		usleep_range(2000, 3000);
+		ret = bno055_ser_send_chunk(priv, data, chunk_len);
+		if (ret)
+			goto fail;
+		data += chunk_len;
+		len -= chunk_len;
+	}
+
+	return 0;
+fail:
+	/* waiting more than 30mS should clear the BNO055 internal state */
+	usleep_range(40000, 50000);
+	return ret;
+}
+
+static int bno055_ser_send_cmd(struct bno055_ser_priv *priv,
+			       bool read, int addr, int len, const u8 *data)
+{
+	const int retry_max = 5;
+	int retry = retry_max;
+	int ret = 0;
+
+	/*
+	 * In case previous command was interrupted we still need to wait it to
+	 * complete before we can issue new commands
+	 */
+	if (priv->cmd_stale) {
+		ret = wait_for_completion_interruptible_timeout(&priv->cmd_complete,
+								msecs_to_jiffies(100));
+		if (ret == -ERESTARTSYS)
+			return -ERESTARTSYS;
+
+		priv->cmd_stale = false;
+		/* if serial protocol broke, bail out */
+		if (priv->cmd_status == STATUS_CRIT)
+			return -EIO;
+	}
+
+	/*
+	 * Try to convince the IMU to cooperate.. as explained in the comments
+	 * at the top of this file, the IMU could also refuse the command (i.e.
+	 * it is not ready yet); retry in this case.
+	 */
+	do {
+		mutex_lock(&priv->lock);
+		priv->expect_response = read ? CMD_READ : CMD_WRITE;
+		reinit_completion(&priv->cmd_complete);
+		mutex_unlock(&priv->lock);
+
+		if (retry != retry_max)
+			trace_cmd_retry(read, addr, retry_max - retry);
+		ret = bno055_ser_do_send_cmd(priv, read, addr, len, data);
+		if (ret)
+			continue;
+
+		ret = wait_for_completion_interruptible_timeout(&priv->cmd_complete,
+								msecs_to_jiffies(100));
+		if (ret == -ERESTARTSYS) {
+			priv->cmd_stale = true;
+			return -ERESTARTSYS;
+		}
+
+		if (!ret)
+			return -ETIMEDOUT;
+
+		if (priv->cmd_status == STATUS_OK)
+			return 0;
+		if (priv->cmd_status == STATUS_CRIT)
+			return -EIO;
+
+		/* loop in case priv->cmd_status == STATUS_FAIL */
+	} while (--retry);
+
+	if (ret < 0)
+		return ret;
+	if (priv->cmd_status == STATUS_FAIL)
+		return -EINVAL;
+	return 0;
+}
+
+static int bno055_ser_write_reg(void *context, const void *_data, size_t count)
+{
+	const u8 *data = _data;
+	struct bno055_ser_priv *priv = context;
+
+	if (count < 2) {
+		dev_err(&priv->serdev->dev, "Invalid write count %zu", count);
+		return -EINVAL;
+	}
+
+	trace_write_reg(data[0], data[1]);
+	return bno055_ser_send_cmd(priv, 0, data[0], count - 1, data + 1);
+}
+
+static int bno055_ser_read_reg(void *context,
+			       const void *_reg, size_t reg_size,
+			       void *val, size_t val_size)
+{
+	int ret;
+	int reg_addr;
+	const u8 *reg = _reg;
+	struct bno055_ser_priv *priv = context;
+
+	if (val_size > 128) {
+		dev_err(&priv->serdev->dev, "Invalid read valsize %zu", val_size);
+		return -EINVAL;
+	}
+
+	reg_addr = *reg;
+	trace_read_reg(reg_addr, val_size);
+	mutex_lock(&priv->lock);
+	priv->expected_data_len = val_size;
+	priv->response_buf = val;
+	mutex_unlock(&priv->lock);
+
+	ret = bno055_ser_send_cmd(priv, 1, reg_addr, val_size, NULL);
+
+	mutex_lock(&priv->lock);
+	priv->response_buf = NULL;
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+/*
+ * Handler for received data; this is called from the reicever callback whenever
+ * it got some packet from the serial bus. The status tell us whether the
+ * packet is valid (i.e. header ok && received payload len consistent wrt the
+ * header). It's now our responsability to check whether this is what we
+ * expected, of whether we got some unexpected, yet valid, packet.
+ */
+static void bno055_ser_handle_rx(struct bno055_ser_priv *priv, int status)
+{
+	mutex_lock(&priv->lock);
+	switch (priv->expect_response) {
+	case CMD_NONE:
+		dev_warn(&priv->serdev->dev, "received unexpected, yet valid, data from sensor");
+		mutex_unlock(&priv->lock);
+		return;
+
+	case CMD_READ:
+		priv->cmd_status = status;
+		if (status == STATUS_OK &&
+		    priv->rx.databuf_count != priv->expected_data_len) {
+			/*
+			 * If we got here, then the lower layer serial protocol
+			 * seems consistent with itself; if we got an unexpected
+			 * amount of data then signal it as a non critical error
+			 */
+			priv->cmd_status = STATUS_FAIL;
+			dev_warn(&priv->serdev->dev,
+				 "received an unexpected amount of, yet valid, data from sensor");
+		}
+		break;
+
+	case CMD_WRITE:
+		priv->cmd_status = status;
+		break;
+	}
+
+	priv->expect_response = CMD_NONE;
+	mutex_unlock(&priv->lock);
+	complete(&priv->cmd_complete);
+}
+
+/*
+ * Serdev receiver FSM. This tracks the serial communication and parse the
+ * header. It pushes packets to bno055_ser_handle_rx(), eventually communicating
+ * failures (i.e. malformed packets).
+ * Ideally it doesn't know anything about upper layer (i.e. if this is the
+ * packet we were really expecting), but since we copies the payload into the
+ * receiver buffer (that is not valid when i.e. we don't expect data), we
+ * snoop a bit in the upper layer..
+ * Also, we assume to RX one pkt per time (i.e. the HW doesn't send anything
+ * unless we require to AND we don't queue more than one request per time).
+ */
+static int bno055_ser_receive_buf(struct serdev_device *serdev,
+				  const unsigned char *buf, size_t size)
+{
+	int status;
+	struct bno055_ser_priv *priv = serdev_device_get_drvdata(serdev);
+	int remaining = size;
+
+	if (size == 0)
+		return 0;
+
+	trace_recv(size, buf);
+	switch (priv->rx.state) {
+	case RX_IDLE:
+		/*
+		 * New packet.
+		 * Check for its 1st byte, that identifies the pkt type.
+		 */
+		if (buf[0] != 0xEE && buf[0] != 0xBB) {
+			dev_err(&priv->serdev->dev,
+				"Invalid packet start %x", buf[0]);
+			bno055_ser_handle_rx(priv, STATUS_CRIT);
+			break;
+		}
+		priv->rx.type = buf[0];
+		priv->rx.state = RX_START;
+		remaining--;
+		buf++;
+		priv->rx.databuf_count = 0;
+		fallthrough;
+
+	case RX_START:
+		/*
+		 * Packet RX in progress, we expect either 1-byte len or 1-byte
+		 * status depending by the packet type.
+		 */
+		if (remaining == 0)
+			break;
+
+		if (priv->rx.type == 0xEE) {
+			if (remaining > 1) {
+				dev_err(&priv->serdev->dev, "EE pkt. Extra data received");
+				status = STATUS_CRIT;
+			} else {
+				status = (buf[0] == 1) ? STATUS_OK : STATUS_FAIL;
+			}
+			bno055_ser_handle_rx(priv, status);
+			priv->rx.state = RX_IDLE;
+			break;
+
+		} else {
+			/*priv->rx.type == 0xBB */
+			priv->rx.state = RX_DATA;
+			priv->rx.expected_len = buf[0];
+			remaining--;
+			buf++;
+		}
+		fallthrough;
+
+	case RX_DATA:
+		/* Header parsed; now receiving packet data payload */
+		if (remaining == 0)
+			break;
+
+		if (priv->rx.databuf_count + remaining > priv->rx.expected_len) {
+			/*
+			 * This is an inconsistency in serial protocol, we lost
+			 * sync and we don't know how to handle further data
+			 */
+			dev_err(&priv->serdev->dev, "BB pkt. Extra data received");
+			bno055_ser_handle_rx(priv, STATUS_CRIT);
+			priv->rx.state = RX_IDLE;
+			break;
+		}
+
+		mutex_lock(&priv->lock);
+		/*
+		 * NULL e.g. when read cmd is stale or when no read cmd is
+		 * actually pending.
+		 */
+		if (priv->response_buf &&
+		    /*
+		     * Snoop on the upper layer protocol stuff to make sure not
+		     * to write to an invalid memory. Apart for this, let's the
+		     * upper layer manage any inconsistency wrt expected data
+		     * len (as long as the serial protocol is consistent wrt
+		     * itself (i.e. response header is consistent with received
+		     * response len.
+		     */
+		    (priv->rx.databuf_count + remaining <= priv->expected_data_len))
+			memcpy(priv->response_buf + priv->rx.databuf_count,
+			       buf, remaining);
+		mutex_unlock(&priv->lock);
+
+		priv->rx.databuf_count += remaining;
+
+		/*
+		 * Reached expected len advertised by the IMU for the current
+		 * packet. Pass it to the upper layer (for us it is just valid).
+		 */
+		if (priv->rx.databuf_count == priv->rx.expected_len) {
+			bno055_ser_handle_rx(priv, STATUS_OK);
+			priv->rx.state = RX_IDLE;
+		}
+		break;
+	}
+
+	return size;
+}
+
+static const struct serdev_device_ops bno055_ser_serdev_ops = {
+	.receive_buf = bno055_ser_receive_buf,
+	.write_wakeup = serdev_device_write_wakeup,
+};
+
+static struct regmap_bus bno055_ser_regmap_bus = {
+	.write = bno055_ser_write_reg,
+	.read = bno055_ser_read_reg,
+};
+
+static int bno055_ser_probe(struct serdev_device *serdev)
+{
+	struct bno055_ser_priv *priv;
+	struct regmap *regmap;
+	int ret;
+
+	priv = devm_kzalloc(&serdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	serdev_device_set_drvdata(serdev, priv);
+	priv->serdev = serdev;
+	mutex_init(&priv->lock);
+	init_completion(&priv->cmd_complete);
+
+	serdev_device_set_client_ops(serdev, &bno055_ser_serdev_ops);
+	ret = devm_serdev_device_open(&serdev->dev, serdev);
+	if (ret)
+		return ret;
+
+	if (serdev_device_set_baudrate(serdev, 115200) != 115200) {
+		dev_err(&serdev->dev, "Cannot set required baud rate");
+		return -EIO;
+	}
+
+	ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
+	if (ret) {
+		dev_err(&serdev->dev, "Cannot set required parity setting");
+		return ret;
+	}
+	serdev_device_set_flow_control(serdev, false);
+
+	regmap = devm_regmap_init(&serdev->dev, &bno055_ser_regmap_bus,
+				  priv, &bno055_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(&serdev->dev, PTR_ERR(regmap),
+				     "Unable to init register map");
+
+	return bno055_probe(&serdev->dev, regmap,
+			    BNO055_SER_XFER_BURST_BREAK_THRESHOLD, false);
+}
+
+static const struct of_device_id bno055_ser_of_match[] = {
+	{ .compatible = "bosch,bno055" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, bno055_ser_of_match);
+
+static struct serdev_device_driver bno055_ser_driver = {
+	.driver = {
+		.name = "bno055-ser",
+		.of_match_table = bno055_ser_of_match,
+	},
+	.probe = bno055_ser_probe,
+};
+module_serdev_device_driver(bno055_ser_driver);
+
+MODULE_AUTHOR("Andrea Merello <andrea.merello@iit.it>");
+MODULE_DESCRIPTION("Bosch BNO055 serdev interface");
+MODULE_IMPORT_NS(IIO_BNO055);
+MODULE_LICENSE("GPL");
diff --git a/drivers/iio/imu/bno055/bno055_ser_trace.h b/drivers/iio/imu/bno055/bno055_ser_trace.h
new file mode 100644
index 000000000000..51d079b91f63
--- /dev/null
+++ b/drivers/iio/imu/bno055/bno055_ser_trace.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#if !defined(__BNO055_SERDEV_TRACE_H__) || defined(TRACE_HEADER_MULTI_READ)
+#define __BNO055_SERDEV_TRACE_H__
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bno055_ser
+
+TRACE_EVENT(send_chunk,
+	    TP_PROTO(int len, const u8 *data),
+	    TP_ARGS(len, data),
+	    TP_STRUCT__entry(
+		    __field(int, len)
+		    __dynamic_array(u8, chunk, len)
+	    ),
+	    TP_fast_assign(
+		    __entry->len = len;
+		    memcpy(__get_dynamic_array(chunk),
+			   data, __entry->len);
+	    ),
+	    TP_printk("len: %d, data: = %*ph",
+		      __entry->len, __entry->len, __get_dynamic_array(chunk)
+	    )
+);
+
+TRACE_EVENT(cmd_retry,
+	    TP_PROTO(bool read, int addr, int retry),
+	    TP_ARGS(read, addr, retry),
+	    TP_STRUCT__entry(
+		    __field(bool, read)
+		    __field(int, addr)
+		    __field(int, retry)
+	    ),
+	    TP_fast_assign(
+		    __entry->read = read;
+		    __entry->addr = addr;
+		    __entry->retry = retry;
+	    ),
+	    TP_printk("%s addr 0x%x retry #%d",
+		      __entry->read ? "read" : "write",
+		      __entry->addr, __entry->retry
+	    )
+);
+
+TRACE_EVENT(write_reg,
+	    TP_PROTO(u8 addr, u8 value),
+	    TP_ARGS(addr, value),
+	    TP_STRUCT__entry(
+		    __field(u8, addr)
+		    __field(u8, value)
+	    ),
+	    TP_fast_assign(
+		    __entry->addr = addr;
+		    __entry->value = value;
+	    ),
+	    TP_printk("reg 0x%x = 0x%x",
+		      __entry->addr, __entry->value
+	    )
+);
+
+TRACE_EVENT(read_reg,
+	    TP_PROTO(int addr, size_t len),
+	    TP_ARGS(addr, len),
+	    TP_STRUCT__entry(
+		    __field(int, addr)
+		    __field(size_t, len)
+	    ),
+	    TP_fast_assign(
+		    __entry->addr = addr;
+		    __entry->len = len;
+	    ),
+	    TP_printk("reg 0x%x (len %zu)",
+		      __entry->addr, __entry->len
+	    )
+);
+
+TRACE_EVENT(recv,
+	    TP_PROTO(size_t len, const unsigned char *buf),
+	    TP_ARGS(len, buf),
+	    TP_STRUCT__entry(
+		    __field(size_t, len)
+		    __dynamic_array(unsigned char, buf, len)
+	    ),
+	    TP_fast_assign(
+		    __entry->len = len;
+		    memcpy(__get_dynamic_array(buf),
+			   buf, __entry->len);
+	    ),
+	    TP_printk("len: %d, data: = %*ph",
+		      __entry->len, __entry->len, __get_dynamic_array(buf)
+	    )
+);
+
+#endif /* __BNO055_SERDEV_TRACE_H__ || TRACE_HEADER_MULTI_READ */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE bno055_ser_trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.17.1

