[PATCH v10 01/18] counter: Introduce the Generic Counter interface

William Breathitt Gray
2019-04-02T06:30:28Z

This patch introduces the Generic Counter interface for supporting
counter devices.

In the context of the Generic Counter interface, a counter is defined as
a device that reports one or more "counts" based on the state changes of
one or more "signals" as evaluated by a defined "count function."

Driver callbacks should be provided to communicate with the device: to
read and write various Signals and Counts, and to set and get the
"action mode" and "count function" for various Synapses and Counts
respectively.

To support a counter device, a driver must first allocate the available
Counter Signals via counter_signal structures. These Signals should
be stored as an array and set to the signals array member of an
allocated counter_device structure before the Counter is registered to
the system.

Counter Counts may be allocated via counter_count structures, and
respective Counter Signal associations (Synapses) made via
counter_synapse structures. Associated counter_synapse structures are
stored as an array and set to the the synapses array member of the
respective counter_count structure. These counter_count structures are
set to the counts array member of an allocated counter_device structure
before the Counter is registered to the system.

A counter device is registered to the system by passing the respective
initialized counter_device structure to the counter_register function;
similarly, the counter_unregister function unregisters the respective
Counter. The devm_counter_register and devm_counter_unregister functions
serve as device memory-managed versions of the counter_register and
counter_unregister functions respectively.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
MAINTAINERS | 8 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/counter/Kconfig | 10 +
drivers/counter/Makefile | 5 +
drivers/counter/counter.c | 1567 ++++++++++++++++++++++++++++++++++
include/linux/counter.h | 510 +++++++++++
include/linux/counter_enum.h | 45 +
8 files changed, 2148 insertions(+)
create mode 100644 drivers/counter/Kconfig
create mode 100644 drivers/counter/Makefile
create mode 100644 drivers/counter/counter.c
create mode 100644 include/linux/counter.h
create mode 100644 include/linux/counter_enum.h

diff --git a/MAINTAINERS b/MAINTAINERS
index ff2c2f2e6da3..ef497d470501 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3966,6 +3966,14 @@ W: http://www.fi.muni.cz/~kas/cosa/
S: Maintained
F: drivers/net/wan/cosa*

+COUNTER SUBSYSTEM
+M: William Breathitt Gray <vilhelm.gray@gmail.com>
+L: linux-iio@vger.kernel.org
+S: Maintained
+F: drivers/counter/
+F: include/linux/counter.h
+F: include/linux/counter_enum.h
+
CPMAC ETHERNET DRIVER
M: Florian Fainelli <f.fainelli@gmail.com>
L: netdev@vger.kernel.org
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 4f9f99057ff8..e1fd5d783e39 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -228,4 +228,6 @@ source "drivers/siox/Kconfig"

source "drivers/slimbus/Kconfig"

+source "drivers/counter/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index e1ce029d28fd..7ea509ad6d43 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -186,3 +186,4 @@ obj-$(CONFIG_MULTIPLEXER) += mux/
obj-$(CONFIG_UNISYS_VISORBUS) += visorbus/
obj-$(CONFIG_SIOX) += siox/
obj-$(CONFIG_GNSS) += gnss/
+obj-$(CONFIG_COUNTER) += counter/
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
new file mode 100644
index 000000000000..a74998400282
--- /dev/null
+++ b/drivers/counter/Kconfig
@@ -0,0 +1,10 @@
+#
+# Counter devices
+#
+
+menuconfig COUNTER
+ tristate "Counter support"
+ help
+ This enables counter device support through the Generic Counter
+ interface. You only need to enable this, if you also want to enable
+ one or more of the counter device drivers below.
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
new file mode 100644
index 000000000000..b1464604bdbe
--- /dev/null
+++ b/drivers/counter/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for Counter devices
+#
+
+obj-$(CONFIG_COUNTER) += counter.o
diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
new file mode 100644
index 000000000000..106bc7180cd8
--- /dev/null
+++ b/drivers/counter/counter.c
@@ -0,0 +1,1567 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter interface
+ * Copyright (C) 2018 William Breathitt Gray
+ */
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+const char *const counter_count_direction_str[2] = {
+ [COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
+ [COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
+};
+EXPORT_SYMBOL_GPL(counter_count_direction_str);
+
+const char *const counter_count_mode_str[4] = {
+ [COUNTER_COUNT_MODE_NORMAL] = "normal",
+ [COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
+ [COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
+ [COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
+};
+EXPORT_SYMBOL_GPL(counter_count_mode_str);
+
+ssize_t counter_signal_enum_read(struct counter_device *counter,
+ struct counter_signal *signal, void *priv,
+ char *buf)
+{
+ const struct counter_signal_enum_ext *const e = priv;
+ int err;
+ size_t index;
+
+ if (!e->get)
+ return -EINVAL;
+
+ err = e->get(counter, signal, &index);
+ if (err)
+ return err;
+
+ if (index >= e->num_items)
+ return -EINVAL;
+
+ return sprintf(buf, "%s\n", e->items[index]);
+}
+EXPORT_SYMBOL_GPL(counter_signal_enum_read);
+
+ssize_t counter_signal_enum_write(struct counter_device *counter,
+ struct counter_signal *signal, void *priv,
+ const char *buf, size_t len)
+{
+ const struct counter_signal_enum_ext *const e = priv;
+ ssize_t index;
+ int err;
+
+ if (!e->set)
+ return -EINVAL;
+
+ index = __sysfs_match_string(e->items, e->num_items, buf);
+ if (index < 0)
+ return index;
+
+ err = e->set(counter, signal, index);
+ if (err)
+ return err;
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(counter_signal_enum_write);
+
+ssize_t counter_signal_enum_available_read(struct counter_device *counter,
+ struct counter_signal *signal,
+ void *priv, char *buf)
+{
+ const struct counter_signal_enum_ext *const e = priv;
+ size_t i;
+ size_t len = 0;
+
+ if (!e->num_items)
+ return 0;
+
+ for (i = 0; i < e->num_items; i++)
+ len += sprintf(buf + len, "%s\n", e->items[i]);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(counter_signal_enum_available_read);
+
+ssize_t counter_count_enum_read(struct counter_device *counter,
+ struct counter_count *count, void *priv,
+ char *buf)
+{
+ const struct counter_count_enum_ext *const e = priv;
+ int err;
+ size_t index;
+
+ if (!e->get)
+ return -EINVAL;
+
+ err = e->get(counter, count, &index);
+ if (err)
+ return err;
+
+ if (index >= e->num_items)
+ return -EINVAL;
+
+ return sprintf(buf, "%s\n", e->items[index]);
+}
+EXPORT_SYMBOL_GPL(counter_count_enum_read);
+
+ssize_t counter_count_enum_write(struct counter_device *counter,
+ struct counter_count *count, void *priv,
+ const char *buf, size_t len)
+{
+ const struct counter_count_enum_ext *const e = priv;
+ ssize_t index;
+ int err;
+
+ if (!e->set)
+ return -EINVAL;
+
+ index = __sysfs_match_string(e->items, e->num_items, buf);
+ if (index < 0)
+ return index;
+
+ err = e->set(counter, count, index);
+ if (err)
+ return err;
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(counter_count_enum_write);
+
+ssize_t counter_count_enum_available_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, char *buf)
+{
+ const struct counter_count_enum_ext *const e = priv;
+ size_t i;
+ size_t len = 0;
+
+ if (!e->num_items)
+ return 0;
+
+ for (i = 0; i < e->num_items; i++)
+ len += sprintf(buf + len, "%s\n", e->items[i]);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(counter_count_enum_available_read);
+
+ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
+ char *buf)
+{
+ const struct counter_device_enum_ext *const e = priv;
+ int err;
+ size_t index;
+
+ if (!e->get)
+ return -EINVAL;
+
+ err = e->get(counter, &index);
+ if (err)
+ return err;
+
+ if (index >= e->num_items)
+ return -EINVAL;
+
+ return sprintf(buf, "%s\n", e->items[index]);
+}
+EXPORT_SYMBOL_GPL(counter_device_enum_read);
+
+ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
+ const char *buf, size_t len)
+{
+ const struct counter_device_enum_ext *const e = priv;
+ ssize_t index;
+ int err;
+
+ if (!e->set)
+ return -EINVAL;
+
+ index = __sysfs_match_string(e->items, e->num_items, buf);
+ if (index < 0)
+ return index;
+
+ err = e->set(counter, index);
+ if (err)
+ return err;
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(counter_device_enum_write);
+
+ssize_t counter_device_enum_available_read(struct counter_device *counter,
+ void *priv, char *buf)
+{
+ const struct counter_device_enum_ext *const e = priv;
+ size_t i;
+ size_t len = 0;
+
+ if (!e->num_items)
+ return 0;
+
+ for (i = 0; i < e->num_items; i++)
+ len += sprintf(buf + len, "%s\n", e->items[i]);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(counter_device_enum_available_read);
+
+static const char *const counter_signal_level_str[] = {
+ [COUNTER_SIGNAL_LEVEL_LOW] = "low",
+ [COUNTER_SIGNAL_LEVEL_HIGH] = "high"
+};
+
+/**
+ * counter_signal_read_value_set - set counter_signal_read_value data
+ * @val: counter_signal_read_value structure to set
+ * @type: property Signal data represents
+ * @data: Signal data
+ *
+ * This function sets an opaque counter_signal_read_value structure with the
+ * provided Signal data.
