Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

7 files changed, 1733 insertions, 0 deletions

diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
new file mode 100644
index 000000000..52899c22d
--- /dev/null
+++ b/drivers/iio/trigger/Kconfig
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Industrial I/O standalone triggers
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Triggers - standalone"
+
+config IIO_HRTIMER_TRIGGER
+	tristate "High resolution timer trigger"
+	depends on IIO_SW_TRIGGER
+	help
+	  Provides a frequency based IIO trigger using high resolution
+	  timers as interrupt source.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-trig-hrtimer.
+
+config IIO_STM32_LPTIMER_TRIGGER
+	tristate "STM32 Low-Power Timer Trigger"
+	depends on MFD_STM32_LPTIMER || COMPILE_TEST
+	help
+	  Select this option to enable STM32 Low-Power Timer Trigger.
+	  This can be used as trigger source for STM32 internal ADC
+	  and/or DAC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32-lptimer-trigger.
+
+config IIO_STM32_TIMER_TRIGGER
+	tristate "STM32 Timer Trigger"
+	depends on (ARCH_STM32 && MFD_STM32_TIMERS) || COMPILE_TEST
+	help
+	  Select this option to enable STM32 Timer Trigger
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32-timer-trigger.
+
+config IIO_TIGHTLOOP_TRIGGER
+	tristate "A kthread based hammering loop trigger"
+	depends on IIO_SW_TRIGGER
+	help
+	  An experimental trigger, used to allow sensors to be sampled as fast
+	  as possible under the limitations of whatever else is going on.
+	  Uses a tight loop in a kthread.  Will only work with lower half only
+	  trigger consumers.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-trig-loop.
+
+config IIO_SYSFS_TRIGGER
+	tristate "SYSFS trigger"
+	depends on SYSFS
+	select IRQ_WORK
+	help
+	  Provides support for using SYSFS entries as IIO triggers.
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-trig-sysfs.
+
+endmenu
diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
new file mode 100644
index 000000000..fc1fd5661
--- /dev/null
+++ b/drivers/iio/trigger/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for triggers not associated with iio-devices
+#
+
+# When adding new entries keep the list in alphabetical order
+
+obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o
+obj-$(CONFIG_IIO_STM32_LPTIMER_TRIGGER) += stm32-lptimer-trigger.o
+obj-$(CONFIG_IIO_STM32_TIMER_TRIGGER) += stm32-timer-trigger.o
+obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o
+obj-$(CONFIG_IIO_TIGHTLOOP_TRIGGER) += iio-trig-loop.o
diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c
new file mode 100644
index 000000000..57550b581
--- /dev/null
+++ b/drivers/iio/trigger/iio-trig-hrtimer.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * The industrial I/O periodic hrtimer trigger driver
+ *
+ * Copyright (C) Intuitive Aerial AB
+ * Written by Marten Svanfeldt, marten@intuitiveaerial.com
+ * Copyright (C) 2012, Analog Devices Inc.
+ *	Author: Lars-Peter Clausen <lars@metafoo.de>
+ * Copyright (C) 2015, Intel Corporation
+ */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/hrtimer.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/sw_trigger.h>
+
+/* Defined locally, not in time64.h yet. */
+#define PSEC_PER_SEC   1000000000000LL
+
+/* default sampling frequency - 100Hz */
+#define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100
+
+struct iio_hrtimer_info {
+	struct iio_sw_trigger swt;
+	struct hrtimer timer;
+	int sampling_frequency[2];
+	ktime_t period;
+};
+
+static const struct config_item_type iio_hrtimer_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static
+ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev,
+					    struct device_attribute *attr,
+					    char *buf)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
+
+	return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO,
+			ARRAY_SIZE(info->sampling_frequency),
+			info->sampling_frequency);
+}
+
+static
+ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
+					     struct device_attribute *attr,
+					     const char *buf, size_t len)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
+	unsigned long long val;
+	u64 period;
+	int integer, fract, ret;
+
+	ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
+	if (ret)
+		return ret;
+	if (integer < 0 || fract < 0)
+		return -ERANGE;
+
+	val = fract + 1000ULL * integer;  /* mHz */
+
+	if (!val || val > UINT_MAX)
+		return -EINVAL;
+
+	info->sampling_frequency[0] = integer;  /* Hz */
+	info->sampling_frequency[1] = fract * 1000;  /* uHz */
+	period = PSEC_PER_SEC;
+	do_div(period, val);
+	info->period = period;  /* nS */
+
+	return len;
+}
+
+static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,
+		   iio_hrtimer_show_sampling_frequency,
+		   iio_hrtimer_store_sampling_frequency);
+
+static struct attribute *iio_hrtimer_attrs[] = {
+	&dev_attr_sampling_frequency.attr,
+	NULL
+};
+
+static const struct attribute_group iio_hrtimer_attr_group = {
+	.attrs = iio_hrtimer_attrs,
+};
+
+static const struct attribute_group *iio_hrtimer_attr_groups[] = {
+	&iio_hrtimer_attr_group,
+	NULL
+};
+
+static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer)
+{
+	struct iio_hrtimer_info *info;
+
+	info = container_of(timer, struct iio_hrtimer_info, timer);
+
+	hrtimer_forward_now(timer, info->period);
+	iio_trigger_poll(info->swt.trigger);
+
+	return HRTIMER_RESTART;
+}
+
+static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_hrtimer_info *trig_info;
