Merge tag 'counter-for-5.16a-take2' of...

Merge tag 'counter-for-5.16a-take2' of https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into char-misc-next

Jonathan writes:

First set of counter subsystem new feature support for the 5.16 cycle

Most interesting element this time is the new chrdev based interface
for the counter subsystem.  Affects all drivers. Some minor precursor
patches.

Major parts:
* Bring all the sysfs attribute setup into the counter core rather than
  leaving it to individual drivers.  Docs updates accompany these changes.
* Move various definitions to a uapi header as now needed from userspace.
* Add the chardev interface + extensive documentation and example tool
* Add new ABI needed to identify indexes needed for chrdev interface
* Implement new interface for the 104-quad-8
* Follow up deals with wrong path for documentation build
* Various trivial cleanups and missing feature additions related to this
  series

* tag 'counter-for-5.16a-take2' of https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio:
  docs: counter: Include counter-chrdev kernel-doc to generic-counter.rst
  counter: fix docum. build problems after filename change
  counter: microchip-tcb-capture: Tidy up a false kernel-doc /** marking.
  counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8
  counter: 104-quad-8: Replace mutex with spinlock
  counter: Implement events_queue_size sysfs attribute
  counter: Implement *_component_id sysfs attributes
  counter: Implement signalZ_action_component_id sysfs attribute
  tools/counter: Create Counter tools
  docs: counter: Document character device interface
  counter: Add character device interface
  counter: Move counter enums to uapi header
  docs: counter: Update to reflect sysfs internalization
  counter: Update counter.h comments to reflect sysfs internalization
  counter: Internalize sysfs interface code
  counter: stm32-timer-cnt: Provide defines for slave mode selection
  counter: stm32-lptimer-cnt: Provide defines for clock polarities

Documentation/ABI/testing/sysfs-bus-counter

@@ -203,6 +203,27 @@ Description:
 		both edges:
 			Any state transition.
 
+What:		/sys/bus/counter/devices/counterX/countY/ceiling_component_id
+What:		/sys/bus/counter/devices/counterX/countY/floor_component_id
+What:		/sys/bus/counter/devices/counterX/countY/count_mode_component_id
+What:		/sys/bus/counter/devices/counterX/countY/direction_component_id
+What:		/sys/bus/counter/devices/counterX/countY/enable_component_id
+What:		/sys/bus/counter/devices/counterX/countY/error_noise_component_id
+What:		/sys/bus/counter/devices/counterX/countY/prescaler_component_id
+What:		/sys/bus/counter/devices/counterX/countY/preset_component_id
+What:		/sys/bus/counter/devices/counterX/countY/preset_enable_component_id
+What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id
+KernelVersion:	5.16
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Read-only attribute that indicates the component ID of the
+		respective extension or Synapse.
+
 What:		/sys/bus/counter/devices/counterX/countY/spike_filter_ns
 KernelVersion:	5.14
 Contact:	linux-iio@vger.kernel.org
@@ -212,6 +233,14 @@ Description:
 		shorter or equal to configured value are ignored. Value 0 means
 		filter is disabled.
 
+What:		/sys/bus/counter/devices/counterX/events_queue_size
+KernelVersion:	5.16
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Size of the Counter events queue in number of struct
+		counter_event data structures. The number of elements will be
+		rounded-up to a power of 2.
+
 What:		/sys/bus/counter/devices/counterX/name
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
@@ -286,7 +315,14 @@ What:		/sys/bus/counter/devices/counterX/signalY/signal
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
 Description:
-		Signal data of Signal Y represented as a string.
+		Signal level state of Signal Y. The following signal level
+		states are available:
+
+		low:
+			Low level state.
+
+		high:
+			High level state.
 