[v5 13/14] iio: imu: add BNO055 I2C driver

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

Add an I2C driver for communicating to a BNO055 IMU via I2C bus and enable
the BNO055 core driver to work in this scenario.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 drivers/iio/imu/bno055/Kconfig      | 11 ++++++
 drivers/iio/imu/bno055/Makefile     |  2 +
 drivers/iio/imu/bno055/bno055_i2c.c | 57 +++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 drivers/iio/imu/bno055/bno055_i2c.c

diff --git a/drivers/iio/imu/bno055/Kconfig b/drivers/iio/imu/bno055/Kconfig
index d014b68cd43d..ccf9ea7c50f8 100644
--- a/drivers/iio/imu/bno055/Kconfig
+++ b/drivers/iio/imu/bno055/Kconfig
@@ -12,3 +12,14 @@ config BOSCH_BNO055_SERIAL
 
 	  This driver can also be built as a module. If so, the module will be
 	  called bno055_sl.
+
+config BOSCH_BNO055_I2C
+	tristate "Bosch BNO055 attached via I2C bus"
+	depends on I2C
+	select REGMAP_I2C
+	select BOSCH_BNO055_IIO
+	help
+	  Enable this to support Bosch BNO055 IMUs attached via I2C bus.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bno055_i2c.
diff --git a/drivers/iio/imu/bno055/Makefile b/drivers/iio/imu/bno055/Makefile
index 212307ce9c08..f0be80accb5b 100644
--- a/drivers/iio/imu/bno055/Makefile
+++ b/drivers/iio/imu/bno055/Makefile
@@ -6,3 +6,5 @@ bno055_ser-y := bno055_ser_core.o
 # define_trace.h needs to know how to find our header
 CFLAGS_bno055_ser_trace.o := -I$(src)
 bno055_ser-$(CONFIG_TRACING) += bno055_ser_trace.o
+
+obj-$(CONFIG_BOSCH_BNO055_I2C) += bno055_i2c.o
diff --git a/drivers/iio/imu/bno055/bno055_i2c.c b/drivers/iio/imu/bno055/bno055_i2c.c
new file mode 100644
index 000000000000..9bb256fdb0d3
--- /dev/null
+++ b/drivers/iio/imu/bno055/bno055_i2c.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support for I2C-interfaced Bosch BNO055 IMU.
+ *
+ * Copyright (C) 2021-2022 Istituto Italiano di Tecnologia
+ * Electronic Design Laboratory
+ * Written by Andrea Merello <andrea.merello@iit.it>
+ */
+
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "bno055.h"
+
+#define BNO055_I2C_XFER_BURST_BREAK_THRESHOLD 3 /* FIXME */
+
+static int bno055_i2c_probe(struct i2c_client *client)
+{
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(client, &bno055_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(regmap),
+				     "Unable to init register map");
+
+	return bno055_probe(&client->dev, regmap,
+			    BNO055_I2C_XFER_BURST_BREAK_THRESHOLD, true);
+}
+
+static const struct i2c_device_id bno055_i2c_id[] = {
+	{"bno055", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, bno055_i2c_id);
+
+static const struct of_device_id __maybe_unused bno055_i2c_of_match[] = {
+	{ .compatible = "bosch,bno055" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bno055_i2c_of_match);
+
+static struct i2c_driver bno055_driver = {
+	.driver = {
+		.name = "bno055-i2c",
+		.of_match_table = of_match_ptr(bno055_i2c_of_match),
+	},
+	.probe_new = bno055_i2c_probe,
+	.id_table = bno055_i2c_id,
+};
+module_i2c_driver(bno055_driver);
+
+MODULE_AUTHOR("Andrea Merello");
+MODULE_DESCRIPTION("Bosch BNO055 I2C interface");
+MODULE_IMPORT_NS(IIO_BNO055);
+MODULE_LICENSE("GPL");
-- 
2.17.1

[v5 14/14] docs: iio: add documentation for BNO055 driver

[Andrea Merello]

From: Andrea Merello <andrea.merello@iit.it>

The bno055 driver is rather complex and have some oddities and not-obvious
things that worth to document (e.g. calibration files).