+ */
+void counter_signal_read_value_set(struct counter_signal_read_value *const val,
+ const enum counter_signal_value_type type,
+ void *const data)
+{
+ if (type == COUNTER_SIGNAL_LEVEL)
+ val->len = sprintf(val->buf, "%s\n",
+ counter_signal_level_str[*(enum counter_signal_level *)data]);
+ else
+ val->len = 0;
+}
+EXPORT_SYMBOL_GPL(counter_signal_read_value_set);
+
+/**
+ * counter_count_read_value_set - set counter_count_read_value data
+ * @val: counter_count_read_value structure to set
+ * @type: property Count data represents
+ * @data: Count data
+ *
+ * This function sets an opaque counter_count_read_value structure with the
+ * provided Count data.
+ */
+void counter_count_read_value_set(struct counter_count_read_value *const val,
+ const enum counter_count_value_type type,
+ void *const data)
+{
+ switch (type) {
+ case COUNTER_COUNT_POSITION:
+ val->len = sprintf(val->buf, "%lu\n", *(unsigned long *)data);
+ break;
+ default:
+ val->len = 0;
+ }
+}
+EXPORT_SYMBOL_GPL(counter_count_read_value_set);
+
+/**
+ * counter_count_write_value_get - get counter_count_write_value data
+ * @data: Count data
+ * @type: property Count data represents
+ * @val: counter_count_write_value structure containing data
+ *
+ * This function extracts Count data from the provided opaque
+ * counter_count_write_value structure and stores it at the address provided by
+ * @data.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int counter_count_write_value_get(void *const data,
+ const enum counter_count_value_type type,
+ const struct counter_count_write_value *const val)
+{
+ int err;
+
+ switch (type) {
+ case COUNTER_COUNT_POSITION:
+ err = kstrtoul(val->buf, 0, data);
+ if (err)
+ return err;
+ break;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(counter_count_write_value_get);
+
+struct counter_attr_parm {
+ struct counter_device_attr_group *group;
+ const char *prefix;
+ const char *name;
+ ssize_t (*show)(struct device *dev, struct device_attribute *attr,
+ char *buf);
+ ssize_t (*store)(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len);
+ void *component;
+};
+
+struct counter_device_attr {
+ struct device_attribute dev_attr;
+ struct list_head l;
+ void *component;
+};
+
+static int counter_attribute_create(const struct counter_attr_parm *const parm)
+{
+ struct counter_device_attr *counter_attr;
+ struct device_attribute *dev_attr;
+ int err;
+ struct list_head *const attr_list = &parm->group->attr_list;
+
+ /* Allocate a Counter device attribute */
+ counter_attr = kzalloc(sizeof(*counter_attr), GFP_KERNEL);
+ if (!counter_attr)
+ return -ENOMEM;
+ dev_attr = &counter_attr->dev_attr;
+
+ sysfs_attr_init(&dev_attr->attr);
+
+ /* Configure device attribute */
+ dev_attr->attr.name = kasprintf(GFP_KERNEL, "%s%s", parm->prefix,
+ parm->name);
+ if (!dev_attr->attr.name) {
+ err = -ENOMEM;
+ goto err_free_counter_attr;
+ }
+ if (parm->show) {
+ dev_attr->attr.mode |= 0444;
+ dev_attr->show = parm->show;
+ }
+ if (parm->store) {
+ dev_attr->attr.mode |= 0200;
+ dev_attr->store = parm->store;
+ }
+
+ /* Store associated Counter component with attribute */
+ counter_attr->component = parm->component;
+
+ /* Keep track of the attribute for later cleanup */
+ list_add(&counter_attr->l, attr_list);
+ parm->group->num_attr++;
+
+ return 0;
+
+err_free_counter_attr:
+ kfree(counter_attr);
+ return err;
+}
+
+#define to_counter_attr(_dev_attr) \
+ container_of(_dev_attr, struct counter_device_attr, dev_attr)
+
+struct counter_signal_unit {
+ struct counter_signal *signal;
+};
+
+static ssize_t counter_signal_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct counter_device *const counter = dev_get_drvdata(dev);
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_signal_unit *const component = devattr->component;
+ struct counter_signal *const signal = component->signal;
+ int err;
+ struct counter_signal_read_value val = { .buf = buf };
+
+ err = counter->ops->signal_read(counter, signal, &val);
+ if (err)
+ return err;
+
+ return val.len;
+}
+
+struct counter_name_unit {
+ const char *name;
+};
+
+static ssize_t counter_device_attr_name_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct counter_name_unit *const comp = to_counter_attr(attr)->component;
+
+ return sprintf(buf, "%s\n", comp->name);
+}
+
+static int counter_name_attribute_create(
+ struct counter_device_attr_group *const group,
+ const char *const name)
+{
+ struct counter_name_unit *name_comp;
+ struct counter_attr_parm parm;
+ int err;
+
+ /* Skip if no name */
+ if (!name)
+ return 0;
+
+ /* Allocate name attribute component */
+ name_comp = kmalloc(sizeof(*name_comp), GFP_KERNEL);
+ if (!name_comp)
+ return -ENOMEM;
+ name_comp->name = name;
+
+ /* Allocate Signal name attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = "name";
+ parm.show = counter_device_attr_name_show;
+ parm.store = NULL;
+ parm.component = name_comp;
+ err = counter_attribute_create(&parm);
+ if (err)
+ goto err_free_name_comp;
+
+ return 0;
+
+err_free_name_comp:
+ kfree(name_comp);
+ return err;
+}
+
+struct counter_signal_ext_unit {
+ struct counter_signal *signal;
+ const struct counter_signal_ext *ext;
+};
+
+static ssize_t counter_signal_ext_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_signal_ext_unit *const comp = devattr->component;
+ const struct counter_signal_ext *const ext = comp->ext;
+
+ return ext->read(dev_get_drvdata(dev), comp->signal, ext->priv, buf);
+}
+
+static ssize_t counter_signal_ext_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_signal_ext_unit *const comp = devattr->component;
+ const struct counter_signal_ext *const ext = comp->ext;
+
+ return ext->write(dev_get_drvdata(dev), comp->signal, ext->priv, buf,
+ len);
+}
+
+static void counter_device_attr_list_free(struct list_head *attr_list)
+{
+ struct counter_device_attr *p, *n;
+
+ list_for_each_entry_safe(p, n, attr_list, l) {
+ /* free attribute name and associated component memory */
+ kfree(p->dev_attr.attr.name);
+ kfree(p->component);
+ list_del(&p->l);
+ kfree(p);
+ }
+}
+
+static int counter_signal_ext_register(
+ struct counter_device_attr_group *const group,
+ struct counter_signal *const signal)
+{
+ const size_t num_ext = signal->num_ext;
+ size_t i;
+ const struct counter_signal_ext *ext;
+ struct counter_signal_ext_unit *signal_ext_comp;
+ struct counter_attr_parm parm;
+ int err;
+
+ /* Create an attribute for each extension */
+ for (i = 0 ; i < num_ext; i++) {
+ ext = signal->ext + i;
+
+ /* Allocate signal_ext attribute component */
+ signal_ext_comp = kmalloc(sizeof(*signal_ext_comp), GFP_KERNEL);
+ if (!signal_ext_comp) {