+
+	trig_info = iio_trigger_get_drvdata(trig);
+
+	if (state)
+		hrtimer_start(&trig_info->timer, trig_info->period,
+			      HRTIMER_MODE_REL_HARD);
+	else
+		hrtimer_cancel(&trig_info->timer);
+
+	return 0;
+}
+
+static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
+	.set_trigger_state = iio_trig_hrtimer_set_state,
+};
+
+static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name)
+{
+	struct iio_hrtimer_info *trig_info;
+	int ret;
+
+	trig_info = kzalloc_obj(*trig_info);
+	if (!trig_info)
+		return ERR_PTR(-ENOMEM);
+
+	trig_info->swt.trigger = iio_trigger_alloc(NULL, "%s", name);
+	if (!trig_info->swt.trigger) {
+		ret = -ENOMEM;
+		goto err_free_trig_info;
+	}
+
+	iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info);
+	trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops;
+	trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups;
+
+	hrtimer_setup(&trig_info->timer, iio_hrtimer_trig_handler, CLOCK_MONOTONIC,
+		      HRTIMER_MODE_REL_HARD);
+
+	trig_info->sampling_frequency[0] = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;
+	trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency[0];
+
+	ret = iio_trigger_register(trig_info->swt.trigger);
+	if (ret)
+		goto err_free_trigger;
+
+	iio_swt_group_init_type_name(&trig_info->swt, name, &iio_hrtimer_type);
+	return &trig_info->swt;
+err_free_trigger:
+	iio_trigger_free(trig_info->swt.trigger);
+err_free_trig_info:
+	kfree(trig_info);
+
+	return ERR_PTR(ret);
+}
+
+static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt)
+{
+	struct iio_hrtimer_info *trig_info;
+
+	trig_info = iio_trigger_get_drvdata(swt->trigger);
+
+	iio_trigger_unregister(swt->trigger);
+
+	/* cancel the timer after unreg to make sure no one rearms it */
+	hrtimer_cancel(&trig_info->timer);
+	iio_trigger_free(swt->trigger);
+	kfree(trig_info);
+
+	return 0;
+}
+
+static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = {
+	.probe		= iio_trig_hrtimer_probe,
+	.remove		= iio_trig_hrtimer_remove,
+};
+
+static struct iio_sw_trigger_type iio_trig_hrtimer = {
+	.name = "hrtimer",
+	.owner = THIS_MODULE,
+	.ops = &iio_trig_hrtimer_ops,
+};
+
+module_iio_sw_trigger_driver(iio_trig_hrtimer);
+
+MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>");
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/trigger/iio-trig-loop.c b/drivers/iio/trigger/iio-trig-loop.c
new file mode 100644
index 000000000..580a46503
--- /dev/null
+++ b/drivers/iio/trigger/iio-trig-loop.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2016 Jonathan Cameron <jic23@kernel.org>
+ *
+ * Based on a mashup of the hrtimer trigger and continuous sampling proposal of
+ * Gregor Boirie <gregor.boirie@parrot.com>
+ *
+ * Note this is still rather experimental and may eat babies.
+ *
+ * Todo
+ * * Protect against connection of devices that 'need' the top half
+ *   handler.
+ * * Work out how to run top half handlers in this context if it is
+ *   safe to do so (timestamp grabbing for example)
+ *
+ * Tested against a max1363. Used about 33% cpu for the thread and 20%
+ * for generic_buffer piping to /dev/null. Watermark set at 64 on a 128
+ * element kfifo buffer.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/irq_work.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/sw_trigger.h>
+
+struct iio_loop_info {
+	struct iio_sw_trigger swt;
+	struct task_struct *task;
+};
+
+static const struct config_item_type iio_loop_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static int iio_loop_thread(void *data)
+{
+	struct iio_trigger *trig = data;
+
+	set_freezable();
+
+	do {
+		iio_trigger_poll_nested(trig);
+	} while (likely(!kthread_freezable_should_stop(NULL)));
+
+	return 0;
+}
+
+static int iio_loop_trigger_set_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_loop_info *loop_trig = iio_trigger_get_drvdata(trig);
+
+	if (state) {
+		loop_trig->task = kthread_run(iio_loop_thread,
+					      trig, trig->name);
+		if (IS_ERR(loop_trig->task)) {
+			dev_err(&trig->dev,
+				"failed to create trigger loop thread\n");
+			return PTR_ERR(loop_trig->task);
+		}
+	} else {
+		kthread_stop(loop_trig->task);
+	}
+
+	return 0;
+}
+
+static const struct iio_trigger_ops iio_loop_trigger_ops = {
+	.set_trigger_state = iio_loop_trigger_set_state,
+};
+
+static struct iio_sw_trigger *iio_trig_loop_probe(const char *name)
+{
+	struct iio_loop_info *trig_info;
+	int ret;
+
+	trig_info = kzalloc_obj(*trig_info);
+	if (!trig_info)
+		return ERR_PTR(-ENOMEM);
+
+	trig_info->swt.trigger = iio_trigger_alloc(NULL, "%s", name);
+	if (!trig_info->swt.trigger) {
+		ret = -ENOMEM;
+		goto err_free_trig_info;
+	}
+
+	iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info);
+	trig_info->swt.trigger->ops = &iio_loop_trigger_ops;
+
+	ret = iio_trigger_register(trig_info->swt.trigger);
+	if (ret)
+		goto err_free_trigger;
+
+	iio_swt_group_init_type_name(&trig_info->swt, name, &iio_loop_type);
+
+	return &trig_info->swt;
+
+err_free_trigger:
+	iio_trigger_free(trig_info->swt.trigger);
+err_free_trig_info:
+	kfree(trig_info);
+
+	return ERR_PTR(ret);
+}
+
+static int iio_trig_loop_remove(struct iio_sw_trigger *swt)
+{
+	struct iio_loop_info *trig_info;
+
+	trig_info = iio_trigger_get_drvdata(swt->trigger);
+
+	iio_trigger_unregister(swt->trigger);
+	iio_trigger_free(swt->trigger);
+	kfree(trig_info);
+
+	return 0;
+}
+
+static const struct iio_sw_trigger_ops iio_trig_loop_ops = {
+	.probe = iio_trig_loop_probe,
+	.remove = iio_trig_loop_remove,
+};
+
