iio: trigger: stm32-timer: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230919174931.1417681-50-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:adc:stm32*: Use pm[_sleep]_ptr() etc to avoid need to make pm __maybe_unused

The combinations of either
* pm_sleep_ptr() and DEFINE_SIMPLE_DEV_PM_OPS()
* pm_ptr() and RUNTIME_PM_OPS()/SYSTEM_SLEEP_PM_OPS
Make sure the functions are always visible to the compiler and removed by
it rather than requring #ifdef magic.

This removes the need to mark the functions as __maybe_unused and saves
additional space with some build options as the dev_pm_ops structure
itself can be dropped automatically if CONFIG_PM is not enabled.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Olivier Moysan <olivier.moysan@st.com>
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-51-jic23@kernel.org

iio: trigger: stm32-timer: Make use of device properties

Convert the module to be property provider agnostic and allow
it to be used on non-OF platforms.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220202204112.57095-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: expose shared parameter in IIO_ENUM_AVAILABLE

The shared parameter should be configurable based on its usage, and not
constrained to IIO_SHARED_BY_TYPE.

This patch aims to improve the flexibility in using the
IIO_ENUM_AVAILABLE define and avoid redefining custom iio enums that
expose the shared parameter.

An example is the ad5766.c driver where IIO_ENUM_AVAILABLE_SHARED was
defined in order to achieve `shared` parameter customization.

The current state of the IIO_ENUM_AVAILABLE implementation will imply
similar redefinitions each time a driver will require access to the
`shared` parameter. An example would be admv1013 driver which will
require custom device attribute for the frequency translation modes:
Quadrature I/Q mode and Intermediate Frequency mode.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20211119085627.6348-1-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: fix MODULE_ALIAS

modprobe can't handle spaces in aliases.

Fixes: 93fbe91b5521 ("iio: Add STM32 timer trigger driver")
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Link: https://lore.kernel.org/r/20211125182850.2645424-1-hi@alyssa.is
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: Convert sysfs sprintf/snprintf family to sysfs_emit

Fix the following coccicheck warning:
drivers/iio/trigger/stm32-timer-trigger.c:299:8-16: WARNING:
use scnprintf or sprintf

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1618216751-1678-4-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Remove superfluous of_node assignments

If a driver does not assign an of_node to a IIO device to IIO core will
automatically assign the of_node of the parent device. This automatic
assignment is done in the iio_device_register() function.

There is a fair amount of drivers that currently manually assign the
of_node of the IIO device. All but 4 of them can make use of the automatic
assignment though.

The exceptions are:
* mxs-lradc-adc: Which uses the of_node of the parent of the parent.
* stm32-dfsdm-adc, stm32-adc and stm32-dac: Which reference the of_node
assigned to the IIO device before iio_device_register() is called.

All other drivers are updated to use automatic assignment. This reduces
the amount of boilerplate code involved in setting up the IIO device.

The patch has mostly been auto-generated with the following semantic patch

// <smpl>
@exists@
expression indio_dev;
expression parent;
@@
indio_dev = \(devm_iio_device_alloc\|iio_device_alloc\)(&parent, ...)
...
-indio_dev->dev.of_node = parent.of_node;

@exists@
expression indio_dev;
expression parent;
@@
indio_dev = \(devm_iio_device_alloc\|iio_device_alloc\)(parent, ...)
...
-indio_dev->dev.of_node = parent->of_node;
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
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: trigger: stm32-timer: add power management support

Add suspend/resume PM sleep ops to stm32-timer-trigger driver.
Register contents may be lost depending on low power modes.
When going to low power, enforce the timer isn't active. Gracefully
restore its state upon resume in case it's been left enabled prior to
suspend.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: rename enabled flag

"clk_enabled" flag reflects enabled state of the timer, for master mode,
slave mode or trigger (with sampling_frequency). So rename it to "enabled".

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: enable clock when in master mode

Clock should be enabled as soon as using master modes, even before
enabling timer. Or, this may provoke bad behavior on the other end
(slave timer). Then, introduce 'clk_enabled' flag, instead of relying
on CR1 EN bit, to keep track of clock being enabled (balanced refcount).
Propagate this anywhere else in the driver.

Also add 'remove' routine to stop timer and disable clock in case it
has been left enabled. Enforce the user interface has been unregistered
in the remove routine, before disabling the hardware to avoid possible
race. So, remove use of devm_ variant to register triggers and unregister
them before the hardware gets disabled [1].
[1] https://patchwork.kernel.org/patch/9956247/

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: disable master mode when stopping

Master mode should be disabled when stopping. This mainly impacts
possible other use-case after timer has been stopped. Currently,
master mode remains set (from start routine).

Fixes: 6fb34812c2a2 ("iio: stm32 trigger: Add support for TRGO2 triggers")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: remove unnecessary update event

There is no need to explicitly generate update event to update
timer master mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: stm32: Remove quadrature related functions from trigger driver

Quadrature feature is now hosted on it own framework.
Remove quadrature related code from stm32-trigger driver to avoid
code duplication and simplify the ABI.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: stm32: Adopt SPDX identifier

Add SPDX identifier in stm32's files in IIO directory

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: trigger: stm32-timer: fix a corner case to write preset

Balance timer start routine that sets ARPE: clear it in stop routine.
This fixes a corner case, when timer is used successively as trigger
(with sampling_frequency start/stop routines), then as a counter
(with preset).