+ err = -ENOMEM;
+ goto err_free_attr_list;
+ }
+ signal_ext_comp->signal = signal;
+ signal_ext_comp->ext = ext;
+
+ /* Allocate a Counter device attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = ext->name;
+ parm.show = (ext->read) ? counter_signal_ext_show : NULL;
+ parm.store = (ext->write) ? counter_signal_ext_store : NULL;
+ parm.component = signal_ext_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(signal_ext_comp);
+ goto err_free_attr_list;
+ }
+ }
+
+ return 0;
+
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+static int counter_signal_attributes_create(
+ struct counter_device_attr_group *const group,
+ const struct counter_device *const counter,
+ struct counter_signal *const signal)
+{
+ struct counter_signal_unit *signal_comp;
+ struct counter_attr_parm parm;
+ int err;
+
+ /* Allocate Signal attribute component */
+ signal_comp = kmalloc(sizeof(*signal_comp), GFP_KERNEL);
+ if (!signal_comp)
+ return -ENOMEM;
+ signal_comp->signal = signal;
+
+ /* Create main Signal attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = "signal";
+ parm.show = (counter->ops->signal_read) ? counter_signal_show : NULL;
+ parm.store = NULL;
+ parm.component = signal_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(signal_comp);
+ return err;
+ }
+
+ /* Create Signal name attribute */
+ err = counter_name_attribute_create(group, signal->name);
+ if (err)
+ goto err_free_attr_list;
+
+ /* Register Signal extension attributes */
+ err = counter_signal_ext_register(group, signal);
+ if (err)
+ goto err_free_attr_list;
+
+ return 0;
+
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+static int counter_signals_register(
+ struct counter_device_attr_group *const groups_list,
+ const struct counter_device *const counter)
+{
+ const size_t num_signals = counter->num_signals;
+ size_t i;
+ struct counter_signal *signal;
+ const char *name;
+ int err;
+
+ /* Register each Signal */
+ for (i = 0; i < num_signals; i++) {
+ signal = counter->signals + i;
+
+ /* Generate Signal attribute directory name */
+ name = kasprintf(GFP_KERNEL, "signal%d", signal->id);
+ if (!name) {
+ err = -ENOMEM;
+ goto err_free_attr_groups;
+ }
+ groups_list[i].attr_group.name = name;
+
+ /* Create all attributes associated with Signal */
+ err = counter_signal_attributes_create(groups_list + i, counter,
+ signal);
+ if (err)
+ goto err_free_attr_groups;
+ }
+
+ return 0;
+
+err_free_attr_groups:
+ do {
+ kfree(groups_list[i].attr_group.name);
+ counter_device_attr_list_free(&groups_list[i].attr_list);
+ } while (i--);
+ return err;
+}
+
+static const char *const counter_synapse_action_str[] = {
+ [COUNTER_SYNAPSE_ACTION_NONE] = "none",
+ [COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
+ [COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
+ [COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
+};
+
+struct counter_action_unit {
+ struct counter_synapse *synapse;
+ struct counter_count *count;
+};
+
+static ssize_t counter_action_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ int err;
+ struct counter_device *const counter = dev_get_drvdata(dev);
+ const struct counter_action_unit *const component = devattr->component;
+ struct counter_count *const count = component->count;
+ struct counter_synapse *const synapse = component->synapse;
+ size_t action_index;
+ enum counter_synapse_action action;
+
+ err = counter->ops->action_get(counter, count, synapse, &action_index);
+ if (err)
+ return err;
+
+ synapse->action = action_index;
+
+ action = synapse->actions_list[action_index];
+ return sprintf(buf, "%s\n", counter_synapse_action_str[action]);
+}
+
+static ssize_t counter_action_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_action_unit *const component = devattr->component;
+ struct counter_synapse *const synapse = component->synapse;
+ size_t action_index;
+ const size_t num_actions = synapse->num_actions;
+ enum counter_synapse_action action;
+ int err;
+ struct counter_device *const counter = dev_get_drvdata(dev);
+ struct counter_count *const count = component->count;
+
+ /* Find requested action mode */
+ for (action_index = 0; action_index < num_actions; action_index++) {
+ action = synapse->actions_list[action_index];
+ if (sysfs_streq(buf, counter_synapse_action_str[action]))
+ break;
+ }
+ /* If requested action mode not found */
+ if (action_index >= num_actions)
+ return -EINVAL;
+
+ err = counter->ops->action_set(counter, count, synapse, action_index);
+ if (err)
+ return err;
+
+ synapse->action = action_index;
+
+ return len;
+}
+
+struct counter_action_avail_unit {
+ const enum counter_synapse_action *actions_list;
+ size_t num_actions;
+};
+
+static ssize_t counter_synapse_action_available_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_action_avail_unit *const component = devattr->component;
+ size_t i;
+ enum counter_synapse_action action;
+ ssize_t len = 0;
+
+ for (i = 0; i < component->num_actions; i++) {
+ action = component->actions_list[i];
+ len += sprintf(buf + len, "%s\n",
+ counter_synapse_action_str[action]);
+ }
+
+ return len;
+}
+
+static int counter_synapses_register(
+ struct counter_device_attr_group *const group,
+ const struct counter_device *const counter,
+ struct counter_count *const count, const char *const count_attr_name)
+{
+ size_t i;
+ struct counter_synapse *synapse;
+ const char *prefix;
+ struct counter_action_unit *action_comp;
+ struct counter_attr_parm parm;
+ int err;
+ struct counter_action_avail_unit *avail_comp;
+
+ /* Register each Synapse */
+ for (i = 0; i < count->num_synapses; i++) {
+ synapse = count->synapses + i;
+
+ /* Generate attribute prefix */
+ prefix = kasprintf(GFP_KERNEL, "signal%d_",
+ synapse->signal->id);
+ if (!prefix) {
+ err = -ENOMEM;
+ goto err_free_attr_list;
+ }
+
+ /* Allocate action attribute component */
+ action_comp = kmalloc(sizeof(*action_comp), GFP_KERNEL);
+ if (!action_comp) {
+ err = -ENOMEM;
+ goto err_free_prefix;
+ }
+ action_comp->synapse = synapse;
+ action_comp->count = count;
+
+ /* Create action attribute */
+ parm.group = group;
+ parm.prefix = prefix;
+ parm.name = "action";
+ parm.show = (counter->ops->action_get) ? counter_action_show : NULL;
+ parm.store = (counter->ops->action_set) ? counter_action_store : NULL;
+ parm.component = action_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(action_comp);
+ goto err_free_prefix;
+ }
+
+ /* Allocate action available attribute component */
+ avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
+ if (!avail_comp) {
+ err = -ENOMEM;
+ goto err_free_prefix;
+ }
+ avail_comp->actions_list = synapse->actions_list;