+static struct iio_sw_trigger_type iio_trig_loop = {
+	.name = "loop",
+	.owner = THIS_MODULE,
+	.ops = &iio_trig_loop_ops,
+};
+
+module_iio_sw_trigger_driver(iio_trig_loop);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("Loop based trigger for the iio subsystem");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:iio-trig-loop");
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c
new file mode 100644
index 000000000..b242b050b
--- /dev/null
+++ b/drivers/iio/trigger/iio-trig-sysfs.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2011 Analog Devices Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/irq_work.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+
+struct iio_sysfs_trig {
+	struct iio_trigger *trig;
+	struct irq_work work;
+	int id;
+	struct list_head l;
+};
+
+static LIST_HEAD(iio_sysfs_trig_list);
+static DEFINE_MUTEX(iio_sysfs_trig_list_mut);
+
+static int iio_sysfs_trigger_probe(int id);
+static ssize_t iio_sysfs_trig_add(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	int ret;
+	unsigned long input;
+
+	ret = kstrtoul(buf, 10, &input);
+	if (ret)
+		return ret;
+	ret = iio_sysfs_trigger_probe(input);
+	if (ret)
+		return ret;
+	return len;
+}
+static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
+
+static int iio_sysfs_trigger_remove(int id);
+static ssize_t iio_sysfs_trig_remove(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf,
+				     size_t len)
+{
+	int ret;
+	unsigned long input;
+
+	ret = kstrtoul(buf, 10, &input);
+	if (ret)
+		return ret;
+	ret = iio_sysfs_trigger_remove(input);
+	if (ret)
+		return ret;
+	return len;
+}
+
+static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
+
+static struct attribute *iio_sysfs_trig_attrs[] = {
+	&dev_attr_add_trigger.attr,
+	&dev_attr_remove_trigger.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_sysfs_trig_group = {
+	.attrs = iio_sysfs_trig_attrs,
+};
+
+static const struct attribute_group *iio_sysfs_trig_groups[] = {
+	&iio_sysfs_trig_group,
+	NULL
+};
+
+
+/* Nothing to actually do upon release */
+static void iio_trigger_sysfs_release(struct device *dev)
+{
+}
+
+static struct device iio_sysfs_trig_dev = {
+	.bus = &iio_bus_type,
+	.groups = iio_sysfs_trig_groups,
+	.release = &iio_trigger_sysfs_release,
+};
+
+static void iio_sysfs_trigger_work(struct irq_work *work)
+{
+	struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
+							work);
+
+	iio_trigger_poll(trig->trig);
+}
+
+static ssize_t iio_sysfs_trigger_poll(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
+
+	irq_work_queue(&sysfs_trig->work);
+
+	return count;
+}
+
+static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
+
+static struct attribute *iio_sysfs_trigger_attrs[] = {
+	&dev_attr_trigger_now.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_sysfs_trigger_attr_group = {
+	.attrs = iio_sysfs_trigger_attrs,
+};
+
+static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
+	&iio_sysfs_trigger_attr_group,
+	NULL
+};
+
+static int iio_sysfs_trigger_probe(int id)
+{
+	struct iio_sysfs_trig *t;
+	int ret;
+	bool foundit = false;
+
+	mutex_lock(&iio_sysfs_trig_list_mut);
+	list_for_each_entry(t, &iio_sysfs_trig_list, l)
+		if (id == t->id) {
+			foundit = true;
+			break;
+		}
+	if (foundit) {
+		ret = -EINVAL;
+		goto err_unlock;
+	}
+	t = kmalloc_obj(*t);
+	if (t == NULL) {
+		ret = -ENOMEM;
+		goto err_unlock;
+	}
+	t->id = id;
+	t->trig = iio_trigger_alloc(&iio_sysfs_trig_dev, "sysfstrig%d", id);
+	if (!t->trig) {
+		ret = -ENOMEM;
+		goto err_free_sys_trig;
+	}
+
+	t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
+	iio_trigger_set_drvdata(t->trig, t);
+
+	t->work = IRQ_WORK_INIT_HARD(iio_sysfs_trigger_work);
+
+	ret = iio_trigger_register(t->trig);
+	if (ret)
+		goto err_free_trig;
+	list_add(&t->l, &iio_sysfs_trig_list);
+	__module_get(THIS_MODULE);
+	mutex_unlock(&iio_sysfs_trig_list_mut);
+	return 0;
+
+err_free_trig:
+	iio_trigger_free(t->trig);
+err_free_sys_trig:
+	kfree(t);
+err_unlock:
+	mutex_unlock(&iio_sysfs_trig_list_mut);
+	return ret;
+}
+
+static int iio_sysfs_trigger_remove(int id)
+{
+	struct iio_sysfs_trig *t = NULL, *iter;
+
+	mutex_lock(&iio_sysfs_trig_list_mut);
+	list_for_each_entry(iter, &iio_sysfs_trig_list, l)
+		if (id == iter->id) {
+			t = iter;
+			break;
+		}
+	if (!t) {
+		mutex_unlock(&iio_sysfs_trig_list_mut);
+		return -EINVAL;
+	}
+
+	iio_trigger_unregister(t->trig);
+	irq_work_sync(&t->work);
+	iio_trigger_free(t->trig);
+
+	list_del(&t->l);
+	kfree(t);
+	module_put(THIS_MODULE);
+	mutex_unlock(&iio_sysfs_trig_list_mut);
+	return 0;
+}
+
+
+static int __init iio_sysfs_trig_init(void)
+{
+	int ret;
+	device_initialize(&iio_sysfs_trig_dev);
+	dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
+	ret = device_add(&iio_sysfs_trig_dev);
+	if (ret)
+		put_device(&iio_sysfs_trig_dev);
+	return ret;
+}
+module_init(iio_sysfs_trig_init);
+
+static void __exit iio_sysfs_trig_exit(void)
+{
+	device_unregister(&iio_sysfs_trig_dev);
+}
+module_exit(iio_sysfs_trig_exit);
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:iio-trig-sysfs");
diff --git a/drivers/iio/trigger/stm32-lptimer-trigger.c b/drivers/iio/trigger/stm32-lptimer-trigger.c
new file mode 100644
index 000000000..828890fe3
--- /dev/null
+++ b/drivers/iio/trigger/stm32-lptimer-trigger.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Low-Power Timer Trigger driver
+ *
+ * Copyright (C) STMicroelectronics 2017
+ *
+ * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
+ *