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
---
 Documentation/iio/bno055.rst | 50 ++++++++++++++++++++++++++++++++++++
 Documentation/iio/index.rst  |  2 ++
 2 files changed, 52 insertions(+)
 create mode 100644 Documentation/iio/bno055.rst

diff --git a/Documentation/iio/bno055.rst b/Documentation/iio/bno055.rst
new file mode 100644
index 000000000000..af21376d7a25
--- /dev/null
+++ b/Documentation/iio/bno055.rst
@@ -0,0 +1,50 @@
+.. SPDX-License-Identifier: GPL-2.0
+==============================
+BNO055 driver
+==============================
+
+1. Overview
+===========
+
+This driver supports Bosch BNO055 IMUs (on both serial and I2C busses).
+
+Accelerometer, magnetometer and gyroscope measures are always provided.
+When "fusion_enable" sysfs attribute is set to 1, orientation (both Euler
+angles and quaternion), linear velocity and gravity vector are also
+provided, but some sensor settings (e.g. low pass filtering and range)
+became locked (the IMU firmware controls them).
+
+This driver supports also IIO buffers.
+
+2. Calibration
+==============
+
+The IMU continuously performs an autocalibration procedure if (and only if)
+operating in fusion mode. The magnetometer autocalibration can however be
+disabled writing 0 in the sysfs in_magn_calibration_fast_enable attribute.
+
+The driver provides access to autocalibration flags (i.e. you can known if
+the IMU has successfully autocalibrated) and to the calibration data blob.
+
+The user can save this blob in a firmware file (i.e. in /lib/firmware) that
+the driver looks for at probe time. If found, then the IMU is initialized
+with this calibration data. This saves the user from performing the
+calibration procedure every time (which consist of moving the IMU in
+various way).
+
+The driver looks for calibration data file using two different names: first
+a file whose name is suffixed with the IMU unique ID (exposed in sysfs as
+serial_number) is searched for; this is useful when there is more than one
+IMU instance. If this file is not found, then a "generic" calibration file
+is searched for (which can be used when only one IMU is present, without
+struggling with fancy names, that change on each device).
+
+Valid calibration file names would be e.g.
+ bno055-caldata-0e7c26a33541515120204a35342b04ff.dat
+ bno055-caldata.dat
+
+In non-fusion mode the IIO 'offset' attributes provide access to the
+offsets from calibration data (if any), so that the user can apply them to
+the accel, angvel and magn IIO attributes. In fusion mode they are not
+needed (the IMU firmware internally applies those corrections) and they
+read as zero.
diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
index 58b7a4ebac51..1b7292c58cd0 100644
--- a/Documentation/iio/index.rst
+++ b/Documentation/iio/index.rst
@@ -10,3 +10,5 @@ Industrial I/O
    iio_configfs
 
    ep93xx_adc
+
+   bno055
-- 
2.17.1

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[kernel test robot]

Hi Andrea,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on jic23-iio/togreg]
[also build test ERROR on linus/master linux/master v5.18-rc4 next-20220426]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220427/202204271554.EiuIRNPI-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/675ca9cd13af45cc5943dd15caad5e866fd7c971
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
        git checkout 675ca9cd13af45cc5943dd15caad5e866fd7c971
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> make[5]: *** No rule to make target 'drivers/iio/imu/bno055/bno055_ser_trace.o', needed by 'drivers/iio/imu/bno055/built-in.a'.
   make[5]: Target '__build' not remade because of errors.

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [v5 08/14] iio: imu: add Bosch Sensortec BNO055 core driver

[Andy Shevchenko]

On Tue, Apr 26, 2022 at 3:11 PM Andrea Merello <andrea.merello@gmail.com> wrote:
>
> From: Andrea Merello <andrea.merello@iit.it>
>
> Add the core driver for the BNO055 IMU from Bosch. This IMU can be
> connected via both serial and I2C busses; separate patches will add support
> for them.
>
> The driver supports "AMG" (Accelerometer, Magnetometer, Gyroscope) mode,
> that provides raw data from the said internal sensors, and a couple of
> "fusion" modes (i.e. the IMU also do calculations in order to provide euler

does

> angles, quaternions, linear acceleration and gravity measurements).
>
> In fusion modes the AMG data is still available (with some calibration
> refinements done by the IMU), but certain settings such as low pass filters
> cut-off frequency and sensors ranges are fixed, while in AMG mode they can

sensor?
sensors'?

> be customized; this is why AMG mode can still be interesting.

...

> +#include <linux/bitmap.h>
> +#include <linux/clk.h>
> +#include <linux/bitfield.h>
> +#include <linux/debugfs.h>
> +#include <linux/device.h>
> +#include <linux/firmware.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/regmap.h>
> +#include <linux/util_macros.h>

Keep them ordered?

...

> +#include <linux/iio/iio.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/sysfs.h>

Ditto.

...

> +#define BNO055_FW_NAME "bno055-caldata"
> +#define BNO055_FW_EXT ".dat"
> +#define BNO055_FW_UID_NAME BNO055_FW_NAME "-%*phN" BNO055_FW_EXT

I believe this should be _FMT prefix, since it's not a name (I don't
think %*phN is a part of the actual file name).

> +#define BNO055_FW_GENERIC_NAME (BNO055_FW_NAME BNO055_FW_EXT)

And these macros of macros look unreadable, can we just hardcode
format and generic name?

...

> +#define BNO055_ATTR_VALS(...)          \
> +       .vals = (int[]){ __VA_ARGS__},  \
> +       .len = ARRAY_SIZE(((int[]){__VA_ARGS__}))

Not sure this adds any readability to the code. Can we simply have an
array of int for each case with the explicit ARRAY_SIZE() calls?

...

> +/*
> + * Theoretically the IMU should return data in a given (i.e. fixed) unit
> + * regardless the range setting. This happens for the accelerometer, but not for

regardless of

> + * the gyroscope; the gyroscope range setting affects the scale.
> + * This is probably due to this[0] bug.
> + * For this reason we map the internal range setting onto the standard IIO scale
> + * attribute for gyro.
> + * Since the bug[0] may be fixed in future, we check for the IMU FW version and
> + * eventually warn the user.
> + * Currently we just don't care about "range" attributes for gyro.
> + *
> + * [0]  https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/BNO055-Wrong-sensitivity-resolution-in-datasheet/td-p/10266
> + */

...

> +       /* calibration data may be updated by the IMU */
> +       if (reg >= BNO055_CALDATA_START && reg <= BNO055_CALDATA_END)
> +               return true;
> +
> +       return false;

Can be done in one return statement w/o branch, but probably OK taking
into account other related functions.

> +}

...

> +       {
> +               .range_min = 0,
> +               .range_max = 0x7f * 2,
> +               .selector_reg = BNO055_PAGESEL_REG,
> +               .selector_mask = GENMASK(7, 0),
> +               .selector_shift = 0,
> +               .window_start = 0,
> +               .window_len = 0x80

In all cases like this, keep the trailing comma.

> +       },

...

> +       msleep(20);

Perhaps a comment why so long sleep is needed.

...

> +static int bno055_system_reset(struct bno055_priv *priv)
> +{
> +       int ret;
> +
> +       if (priv->reset_gpio) {
> +               gpiod_set_value_cansleep(priv->reset_gpio, 0);
> +               usleep_range(5000, 10000);
> +               gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +       } else {
> +               if (!priv->sw_reset)
> +                       return 0;

Can be unified with the above 'else':

} else if (...) {
  return 0;
} else {

> +               ret = regmap_write(priv->regmap, BNO055_SYS_TRIGGER_REG,
> +                                  BNO055_SYS_TRIGGER_RST_SYS);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       regcache_drop_region(priv->regmap, 0x0, 0xff);
> +       usleep_range(650000, 700000);
> +
> +       return 0;
> +}

...

> +exit:

exit_unlock: ?

> +       mutex_unlock(&priv->lock);
> +       return ret;
> +}

...

> +       .scan_type = {                                                          \
> +               .sign = 's',                                                    \
> +               .realbits = 16,                                                 \
> +               .storagebits = 16,                                              \
> +               .endianness = IIO_LE,                                           \
> +               .repeat = IIO_MOD_##_axis == IIO_MOD_QUATERNION ? 4 : 0         \

+ Comma.

> +       },                                                                      \

...

> +       {
> +               .type = IIO_TEMP,
> +               .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> +               .scan_index = -1

+ Comma.

> +       },

...

> +       /*
> +        * We always get a request in INT_PLUS_MICRO, but we
> +        * take care of the micro part only when we really have
> +        * non-integer tables. This prevents 32-bit overflow with
> +        * larger integers contained in integer tables.
> +        */
> +       req_val = val;
> +       if (attr->type != IIO_VAL_INT) {


> +               if (val > 2147)
> +                       val = 2147;

min() ?

It seems it's not used outside of this branch, so this min() can be
integrated into below without corrupting val itself.

> +               len /= 2;
> +               req_val = val * 1000000 + val2;
> +       }

...

> +               if (first || delta < best_delta) {

In such cases checking 'first' last might slightly be better.

> +                       best_delta = delta;
> +                       hwval = i;
> +                       first = false;
> +               }

...

> +                       /*
> +                        * IMU reports sensor offests; IIO wants correction

offsets

> +                        * offset, thus we need the 'minus' here.
> +                        */

...

> +       case IIO_CHAN_INFO_SAMP_FREQ:
> +               if (chan->type != IIO_MAGN)
> +                       return -EINVAL;

> +               else

redundant.

> +                       return bno055_get_regmask(priv, val, val2,
> +                                                 BNO055_MAG_CONFIG_REG,
> +                                                 BNO055_MAG_CONFIG_ODR_MASK,
> +                                                 &bno055_mag_odr);

...

> +       for (i = 0; i < bno055_acc_range.len; i++)
> +               len += sysfs_emit_at(buf, len, "%d%c", bno055_acc_range.vals[i],
> +                                    (i == bno055_acc_range.len - 1) ? '\n' : ' ');

You may move the condition out of the loop.

...

> +       int ret = 0;

Redundant assignment, see below.

> +       if (indio_dev->active_scan_mask &&
> +           !bitmap_empty(indio_dev->active_scan_mask, _BNO055_SCAN_MAX))
> +               return -EBUSY;
> +
> +       if (sysfs_streq(buf, "0")) {
> +               ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_AMG);

return bno055_operation_mode_set(...);

> +       } else {

...and drop this with the following decreasing indentation.

> +               /*
> +                * Coming from AMG means the FMC was off, just switch to fusion
> +                * but don't change anything that doesn't belong to us (i.e let
> +                * FMC stay off.
> +                * Coming from any other fusion mode means we don't need to do
> +                * anything.
> +                */
> +               if (priv->operation_mode == BNO055_OPR_MODE_AMG)
> +                       ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_FUSION_FMC_OFF);
> +       }
> +       if (ret)
> +               return ret;
> +       return len;

...

> +       if (count < BNO055_CALDATA_LEN || pos != 0)

Drop ' != 0' part ?

> +               return -EINVAL;

...

> +unlock:

exit_unlock: to be consistent?

> +       mutex_unlock(&priv->lock);
> +       return ret;

...

> +       /*
> +        * Walk the bitmap and eventually perform several transfers.
> +        * Bitmap ones-fileds that are separated by gaps <= xfer_burst_break_thr

ones-fields ?

> +        * will be included in same transfer.
> +        * Every time the bitmap contains a gap wider than xfer_burst_break_thr
> +        * then we split the transfer, skipping the gap.
> +        */

...