+ avail_comp->num_actions = synapse->num_actions;
+
+ /* Create action_available attribute */
+ parm.group = group;
+ parm.prefix = prefix;
+ parm.name = "action_available";
+ parm.show = counter_synapse_action_available_show;
+ parm.store = NULL;
+ parm.component = avail_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(avail_comp);
+ goto err_free_prefix;
+ }
+
+ kfree(prefix);
+ }
+
+ return 0;
+
+err_free_prefix:
+ kfree(prefix);
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+struct counter_count_unit {
+ struct counter_count *count;
+};
+
+static ssize_t counter_count_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct counter_device *const counter = dev_get_drvdata(dev);
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_count_unit *const component = devattr->component;
+ struct counter_count *const count = component->count;
+ int err;
+ struct counter_count_read_value val = { .buf = buf };
+
+ err = counter->ops->count_read(counter, count, &val);
+ if (err)
+ return err;
+
+ return val.len;
+}
+
+static ssize_t counter_count_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct counter_device *const counter = dev_get_drvdata(dev);
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_count_unit *const component = devattr->component;
+ struct counter_count *const count = component->count;
+ int err;
+ struct counter_count_write_value val = { .buf = buf };
+
+ err = counter->ops->count_write(counter, count, &val);
+ if (err)
+ return err;
+
+ return len;
+}
+
+static const char *const counter_count_function_str[] = {
+ [COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
+ [COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
+ [COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
+ [COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
+ [COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
+ [COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
+ [COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
+ [COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
+};
+
+static ssize_t counter_function_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int err;
+ struct counter_device *const counter = dev_get_drvdata(dev);
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_count_unit *const component = devattr->component;
+ struct counter_count *const count = component->count;
+ size_t func_index;
+ enum counter_count_function function;
+
+ err = counter->ops->function_get(counter, count, &func_index);
+ if (err)
+ return err;
+
+ count->function = func_index;
+
+ function = count->functions_list[func_index];
+ return sprintf(buf, "%s\n", counter_count_function_str[function]);
+}
+
+static ssize_t counter_function_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_count_unit *const component = devattr->component;
+ struct counter_count *const count = component->count;
+ const size_t num_functions = count->num_functions;
+ size_t func_index;
+ enum counter_count_function function;
+ int err;
+ struct counter_device *const counter = dev_get_drvdata(dev);
+
+ /* Find requested Count function mode */
+ for (func_index = 0; func_index < num_functions; func_index++) {
+ function = count->functions_list[func_index];
+ if (sysfs_streq(buf, counter_count_function_str[function]))
+ break;
+ }
+ /* Return error if requested Count function mode not found */
+ if (func_index >= num_functions)
+ return -EINVAL;
+
+ err = counter->ops->function_set(counter, count, func_index);
+ if (err)
+ return err;
+
+ count->function = func_index;
+
+ return len;
+}
+
+struct counter_count_ext_unit {
+ struct counter_count *count;
+ const struct counter_count_ext *ext;
+};
+
+static ssize_t counter_count_ext_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_count_ext_unit *const comp = devattr->component;
+ const struct counter_count_ext *const ext = comp->ext;
+
+ return ext->read(dev_get_drvdata(dev), comp->count, ext->priv, buf);
+}
+
+static ssize_t counter_count_ext_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_count_ext_unit *const comp = devattr->component;
+ const struct counter_count_ext *const ext = comp->ext;
+
+ return ext->write(dev_get_drvdata(dev), comp->count, ext->priv, buf,
+ len);
+}
+
+static int counter_count_ext_register(
+ struct counter_device_attr_group *const group,
+ struct counter_count *const count)
+{
+ size_t i;
+ const struct counter_count_ext *ext;
+ struct counter_count_ext_unit *count_ext_comp;
+ struct counter_attr_parm parm;
+ int err;
+
+ /* Create an attribute for each extension */
+ for (i = 0 ; i < count->num_ext; i++) {
+ ext = count->ext + i;
+
+ /* Allocate count_ext attribute component */
+ count_ext_comp = kmalloc(sizeof(*count_ext_comp), GFP_KERNEL);
+ if (!count_ext_comp) {
+ err = -ENOMEM;
+ goto err_free_attr_list;
+ }
+ count_ext_comp->count = count;
+ count_ext_comp->ext = ext;
+
+ /* Allocate count_ext attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = ext->name;
+ parm.show = (ext->read) ? counter_count_ext_show : NULL;
+ parm.store = (ext->write) ? counter_count_ext_store : NULL;
+ parm.component = count_ext_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(count_ext_comp);
+ goto err_free_attr_list;
+ }
+ }
+
+ return 0;
+
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+struct counter_func_avail_unit {
+ const enum counter_count_function *functions_list;
+ size_t num_functions;
+};
+
+static ssize_t counter_count_function_available_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_func_avail_unit *const component = devattr->component;
+ const enum counter_count_function *const func_list = component->functions_list;
+ const size_t num_functions = component->num_functions;
+ size_t i;
+ enum counter_count_function function;
+ ssize_t len = 0;
+
+ for (i = 0; i < num_functions; i++) {
+ function = func_list[i];
+ len += sprintf(buf + len, "%s\n",
+ counter_count_function_str[function]);
+ }
+
+ return len;
+}
+
+static int counter_count_attributes_create(
+ struct counter_device_attr_group *const group,
+ const struct counter_device *const counter,
+ struct counter_count *const count)
+{
+ struct counter_count_unit *count_comp;
+ struct counter_attr_parm parm;
+ int err;
+ struct counter_count_unit *func_comp;
+ struct counter_func_avail_unit *avail_comp;
+
+ /* Allocate count attribute component */
+ count_comp = kmalloc(sizeof(*count_comp), GFP_KERNEL);
+ if (!count_comp)
+ return -ENOMEM;
+ count_comp->count = count;
+
+ /* Create main Count attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = "count";
+ parm.show = (counter->ops->count_read) ? counter_count_show : NULL;