+ * Inspired by Benjamin Gaignard's stm32-timer-trigger driver
+ */
+
+#include <linux/export.h>
+#include <linux/iio/timer/stm32-lptim-trigger.h>
+#include <linux/mfd/stm32-lptimer.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+/* Maximum triggers + one trailing null entry to indicate the end of array */
+#define MAX_TRIGGERS 3
+
+struct stm32_lptim_cfg {
+	const char * const (*triggers)[MAX_TRIGGERS];
+	unsigned int nb_triggers;
+};
+
+/* List Low-Power Timer triggers for H7, MP13, MP15 */
+static const char * const stm32_lptim_triggers[][MAX_TRIGGERS] = {
+	{ LPTIM1_OUT,},
+	{ LPTIM2_OUT,},
+	{ LPTIM3_OUT,},
+};
+
+/* List Low-Power Timer triggers for STM32MP25 */
+static const char * const stm32mp25_lptim_triggers[][MAX_TRIGGERS] = {
+	{ LPTIM1_CH1, LPTIM1_CH2, },
+	{ LPTIM2_CH1, LPTIM2_CH2, },
+	{ LPTIM3_CH1,},
+	{ LPTIM4_CH1,},
+	{ LPTIM5_OUT,},
+};
+
+static const struct stm32_lptim_cfg stm32mp15_lptim_cfg = {
+	.triggers = stm32_lptim_triggers,
+	.nb_triggers = ARRAY_SIZE(stm32_lptim_triggers),
+};
+
+static const struct stm32_lptim_cfg stm32mp25_lptim_cfg = {
+	.triggers = stm32mp25_lptim_triggers,
+	.nb_triggers = ARRAY_SIZE(stm32mp25_lptim_triggers),
+};
+
+struct stm32_lptim_trigger {
+	struct device *dev;
+	const char * const *triggers;
+};
+
+static int stm32_lptim_validate_device(struct iio_trigger *trig,
+				       struct iio_dev *indio_dev)
+{
+	if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
+		return 0;
+
+	return -EINVAL;
+}
+
+static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
+	.validate_device = stm32_lptim_validate_device,
+};
+
+/**
+ * is_stm32_lptim_trigger
+ * @trig: trigger to be checked
+ *
+ * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
+ * either return false
+ */
+bool is_stm32_lptim_trigger(struct iio_trigger *trig)
+{
+	return (trig->ops == &stm32_lptim_trigger_ops);
+}
+EXPORT_SYMBOL(is_stm32_lptim_trigger);
+
+static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
+{
+	const char * const *cur = priv->triggers;
+	int ret;
+
+	while (cur && *cur) {
+		struct iio_trigger *trig;
+
+		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
+		if  (!trig)
+			return -ENOMEM;
+
+		trig->dev.parent = priv->dev->parent;
+		trig->ops = &stm32_lptim_trigger_ops;
+		iio_trigger_set_drvdata(trig, priv);
+
+		ret = devm_iio_trigger_register(priv->dev, trig);
+		if (ret)
+			return ret;
+		cur++;
+	}
+
+	return 0;
+}
+
+static int stm32_lptim_trigger_probe(struct platform_device *pdev)
+{
+	struct stm32_lptim_trigger *priv;
+	struct stm32_lptim_cfg const *lptim_cfg;
+	u32 index;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	if (device_property_read_u32(&pdev->dev, "reg", &index))
+		return -EINVAL;
+
+	lptim_cfg = device_get_match_data(&pdev->dev);
+
+	if (index >= lptim_cfg->nb_triggers)
+		return -EINVAL;
+
+	priv->dev = &pdev->dev;
+	priv->triggers = lptim_cfg->triggers[index];
+
+	return stm32_lptim_setup_trig(priv);
+}
+
+static const struct of_device_id stm32_lptim_trig_of_match[] = {
+	{ .compatible = "st,stm32-lptimer-trigger", .data = &stm32mp15_lptim_cfg },
+	{ .compatible = "st,stm32mp25-lptimer-trigger", .data = &stm32mp25_lptim_cfg},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
+
+static struct platform_driver stm32_lptim_trigger_driver = {
+	.probe = stm32_lptim_trigger_probe,
+	.driver = {
+		.name = "stm32-lptimer-trigger",
+		.of_match_table = stm32_lptim_trig_of_match,
+	},
+};
+module_platform_driver(stm32_lptim_trigger_driver);
+
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
+MODULE_ALIAS("platform:stm32-lptimer-trigger");
+MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
new file mode 100644
index 000000000..4f6ff1e72
--- /dev/null
+++ b/drivers/iio/trigger/stm32-timer-trigger.c
@@ -0,0 +1,941 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ */
+
+#include <linux/export.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/timer/stm32-timer-trigger.h>
+#include <linux/iio/trigger.h>
+#include <linux/mfd/stm32-timers.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define MAX_TRIGGERS 7
+#define MAX_VALIDS 5
+
+/* List the triggers created by each timer */
+static const void *triggers_table[][MAX_TRIGGERS] = {
+	{ TIM1_TRGO, TIM1_TRGO2, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
+	{ TIM2_TRGO, TIM2_CH1, TIM2_CH2, TIM2_CH3, TIM2_CH4,},
+	{ TIM3_TRGO, TIM3_CH1, TIM3_CH2, TIM3_CH3, TIM3_CH4,},
+	{ TIM4_TRGO, TIM4_CH1, TIM4_CH2, TIM4_CH3, TIM4_CH4,},
+	{ TIM5_TRGO, TIM5_CH1, TIM5_CH2, TIM5_CH3, TIM5_CH4,},
+	{ TIM6_TRGO,},
+	{ TIM7_TRGO,},
+	{ TIM8_TRGO, TIM8_TRGO2, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
+	{ TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
+	{ TIM10_OC1,},
+	{ TIM11_OC1,},
+	{ TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
+	{ TIM13_OC1,},
+	{ TIM14_OC1,},
+	{ TIM15_TRGO,},
+	{ TIM16_OC1,},
+	{ TIM17_OC1,},
+	{ }, /* timer 18 */
+	{ }, /* timer 19 */
+	{ TIM20_TRGO, TIM20_TRGO2, TIM20_OC1, TIM20_OC2, TIM20_OC3, },
+};
+
+/* List the triggers accepted by each timer */
+static const void *valids_table[][MAX_VALIDS] = {
+	{ TIM5_TRGO, TIM2_TRGO, TIM3_TRGO, TIM4_TRGO,},
+	{ TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
+	{ TIM1_TRGO, TIM2_TRGO, TIM5_TRGO, TIM4_TRGO,},
+	{ TIM1_TRGO, TIM2_TRGO, TIM3_TRGO, TIM8_TRGO,},
+	{ TIM2_TRGO, TIM3_TRGO, TIM4_TRGO, TIM8_TRGO,},
+	{ }, /* timer 6 */
+	{ }, /* timer 7 */
+	{ TIM1_TRGO, TIM2_TRGO, TIM4_TRGO, TIM5_TRGO,},
+	{ TIM2_TRGO, TIM3_TRGO, TIM10_OC1, TIM11_OC1,},
+	{ }, /* timer 10 */