> +               /*
> +                * First transfer will start from the beginnig of the first

beginning

> +                * ones-field in the bitmap
> +                */
> +               if (first)
> +                       xfer_start = start;
> +
> +               /*
> +                * We found the next ones-field; check whether to include it in
> +                * the current transfer or not (i.e. let's perform the current
> +                * transfer and prepare for another one).
> +                */

> +               if (!first) {

'else {' ?


> +               }

...

> +static void bno055_clk_disable(void *arg)
> +{
> +       clk_disable_unprepare((struct clk *)arg);

Redundant casting.

> +}

...

> +       const u8 *caldata_data = NULL;

> +       int caldata_size = 0;

No need. See below.

...

> +       if (priv->reset_gpio) {
> +               usleep_range(5000, 10000);
> +               gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +               usleep_range(650000, 750000);

> +       } else {
> +               if (!sw_reset)

} else if () {

> +                       dev_warn(dev, "No usable reset method; IMU may be unreliable");
> +       }

...

> +       /*
> +        * Seems that stock FW version conains a bug (see comment at the

the stock
contains

> +        * beginning of this file) that causes the anglvel scale to be changed
> +        * depending by the chip range setting. We workaround this, but we don't

on the chip

> +        * know what other FW version might do..

versions

One period at the end is enough, or add another one if there is a
continuation below.

> +        */

...

> +       ret = request_firmware(&caldata, fw_name_buf, dev);
> +       kfree(fw_name_buf);
> +       if (ret)
> +               ret = request_firmware(&caldata, BNO055_FW_GENERIC_NAME, dev);

> +

Can be removed to group all related checks together.

> +       if (ret)
> +               dev_notice(dev, "Calibration file load failed. See instruction in kernel Documentation/iio/bno055.rst");
> +
> +       if (caldata) {
> +               caldata_data = caldata->data;
> +               caldata_size = caldata->size;
> +       }
> +       ret = bno055_init(priv, caldata_data, caldata_size);

> +       if (caldata)
> +               release_firmware(caldata);

> +       if (ret)
> +               return ret;

Can be rewritten in a form of

if (caldata) {
 ret = bno055_init();
 release_firmware(...);
} else {
 ret = bno055_init();
}
if (ret)
  return ret;

?

...

> +#include <linux/regmap.h>

Missed types.h.

> +struct device;
> +int bno055_probe(struct device *dev, struct regmap *regmap,
> +                int xfer_burst_break_thr, bool sw_reset);
> +extern const struct regmap_config bno055_regmap_config;

-- 
With Best Regards,
Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andy Shevchenko]

On Wed, Apr 27, 2022 at 10:11 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Andrea,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on jic23-iio/togreg]
> [also build test ERROR on linus/master linux/master v5.18-rc4 next-20220426]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
> config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220427/202204271554.EiuIRNPI-lkp@intel.com/config)
> compiler: arceb-elf-gcc (GCC) 11.3.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://github.com/intel-lab-lkp/linux/commit/675ca9cd13af45cc5943dd15caad5e866fd7c971
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
>         git checkout 675ca9cd13af45cc5943dd15caad5e866fd7c971
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
> >> make[5]: *** No rule to make target 'drivers/iio/imu/bno055/bno055_ser_trace.o', needed by 'drivers/iio/imu/bno055/built-in.a'.
>    make[5]: Target '__build' not remade because of errors.

You need to add a C-file with the only line

#include <..._trace.h>

And drop that include from the ..._core.c.


-- 
With Best Regards,
Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andy Shevchenko]

[-- Attachment #1: Type: text/plain, Size: 2108 bytes --]

On Wed, Apr 27, 2022 at 10:11 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Andrea,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on jic23-iio/togreg]
> [also build test ERROR on linus/master linux/master v5.18-rc4 next-20220426]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
> config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220427/202204271554.EiuIRNPI-lkp(a)intel.com/config)
> compiler: arceb-elf-gcc (GCC) 11.3.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://github.com/intel-lab-lkp/linux/commit/675ca9cd13af45cc5943dd15caad5e866fd7c971
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
>         git checkout 675ca9cd13af45cc5943dd15caad5e866fd7c971
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
> >> make[5]: *** No rule to make target 'drivers/iio/imu/bno055/bno055_ser_trace.o', needed by 'drivers/iio/imu/bno055/built-in.a'.
>    make[5]: Target '__build' not remade because of errors.

You need to add a C-file with the only line

#include <..._trace.h>

And drop that include from the ..._core.c.


-- 
With Best Regards,
Andy Shevchenko

Re: [v5 00/14] Add support for Bosch BNO055 IMU

[Andy Shevchenko]

On Tue, Apr 26, 2022 at 3:11 PM Andrea Merello <andrea.merello@gmail.com> wrote:
>
> From: Andrea Merello <andrea.merello@iit.it>
>
> This series (tries to) add support for Bosch BNO055 IMU to Linux IIO
> subsystem. It is made up several patches:
>
>   1/14 to 6/14: add some IIO modifiers, and their documentation, to the IIO
>                 core layer, in order to being able to expose the linear
>                 acceleration and Euler angles among standard attributes.
>                 Also update the IIO event monitor tool
>
>   7/14: fix binary attributes didn't work with IIO
>
>   8/14 to 11/14: add the core IIO BNO055 driver and documentation for sysfs
>                  attributes and DT bindings
>
>   12/14: adds serdev BNO055 driver to actually use the IMU via serial line
>
>   13/14: adds I2C BNO055 driver to actually use the IMU via I2C wiring
>
>   14/14: add a documentation file that describe the bno055 driver and
>          specifically the calibration

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
for non-commented patches (12 out of 14 AFAICS).

> Differences wrt v4:
> - be more tolerant wrt unrecognized chip IDs
> - rename 'serial_number' attribute in 'serialnumber'
> - fix missing NULL variable initialization
> - use sign_extend32() instead of s16 casting where appropriate
> - fix quaternion unit
> - minor stuff (e.g. comments..)
> - reduce (slightly) locking in serdev driver
> - rework tracepoint support (e.g. remove dedicated config option)
>
> Differences wrt other BNO055 drivers:
>
>   Previously at least another driver for the very same chip has been posted
>   to the Linux ML [0], but it has been never merged, and it seems no one
>   cared of it since quite a long time.
>
>   This driver differs from the above driver on the following aspects:
>
>   - This driver supports also serial access (to be reliable, reset pin is
>     required to be wired)
>
>   - The above driver tried to support all IMU HW modes by allowing to
>     choose one in the DT, and adapting IIO attributes accordingly. This
>     driver does not rely on DT for this, instead settings are done via
>     sysfs attributes.  All IIO attributes are always exposed; more on this
>     later on. This driver however supports only a subset of the
>     HW-supported modes.
>
>   - This driver has some support for managing the IMU calibration
>
> Supported operation modes:
>
>   - AMG (accelerometer, magnetometer and gyroscope) mode, which provides
>     raw (uncalibrated) measurements from the said sensors, and allows for
>     setting some parameters about them (e.g. filter cut-off frequency, max
>     sensor ranges, etc).
>
>   - Fusion mode, which still provides AMG measures, while it also provides
>     other data calculated by the IMU (e.g. rotation angles, linear
>     acceleration, etc). In this mode user has no freedom to set any sensor
>     parameter, since the HW locks them. Autocalibration and correction is
>     performed by the IMU.
>
>   IIO attributes exposing sensors parameters are always present, but in
>   fusion modes the available values are constrained to just the one used by
>   the HW. This is reflected in the '*_available' IIO attributes.
>
>   Trying to set a not-supported value always falls back to the closest
>   supported one, which in this case is just the one in use by the HW.
>
>   IIO attributes for unavailable measurements (e.g. Euler angles in AMG
>   mode) can't be read (return -EBUSY, or refuse to enable buffer).
>
> IMU calibration:
>
>   The IMU supports for two sets of calibration parameters:
>
>   - SIC matrix. user-provided; this driver doesn't currently support it
>
>   - Offset and radius parameters. The IMU automatically finds out them when
>     it is running in fusion mode; supported by this driver.
>
>   The driver provides access to autocalibration flags (i.e. you can known
>   if the IMU has successfully autocalibrated) and to calibration data blob.
>   The user can save this blob in a "firmware" file (i.e. in /lib/firmware)
>   that the driver looks for at probe time. If found, then the IMU is
>   initialized with this calibration data. This saves the user from
>   performing the calibration procedure every time (which consist of moving
>   the IMU in various way).
>
>   The driver looks for calibration data file using two different names:
>   first a file whose name is suffixed with the IMU unique ID is searched
>   for; this is useful when there is more than one IMU instance. If this
>   file is not found, then a "generic" calibration file is searched for
>   (which can be used when only one IMU is present, without struggling with
>   fancy names, that changes on each device).
>
>   In AMG mode the IIO 'offset' attributes provide access to the offsets
>   from calibration data (if any), so that the user can apply them to the
>   accel, angvel and magn IIO attributes. In fusion mode they are not needed
>   and read as zero.
>
>
> Access protocols and serdev module:
>
>   The serial protocol is quite simple, but there are tricks to make it
>   really works. Those tricks and workarounds are documented in the driver
>   source file.
>
>   The core BNO055 driver tries to group readings in burst when appropriate,
>   in order to optimize triggered buffer operation. The threshold for
>   splitting a burst (i.e. max number of unused bytes in the middle of a
>   burst that will be throw away) is provided to the core driver by the
>   lowlevel access driver (either serdev or I2C) at probe time.
>
> [0] https://www.spinics.net/lists/linux-iio/msg25508.html
>
> Andrea Merello (14):
>   iio: add modifiers for linear acceleration
>   iio: document linear acceleration modifiers
>   iio: event_monitor: add linear acceleration modifiers
>   iio: add modifers for pitch, yaw, roll
>   iio: document pitch, yaw, roll modifiers
>   iio: event_monitor: add pitch, yaw and roll modifiers
>   iio: add support for binary attributes
>   iio: imu: add Bosch Sensortec BNO055 core driver
>   iio: document bno055 private sysfs attributes
>   iio: document "serialnumber" sysfs attribute
>   dt-bindings: iio/imu: Add Bosch BNO055
>   iio: imu: add BNO055 serdev driver
>   iio: imu: add BNO055 I2C driver
>   docs: iio: add documentation for BNO055 driver
>
>  Documentation/ABI/testing/sysfs-bus-iio       |   25 +
>  .../ABI/testing/sysfs-bus-iio-bno055          |   81 +
>  .../bindings/iio/imu/bosch,bno055.yaml        |   59 +
>  Documentation/iio/bno055.rst                  |   50 +
>  Documentation/iio/index.rst                   |    2 +
>  drivers/iio/imu/Kconfig                       |    1 +
>  drivers/iio/imu/Makefile                      |    1 +
>  drivers/iio/imu/bno055/Kconfig                |   25 +
>  drivers/iio/imu/bno055/Makefile               |   10 +
>  drivers/iio/imu/bno055/bno055.c               | 1710 +++++++++++++++++
>  drivers/iio/imu/bno055/bno055.h               |   12 +
>  drivers/iio/imu/bno055/bno055_i2c.c           |   57 +
>  drivers/iio/imu/bno055/bno055_ser_core.c      |  560 ++++++
>  drivers/iio/imu/bno055/bno055_ser_trace.h     |  104 +
>  drivers/iio/industrialio-core.c               |   10 +-
>  include/uapi/linux/iio/types.h                |    7 +-
>  tools/iio/iio_event_monitor.c                 |    6 +
>  17 files changed, 2718 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-bno055
>  create mode 100644 Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml
>  create mode 100644 Documentation/iio/bno055.rst
>  create mode 100644 drivers/iio/imu/bno055/Kconfig
>  create mode 100644 drivers/iio/imu/bno055/Makefile
>  create mode 100644 drivers/iio/imu/bno055/bno055.c
>  create mode 100644 drivers/iio/imu/bno055/bno055.h
>  create mode 100644 drivers/iio/imu/bno055/bno055_i2c.c
>  create mode 100644 drivers/iio/imu/bno055/bno055_ser_core.c
>  create mode 100644 drivers/iio/imu/bno055/bno055_ser_trace.h
>
> --
> 2.17.1