+ parm.store = (counter->ops->count_write) ? counter_count_store : NULL;
+ parm.component = count_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(count_comp);
+ return err;
+ }
+
+ /* Allocate function attribute component */
+ func_comp = kmalloc(sizeof(*func_comp), GFP_KERNEL);
+ if (!func_comp) {
+ err = -ENOMEM;
+ goto err_free_attr_list;
+ }
+ func_comp->count = count;
+
+ /* Create Count function attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = "function";
+ parm.show = (counter->ops->function_get) ? counter_function_show : NULL;
+ parm.store = (counter->ops->function_set) ? counter_function_store : NULL;
+ parm.component = func_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(func_comp);
+ goto err_free_attr_list;
+ }
+
+ /* Allocate function available attribute component */
+ avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
+ if (!avail_comp) {
+ err = -ENOMEM;
+ goto err_free_attr_list;
+ }
+ avail_comp->functions_list = count->functions_list;
+ avail_comp->num_functions = count->num_functions;
+
+ /* Create Count function_available attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = "function_available";
+ parm.show = counter_count_function_available_show;
+ parm.store = NULL;
+ parm.component = avail_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(avail_comp);
+ goto err_free_attr_list;
+ }
+
+ /* Create Count name attribute */
+ err = counter_name_attribute_create(group, count->name);
+ if (err)
+ goto err_free_attr_list;
+
+ /* Register Count extension attributes */
+ err = counter_count_ext_register(group, count);
+ if (err)
+ goto err_free_attr_list;
+
+ return 0;
+
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+static int counter_counts_register(
+ struct counter_device_attr_group *const groups_list,
+ const struct counter_device *const counter)
+{
+ size_t i;
+ struct counter_count *count;
+ const char *name;
+ int err;
+
+ /* Register each Count */
+ for (i = 0; i < counter->num_counts; i++) {
+ count = counter->counts + i;
+
+ /* Generate Count attribute directory name */
+ name = kasprintf(GFP_KERNEL, "count%d", count->id);
+ if (!name) {
+ err = -ENOMEM;
+ goto err_free_attr_groups;
+ }
+ groups_list[i].attr_group.name = name;
+
+ /* Register the Synapses associated with each Count */
+ err = counter_synapses_register(groups_list + i, counter, count,
+ name);
+ if (err)
+ goto err_free_attr_groups;
+
+ /* Create all attributes associated with Count */
+ err = counter_count_attributes_create(groups_list + i, counter,
+ count);
+ if (err)
+ goto err_free_attr_groups;
+ }
+
+ return 0;
+
+err_free_attr_groups:
+ do {
+ kfree(groups_list[i].attr_group.name);
+ counter_device_attr_list_free(&groups_list[i].attr_list);
+ } while (i--);
+ return err;
+}
+
+struct counter_size_unit {
+ size_t size;
+};
+
+static ssize_t counter_device_attr_size_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct counter_size_unit *const comp = to_counter_attr(attr)->component;
+
+ return sprintf(buf, "%zu\n", comp->size);
+}
+
+static int counter_size_attribute_create(
+ struct counter_device_attr_group *const group,
+ const size_t size, const char *const name)
+{
+ struct counter_size_unit *size_comp;
+ struct counter_attr_parm parm;
+ int err;
+
+ /* Allocate size attribute component */
+ size_comp = kmalloc(sizeof(*size_comp), GFP_KERNEL);
+ if (!size_comp)
+ return -ENOMEM;
+ size_comp->size = size;
+
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = name;
+ parm.show = counter_device_attr_size_show;
+ parm.store = NULL;
+ parm.component = size_comp;
+ err = counter_attribute_create(&parm);
+ if (err)
+ goto err_free_size_comp;
+
+ return 0;
+
+err_free_size_comp:
+ kfree(size_comp);
+ return err;
+}
+
+struct counter_ext_unit {
+ const struct counter_device_ext *ext;
+};
+
+static ssize_t counter_device_ext_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_ext_unit *const component = devattr->component;
+ const struct counter_device_ext *const ext = component->ext;
+
+ return ext->read(dev_get_drvdata(dev), ext->priv, buf);
+}
+
+static ssize_t counter_device_ext_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ const struct counter_device_attr *const devattr = to_counter_attr(attr);
+ const struct counter_ext_unit *const component = devattr->component;
+ const struct counter_device_ext *const ext = component->ext;
+
+ return ext->write(dev_get_drvdata(dev), ext->priv, buf, len);
+}
+
+static int counter_device_ext_register(
+ struct counter_device_attr_group *const group,
+ struct counter_device *const counter)
+{
+ size_t i;
+ struct counter_ext_unit *ext_comp;
+ struct counter_attr_parm parm;
+ int err;
+
+ /* Create an attribute for each extension */
+ for (i = 0 ; i < counter->num_ext; i++) {
+ /* Allocate extension attribute component */
+ ext_comp = kmalloc(sizeof(*ext_comp), GFP_KERNEL);
+ if (!ext_comp) {
+ err = -ENOMEM;
+ goto err_free_attr_list;
+ }
+
+ ext_comp->ext = counter->ext + i;
+
+ /* Allocate extension attribute */
+ parm.group = group;
+ parm.prefix = "";
+ parm.name = counter->ext[i].name;
+ parm.show = (counter->ext[i].read) ? counter_device_ext_show : NULL;
+ parm.store = (counter->ext[i].write) ? counter_device_ext_store : NULL;
+ parm.component = ext_comp;
+ err = counter_attribute_create(&parm);
+ if (err) {
+ kfree(ext_comp);
+ goto err_free_attr_list;
+ }
+ }
+
+ return 0;
+
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+static int counter_global_attr_register(
+ struct counter_device_attr_group *const group,
+ struct counter_device *const counter)
+{
+ int err;
+
+ /* Create name attribute */
+ err = counter_name_attribute_create(group, counter->name);
+ if (err)
+ return err;
+
+ /* Create num_counts attribute */
+ err = counter_size_attribute_create(group, counter->num_counts,
+ "num_counts");
+ if (err)
+ goto err_free_attr_list;
+
+ /* Create num_signals attribute */
+ err = counter_size_attribute_create(group, counter->num_signals,
+ "num_signals");
+ if (err)
+ goto err_free_attr_list;
+
+ /* Register Counter device extension attributes */
+ err = counter_device_ext_register(group, counter);
+ if (err)
+ goto err_free_attr_list;
+
+ return 0;
+
+err_free_attr_list:
+ counter_device_attr_list_free(&group->attr_list);
+ return err;
+}
+
+static void counter_device_groups_list_free(
+ struct counter_device_attr_group *const groups_list,
+ const size_t num_groups)
+{
+ struct counter_device_attr_group *group;
+ size_t i;
+
+ /* loop through all attribute groups (signals, counts, global, etc.) */
+ for (i = 0; i < num_groups; i++) {
+ group = groups_list + i;
+
+ /* free all attribute group and associated attributes memory */