+	{ }, /* timer 11 */
+	{ TIM4_TRGO, TIM5_TRGO, TIM13_OC1, TIM14_OC1,},
+};
+
+static const void *stm32h7_valids_table[][MAX_VALIDS] = {
+	{ TIM15_TRGO, TIM2_TRGO, TIM3_TRGO, TIM4_TRGO,},
+	{ TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
+	{ TIM1_TRGO, TIM2_TRGO, TIM15_TRGO, TIM4_TRGO,},
+	{ TIM1_TRGO, TIM2_TRGO, TIM3_TRGO, TIM8_TRGO,},
+	{ TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
+	{ }, /* timer 6 */
+	{ }, /* timer 7 */
+	{ TIM1_TRGO, TIM2_TRGO, TIM4_TRGO, TIM5_TRGO,},
+	{ }, /* timer 9 */
+	{ }, /* timer 10 */
+	{ }, /* timer 11 */
+	{ TIM4_TRGO, TIM5_TRGO, TIM13_OC1, TIM14_OC1,},
+	{ }, /* timer 13 */
+	{ }, /* timer 14 */
+	{ TIM1_TRGO, TIM3_TRGO, TIM16_OC1, TIM17_OC1,},
+	{ }, /* timer 16 */
+	{ }, /* timer 17 */
+};
+
+struct stm32_timer_trigger_regs {
+	u32 cr1;
+	u32 cr2;
+	u32 psc;
+	u32 arr;
+	u32 cnt;
+	u32 smcr;
+};
+
+struct stm32_timer_trigger {
+	struct device *dev;
+	struct regmap *regmap;
+	struct clk *clk;
+	bool enabled;
+	u32 max_arr;
+	const void *triggers;
+	const void *valids;
+	bool has_trgo2;
+	struct mutex lock; /* concurrent sysfs configuration */
+	struct list_head tr_list;
+	struct stm32_timer_trigger_regs bak;
+};
+
+struct stm32_timer_trigger_cfg {
+	const void *(*valids_table)[MAX_VALIDS];
+	const unsigned int num_valids_table;
+};
+
+static bool stm32_timer_is_trgo2_name(const char *name)
+{
+	return !!strstr(name, "trgo2");
+}
+
+static bool stm32_timer_is_trgo_name(const char *name)
+{
+	return (!!strstr(name, "trgo") && !strstr(name, "trgo2"));
+}
+
+static int stm32_timer_start(struct stm32_timer_trigger *priv,
+			     struct iio_trigger *trig,
+			     unsigned int frequency)
+{
+	unsigned long long prd, div;
+	int prescaler = 0, ret;
+	u32 ccer;
+
+	/* Period and prescaler values depends of clock rate */
+	div = (unsigned long long)clk_get_rate(priv->clk);
+
+	do_div(div, frequency);
+
+	prd = div;
+
+	/*
+	 * Increase prescaler value until we get a result that fit
+	 * with auto reload register maximum value.
+	 */
+	while (div > priv->max_arr) {
+		prescaler++;
+		div = prd;
+		do_div(div, (prescaler + 1));
+	}
+	prd = div;
+
+	if (prescaler > MAX_TIM_PSC) {
+		dev_err(priv->dev, "prescaler exceeds the maximum value\n");
+		return -EINVAL;
+	}
+
+	/* Check if nobody else use the timer */
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	if (ccer & TIM_CCER_CCXE)
+		return -EBUSY;
+
+	guard(mutex)(&priv->lock);
+	if (!priv->enabled) {
+		priv->enabled = true;
+		ret = clk_enable(priv->clk);
+		if (ret)
+			return ret;
+	}
+
+	regmap_write(priv->regmap, TIM_PSC, prescaler);
+	regmap_write(priv->regmap, TIM_ARR, prd - 1);
+	regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
+
+	/* Force master mode to update mode */
+	if (stm32_timer_is_trgo2_name(trig->name))
+		regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2,
+				   0x2 << TIM_CR2_MMS2_SHIFT);
+	else
+		regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS,
+				   0x2 << TIM_CR2_MMS_SHIFT);
+
+	/* Make sure that registers are updated */
+	regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
+
+	/* Enable controller */
+	regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
+
+	return 0;
+}
+
+static void stm32_timer_stop(struct stm32_timer_trigger *priv,
+			     struct iio_trigger *trig)
+{
+	u32 ccer;
+
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	if (ccer & TIM_CCER_CCXE)
+		return;
+
+	mutex_lock(&priv->lock);
+	/* Stop timer */
+	regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
+	regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
+	regmap_write(priv->regmap, TIM_PSC, 0);
+	regmap_write(priv->regmap, TIM_ARR, 0);
+
+	/* Force disable master mode */
+	if (stm32_timer_is_trgo2_name(trig->name))
+		regmap_clear_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2);
+	else
+		regmap_clear_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS);
+
+	/* Make sure that registers are updated */
+	regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
+
+	if (priv->enabled) {
+		priv->enabled = false;
+		clk_disable(priv->clk);
+	}
+	mutex_unlock(&priv->lock);
+}
+
+static ssize_t stm32_tt_store_frequency(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
+	unsigned int freq;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &freq);
+	if (ret)
+		return ret;
+
+	if (freq == 0) {
+		stm32_timer_stop(priv, trig);
+	} else {
+		ret = stm32_timer_start(priv, trig, freq);
+		if (ret)
+			return ret;
+	}
+
+	return len;
+}
+
+static ssize_t stm32_tt_read_frequency(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
+	u32 psc, arr, cr1;
+	unsigned long long freq = 0;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	regmap_read(priv->regmap, TIM_PSC, &psc);
+	regmap_read(priv->regmap, TIM_ARR, &arr);
+
+	if (cr1 & TIM_CR1_CEN) {
+		freq = (unsigned long long)clk_get_rate(priv->clk);
+		do_div(freq, psc + 1);
+		do_div(freq, arr + 1);
+	}
+
+	return sprintf(buf, "%d\n", (unsigned int)freq);
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(0660,
+			      stm32_tt_read_frequency,
+			      stm32_tt_store_frequency);
+
+#define MASTER_MODE_MAX		7
+#define MASTER_MODE2_MAX	15
+
+static char *master_mode_table[] = {
+	"reset",
+	"enable",
+	"update",
+	"compare_pulse",
+	"OC1REF",
+	"OC2REF",
+	"OC3REF",
+	"OC4REF",
+	/* Master mode selection 2 only */
+	"OC5REF",
+	"OC6REF",
+	"compare_pulse_OC4REF",
+	"compare_pulse_OC6REF",
+	"compare_pulse_OC4REF_r_or_OC6REF_r",
+	"compare_pulse_OC4REF_r_or_OC6REF_f",
