iio: Switch i2c drivers back to use .probe()

After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498b5 ("i2c: Switch .probe() to not take an id parameter") convert
back to (the new) .probe() to be able to eventually drop .probe_new() from
struct i2c_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230515205048.19561-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: Convert to i2c's .probe_new()

The probe function doesn't make use of the i2c_device_id * parameter so it
can be trivially converted.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221118224540.619276-154-uwe@kleine-koenig.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

i2c: Make remove callback return void

The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

iio: magnetometer: ak8974: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros

Using these new macros allows the compiler to remove the unused dev_pm_ops
structure and related functions if !CONFIG_PM without the need to mark
the functions __maybe_unused.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220621202719.13644-36-jic23@kernel.org

iio: Drop Duplicated "mount-matrix" parameter

All of the users of iio_read_mount_matrix() are using the very same
property name. Moreover, the property name is hard coded in the API
documentation.

Make this clear and avoid duplication now and in the future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sean Nyekjaer <sean@geanix.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210518112546.44592-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:magn:ak8974: Drop of_match_ptr protection

This prevents use of this driver with ACPI via PRP0001 and is
an example of an anti pattern I'm trying to remove from IIO.
Hence drop from this driver.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200910173242.621168-36-jic23@kernel.org

iio: magnetometer: ak8974: Simplify with dev_err_probe()

Common pattern of handling deferred probe can be simplified with
dev_err_probe(). Less code and also it prints the error value.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200829064726.26268-16-krzk@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

iio: magnetometer: ak8974: Add description for ak8974's 'scan' attribute

Fixes the following W=1 kernel build warning(s):

drivers/iio/magnetometer/ak8974.c:200: warning: Function parameter or member 'scan' not described in 'ak8974'

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Samu Onkalo <samu.p.onkalo@nokia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:magnetometer:ak8974: Fix alignment and data leak issues

One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes). This is not guaranteed in
this driver which uses an array of smaller elements on the stack.
As Lars also noted this anti pattern can involve a leak of data to
userspace and that indeed can happen here. We close both issues by
moving to a suitable structure in the iio_priv() data.

This data is allocated with kzalloc so no data can leak appart from
previous readings.

Fixes: 7c94a8b2ee8cf ("iio: magn: add a driver for AK8974")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <Stable@vger.kernel.org>

iio: magnetometer: ak8974: Fix runtime PM imbalance on error

When devm_regmap_init_i2c() returns an error code, a pairing
runtime PM usage counter decrement is needed to keep the
counter balanced. For error paths after ak8974_set_power(),
ak8974_detect() and ak8974_reset(), things are the same.

However, When iio_triggered_buffer_setup() returns an error
code, there will be two PM usgae counter decrements.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Fixes: 7c94a8b2ee8c ("iio: magn: add a driver for AK8974")
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: remove explicit IIO device parent assignment

This patch applies the semantic patch:
@@
expression I, P, SP;
@@
I = devm_iio_device_alloc(P, SP);
...
- I->dev.parent = P;

It updates 302 files and does 307 deletions.
This semantic patch also removes some comments like
'/* Establish that the iio_dev is a child of the i2c device */'

But this is is only done in case where the block is left empty.

The patch does not seem to cover all cases. It looks like in some cases a
different variable is used in some cases to assign the parent, but it
points to the same reference.
In other cases, the block covered by ... may be just too big to be covered
by the semantic patch.

However, this looks pretty good as well, as it does cover a big bulk of the
drivers that should remove the parent assignment.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: Provide scaling

The manual for the HSCDTD008A gives us a scaling for the
three axis as +/- 2.4mT (24 Gauss) per axis.

The manual for the AMI305 and AMI306 gives us a scaling
for the three axis as +/- 12 Gauss per axis.

Tests with the HSCDTD008A sensor, cat the raw values:
$ cat in_magn_*_raw
raw
45
189
-19

The scaling factor in in_magn_*_scale is 0.001464843,
which gives:
0.065 Gauss
0.277 Gauss
-0.027 Gauss

The earths magnetic field is in the range of 0.25 to 0.65
Gauss on the surface according to Wikipedia, so these
seem like reasonable values.

Again we are guessing that the AK8974 has a 12 bit ADC,
based on the similarity with AMI305 and AMI306.

Cc: Nick Reitemeyer <nick.reitemeyer@web.de>
Cc: Stephan Gerhold <stephan@gerhold.net>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: Break out measurement

This breaks out the measurement code to its own function
so we can handle this without swirling it up with the
big switch() statement inside ak8974_read_raw().

Keep a local s16 helper variable for the signed value
coming out of the measurement before assigning it to the
integer *val. The local variable makes the code easier
to read and the compiler will optimize it if possible.

Cc: Nick Reitemeyer <nick.reitemeyer@web.de>
Cc: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: Correct realbits

The HSCDTD008A has 15 bits of actual ADC valie, and the
AMI305 and AMI306 has 12 bits.

Correct this by providing an extra parameter to the channel
macro and define a separate set of channels for each variant
of the chip. The resolution is the actual resolution of the
internal ADC of the chip.

The values are stored in a S16 in 2's complement so all 16
bits are used for storing (no shifting needed).

The AMI305, AMI306 and HSCDTD008A valid bits are picked from
respective datasheet.

My best educated guess is that AK8974 is also 12 bits. The
AK8973 is an 8 bit and earlier version, and the sibling
drivers AMI305 and AMI306 are 12 bits, so it makes sense
to assume that the AK8974 is also 12 bits.