+ kfree(group->attr_group.name);
+ kfree(group->attr_group.attrs);
+ counter_device_attr_list_free(&group->attr_list);
+ }
+
+ kfree(groups_list);
+}
+
+static int counter_device_groups_list_prepare(
+ struct counter_device *const counter)
+{
+ const size_t total_num_groups =
+ counter->num_signals + counter->num_counts + 1;
+ struct counter_device_attr_group *groups_list;
+ size_t i;
+ int err;
+ size_t num_groups = 0;
+
+ /* Allocate space for attribute groups (signals, counts, and ext) */
+ groups_list = kcalloc(total_num_groups, sizeof(*groups_list),
+ GFP_KERNEL);
+ if (!groups_list)
+ return -ENOMEM;
+
+ /* Initialize attribute lists */
+ for (i = 0; i < total_num_groups; i++)
+ INIT_LIST_HEAD(&groups_list[i].attr_list);
+
+ /* Register Signals */
+ err = counter_signals_register(groups_list, counter);
+ if (err)
+ goto err_free_groups_list;
+ num_groups += counter->num_signals;
+
+ /* Register Counts and respective Synapses */
+ err = counter_counts_register(groups_list + num_groups, counter);
+ if (err)
+ goto err_free_groups_list;
+ num_groups += counter->num_counts;
+
+ /* Register Counter global attributes */
+ err = counter_global_attr_register(groups_list + num_groups, counter);
+ if (err)
+ goto err_free_groups_list;
+ num_groups++;
+
+ /* Store groups_list in device_state */
+ counter->device_state->groups_list = groups_list;
+ counter->device_state->num_groups = num_groups;
+
+ return 0;
+
+err_free_groups_list:
+ counter_device_groups_list_free(groups_list, num_groups);
+ return err;
+}
+
+static int counter_device_groups_prepare(
+ struct counter_device_state *const device_state)
+{
+ size_t i, j;
+ struct counter_device_attr_group *group;
+ int err;
+ struct counter_device_attr *p;
+
+ /* Allocate attribute groups for association with device */
+ device_state->groups = kcalloc(device_state->num_groups + 1,
+ sizeof(*device_state->groups),
+ GFP_KERNEL);
+ if (!device_state->groups)
+ return -ENOMEM;
+
+ /* Prepare each group of attributes for association */
+ for (i = 0; i < device_state->num_groups; i++) {
+ group = device_state->groups_list + i;
+
+ /* Allocate space for attribute pointers in attribute group */
+ group->attr_group.attrs = kcalloc(group->num_attr + 1,
+ sizeof(*group->attr_group.attrs), GFP_KERNEL);
+ if (!group->attr_group.attrs) {
+ err = -ENOMEM;
+ goto err_free_groups;
+ }
+
+ /* Add attribute pointers to attribute group */
+ j = 0;
+ list_for_each_entry(p, &group->attr_list, l)
+ group->attr_group.attrs[j++] = &p->dev_attr.attr;
+
+ /* Group attributes in attribute group */
+ device_state->groups[i] = &group->attr_group;
+ }
+ /* Associate attributes with device */
+ device_state->dev.groups = device_state->groups;
+
+ return 0;
+
+err_free_groups:
+ do {
+ group = device_state->groups_list + i;
+ kfree(group->attr_group.attrs);
+ group->attr_group.attrs = NULL;
+ } while (i--);
+ kfree(device_state->groups);
+ return err;
+}
+
+/* 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);
+ struct counter_device_state *const device_state = counter->device_state;
+
+ kfree(device_state->groups);
+ counter_device_groups_list_free(device_state->groups_list,
+ device_state->num_groups);
+ ida_simple_remove(&counter_ida, device_state->id);
+ kfree(device_state);
+}
+
+static struct device_type counter_device_type = {
+ .name = "counter_device",
+ .release = counter_device_release
+};
+
+static struct bus_type counter_bus_type = {
+ .name = "counter"
+};
+
+/**
+ * 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.
+ */
+int counter_register(struct counter_device *const counter)
+{
+ struct counter_device_state *device_state;
+ int err;
+
+ /* Allocate internal state container for Counter device */
+ device_state = kzalloc(sizeof(*device_state), GFP_KERNEL);
+ if (!device_state)
+ return -ENOMEM;
+ counter->device_state = device_state;
+
+ /* Acquire unique ID */
+ device_state->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
+ if (device_state->id < 0) {
+ err = device_state->id;
+ goto err_free_device_state;
+ }
+
+ /* Configure device structure for Counter */
+ device_state->dev.type = &counter_device_type;
+ device_state->dev.bus = &counter_bus_type;
+ if (counter->parent) {
+ device_state->dev.parent = counter->parent;
+ device_state->dev.of_node = counter->parent->of_node;
+ }
+ dev_set_name(&device_state->dev, "counter%d", device_state->id);
+ device_initialize(&device_state->dev);
+ dev_set_drvdata(&device_state->dev, counter);
+
+ /* Prepare device attributes */
+ err = counter_device_groups_list_prepare(counter);
+ if (err)
+ goto err_free_id;
+
+ /* Organize device attributes to groups and match to device */
+ err = counter_device_groups_prepare(device_state);
+ if (err)
+ goto err_free_groups_list;
+
+ /* Add device to system */
+ err = device_add(&device_state->dev);
+ if (err)
+ goto err_free_groups;
+
+ return 0;
+
+err_free_groups:
+ kfree(device_state->groups);
+err_free_groups_list:
+ counter_device_groups_list_free(device_state->groups_list,
+ device_state->num_groups);
+err_free_id:
+ ida_simple_remove(&counter_ida, device_state->id);
+err_free_device_state:
+ kfree(device_state);
+ 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; all allocated memory is freed.
+ */
+void counter_unregister(struct counter_device *const counter)
+{
+ if (counter)
+ device_del(&counter->device_state->dev);
+}
+EXPORT_SYMBOL_GPL(counter_unregister);
+
+static void devm_counter_unreg(struct device *dev, void *res)
+{
+ counter_unregister(*(struct counter_device **)res);
+}
+
+/**
+ * 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.
+ *
+ * If an Counter registered with this function needs to be unregistered
+ * separately, devm_counter_unregister must be used.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int devm_counter_register(struct device *dev,
+ struct counter_device *const counter)
+{
+ struct counter_device **ptr;
+ int ret;
+
+ ptr = devres_alloc(devm_counter_unreg, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ ret = counter_register(counter);
+ if (!ret) {
+ *ptr = counter;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(devm_counter_register);
+
+static int devm_counter_match(struct device *dev, void *res, void *data)
+{
+ struct counter_device **r = res;
+
+ if (!r || !*r) {
+ WARN_ON(!r || !*r);
+ return 0;
+ }
+
+ return *r == data;
+}
+
+/**
+ * devm_counter_unregister - Resource-managed counter_unregister
+ * @dev: device this counter_device belongs to
+ * @counter: pointer to Counter associated with the device
+ *
+ * Unregister Counter registered with devm_counter_register.