+	"compare_pulse_OC5REF_r_or_OC6REF_r",
+	"compare_pulse_OC5REF_r_or_OC6REF_f",
+};
+
+static ssize_t stm32_tt_show_master_mode(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	u32 cr2;
+
+	regmap_read(priv->regmap, TIM_CR2, &cr2);
+
+	if (stm32_timer_is_trgo2_name(trig->name))
+		cr2 = (cr2 & TIM_CR2_MMS2) >> TIM_CR2_MMS2_SHIFT;
+	else
+		cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
+
+	return sysfs_emit(buf, "%s\n", master_mode_table[cr2]);
+}
+
+static ssize_t stm32_tt_store_master_mode(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t len)
+{
+	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	u32 mask, shift, master_mode_max;
+	int i, ret;
+
+	if (stm32_timer_is_trgo2_name(trig->name)) {
+		mask = TIM_CR2_MMS2;
+		shift = TIM_CR2_MMS2_SHIFT;
+		master_mode_max = MASTER_MODE2_MAX;
+	} else {
+		mask = TIM_CR2_MMS;
+		shift = TIM_CR2_MMS_SHIFT;
+		master_mode_max = MASTER_MODE_MAX;
+	}
+
+	for (i = 0; i <= master_mode_max; i++) {
+		if (!strncmp(master_mode_table[i], buf,
+			     strlen(master_mode_table[i]))) {
+			guard(mutex)(&priv->lock);
+			if (!priv->enabled) {
+				/* Clock should be enabled first */
+				priv->enabled = true;
+				ret = clk_enable(priv->clk);
+				if (ret)
+					return ret;
+			}
+			regmap_update_bits(priv->regmap, TIM_CR2, mask,
+					   i << shift);
+			return len;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t stm32_tt_show_master_mode_avail(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	unsigned int i, master_mode_max;
+	size_t len = 0;
+
+	if (stm32_timer_is_trgo2_name(trig->name))
+		master_mode_max = MASTER_MODE2_MAX;
+	else
+		master_mode_max = MASTER_MODE_MAX;
+
+	for (i = 0; i <= master_mode_max; i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len,
+			"%s ", master_mode_table[i]);
+
+	/* replace trailing space by newline */
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(master_mode_available, 0444,
+		       stm32_tt_show_master_mode_avail, NULL, 0);
+
+static IIO_DEVICE_ATTR(master_mode, 0660,
+		       stm32_tt_show_master_mode,
+		       stm32_tt_store_master_mode,
+		       0);
+
+static struct attribute *stm32_trigger_attrs[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_dev_attr_master_mode.dev_attr.attr,
+	&iio_dev_attr_master_mode_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group stm32_trigger_attr_group = {
+	.attrs = stm32_trigger_attrs,
+};
+
+static const struct attribute_group *stm32_trigger_attr_groups[] = {
+	&stm32_trigger_attr_group,
+	NULL,
+};
+
+static const struct iio_trigger_ops timer_trigger_ops = {
+};
+
+static void stm32_unregister_iio_triggers(struct stm32_timer_trigger *priv)
+{
+	struct iio_trigger *tr;
+
+	list_for_each_entry(tr, &priv->tr_list, alloc_list)
+		iio_trigger_unregister(tr);
+}
+
+static int stm32_register_iio_triggers(struct stm32_timer_trigger *priv)
+{
+	int ret;
+	const char * const *cur = priv->triggers;
+
+	INIT_LIST_HEAD(&priv->tr_list);
+
+	while (cur && *cur) {
+		struct iio_trigger *trig;
+		bool cur_is_trgo = stm32_timer_is_trgo_name(*cur);
+		bool cur_is_trgo2 = stm32_timer_is_trgo2_name(*cur);
+
+		if (cur_is_trgo2 && !priv->has_trgo2) {
+			cur++;
+			continue;
+		}
+
+		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
+		if  (!trig)
+			return -ENOMEM;
+
+		trig->dev.parent = priv->dev->parent;
+		trig->ops = &timer_trigger_ops;
+
+		/*
+		 * sampling frequency and master mode attributes
+		 * should only be available on trgo/trgo2 triggers
+		 */
+		if (cur_is_trgo || cur_is_trgo2)
+			trig->dev.groups = stm32_trigger_attr_groups;
+
+		iio_trigger_set_drvdata(trig, priv);
+
+		ret = iio_trigger_register(trig);
+		if (ret) {
+			stm32_unregister_iio_triggers(priv);
+			return ret;
+		}
+
+		list_add_tail(&trig->alloc_list, &priv->tr_list);
+		cur++;
+	}
+
+	return 0;
+}
+
+static int stm32_counter_read_raw(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  int *val, int *val2, long mask)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	u32 dat;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		regmap_read(priv->regmap, TIM_CNT, &dat);
+		*val = dat;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_ENABLE:
+		regmap_read(priv->regmap, TIM_CR1, &dat);
+		*val = (dat & TIM_CR1_CEN) ? 1 : 0;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		regmap_read(priv->regmap, TIM_SMCR, &dat);
+		dat &= TIM_SMCR_SMS;
+
+		*val = 1;
+		*val2 = 0;
+
+		/* in quadrature case scale = 0.25 */
+		if (dat == 3)
+			*val2 = 2;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_counter_write_raw(struct iio_dev *indio_dev,
+				   struct iio_chan_spec const *chan,
+				   int val, int val2, long mask)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		return regmap_write(priv->regmap, TIM_CNT, val);
+
+	case IIO_CHAN_INFO_SCALE:
+		/* fixed scale */
+		return -EINVAL;
+
+	case IIO_CHAN_INFO_ENABLE: {
+		guard(mutex)(&priv->lock);
+		if (val) {
+			if (!priv->enabled) {
+				priv->enabled = true;
+				ret = clk_enable(priv->clk);
+				if (ret)
+					return ret;
+			}
+			regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
+		} else {
+			regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
+			if (priv->enabled) {
+				priv->enabled = false;
+				clk_disable(priv->clk);
+			}
+		}
+
+		return 0;
+	}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int stm32_counter_validate_trigger(struct iio_dev *indio_dev,
+					  struct iio_trigger *trig)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	const char * const *cur = priv->valids;