Cc: Nick Reitemeyer <nick.reitemeyer@web.de>
Cc: Stephan Gerhold <stephan@gerhold.net>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: add Alps hscdtd008a

The hscdtd008a is similar to the AK8974:
Only the whoami value and some registers are different.

Signed-off-by: Nick Reitemeyer <nick.reitemeyer@web.de>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: Silence deferred-probe error

It's not uncommon that voltage regulator becomes available later during
kernel's boot process. This patch adds info message about unavailable
regulators in a case of the deferred-probe error and also amends the
error message with a error code.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: Fix negative raw values in sysfs

At the moment, reading from in_magn_*_raw in sysfs tends to return
large values around 65000, even though the output of ak8974 is actually
limited to ±32768. This happens because the value is never converted
to the signed 16-bit integer variant.

Add an explicit cast to s16 to fix this.

Fixes: 7c94a8b2ee8c ("iio: magn: add a driver for AK8974")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Linus Waleij <linus.walleij@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Add SPDX license identifier for more missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Allow to read mount matrix from ACPI

Currently mount matrix is allowed in Device Tree, though there is
no technical issue to extend it to support ACPI.

Convert the function to use device_property_read_string_array() and
thus allow to read mount matrix from ACPI if available.

Example of use in _DSD method:

Name (_DSD, Package ()
{
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package ()
{
Package () { "mount-matrix", Package() {
"1", "0", "0",
"0", "0.866", "0.5",
"0", "-0.5", "0.866",
} },
}
})

At the same time drop the "of" prefix from its name and
convert current users.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:magnetometer: drop assign iio_info.driver_module and iio_trigger_ops.owner

The equivalent of both of these are now done via macro magic when
the relevant register calls are made. The actual structure
elements will shortly go away.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

iio: magnetometer: ak8974: debug AMI306 calibration data

Use AMI306 calibration data for randomness and debugging.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: mark INT_CLEAR as precious

Reading INT_CLEAR has side effects - disallow reading it via debugfs.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: add_device_randomness (serial number)

Mix device-specific data into randomness pool.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: support AMI306 variant

Add support for AMI306 magnetometer - very similar to AMI305.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: magnetometer: ak8974: remove incorrect __exit markups

Even if bus is not hot-pluggable, devices can be unbound from the
driver via sysfs, so we should not be using __exit annotations on
remove() methods. The only exception is drivers registered with
platform_driver_probe() which specifically disables sysfs bind/unbind
attributes.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: magnetometer: ak8974: remove redundant zero timeout check

At the end of the delay loop timeout will always be zero
and hence the check for !timeout will always be true. Remove
the redundant check and the redundant return 0 at the end of
the function.

Fixes CoverityScan CID#1357168 ("Logically dead code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: magnetometer: ak8974: small endianness fixes

Fixes two cases of 'cast to restricted __le16' as reported by sparse.

Signed-off-by: Ico Doornekamp <ico@pruts.nl>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: magn: ak8974: remove .owner field for driver

Remove .owner field if calls are used which set it automatically.

Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: magn/ak8974: avoid unused function warning

The ak8974_configure() function is used only from the PM code,
but that can be hidden when CONFIG_PM is disabled:

drivers/iio/magnetometer/ak8974.c:201:12: error: 'ak8974_configure' defined but not used [-Werror=unused-function]

This replaces the #ifdef with a __maybe_unused annotation, which
will work correctly in all configurations and avoid the warning,
as the compiler can now see where ak8974_configure is called from.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 7c94a8b2ee8c ("iio: magn: add a driver for AK8974")
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: magn: add a driver for AK8974

This adds a driver for the Asahi Kasei AK8974 and its sibling
AMI305 magnetometers. It was deployed on scale in 2009 on a
multitude of devices. It is distincly different from AK8973
and AK8975 and needs its own driver.

This patch is based on the long lost work of Samu Onkalo at Nokia,
who made a misc character device driver for the Maemo/MeeGo Nokia
devices, before the time of the IIO subsystem. It was mounted in e.g.
the Nokia N950, N8, N86, N97 etc. It is also mounted on the
ST-Ericsson HREF reference designs.

It works nicely in sysfs:

$ cat in_magn_x_raw && cat in_magn_y_raw && cat in_magn_z_raw
-55
-101
161

And with buffered reads using a simple HRTimer trigger:
$ generic_buffer -c10 -a -n ak8974 -t foo
iio device number being used is 3
iio trigger number being used is 2
No channels are enabled, enabling all channels
Enabling: in_magn_x_en
Enabling: in_magn_y_en
Enabling: in_magn_z_en
Enabling: in_timestamp_en
/sys/bus/iio/devices/iio:device3 foo
-58.000000 -102.000000 157.000000 946684970985321044
-60.000000 -98.000000 159.000000 946684971012237548
-60.000000 -106.000000 163.000000 946684971032257080
-62.000000 -94.000000 169.000000 946684971052185058
-58.000000 -98.000000 163.000000 946684971072204589
-54.000000 -100.000000 163.000000 946684971092224121
-53.000000 -103.000000 164.000000 946684971112731933
-50.000000 -102.000000 165.000000 946684971132232666
-61.000000 -101.000000 164.000000 946684971152191162
-57.000000 -99.000000 168.000000 946684971172210693
Disabling: in_magn_x_en
Disabling: in_magn_y_en
Disabling: in_magn_z_en
Disabling: in_timestamp_en

I cannot currently scale these raw values to gauss. This is
because of lack of documentation. I have sent a request for
a datasheet to Asahi Kasei.

The driver can optionally use a DRDY line IRQ to capture data,
else it will sleep and poll.

Cc: Samu Onkalo <samu.onkalo@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>