-- 
With Best Regards,
Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[kernel test robot]

Hi Andrea,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on jic23-iio/togreg]
[also build test WARNING on linus/master linux/master v5.18-rc4 next-20220427]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: alpha-randconfig-r036-20220427 (https://download.01.org/0day-ci/archive/20220427/202204272204.zqCIf1KV-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/675ca9cd13af45cc5943dd15caad5e866fd7c971
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
        git checkout 675ca9cd13af45cc5943dd15caad5e866fd7c971
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=alpha SHELL=/bin/bash drivers/iio/imu/bno055/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/iio/imu/bno055/bno055.c:1317:5: warning: no previous prototype for 'bno055_debugfs_reg_access' [-Wmissing-prototypes]
    1317 | int bno055_debugfs_reg_access(struct iio_dev *iio_dev, unsigned int reg,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/bno055_debugfs_reg_access +1317 drivers/iio/imu/bno055/bno055.c

2f40e22369ed70 Andrea Merello 2022-04-26  1316  
2f40e22369ed70 Andrea Merello 2022-04-26 @1317  int bno055_debugfs_reg_access(struct iio_dev *iio_dev, unsigned int reg,
2f40e22369ed70 Andrea Merello 2022-04-26  1318  			      unsigned int writeval, unsigned int *readval)
2f40e22369ed70 Andrea Merello 2022-04-26  1319  {
2f40e22369ed70 Andrea Merello 2022-04-26  1320  	return 0;
2f40e22369ed70 Andrea Merello 2022-04-26  1321  }
2f40e22369ed70 Andrea Merello 2022-04-26  1322  #endif
2f40e22369ed70 Andrea Merello 2022-04-26  1323  

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [v5 00/14] Add support for Bosch BNO055 IMU

[Jonathan Cameron]

On Wed, 27 Apr 2022 15:42:49 +0200
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Tue, Apr 26, 2022 at 3:11 PM Andrea Merello <andrea.merello@gmail.com> wrote:
> >
> > From: Andrea Merello <andrea.merello@iit.it>
> >
> > This series (tries to) add support for Bosch BNO055 IMU to Linux IIO
> > subsystem. It is made up several patches:
> >
> >   1/14 to 6/14: add some IIO modifiers, and their documentation, to the IIO
> >                 core layer, in order to being able to expose the linear
> >                 acceleration and Euler angles among standard attributes.
> >                 Also update the IIO event monitor tool
> >
> >   7/14: fix binary attributes didn't work with IIO
> >
> >   8/14 to 11/14: add the core IIO BNO055 driver and documentation for sysfs
> >                  attributes and DT bindings
> >
> >   12/14: adds serdev BNO055 driver to actually use the IMU via serial line
> >
> >   13/14: adds I2C BNO055 driver to actually use the IMU via I2C wiring
> >
> >   14/14: add a documentation file that describe the bno055 driver and
> >          specifically the calibration  
> 
> FWIW,
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> for non-commented patches (12 out of 14 AFAICS).
> 
FWIW I'm fine with the series once you've tidied up the stuff Andy picked up
on.

Thanks Andy for the detailed reviewing btw.

Jonathan

> > Differences wrt v4:
> > - be more tolerant wrt unrecognized chip IDs
> > - rename 'serial_number' attribute in 'serialnumber'
> > - fix missing NULL variable initialization
> > - use sign_extend32() instead of s16 casting where appropriate
> > - fix quaternion unit
> > - minor stuff (e.g. comments..)
> > - reduce (slightly) locking in serdev driver
> > - rework tracepoint support (e.g. remove dedicated config option)
> >
> > Differences wrt other BNO055 drivers:
> >
> >   Previously at least another driver for the very same chip has been posted
> >   to the Linux ML [0], but it has been never merged, and it seems no one
> >   cared of it since quite a long time.
> >
> >   This driver differs from the above driver on the following aspects:
> >
> >   - This driver supports also serial access (to be reliable, reset pin is
> >     required to be wired)
> >
> >   - The above driver tried to support all IMU HW modes by allowing to
> >     choose one in the DT, and adapting IIO attributes accordingly. This
> >     driver does not rely on DT for this, instead settings are done via
> >     sysfs attributes.  All IIO attributes are always exposed; more on this
> >     later on. This driver however supports only a subset of the
> >     HW-supported modes.
> >
> >   - This driver has some support for managing the IMU calibration
> >
> > Supported operation modes:
> >
> >   - AMG (accelerometer, magnetometer and gyroscope) mode, which provides
> >     raw (uncalibrated) measurements from the said sensors, and allows for
> >     setting some parameters about them (e.g. filter cut-off frequency, max
> >     sensor ranges, etc).
> >
> >   - Fusion mode, which still provides AMG measures, while it also provides
> >     other data calculated by the IMU (e.g. rotation angles, linear
> >     acceleration, etc). In this mode user has no freedom to set any sensor
> >     parameter, since the HW locks them. Autocalibration and correction is
> >     performed by the IMU.
> >
> >   IIO attributes exposing sensors parameters are always present, but in
> >   fusion modes the available values are constrained to just the one used by
> >   the HW. This is reflected in the '*_available' IIO attributes.
> >
> >   Trying to set a not-supported value always falls back to the closest
> >   supported one, which in this case is just the one in use by the HW.
> >
> >   IIO attributes for unavailable measurements (e.g. Euler angles in AMG
> >   mode) can't be read (return -EBUSY, or refuse to enable buffer).
> >
> > IMU calibration:
> >
> >   The IMU supports for two sets of calibration parameters:
> >
> >   - SIC matrix. user-provided; this driver doesn't currently support it
> >
> >   - Offset and radius parameters. The IMU automatically finds out them when
> >     it is running in fusion mode; supported by this driver.
> >
> >   The driver provides access to autocalibration flags (i.e. you can known
> >   if the IMU has successfully autocalibrated) and to calibration data blob.
> >   The user can save this blob in a "firmware" file (i.e. in /lib/firmware)
> >   that the driver looks for at probe time. If found, then the IMU is
> >   initialized with this calibration data. This saves the user from
> >   performing the calibration procedure every time (which consist of moving
> >   the IMU in various way).
> >
> >   The driver looks for calibration data file using two different names:
> >   first a file whose name is suffixed with the IMU unique ID is searched
> >   for; this is useful when there is more than one IMU instance. If this
> >   file is not found, then a "generic" calibration file is searched for
> >   (which can be used when only one IMU is present, without struggling with
> >   fancy names, that changes on each device).
> >
> >   In AMG mode the IIO 'offset' attributes provide access to the offsets
> >   from calibration data (if any), so that the user can apply them to the
> >   accel, angvel and magn IIO attributes. In fusion mode they are not needed
> >   and read as zero.
> >
> >
> > Access protocols and serdev module:
> >
> >   The serial protocol is quite simple, but there are tricks to make it
> >   really works. Those tricks and workarounds are documented in the driver
> >   source file.
> >
> >   The core BNO055 driver tries to group readings in burst when appropriate,
> >   in order to optimize triggered buffer operation. The threshold for
> >   splitting a burst (i.e. max number of unused bytes in the middle of a
> >   burst that will be throw away) is provided to the core driver by the
> >   lowlevel access driver (either serdev or I2C) at probe time.
> >
> > [0] https://www.spinics.net/lists/linux-iio/msg25508.html
> >
> > Andrea Merello (14):
> >   iio: add modifiers for linear acceleration
> >   iio: document linear acceleration modifiers
> >   iio: event_monitor: add linear acceleration modifiers
> >   iio: add modifers for pitch, yaw, roll
> >   iio: document pitch, yaw, roll modifiers
> >   iio: event_monitor: add pitch, yaw and roll modifiers
> >   iio: add support for binary attributes
> >   iio: imu: add Bosch Sensortec BNO055 core driver
> >   iio: document bno055 private sysfs attributes
> >   iio: document "serialnumber" sysfs attribute
> >   dt-bindings: iio/imu: Add Bosch BNO055
> >   iio: imu: add BNO055 serdev driver
> >   iio: imu: add BNO055 I2C driver
> >   docs: iio: add documentation for BNO055 driver
> >
> >  Documentation/ABI/testing/sysfs-bus-iio       |   25 +
> >  .../ABI/testing/sysfs-bus-iio-bno055          |   81 +
> >  .../bindings/iio/imu/bosch,bno055.yaml        |   59 +
> >  Documentation/iio/bno055.rst                  |   50 +
> >  Documentation/iio/index.rst                   |    2 +
> >  drivers/iio/imu/Kconfig                       |    1 +
> >  drivers/iio/imu/Makefile                      |    1 +
> >  drivers/iio/imu/bno055/Kconfig                |   25 +
> >  drivers/iio/imu/bno055/Makefile               |   10 +
> >  drivers/iio/imu/bno055/bno055.c               | 1710 +++++++++++++++++
> >  drivers/iio/imu/bno055/bno055.h               |   12 +
> >  drivers/iio/imu/bno055/bno055_i2c.c           |   57 +
> >  drivers/iio/imu/bno055/bno055_ser_core.c      |  560 ++++++
> >  drivers/iio/imu/bno055/bno055_ser_trace.h     |  104 +
> >  drivers/iio/industrialio-core.c               |   10 +-
> >  include/uapi/linux/iio/types.h                |    7 +-
> >  tools/iio/iio_event_monitor.c                 |    6 +
> >  17 files changed, 2718 insertions(+), 2 deletions(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-bno055
> >  create mode 100644 Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml
> >  create mode 100644 Documentation/iio/bno055.rst
> >  create mode 100644 drivers/iio/imu/bno055/Kconfig
> >  create mode 100644 drivers/iio/imu/bno055/Makefile
> >  create mode 100644 drivers/iio/imu/bno055/bno055.c
> >  create mode 100644 drivers/iio/imu/bno055/bno055.h
> >  create mode 100644 drivers/iio/imu/bno055/bno055_i2c.c
> >  create mode 100644 drivers/iio/imu/bno055/bno055_ser_core.c
> >  create mode 100644 drivers/iio/imu/bno055/bno055_ser_trace.h
> >
> > --
> > 2.17.1  
> 
> 
> 