+	unsigned int i = 0;
+
+	if (!is_stm32_timer_trigger(trig))
+		return -EINVAL;
+
+	while (cur && *cur) {
+		if (!strncmp(trig->name, *cur, strlen(trig->name))) {
+			regmap_update_bits(priv->regmap,
+					   TIM_SMCR, TIM_SMCR_TS,
+					   i << TIM_SMCR_TS_SHIFT);
+			return 0;
+		}
+		cur++;
+		i++;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info stm32_trigger_info = {
+	.validate_trigger = stm32_counter_validate_trigger,
+	.read_raw = stm32_counter_read_raw,
+	.write_raw = stm32_counter_write_raw
+};
+
+static const char *const stm32_trigger_modes[] = {
+	"trigger",
+};
+
+static int stm32_set_trigger_mode(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan,
+				  unsigned int mode)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+
+	regmap_set_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS);
+
+	return 0;
+}
+
+static int stm32_get_trigger_mode(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	u32 smcr;
+
+	regmap_read(priv->regmap, TIM_SMCR, &smcr);
+
+	return (smcr & TIM_SMCR_SMS) == TIM_SMCR_SMS ? 0 : -EINVAL;
+}
+
+static const struct iio_enum stm32_trigger_mode_enum = {
+	.items = stm32_trigger_modes,
+	.num_items = ARRAY_SIZE(stm32_trigger_modes),
+	.set = stm32_set_trigger_mode,
+	.get = stm32_get_trigger_mode
+};
+
+static const char *const stm32_enable_modes[] = {
+	"always",
+	"gated",
+	"triggered",
+};
+
+static int stm32_enable_mode2sms(int mode)
+{
+	switch (mode) {
+	case 0:
+		return 0;
+	case 1:
+		return 5;
+	case 2:
+		return 6;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_set_enable_mode(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan,
+				 unsigned int mode)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	int sms = stm32_enable_mode2sms(mode);
+	int ret;
+
+	if (sms < 0)
+		return sms;
+	/*
+	 * Triggered mode sets CEN bit automatically by hardware. So, first
+	 * enable counter clock, so it can use it. Keeps it in sync with CEN.
+	 */
+	scoped_guard(mutex, &priv->lock) {
+		if (sms == 6 && !priv->enabled) {
+			ret = clk_enable(priv->clk);
+			if (ret)
+				return ret;
+
+			priv->enabled = true;
+		}
+	}
+
+	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
+
+	return 0;
+}
+
+static int stm32_sms2enable_mode(int mode)
+{
+	switch (mode) {
+	case 0:
+		return 0;
+	case 5:
+		return 1;
+	case 6:
+		return 2;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_get_enable_mode(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	u32 smcr;
+
+	regmap_read(priv->regmap, TIM_SMCR, &smcr);
+	smcr &= TIM_SMCR_SMS;
+
+	return stm32_sms2enable_mode(smcr);
+}
+
+static const struct iio_enum stm32_enable_mode_enum = {
+	.items = stm32_enable_modes,
+	.num_items = ARRAY_SIZE(stm32_enable_modes),
+	.set = stm32_set_enable_mode,
+	.get = stm32_get_enable_mode
+};
+
+static ssize_t stm32_count_get_preset(struct iio_dev *indio_dev,
+				      uintptr_t private,
+				      const struct iio_chan_spec *chan,
+				      char *buf)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	u32 arr;
+
+	regmap_read(priv->regmap, TIM_ARR, &arr);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", arr);
+}
+
+static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
+				      uintptr_t private,
+				      const struct iio_chan_spec *chan,
+				      const char *buf, size_t len)
+{
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	unsigned int preset;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &preset);
+	if (ret)
+		return ret;
+
+	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
+	regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
+	regmap_write(priv->regmap, TIM_ARR, preset);
+
+	return len;
+}
+
+static const struct iio_chan_spec_ext_info stm32_trigger_count_info[] = {
+	{
+		.name = "preset",
+		.shared = IIO_SEPARATE,
+		.read = stm32_count_get_preset,
+		.write = stm32_count_set_preset
+	},
+	IIO_ENUM("enable_mode", IIO_SEPARATE, &stm32_enable_mode_enum),
+	IIO_ENUM_AVAILABLE("enable_mode", IIO_SHARED_BY_TYPE, &stm32_enable_mode_enum),
+	IIO_ENUM("trigger_mode", IIO_SEPARATE, &stm32_trigger_mode_enum),
+	IIO_ENUM_AVAILABLE("trigger_mode", IIO_SHARED_BY_TYPE, &stm32_trigger_mode_enum),
+	{ }
+};
+
+static const struct iio_chan_spec stm32_trigger_channel = {
+	.type = IIO_COUNT,
+	.channel = 0,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			      BIT(IIO_CHAN_INFO_ENABLE) |
+			      BIT(IIO_CHAN_INFO_SCALE),
+	.ext_info = stm32_trigger_count_info,
+	.indexed = 1
+};
+
+static struct stm32_timer_trigger *stm32_setup_counter_device(struct device *dev)
+{
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev,
+					  sizeof(struct stm32_timer_trigger));
+	if (!indio_dev)
+		return NULL;
+
+	indio_dev->name = dev_name(dev);
+	indio_dev->info = &stm32_trigger_info;
+	indio_dev->modes = INDIO_HARDWARE_TRIGGERED;
+	indio_dev->num_channels = 1;
+	indio_dev->channels = &stm32_trigger_channel;
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		return NULL;
+
+	return iio_priv(indio_dev);
+}
+
+/**
+ * is_stm32_timer_trigger
+ * @trig: trigger to be checked
+ *
+ * return true if the trigger is a valid stm32 iio timer trigger
+ * either return false
+ */
+bool is_stm32_timer_trigger(struct iio_trigger *trig)
+{
+	return (trig->ops == &timer_trigger_ops);
+}
+EXPORT_SYMBOL(is_stm32_timer_trigger);
+
+static void stm32_timer_detect_trgo2(struct stm32_timer_trigger *priv)
+{
+	u32 val;
+
+	/*
+	 * Master mode selection 2 bits can only be written and read back when
+	 * timer supports it.