 What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
 KernelVersion:	5.2

Documentation/userspace-api/ioctl/ioctl-number.rst

@@ -88,6 +88,7 @@ Code  Seq#    Include File                                           Comments
                                                                      <http://infiniband.sourceforge.net/>
 0x20  all    drivers/cdrom/cm206.h
 0x22  all    scsi/sg.h
+0x3E  00-0F  linux/counter.h                                         <mailto:linux-iio@vger.kernel.org>
 '!'   00-1F  uapi/linux/seccomp.h
 '#'   00-3F                                                          IEEE 1394 Subsystem
                                                                      Block for the entire subsystem

MAINTAINERS

@@ -4810,7 +4810,8 @@ F:	Documentation/ABI/testing/sysfs-bus-counter
 F:	Documentation/driver-api/generic-counter.rst
 F:	drivers/counter/
 F:	include/linux/counter.h
-F:	include/linux/counter_enum.h
+F:	include/uapi/linux/counter.h
+F:	tools/counter/
 
 CP2615 I2C DRIVER
 M:	Bence Csókás <bence98@sch.bme.hu>

drivers/counter/Kconfig

@@ -23,11 +23,11 @@ config 104_QUAD_8
 	  A counter's respective error flag may be cleared by performing a write
 	  operation on the respective count value attribute. Although the
 	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
-	  set, either directly or via the counter's preset attribute. Interrupts
-	  are not supported by this driver.
+	  set, either directly or via the counter's preset attribute.
 
 	  The base port addresses for the devices may be configured via the base
-	  array module parameter.
+	  array module parameter. The interrupt line numbers for the devices may
+	  be configured via the irq array module parameter.
 
 config INTERRUPT_CNT
 	tristate "Interrupt counter driver"

drivers/counter/Makefile

@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_COUNTER) += counter.o
+counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
 
 obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
 obj-$(CONFIG_INTERRUPT_CNT)		+= interrupt-cnt.o

drivers/counter/counter-chrdev.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter character device interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _COUNTER_CHRDEV_H_
+#define _COUNTER_CHRDEV_H_
+
+#include <linux/counter.h>
+
+int counter_chrdev_add(struct counter_device *const counter);
+void counter_chrdev_remove(struct counter_device *const counter);
+
+#endif /* _COUNTER_CHRDEV_H_ */

drivers/counter/counter-core.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#include <linux/cdev.h>
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/device/bus.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/kdev_t.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "counter-chrdev.h"
+#include "counter-sysfs.h"
+
+/* Provides a unique ID for each counter device */
+static DEFINE_IDA(counter_ida);
+
+static void counter_device_release(struct device *dev)
+{
+	struct counter_device *const counter = dev_get_drvdata(dev);
+
+	counter_chrdev_remove(counter);
+	ida_free(&counter_ida, dev->id);
+}
+
+static struct device_type counter_device_type = {
+	.name = "counter_device",
+	.release = counter_device_release,
+};
+
+static struct bus_type counter_bus_type = {
+	.name = "counter",
+	.dev_name = "counter",
+};
+
+static dev_t counter_devt;
+
+/**
+ * counter_register - register Counter to the system
+ * @counter:	pointer to Counter to register
+ *
+ * This function registers a Counter to the system. A sysfs "counter" directory
+ * will be created and populated with sysfs attributes correlating with the
+ * Counter Signals, Synapses, and Counts respectively.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int counter_register(struct counter_device *const counter)
+{
+	struct device *const dev = &counter->dev;
+	int id;
+	int err;
+
+	/* Acquire unique ID */
+	id = ida_alloc(&counter_ida, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	mutex_init(&counter->ops_exist_lock);
+
+	/* Configure device structure for Counter */
+	dev->id = id;
+	dev->type = &counter_device_type;
+	dev->bus = &counter_bus_type;
+	dev->devt = MKDEV(MAJOR(counter_devt), id);
+	if (counter->parent) {
+		dev->parent = counter->parent;
+		dev->of_node = counter->parent->of_node;
+	}
+	device_initialize(dev);
+	dev_set_drvdata(dev, counter);
+
+	err = counter_sysfs_add(counter);
+	if (err < 0)
+		goto err_free_id;
+
+	err = counter_chrdev_add(counter);
+	if (err < 0)
+		goto err_free_id;
+
+	err = cdev_device_add(&counter->chrdev, dev);
+	if (err < 0)
+		goto err_remove_chrdev;
+
+	return 0;
+
+err_remove_chrdev:
+	counter_chrdev_remove(counter);
+err_free_id:
+	put_device(dev);
+	return err;
+}
+EXPORT_SYMBOL_GPL(counter_register);
+
+/**
+ * counter_unregister - unregister Counter from the system
+ * @counter:	pointer to Counter to unregister
+ *
+ * The Counter is unregistered from the system.
+ */
+void counter_unregister(struct counter_device *const counter)
+{
+	if (!counter)
+		return;
+
+	cdev_device_del(&counter->chrdev, &counter->dev);
+
+	mutex_lock(&counter->ops_exist_lock);
+
+	counter->ops = NULL;
+	wake_up(&counter->events_wait);
+
+	mutex_unlock(&counter->ops_exist_lock);
+
+	put_device(&counter->dev);
+}
+EXPORT_SYMBOL_GPL(counter_unregister);
+
+static void devm_counter_release(void *counter)
+{
+	counter_unregister(counter);
+}
+
+/**
+ * devm_counter_register - Resource-managed counter_register
+ * @dev:	device to allocate counter_device for
+ * @counter:	pointer to Counter to register
+ *
+ * Managed counter_register. The Counter registered with this function is
+ * automatically unregistered on driver detach. This function calls
+ * counter_register internally. Refer to that function for more information.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int devm_counter_register(struct device *dev,
+			  struct counter_device *const counter)
+{
+	int err;
+
+	err = counter_register(counter);
+	if (err < 0)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_counter_release, counter);
+}
+EXPORT_SYMBOL_GPL(devm_counter_register);
+
+#define COUNTER_DEV_MAX 256
+
+static int __init counter_init(void)
+{
+	int err;
+
+	err = bus_register(&counter_bus_type);
+	if (err < 0)
+		return err;
+
+	err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
+	if (err < 0)
+		goto err_unregister_bus;
+
+	return 0;
+
+err_unregister_bus:
+	bus_unregister(&counter_bus_type);
+	return err;
+}
+
+static void __exit counter_exit(void)
+{
+	unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
+	bus_unregister(&counter_bus_type);
+}
+
+subsys_initcall(counter_init);
+module_exit(counter_exit);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("Generic Counter interface");
+MODULE_LICENSE("GPL v2");