Fixes: 93fbe91b5521 ("iio: Add STM32 timer trigger driver")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: preset shouldn't be buffered

Currently, setting preset value (ARR) will update directly 'Auto reload
value' only on 1st write access. But then, ARPE is set. This makes
ARR a shadow register. Preset value should be updated upon each
write request: ensure ARPE is 0. This fixes successive writes to
preset attribute.

Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:triggers: 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.

Note that stm32-timer-trigger has expanded rather beyond triggers
(to include encoder input counting for example) and hence has an
iio_info structure.

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

iio: trigger: stm32-timer: fix get trigger mode

Fix reading trigger mode, when other bit-fields are set. SMCR register
value must be masked to read SMS (slave mode selection) only.

Fixes: 9eba381 ("iio: make stm32 trigger driver use
INDIO_HARDWARE_TRIGGERED mode")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: add output compare triggers

Add output compare trigger sources available on some instances.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: add support for STM32H7

Add support for STM32H7 timer triggers:
- Add new valids_table
- Introduce compatible, with configuration data
- Extend up to 15 timers, available on STM32H7

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: add enable attribute

In order to use encoder mode, timers needs to be enabled (e.g. CEN bit)
along with peripheral clock.
Add IIO_CHAN_INFO_ENABLE attribute to handle this.
Also, in triggered mode, CEN bit is set automatically in hardware.
Then clock must be enabled before starting triggered mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: fix get/set down count direction

Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device")

This fixes two issues:
- stm32_set_count_direction: to set down direction
- stm32_get_count_direction: to get down direction

IIO core provides/expects value to be an index of iio_enum items array.
This needs to be turned by these routines into TIM_CR1_DIR (e.g. BIT(4))
value.
Also, report error when attempting to write direction, when in encoder
mode: in this case, direction is read only (given by encoder inputs).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: fix write_raw return value

Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device")

IIO core expects zero as return value for write_raw() callback
in case of success.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: stm32-timer: fix quadrature mode get routine

Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device")

SMS bitfiled is mode + 1. After reset, upon boot, SMS = 0. When reading
from sysfs, stm32_get_quadrature_mode() returns -1 (e.g. -EPERM) which is
wrong error code here. So, check SMS bitfiled matches valid encoder mode,
or return -EINVAL.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: make stm32 trigger driver use INDIO_HARDWARE_TRIGGERED mode

Add validate function to be use to use the correct trigger.
Add an attribute to configure device mode like for quadrature and
enable modes

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: stm32 trigger: Add support for TRGO2 triggers

Add support for TRGO2 trigger that can be found on STM32F7.
Add additional master modes supported by TRGO2.
Register additional "tim[1/8]_trgo2" triggers for timer1 & timer8.
Detect TRGO2 timer capability (master mode selection 2).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: stm32 trigger: Add counter enable modes

Device counting could be controlled by the level or the edges of
a trigger.
in_count0_enable_mode attibute allow to set the control mode.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: stm32 trigger: Add quadrature encoder device

One of the features of STM32 trigger hardware block is a quadrature
encoder that can counts up/down depending of the levels and edges
of the selected external pins.

This patch allow to read/write the counter, get it direction,
set/get quadrature modes and get scale factor.

When counting up preset value is the limit of the counter.
When counting down the counter start from preset value down to 0.
This preset value could be set/get by using
/sys/bus/iio/devices/iio:deviceX/in_count0_preset attribute.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: stm32 trigger: fix sampling_frequency read

When prescaler (PSC) is 0, it means div factor is 1: counter clock
frequency is equal to input clk / (PSC + 1).
When reload value is 8 for example, counter counts 9 cycles, from 0 to 8.
This is handled in frequency write routine, by writing respectively:
- prescaler - 1 to PSC
- reload value - 1 to ARR
This fix does the opposite when reading the frequency from PSC and ARR:
- prescaler is PSC + 1
- reload value is ARR + 1

Thus, PSC may be 0, depending on requested sampling frequency (div 1).
In this case, reading freq wrongly reports 0, instead of computing and
reporting correct value.
Remove test on !psc and !arr.

Small test on stm32f4 (example on tim1_trgo), before this fix:
$ cd /sys/bus/iio/devices/triggerX
$ echo 10000 > sampling_frequency
$ cat sampling_frequency
0

After this fix:
$ echo 10000 > sampling_frequency
$ cat sampling_frequency
10000

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add STM32 timer trigger driver

Timers IPs can be used to generate triggers for other IPs like
DAC or ADC.
Each trigger may result of timer internals signals like counter enable,
reset or edge, this configuration could be done through "master_mode"
device attribute.

Since triggers could be used by DAC or ADC their names are defined
in include/ nux/iio/timer/stm32-timer-trigger.h and is_stm32_iio_timer_trigger
function could be used to check if the trigger is valid or not.

"trgo" trigger have a "sampling_frequency" attribute which allow to configure
timer sampling frequency.

version 8:
- change kernel version from 4.10 to 4.11 in ABI documentation

version 7:
- remove all iio_device related code
- move driver into trigger directory

version 5:
- simplify tables of triggers
- only create an IIO device when needed

version 4:
- get triggers configuration from "reg" in DT
- add tables of triggers
- sampling frequency is enable/disable when writing in trigger
sampling_frequency attribute
- no more use of interruptions

version 3:
- change compatible to "st,stm32-timer-trigger"
- fix attributes access right
- use string instead of int for master_mode and slave_mode
- document device attributes in sysfs-bus-iio-timer-stm32

version 2:
- keep only one compatible
- use st,input-triggers-names and st,output-triggers-names
to know which triggers are accepted and/or create by the device

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>