+	 */
+	regmap_set_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2);
+	regmap_read(priv->regmap, TIM_CR2, &val);
+	regmap_clear_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2);
+	priv->has_trgo2 = !!val;
+}
+
+static int stm32_timer_trigger_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_timer_trigger *priv;
+	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
+	const struct stm32_timer_trigger_cfg *cfg;
+	unsigned int index;
+	int ret;
+
+	ret = device_property_read_u32(dev, "reg", &index);
+	if (ret)
+		return ret;
+
+	cfg = device_get_match_data(dev);
+
+	if (index >= ARRAY_SIZE(triggers_table) ||
+	    index >= cfg->num_valids_table)
+		return -EINVAL;
+
+	/* Create an IIO device only if we have triggers to be validated */
+	if (cfg->valids_table && *cfg->valids_table[index])
+		priv = stm32_setup_counter_device(dev);
+	else
+		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->max_arr = ddata->max_arr;
+	priv->triggers = triggers_table[index];
+	if (cfg->valids_table && *cfg->valids_table[index])
+		priv->valids = cfg->valids_table[index];
+	stm32_timer_detect_trgo2(priv);
+	mutex_init(&priv->lock);
+
+	ret = stm32_register_iio_triggers(priv);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static void stm32_timer_trigger_remove(struct platform_device *pdev)
+{
+	struct stm32_timer_trigger *priv = platform_get_drvdata(pdev);
+	u32 val;
+
+	/* Unregister triggers before everything can be safely turned off */
+	stm32_unregister_iio_triggers(priv);
+
+	/* Check if nobody else use the timer, then disable it */
+	regmap_read(priv->regmap, TIM_CCER, &val);
+	if (!(val & TIM_CCER_CCXE))
+		regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
+
+	if (priv->enabled)
+		clk_disable(priv->clk);
+}
+
+static int stm32_timer_trigger_suspend(struct device *dev)
+{
+	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
+
+	/* Only take care of enabled timer: don't disturb other MFD child */
+	if (priv->enabled) {
+		/* Backup registers that may get lost in low power mode */
+		regmap_read(priv->regmap, TIM_CR1, &priv->bak.cr1);
+		regmap_read(priv->regmap, TIM_CR2, &priv->bak.cr2);
+		regmap_read(priv->regmap, TIM_PSC, &priv->bak.psc);
+		regmap_read(priv->regmap, TIM_ARR, &priv->bak.arr);
+		regmap_read(priv->regmap, TIM_CNT, &priv->bak.cnt);
+		regmap_read(priv->regmap, TIM_SMCR, &priv->bak.smcr);
+
+		/* Disable the timer */
+		regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
+		clk_disable(priv->clk);
+	}
+
+	return 0;
+}
+
+static int stm32_timer_trigger_resume(struct device *dev)
+{
+	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
+	int ret;
+
+	if (priv->enabled) {
+		ret = clk_enable(priv->clk);
+		if (ret)
+			return ret;
+
+		/* restore master/slave modes */
+		regmap_write(priv->regmap, TIM_SMCR, priv->bak.smcr);
+		regmap_write(priv->regmap, TIM_CR2, priv->bak.cr2);
+
+		/* restore sampling_frequency (trgo / trgo2 triggers) */
+		regmap_write(priv->regmap, TIM_PSC, priv->bak.psc);
+		regmap_write(priv->regmap, TIM_ARR, priv->bak.arr);
+		regmap_write(priv->regmap, TIM_CNT, priv->bak.cnt);
+
+		/* Also re-enables the timer */
+		regmap_write(priv->regmap, TIM_CR1, priv->bak.cr1);
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(stm32_timer_trigger_pm_ops,
+				stm32_timer_trigger_suspend,
+				stm32_timer_trigger_resume);
+
+static const struct stm32_timer_trigger_cfg stm32_timer_trg_cfg = {
+	.valids_table = valids_table,
+	.num_valids_table = ARRAY_SIZE(valids_table),
+};
+
+static const struct stm32_timer_trigger_cfg stm32h7_timer_trg_cfg = {
+	.valids_table = stm32h7_valids_table,
+	.num_valids_table = ARRAY_SIZE(stm32h7_valids_table),
+};
+
+static const struct stm32_timer_trigger_cfg stm32mp25_timer_trg_cfg = {
+	/*
+	 * valids_table not used: counter framework is now superseding the deprecated IIO
+	 * counter interface (IIO_COUNT), so don't support it. num_valids_table is only
+	 * kept here to register the IIO HW triggers. valids_table should be moved at some
+	 * point to the stm32-timer-cnt driver instead.
+	 */
+	.num_valids_table = ARRAY_SIZE(triggers_table),
+};
+
+static const struct of_device_id stm32_trig_of_match[] = {
+	{
+		.compatible = "st,stm32-timer-trigger",
+		.data = (void *)&stm32_timer_trg_cfg,
+	}, {
+		.compatible = "st,stm32h7-timer-trigger",
+		.data = (void *)&stm32h7_timer_trg_cfg,
+	}, {
+		.compatible = "st,stm32mp25-timer-trigger",
+		.data = (void *)&stm32mp25_timer_trg_cfg,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
+
+static struct platform_driver stm32_timer_trigger_driver = {
+	.probe = stm32_timer_trigger_probe,
+	.remove = stm32_timer_trigger_remove,
+	.driver = {
+		.name = "stm32-timer-trigger",
+		.of_match_table = stm32_trig_of_match,
+		.pm = pm_sleep_ptr(&stm32_timer_trigger_pm_ops),
+	},
+};
+module_platform_driver(stm32_timer_trigger_driver);
+
+MODULE_ALIAS("platform:stm32-timer-trigger");
+MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
+MODULE_LICENSE("GPL v2");