Re: [v5 00/14] Add support for Bosch BNO055 IMU

[Andrea Merello]

Il giorno dom 1 mag 2022 alle ore 18:54 Jonathan Cameron
<jic23@kernel.org> ha scritto:
>
> On Wed, 27 Apr 2022 15:42:49 +0200
> Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
>
> > On Tue, Apr 26, 2022 at 3:11 PM Andrea Merello <andrea.merello@gmail.com> wrote:
> > >
> > > From: Andrea Merello <andrea.merello@iit.it>
> > >
> > > This series (tries to) add support for Bosch BNO055 IMU to Linux IIO
> > > subsystem. It is made up several patches:
> > >
> > >   1/14 to 6/14: add some IIO modifiers, and their documentation, to the IIO
> > >                 core layer, in order to being able to expose the linear
> > >                 acceleration and Euler angles among standard attributes.
> > >                 Also update the IIO event monitor tool
> > >
> > >   7/14: fix binary attributes didn't work with IIO
> > >
> > >   8/14 to 11/14: add the core IIO BNO055 driver and documentation for sysfs
> > >                  attributes and DT bindings
> > >
> > >   12/14: adds serdev BNO055 driver to actually use the IMU via serial line
> > >
> > >   13/14: adds I2C BNO055 driver to actually use the IMU via I2C wiring
> > >
> > >   14/14: add a documentation file that describe the bno055 driver and
> > >          specifically the calibration
> >
> > FWIW,
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> > for non-commented patches (12 out of 14 AFAICS).
> >
> FWIW I'm fine with the series once you've tidied up the stuff Andy picked up
> on.
>
> Thanks Andy for the detailed reviewing btw.
>
> Jonathan

I'm very grateful to both of you and to everyone who commented on
those patches. Thanks :). Beside the "Reviewed-by" tags where
appropriate, is it usual/appropriate to put some tag like "Thanks-to
.. [for comments]" ?

BTW I have also gone through some kernel-robot reports; they also
state "If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>". I'd say that it would
be OK to add this tag to a patch that just fixes what is reported, but
I'm unsure whether it is appropriate to add this tag to the patches in
my series, because they add the code and the fix at once. Any advice
here?

Andrea

Re: [v5 00/14] Add support for Bosch BNO055 IMU

[Andy Shevchenko]

On Mon, May 2, 2022 at 8:33 AM Andrea Merello <andrea.merello@gmail.com> wrote:
> Il giorno dom 1 mag 2022 alle ore 18:54 Jonathan Cameron
> <jic23@kernel.org> ha scritto:
> > On Wed, 27 Apr 2022 15:42:49 +0200
> > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > On Tue, Apr 26, 2022 at 3:11 PM Andrea Merello <andrea.merello@gmail.com> wrote:

...

> > > FWIW,
> > > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> > > for non-commented patches (12 out of 14 AFAICS).
> > >
> > FWIW I'm fine with the series once you've tidied up the stuff Andy picked up
> > on.
> >
> > Thanks Andy for the detailed reviewing btw.

You/re welcome!

> I'm very grateful to both of you and to everyone who commented on
> those patches. Thanks :). Beside the "Reviewed-by" tags where
> appropriate, is it usual/appropriate to put some tag like "Thanks-to
> .. [for comments]" ?

Nope, just mention that in the cover letter.

> BTW I have also gone through some kernel-robot reports; they also
> state "If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>". I'd say that it would
> be OK to add this tag to a patch that just fixes what is reported, but
> I'm unsure whether it is appropriate to add this tag to the patches in
> my series, because they add the code and the fix at once. Any advice
> here?

For this we specifically amended the kernel documentation recently.
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes

"The tag is intended for bugs; please do not use it to credit feature requests."

-- 
With Best Regards,
Andy Shevchenko

Re: [v5 00/14] Add support for Bosch BNO055 IMU

[Andrea Merello]

Il giorno lun 2 mag 2022 alle ore 09:48 Andy Shevchenko
<andy.shevchenko@gmail.com> ha scritto:
>

[ .. ]

> > BTW I have also gone through some kernel-robot reports; they also
> > state "If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>". I'd say that it would
> > be OK to add this tag to a patch that just fixes what is reported, but
> > I'm unsure whether it is appropriate to add this tag to the patches in
> > my series, because they add the code and the fix at once. Any advice
> > here?
>
> For this we specifically amended the kernel documentation recently.
> https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes
>
> "The tag is intended for bugs; please do not use it to credit feature requests."

Well, no any feature request to credit here; a bug and its fix are
involved. Sounds more like a "yes" so far.. But it wouldn't be clear
what the robot did report indeed (squashed bugs and fixes).. Maybe a
"thank" in the cover letter also to it would suffice?

> --
> With Best Regards,
> Andy Shevchenko

Re: [v5 00/14] Add support for Bosch BNO055 IMU

[Andy Shevchenko]

On Mon, May 2, 2022 at 10:31 AM Andrea Merello <andrea.merello@gmail.com> wrote:
> Il giorno lun 2 mag 2022 alle ore 09:48 Andy Shevchenko
> <andy.shevchenko@gmail.com> ha scritto:

...

> > > BTW I have also gone through some kernel-robot reports; they also
> > > state "If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@intel.com>". I'd say that it would
> > > be OK to add this tag to a patch that just fixes what is reported, but
> > > I'm unsure whether it is appropriate to add this tag to the patches in
> > > my series, because they add the code and the fix at once. Any advice
> > > here?
> >
> > For this we specifically amended the kernel documentation recently.
> > https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes
> >
> > "The tag is intended for bugs; please do not use it to credit feature requests."
>
> Well, no any feature request to credit here; a bug and its fix are
> involved. Sounds more like a "yes" so far.. But it wouldn't be clear
> what the robot did report indeed (squashed bugs and fixes).. Maybe a
> "thank" in the cover letter also to it would suffice?

The reported from bots should be used when your patches.changes
induced by those reports, it seems otherwise in your case.,


-- 
With Best Regards,
Andy Shevchenko

Re: [v5 08/14] iio: imu: add Bosch Sensortec BNO055 core driver

[Andrea Merello]

Il giorno mer 27 apr 2022 alle ore 15:23 Andy Shevchenko
<andy.shevchenko@gmail.com> ha scritto:
>

As usual, some inline comments. OK for the rest.

[...]

>
> > +#define BNO055_ATTR_VALS(...)          \
> > +       .vals = (int[]){ __VA_ARGS__},  \
> > +       .len = ARRAY_SIZE(((int[]){__VA_ARGS__}))
>
> Not sure this adds any readability to the code. Can we simply have an
> array of int for each case with the explicit ARRAY_SIZE() calls?

Do you mean moving the vals array out of the structs? Something like:

static int bno055_gyr_scale_vals[] = {125, 1877467, 250, 1877467,
        500, 1877467, 1000, 1877467, 2000, 1877467};

static struct bno055_sysfs_attr_aux_data bno055_gyr_scale_aux = {
        .fusion_vals = (int[]){1, 900},
        .hw_xlate = (int[]){4, 3, 2, 1, 0},
        .type = IIO_VAL_FRACTIONAL

?
But then I'd make also something like:

#define bno055_sysfs_attr_avail(priv, attr, vals, len) \
        _bno055_sysfs_attr_avail(priv, attr##_vals,
ARRAY_SIZE(attr##_vals), attr##_aux, vals, len)

And the same for all other users of those structs.

My point is not about readability, but about avoiding as much as
possible bugs caused by mismatched attr_vals, attr_aux and
ARRAY_SIZE() arg. e.g:
bno055_sysfs_attr_avail(priv, bno_foo_vals, ARRAY_SIZE(bno_bar_vals),
bno_foobar_aux, vals, len)

I used to make quite a lot of mess until I grouped all the stuff in
one struct :/

[...]

>
> > +       msleep(20);
>
> Perhaps a comment why so long sleep is needed.

DS says that switching mode can last from 7mS up to 19mS depending on
the case, but I don't know _why_ it takes so long. I may add a comment
that just states that it's a sensor requirement.

[...]

>
> > +       for (i = 0; i < bno055_acc_range.len; i++)
> > +               len += sysfs_emit_at(buf, len, "%d%c", bno055_acc_range.vals[i],
> > +                                    (i == bno055_acc_range.len - 1) ? '\n' : ' ');
>
> You may move the condition out of the loop.

May you elaborate, please? Do you mean something like: loop one time
less, and then call sysfs_emit_at() once more outside the loop,
getting rid of the conditional ternary operator at all?

[...]

> > +       if (indio_dev->active_scan_mask &&
> > +           !bitmap_empty(indio_dev->active_scan_mask, _BNO055_SCAN_MAX))
> > +               return -EBUSY;
> > +
> > +       if (sysfs_streq(buf, "0")) {
> > +               ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_AMG);
>
> return bno055_operation_mode_set(...);

Why? bno055_operation_mode_set() returns an error code, while here we
need to return the len, or propagate the error code only when it's the
case

> > +       } else {
>
> ...and drop this with the following decreasing indentation.

if you want to drop this, then I can just duplicate if(ret) return
ret; i.e. add it after bno055_operation_mode_set(priv,
BNO055_OPR_MODE_AMG); and get rid of the else branch (see above)

[...]