+ */
+void devm_counter_unregister(struct device *dev,
+ struct counter_device *const counter)
+{
+ int rc;
+
+ rc = devres_release(dev, devm_counter_unreg, devm_counter_match,
+ counter);
+ WARN_ON(rc);
+}
+EXPORT_SYMBOL_GPL(devm_counter_unregister);
+
+static int __init counter_init(void)
+{
+ return bus_register(&counter_bus_type);
+}
+
+static void __exit counter_exit(void)
+{
+ 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");
diff --git a/include/linux/counter.h b/include/linux/counter.h
new file mode 100644
index 000000000000..a061cdcdef7c
--- /dev/null
+++ b/include/linux/counter.h
@@ -0,0 +1,510 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter interface
+ * Copyright (C) 2018 William Breathitt Gray
+ */
+#ifndef _COUNTER_H_
+#define _COUNTER_H_
+
+#include <linux/counter_enum.h>
+#include <linux/device.h>
+#include <linux/types.h>
+
+enum counter_count_direction {
+ COUNTER_COUNT_DIRECTION_FORWARD = 0,
+ COUNTER_COUNT_DIRECTION_BACKWARD
+};
+extern const char *const counter_count_direction_str[2];
+
+enum counter_count_mode {
+ COUNTER_COUNT_MODE_NORMAL = 0,
+ COUNTER_COUNT_MODE_RANGE_LIMIT,
+ COUNTER_COUNT_MODE_NON_RECYCLE,
+ COUNTER_COUNT_MODE_MODULO_N
+};
+extern const char *const counter_count_mode_str[4];
+
+struct counter_device;
+struct counter_signal;
+
+/**
+ * struct counter_signal_ext - Counter Signal extensions
+ * @name: attribute name
+ * @read: read callback for this attribute; may be NULL
+ * @write: write callback for this attribute; may be NULL
+ * @priv: data private to the driver
+ */
+struct counter_signal_ext {
+ const char *name;
+ ssize_t (*read)(struct counter_device *counter,
+ struct counter_signal *signal, void *priv, char *buf);
+ ssize_t (*write)(struct counter_device *counter,
+ struct counter_signal *signal, void *priv,
+ const char *buf, size_t len);
+ void *priv;
+};
+
+/**
+ * struct counter_signal - Counter Signal node
+ * @id: unique ID used to identify signal
+ * @name: device-specific Signal name; ideally, this should match the name
+ * as it appears in the datasheet documentation
+ * @ext: optional array of Counter Signal extensions
+ * @num_ext: number of Counter Signal extensions specified in @ext
+ * @priv: optional private data supplied by driver
+ */
+struct counter_signal {
+ int id;
+ const char *name;
+
+ const struct counter_signal_ext *ext;
+ size_t num_ext;
+
+ void *priv;
+};
+
+/**
+ * struct counter_signal_enum_ext - Signal enum extension attribute
+ * @items: Array of strings
+ * @num_items: Number of items specified in @items
+ * @set: Set callback function; may be NULL
+ * @get: Get callback function; may be NULL
+ *
+ * The counter_signal_enum_ext structure can be used to implement enum style
+ * Signal extension attributes. Enum style attributes are those which have a set
+ * of strings that map to unsigned integer values. The Generic Counter Signal
+ * enum extension helper code takes care of mapping between value and string, as
+ * well as generating a "_available" file which contains a list of all available
+ * items. The get callback is used to query the currently active item; the index
+ * of the item within the respective items array is returned via the 'item'
+ * parameter. The set callback is called when the attribute is updated; the
+ * 'item' parameter contains the index of the newly activated item within the
+ * respective items array.
+ */
+struct counter_signal_enum_ext {
+ const char * const *items;
+ size_t num_items;
+ int (*get)(struct counter_device *counter,
+ struct counter_signal *signal, size_t *item);
+ int (*set)(struct counter_device *counter,
+ struct counter_signal *signal, size_t item);
+};
+
+/**
+ * COUNTER_SIGNAL_ENUM() - Initialize Signal enum extension
+ * @_name: Attribute name
+ * @_e: Pointer to a counter_signal_enum_ext structure
+ *
+ * This should usually be used together with COUNTER_SIGNAL_ENUM_AVAILABLE()
+ */
+#define COUNTER_SIGNAL_ENUM(_name, _e) \
+{ \
+ .name = (_name), \
+ .read = counter_signal_enum_read, \
+ .write = counter_signal_enum_write, \
+ .priv = (_e) \
+}
+
+/**
+ * COUNTER_SIGNAL_ENUM_AVAILABLE() - Initialize Signal enum available extension
+ * @_name: Attribute name ("_available" will be appended to the name)
+ * @_e: Pointer to a counter_signal_enum_ext structure
+ *
+ * Creates a read only attribute that lists all the available enum items in a
+ * newline separated list. This should usually be used together with
+ * COUNTER_SIGNAL_ENUM()
+ */
+#define COUNTER_SIGNAL_ENUM_AVAILABLE(_name, _e) \
+{ \
+ .name = (_name "_available"), \
+ .read = counter_signal_enum_available_read, \
+ .priv = (_e) \
+}
+
+enum counter_synapse_action {
+ COUNTER_SYNAPSE_ACTION_NONE = 0,
+ COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+ COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+ COUNTER_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+/**
+ * struct counter_synapse - Counter Synapse node
+ * @action: index of current action mode
+ * @actions_list: array of available action modes
+ * @num_actions: number of action modes specified in @actions_list
+ * @signal: pointer to associated signal
+ */
+struct counter_synapse {
+ size_t action;
+ const enum counter_synapse_action *actions_list;
+ size_t num_actions;
+
+ struct counter_signal *signal;
+};
+
+struct counter_count;
+
+/**
+ * struct counter_count_ext - Counter Count extension
+ * @name: attribute name
+ * @read: read callback for this attribute; may be NULL
+ * @write: write callback for this attribute; may be NULL
+ * @priv: data private to the driver
+ */
+struct counter_count_ext {
+ const char *name;
+ ssize_t (*read)(struct counter_device *counter,
+ struct counter_count *count, void *priv, char *buf);
+ ssize_t (*write)(struct counter_device *counter,
+ struct counter_count *count, void *priv,
+ const char *buf, size_t len);
+ void *priv;
+};
+
+enum counter_count_function {
+ COUNTER_COUNT_FUNCTION_INCREASE = 0,
+ COUNTER_COUNT_FUNCTION_DECREASE,
+ COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
+ COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
+ COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
+ COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
+ COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
+ COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+};
+
+/**
+ * struct counter_count - Counter Count node
+ * @id: unique ID used to identify Count
+ * @name: device-specific Count name; ideally, this should match
+ * the name as it appears in the datasheet documentation
+ * @function: index of current function mode
+ * @functions_list: array available function modes
+ * @num_functions: number of function modes specified in @functions_list
+ * @synapses: array of synapses for initialization
+ * @num_synapses: number of synapses specified in @synapses
+ * @ext: optional array of Counter Count extensions
+ * @num_ext: number of Counter Count extensions specified in @ext
+ * @priv: optional private data supplied by driver
+ */
+struct counter_count {
+ int id;
+ const char *name;
+
+ size_t function;
+ const enum counter_count_function *functions_list;
+ size_t num_functions;
+
+ struct counter_synapse *synapses;
+ size_t num_synapses;
+
+ const struct counter_count_ext *ext;
+ size_t num_ext;
+
+ void *priv;
+};
+
+/**
+ * struct counter_count_enum_ext - Count enum extension attribute
+ * @items: Array of strings
+ * @num_items: Number of items specified in @items
+ * @set: Set callback function; may be NULL
+ * @get: Get callback function; may be NULL
+ *
+ * The counter_count_enum_ext structure can be used to implement enum style
+ * Count extension attributes. Enum style attributes are those which have a set
+ * of strings that map to unsigned integer values. The Generic Counter Count
+ * enum extension helper code takes care of mapping between value and string, as
+ * well as generating a "_available" file which contains a list of all available
+ * items. The get callback is used to query the currently active item; the index
+ * of the item within the respective items array is returned via the 'item'
+ * parameter. The set callback is called when the attribute is updated; the
+ * 'item' parameter contains the index of the newly activated item within the
+ * respective items array.