drivers/counter/counter-sysfs.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter sysfs interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _COUNTER_SYSFS_H_
+#define _COUNTER_SYSFS_H_
+
+#include <linux/counter.h>
+
+int counter_sysfs_add(struct counter_device *const counter);
+
+#endif /* _COUNTER_SYSFS_H_ */

include/linux/mfd/stm32-lptimer.h

@@ -45,6 +45,11 @@
 #define STM32_LPTIM_PRESC	GENMASK(11, 9)
 #define STM32_LPTIM_CKPOL	GENMASK(2, 1)
 
+/* STM32_LPTIM_CKPOL */
+#define STM32_LPTIM_CKPOL_RISING_EDGE	0
+#define STM32_LPTIM_CKPOL_FALLING_EDGE	1
+#define STM32_LPTIM_CKPOL_BOTH_EDGES	2
+
 /* STM32_LPTIM_ARR */
 #define STM32_LPTIM_MAX_ARR	0xFFFF
 

include/linux/mfd/stm32-timers.h

@@ -82,6 +82,10 @@
 #define MAX_TIM_ICPSC		0x3
 #define TIM_CR2_MMS_SHIFT	4
 #define TIM_CR2_MMS2_SHIFT	20
+#define TIM_SMCR_SMS_SLAVE_MODE_DISABLED	0 /* counts on internal clock when CEN=1 */
+#define TIM_SMCR_SMS_ENCODER_MODE_1		1 /* counts TI1FP1 edges, depending on TI2FP2 level */
+#define TIM_SMCR_SMS_ENCODER_MODE_2		2 /* counts TI2FP2 edges, depending on TI1FP1 level */
+#define TIM_SMCR_SMS_ENCODER_MODE_3		3 /* counts on both TI1FP1 and TI2FP2 edges */
 #define TIM_SMCR_TS_SHIFT	4
 #define TIM_BDTR_BKF_MASK	0xF
 #define TIM_BDTR_BKF_SHIFT(x)	(16 + (x) * 4)

tools/counter/Build

+counter_example-y += counter_example.o