>
> Can be removed to group all related checks together.

I'm not sure what you mean here, but see below

> > +       if (ret)
> > +               dev_notice(dev, "Calibration file load failed. See instruction in kernel Documentation/iio/bno055.rst");
> > +
> > +       if (caldata) {
> > +               caldata_data = caldata->data;
> > +               caldata_size = caldata->size;
> > +       }
> > +       ret = bno055_init(priv, caldata_data, caldata_size);
>
> > +       if (caldata)
> > +               release_firmware(caldata);
>
> > +       if (ret)
> > +               return ret;
>
> Can be rewritten in a form of
>
> if (caldata) {
>  ret = bno055_init();
>  release_firmware(...);
> } else {
>  ret = bno055_init();
> }
> if (ret)
>   return ret;
>
> ?

Indeed I'd say it could be rewritten as:

        if (ret)
                ret = request_firmware(&caldata, BNO055_FW_GENERIC_NAME, dev);
        if (ret) {
                dev_notice(dev, "Calibration file load failed. See
instruction in kernel Documentation/iio/bno055.rst");
                ret = bno055_init(priv, NULL, 0);
        } else {
                ret = bno055_init(priv, caldata->data, caldata->size);
                release_firmware(caldata);
        }
        if (ret)
                return ret;

Re: [v5 08/14] iio: imu: add Bosch Sensortec BNO055 core driver

[Andy Shevchenko]

On Mon, May 2, 2022 at 11:50 AM Andrea Merello <andrea.merello@gmail.com> wrote:
> Il giorno mer 27 apr 2022 alle ore 15:23 Andy Shevchenko
> <andy.shevchenko@gmail.com> ha scritto:

...

> > > +#define BNO055_ATTR_VALS(...)          \
> > > +       .vals = (int[]){ __VA_ARGS__},  \
> > > +       .len = ARRAY_SIZE(((int[]){__VA_ARGS__}))
> >
> > Not sure this adds any readability to the code. Can we simply have an
> > array of int for each case with the explicit ARRAY_SIZE() calls?
>
> Do you mean moving the vals array out of the structs? Something like:
>
> static int bno055_gyr_scale_vals[] = {125, 1877467, 250, 1877467,
>         500, 1877467, 1000, 1877467, 2000, 1877467};

With the better style, but yes

...[] = {
  1, 2, 3, 4, 5
   6, 7, 8, 9, 10,
};

> static struct bno055_sysfs_attr_aux_data bno055_gyr_scale_aux = {
>         .fusion_vals = (int[]){1, 900},
>         .hw_xlate = (int[]){4, 3, 2, 1, 0},
>         .type = IIO_VAL_FRACTIONAL

(with last comma to be kept, but yes)

> ?
> But then I'd make also something like:
>
> #define bno055_sysfs_attr_avail(priv, attr, vals, len) \
>         _bno055_sysfs_attr_avail(priv, attr##_vals,
> ARRAY_SIZE(attr##_vals), attr##_aux, vals, len)
>
> And the same for all other users of those structs.
>
> My point is not about readability,

And my point about readability. The reader, and even the author after
some time, may have no clue in this forest of the macros and castings
what's going on.

> but about avoiding as much as
> possible bugs caused by mismatched attr_vals, attr_aux and
> ARRAY_SIZE() arg. e.g:
> bno055_sysfs_attr_avail(priv, bno_foo_vals, ARRAY_SIZE(bno_bar_vals),
> bno_foobar_aux, vals, len)
>
> I used to make quite a lot of mess until I grouped all the stuff in
> one struct :/

If something you want to prevent at compile time, consider to utilize
static_assert() and / or BUILD_BUG_ON() depending on the place in the
code (the former is preferred).

...

> > > +       msleep(20);
> >
> > Perhaps a comment why so long sleep is needed.
>
> DS says that switching mode can last from 7mS up to 19mS depending on
> the case, but I don't know _why_ it takes so long. I may add a comment
> that just states that it's a sensor requirement.

Yes, please add the comment that this time has been chosen to follow
data sheet recommendations.

...

> > > +       for (i = 0; i < bno055_acc_range.len; i++)
> > > +               len += sysfs_emit_at(buf, len, "%d%c", bno055_acc_range.vals[i],
> > > +                                    (i == bno055_acc_range.len - 1) ? '\n' : ' ');
> >
> > You may move the condition out of the loop.
>
> May you elaborate, please? Do you mean something like: loop one time
> less, and then call sysfs_emit_at() once more outside the loop,
> getting rid of the conditional ternary operator at all?

Regular loop with a space as a delimiter and after it the condition to
check i and replace last space by \n. I.o.w. the ternary is an
invariant to the loop and no need to call it for each iteration.

...

> > > +       if (indio_dev->active_scan_mask &&
> > > +           !bitmap_empty(indio_dev->active_scan_mask, _BNO055_SCAN_MAX))
> > > +               return -EBUSY;
> > > +
> > > +       if (sysfs_streq(buf, "0")) {
> > > +               ret = bno055_operation_mode_set(priv, BNO055_OPR_MODE_AMG);
> >
> > return bno055_operation_mode_set(...);
>
> Why? bno055_operation_mode_set() returns an error code, while here we
> need to return the len, or propagate the error code only when it's the
> case

Ah good point.

> > > +       } else {
> >
> > ...and drop this with the following decreasing indentation.
>
> if you want to drop this, then I can just duplicate if(ret) return
> ret; i.e. add it after bno055_operation_mode_set(priv,
> BNO055_OPR_MODE_AMG); and get rid of the else branch (see above)

Yes, but now, reading the original code again, I'm wondering why you
are not using kstrtobool().

...

> > Can be removed to group all related checks together.
>
> I'm not sure what you mean here, but see below
>
> > > +       if (ret)
> > > +               dev_notice(dev, "Calibration file load failed. See instruction in kernel Documentation/iio/bno055.rst");
> > > +
> > > +       if (caldata) {
> > > +               caldata_data = caldata->data;
> > > +               caldata_size = caldata->size;
> > > +       }
> > > +       ret = bno055_init(priv, caldata_data, caldata_size);
> >
> > > +       if (caldata)
> > > +               release_firmware(caldata);
> >
> > > +       if (ret)
> > > +               return ret;
> >
> > Can be rewritten in a form of
> >
> > if (caldata) {
> >  ret = bno055_init();
> >  release_firmware(...);
> > } else {
> >  ret = bno055_init();
> > }
> > if (ret)
> >   return ret;
> >
> > ?
>
> Indeed I'd say it could be rewritten as:
>
>         if (ret)
>                 ret = request_firmware(&caldata, BNO055_FW_GENERIC_NAME, dev);
>         if (ret) {
>                 dev_notice(dev, "Calibration file load failed. See
> instruction in kernel Documentation/iio/bno055.rst");

Missed \n.

>                 ret = bno055_init(priv, NULL, 0);
>         } else {
>                 ret = bno055_init(priv, caldata->data, caldata->size);
>                 release_firmware(caldata);
>         }
>         if (ret)
>                 return ret;

Yes, something like this. Experiment with it and choose which one is
read better.

-- 
With Best Regards,
Andy Shevchenko

Re: [v5 08/14] iio: imu: add Bosch Sensortec BNO055 core driver

[Andrea Merello]

Il giorno lun 2 mag 2022 alle ore 12:12 Andy Shevchenko
<andy.shevchenko@gmail.com> ha scritto:

One inline comment. OK for the rest

> > > > +#define BNO055_ATTR_VALS(...)          \
> > > > +       .vals = (int[]){ __VA_ARGS__},  \
> > > > +       .len = ARRAY_SIZE(((int[]){__VA_ARGS__}))

[...]

> And my point about readability. The reader, and even the author after
> some time, may have no clue in this forest of the macros and castings
> what's going on.

While I'm OK wrt your point in general, consider that it's just a
three LOC macro, used only in a few structs just below. I wouldn't say
it's so inricated; I've seen by far worse in the kernel :)

> > but about avoiding as much as
> > possible bugs caused by mismatched attr_vals, attr_aux and
> > ARRAY_SIZE() arg. e.g:
> > bno055_sysfs_attr_avail(priv, bno_foo_vals, ARRAY_SIZE(bno_bar_vals),
> > bno_foobar_aux, vals, len)
> >
> > I used to make quite a lot of mess until I grouped all the stuff in
> > one struct :/
>
> If something you want to prevent at compile time, consider to utilize
> static_assert() and / or BUILD_BUG_ON() depending on the place in the
> code (the former is preferred).

I would be happy to get rid of my macro and use those assertion
things, but I can't see how exactly. Do you have any advice about how
to take advantage of them for catching bugs like the one above in this
specific case?

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andrea Merello]

Il giorno mer 27 apr 2022 alle ore 15:41 Andy Shevchenko
<andy.shevchenko@gmail.com> ha scritto:
>
> On Wed, Apr 27, 2022 at 10:11 AM kernel test robot <lkp@intel.com> wrote:
> >
> > Hi Andrea,
> >
> > Thank you for the patch! Yet something to improve:
> >
> > [auto build test ERROR on jic23-iio/togreg]
> > [also build test ERROR on linus/master linux/master v5.18-rc4 next-20220426]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch]
> >
> > url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
> > config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220427/202204271554.EiuIRNPI-lkp@intel.com/config)
> > compiler: arceb-elf-gcc (GCC) 11.3.0
> > reproduce (this is a W=1 build):
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # https://github.com/intel-lab-lkp/linux/commit/675ca9cd13af45cc5943dd15caad5e866fd7c971
> >         git remote add linux-review https://github.com/intel-lab-lkp/linux
> >         git fetch --no-tags linux-review Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
> >         git checkout 675ca9cd13af45cc5943dd15caad5e866fd7c971
> >         # save the config file
> >         mkdir build_dir && cp config build_dir/.config
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All errors (new ones prefixed by >>):
> >
> > >> make[5]: *** No rule to make target 'drivers/iio/imu/bno055/bno055_ser_trace.o', needed by 'drivers/iio/imu/bno055/built-in.a'.
> >    make[5]: Target '__build' not remade because of errors.
>
> You need to add a C-file with the only line
>
> #include <..._trace.h>
>
> And drop that include from the _core.c.

Hum, I'm a bit confused here: the bno055_ser_core.c file explicitly
looks for that tracepoints (e.g. it calls trace_send_chunks() and
friends); dropping the include prevents build here because there would
be no definition for those tracepoints.

There is already a C file bno055_ser_trace.c that just contains the
said include and it defines CREATE_TRACE_POINTS; I see other drivers
like dwc3 do the same..

But my problem is that I cannot reproduce the issue found by the bot:
the compiler that is downloaded by the script doesn't run on my build
box because it wants a newer libc (I was hoping that those compilers
were statically linked, but they aren't), while any other attempt I
did with other older compilers resulted in either successful build or
failed with other weird, apparently unrelated, errors about relocation
issues (of course I tried with the arch and config used by the build
bot).

Is there any build farm publicly available or something like that?

> --
> With Best Regards,
> Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andrea Merello]

[-- Attachment #1: Type: text/plain, Size: 3277 bytes --]

Il giorno mer 27 apr 2022 alle ore 15:41 Andy Shevchenko
<andy.shevchenko@gmail.com> ha scritto:
>
> On Wed, Apr 27, 2022 at 10:11 AM kernel test robot <lkp@intel.com> wrote:
> >
> > Hi Andrea,
> >
> > Thank you for the patch! Yet something to improve:
> >
> > [auto build test ERROR on jic23-iio/togreg]
> > [also build test ERROR on linus/master linux/master v5.18-rc4 next-20220426]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch]
> >
> > url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
> > config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220427/202204271554.EiuIRNPI-lkp(a)intel.com/config)
> > compiler: arceb-elf-gcc (GCC) 11.3.0
> > reproduce (this is a W=1 build):
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # https://github.com/intel-lab-lkp/linux/commit/675ca9cd13af45cc5943dd15caad5e866fd7c971
> >         git remote add linux-review https://github.com/intel-lab-lkp/linux
> >         git fetch --no-tags linux-review Andrea-Merello/Add-support-for-Bosch-BNO055-IMU/20220426-212132
> >         git checkout 675ca9cd13af45cc5943dd15caad5e866fd7c971
> >         # save the config file
> >         mkdir build_dir && cp config build_dir/.config
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All errors (new ones prefixed by >>):
> >
> > >> make[5]: *** No rule to make target 'drivers/iio/imu/bno055/bno055_ser_trace.o', needed by 'drivers/iio/imu/bno055/built-in.a'.
> >    make[5]: Target '__build' not remade because of errors.
>
> You need to add a C-file with the only line
>
> #include <..._trace.h>
>
> And drop that include from the _core.c.

Hum, I'm a bit confused here: the bno055_ser_core.c file explicitly
looks for that tracepoints (e.g. it calls trace_send_chunks() and
friends); dropping the include prevents build here because there would
be no definition for those tracepoints.

There is already a C file bno055_ser_trace.c that just contains the
said include and it defines CREATE_TRACE_POINTS; I see other drivers
like dwc3 do the same..

But my problem is that I cannot reproduce the issue found by the bot:
the compiler that is downloaded by the script doesn't run on my build
box because it wants a newer libc (I was hoping that those compilers
were statically linked, but they aren't), while any other attempt I
did with other older compilers resulted in either successful build or
failed with other weird, apparently unrelated, errors about relocation
issues (of course I tried with the arch and config used by the build
bot).

Is there any build farm publicly available or something like that?

> --
> With Best Regards,
> Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andrea Merello]

Il giorno mar 3 mag 2022 alle ore 09:48 Andrea Merello
<andrea.merello@gmail.com> ha scritto:

[...]

> > You need to add a C-file with the only line
> >
> > #include <..._trace.h>
> >
> > And drop that include from the _core.c.
>
> Hum, I'm a bit confused here: the bno055_ser_core.c file explicitly
> looks for that tracepoints (e.g. it calls trace_send_chunks() and
> friends); dropping the include prevents build here because there would
> be no definition for those tracepoints.
>
> There is already a C file bno055_ser_trace.c that just contains the
> said include and it defines CREATE_TRACE_POINTS; I see other drivers
> like dwc3 do the same..

Oops.. it turned out that I just had this almost-empty C file as
untracked in my git tree, and it ended up not being included in
patches also. Being it laying in my src tree caused the build to
succeed.

I have been misled by the other problem I (still) have (below); I was
focused on the wrong thing, sorry.

> But my problem is that I cannot reproduce the issue found by the bot:
> the compiler that is downloaded by the script doesn't run on my build
> box because it wants a newer libc (I was hoping that those compilers
> were statically linked, but they aren't), while any other attempt I
> did with other older compilers resulted in either successful build or
> failed with other weird, apparently unrelated, errors about relocation
> issues (of course I tried with the arch and config used by the build
> bot).
>
> Is there any build farm publicly available or something like that?
>
> > --
> > With Best Regards,
> > Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andrea Merello]

[-- Attachment #1: Type: text/plain, Size: 1636 bytes --]

Il giorno mar 3 mag 2022 alle ore 09:48 Andrea Merello
<andrea.merello@gmail.com> ha scritto:

[...]

> > You need to add a C-file with the only line
> >
> > #include <..._trace.h>
> >
> > And drop that include from the _core.c.
>
> Hum, I'm a bit confused here: the bno055_ser_core.c file explicitly
> looks for that tracepoints (e.g. it calls trace_send_chunks() and
> friends); dropping the include prevents build here because there would
> be no definition for those tracepoints.
>
> There is already a C file bno055_ser_trace.c that just contains the
> said include and it defines CREATE_TRACE_POINTS; I see other drivers
> like dwc3 do the same..

Oops.. it turned out that I just had this almost-empty C file as
untracked in my git tree, and it ended up not being included in
patches also. Being it laying in my src tree caused the build to
succeed.

I have been misled by the other problem I (still) have (below); I was
focused on the wrong thing, sorry.

> But my problem is that I cannot reproduce the issue found by the bot:
> the compiler that is downloaded by the script doesn't run on my build
> box because it wants a newer libc (I was hoping that those compilers
> were statically linked, but they aren't), while any other attempt I
> did with other older compilers resulted in either successful build or
> failed with other weird, apparently unrelated, errors about relocation
> issues (of course I tried with the arch and config used by the build
> bot).
>
> Is there any build farm publicly available or something like that?
>
> > --
> > With Best Regards,
> > Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andy Shevchenko]

On Tue, May 3, 2022 at 3:30 PM Andrea Merello <andrea.merello@gmail.com> wrote:
>
> Il giorno mar 3 mag 2022 alle ore 09:48 Andrea Merello
> <andrea.merello@gmail.com> ha scritto:
>
> [...]
>
> > > You need to add a C-file with the only line
> > >
> > > #include <..._trace.h>
> > >
> > > And drop that include from the _core.c.
> >
> > Hum, I'm a bit confused here: the bno055_ser_core.c file explicitly
> > looks for that tracepoints (e.g. it calls trace_send_chunks() and
> > friends); dropping the include prevents build here because there would
> > be no definition for those tracepoints.
> >
> > There is already a C file bno055_ser_trace.c that just contains the
> > said include and it defines CREATE_TRACE_POINTS; I see other drivers
> > like dwc3 do the same..
>
> Oops.. it turned out that I just had this almost-empty C file as
> untracked in my git tree, and it ended up not being included in
> patches also. Being it laying in my src tree caused the build to
> succeed.
>
> I have been misled by the other problem I (still) have (below); I was
> focused on the wrong thing, sorry.

So, there are two reports:
1) missed C file;
2) possible missed prototype.

To solve 1) you need to add the C file to the patch.
To solve 2) you need either declare it static or put it into the
header file (I haven't checked deeply which one is your case).

> > But my problem is that I cannot reproduce the issue found by the bot:
> > the compiler that is downloaded by the script doesn't run on my build
> > box because it wants a newer libc (I was hoping that those compilers
> > were statically linked, but they aren't), while any other attempt I
> > did with other older compilers resulted in either successful build or
> > failed with other weird, apparently unrelated, errors about relocation
> > issues (of course I tried with the arch and config used by the build
> > bot).

You may use compilers from kernel.org that don't require any libc at
all (only good for kernel compilation).

> > Is there any build farm publicly available or something like that?

Not of my knowledge.


-- 
With Best Regards,
Andy Shevchenko

Re: [v5 12/14] iio: imu: add BNO055 serdev driver

[Andy Shevchenko]

[-- Attachment #1: Type: text/plain, Size: 2180 bytes --]

On Tue, May 3, 2022 at 3:30 PM Andrea Merello <andrea.merello@gmail.com> wrote:
>
> Il giorno mar 3 mag 2022 alle ore 09:48 Andrea Merello
> <andrea.merello@gmail.com> ha scritto:
>
> [...]
>
> > > You need to add a C-file with the only line
> > >
> > > #include <..._trace.h>
> > >
> > > And drop that include from the _core.c.
> >
> > Hum, I'm a bit confused here: the bno055_ser_core.c file explicitly
> > looks for that tracepoints (e.g. it calls trace_send_chunks() and
> > friends); dropping the include prevents build here because there would
> > be no definition for those tracepoints.
> >
> > There is already a C file bno055_ser_trace.c that just contains the
> > said include and it defines CREATE_TRACE_POINTS; I see other drivers
> > like dwc3 do the same..
>
> Oops.. it turned out that I just had this almost-empty C file as
> untracked in my git tree, and it ended up not being included in
> patches also. Being it laying in my src tree caused the build to
> succeed.
>
> I have been misled by the other problem I (still) have (below); I was
> focused on the wrong thing, sorry.

So, there are two reports:
1) missed C file;
2) possible missed prototype.

To solve 1) you need to add the C file to the patch.
To solve 2) you need either declare it static or put it into the
header file (I haven't checked deeply which one is your case).

> > But my problem is that I cannot reproduce the issue found by the bot:
> > the compiler that is downloaded by the script doesn't run on my build
> > box because it wants a newer libc (I was hoping that those compilers
> > were statically linked, but they aren't), while any other attempt I
> > did with other older compilers resulted in either successful build or
> > failed with other weird, apparently unrelated, errors about relocation
> > issues (of course I tried with the arch and config used by the build
> > bot).

You may use compilers from kernel.org that don't require any libc at
all (only good for kernel compilation).

> > Is there any build farm publicly available or something like that?

Not of my knowledge.


-- 
With Best Regards,
Andy Shevchenko