+ */
+struct counter_count_enum_ext {
+ const char * const *items;
+ size_t num_items;
+ int (*get)(struct counter_device *counter, struct counter_count *count,
+ size_t *item);
+ int (*set)(struct counter_device *counter, struct counter_count *count,
+ size_t item);
+};
+
+/**
+ * COUNTER_COUNT_ENUM() - Initialize Count enum extension
+ * @_name: Attribute name
+ * @_e: Pointer to a counter_count_enum_ext structure
+ *
+ * This should usually be used together with COUNTER_COUNT_ENUM_AVAILABLE()
+ */
+#define COUNTER_COUNT_ENUM(_name, _e) \
+{ \
+ .name = (_name), \
+ .read = counter_count_enum_read, \
+ .write = counter_count_enum_write, \
+ .priv = (_e) \
+}
+
+/**
+ * COUNTER_COUNT_ENUM_AVAILABLE() - Initialize Count enum available extension
+ * @_name: Attribute name ("_available" will be appended to the name)
+ * @_e: Pointer to a counter_count_enum_ext structure
+ *
+ * Creates a read only attribute that lists all the available enum items in a
+ * newline separated list. This should usually be used together with
+ * COUNTER_COUNT_ENUM()
+ */
+#define COUNTER_COUNT_ENUM_AVAILABLE(_name, _e) \
+{ \
+ .name = (_name "_available"), \
+ .read = counter_count_enum_available_read, \
+ .priv = (_e) \
+}
+
+/**
+ * struct counter_device_attr_group - internal container for attribute group
+ * @attr_group: Counter sysfs attributes group
+ * @attr_list: list to keep track of created Counter sysfs attributes
+ * @num_attr: number of Counter sysfs attributes
+ */
+struct counter_device_attr_group {
+ struct attribute_group attr_group;
+ struct list_head attr_list;
+ size_t num_attr;
+};
+
+/**
+ * struct counter_device_state - internal state container for a Counter device
+ * @id: unique ID used to identify the Counter
+ * @dev: internal device structure
+ * @groups_list: attribute groups list (for Signals, Counts, and ext)
+ * @num_groups: number of attribute groups containers
+ * @groups: Counter sysfs attribute groups (to populate @dev.groups)
+ */
+struct counter_device_state {
+ int id;
+ struct device dev;
+ struct counter_device_attr_group *groups_list;
+ size_t num_groups;
+ const struct attribute_group **groups;
+};
+
+/**
+ * struct counter_signal_read_value - Opaque Signal read value
+ * @buf: string representation of Signal read value
+ * @len: length of string in @buf
+ */
+struct counter_signal_read_value {
+ char *buf;
+ size_t len;
+};
+
+/**
+ * struct counter_count_read_value - Opaque Count read value
+ * @buf: string representation of Count read value
+ * @len: length of string in @buf
+ */
+struct counter_count_read_value {
+ char *buf;
+ size_t len;
+};
+
+/**
+ * struct counter_count_write_value - Opaque Count write value
+ * @buf: string representation of Count write value
+ */
+struct counter_count_write_value {
+ const char *buf;
+};
+
+/**
+ * struct counter_ops - Callbacks from driver
+ * @signal_read: optional read callback for Signal attribute. The read
+ * value of the respective Signal should be passed back via
+ * the val parameter. val points to an opaque type which
+ * should be set only by calling the
+ * counter_signal_read_value_set function from within the
+ * signal_read callback.
+ * @count_read: optional read callback for Count attribute. The read
+ * value of the respective Count should be passed back via
+ * the val parameter. val points to an opaque type which
+ * should be set only by calling the
+ * counter_count_read_value_set function from within the
+ * count_read callback.
+ * @count_write: optional write callback for Count attribute. The write
+ * value for the respective Count is passed in via the val
+ * parameter. val points to an opaque type which should be
+ * accessed only by calling the
+ * counter_count_write_value_get function.
+ * @function_get: function to get the current count function mode. Returns
+ * 0 on success and negative error code on error. The index
+ * of the respective Count's returned function mode should
+ * be passed back via the function parameter.
+ * @function_set: function to set the count function mode. function is the
+ * index of the requested function mode from the respective
+ * Count's functions_list array.
+ * @action_get: function to get the current action mode. Returns 0 on
+ * success and negative error code on error. The index of
+ * the respective Signal's returned action mode should be
+ * passed back via the action parameter.
+ * @action_set: function to set the action mode. action is the index of
+ * the requested action mode from the respective Synapse's
+ * actions_list array.
+ */
+struct counter_ops {
+ int (*signal_read)(struct counter_device *counter,
+ struct counter_signal *signal,
+ struct counter_signal_read_value *val);
+ int (*count_read)(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_count_read_value *val);
+ int (*count_write)(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_count_write_value *val);
+ int (*function_get)(struct counter_device *counter,
+ struct counter_count *count, size_t *function);
+ int (*function_set)(struct counter_device *counter,
+ struct counter_count *count, size_t function);
+ int (*action_get)(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse, size_t *action);
+ int (*action_set)(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse, size_t action);
+};
+
+/**
+ * struct counter_device_ext - Counter device extension
+ * @name: attribute name
+ * @read: read callback for this attribute; may be NULL
+ * @write: write callback for this attribute; may be NULL
+ * @priv: data private to the driver
+ */
+struct counter_device_ext {
+ const char *name;
+ ssize_t (*read)(struct counter_device *counter, void *priv, char *buf);
+ ssize_t (*write)(struct counter_device *counter, void *priv,
+ const char *buf, size_t len);
+ void *priv;
+};
+
+/**
+ * struct counter_device_enum_ext - Counter enum extension attribute
+ * @items: Array of strings
+ * @num_items: Number of items specified in @items
+ * @set: Set callback function; may be NULL
+ * @get: Get callback function; may be NULL
+ *
+ * The counter_device_enum_ext structure can be used to implement enum style
+ * Counter extension attributes. Enum style attributes are those which have a
+ * set of strings that map to unsigned integer values. The Generic Counter enum
+ * extension helper code takes care of mapping between value and string, as well
+ * as generating a "_available" file which contains a list of all available
+ * items. The get callback is used to query the currently active item; the index
+ * of the item within the respective items array is returned via the 'item'
+ * parameter. The set callback is called when the attribute is updated; the
+ * 'item' parameter contains the index of the newly activated item within the
+ * respective items array.
+ */
+struct counter_device_enum_ext {
+ const char * const *items;
+ size_t num_items;
+ int (*get)(struct counter_device *counter, size_t *item);
+ int (*set)(struct counter_device *counter, size_t item);
+};
+
+/**
+ * COUNTER_DEVICE_ENUM() - Initialize Counter enum extension
+ * @_name: Attribute name
+ * @_e: Pointer to a counter_device_enum_ext structure
+ *
+ * This should usually be used together with COUNTER_DEVICE_ENUM_AVAILABLE()
+ */
+#define COUNTER_DEVICE_ENUM(_name, _e) \
+{ \
+ .name = (_name), \
+ .read = counter_device_enum_read, \
+ .write = counter_device_enum_write, \
+ .priv = (_e) \
+}
+
+/**
+ * COUNTER_DEVICE_ENUM_AVAILABLE() - Initialize Counter enum available extension
+ * @_name: Attribute name ("_available" will be appended to the name)
+ * @_e: Pointer to a counter_device_enum_ext structure
+ *
+ * Creates a read only attribute that lists all the available enum items in a
+ * newline separated list. This should usually be used together with
+ * COUNTER_DEVICE_ENUM()
+ */
+#define COUNTER_DEVICE_ENUM_AVAILABLE(_name, _e) \
+{ \
+ .name = (_name "_available"), \
+ .read = counter_device_enum_available_read, \
+ .priv = (_e) \
+}
+
+/**
+ * struct counter_device - Counter data structure
+ * @name: name of the device as it appears in the datasheet
+ * @parent: optional parent device providing the counters
+ * @device_state: internal device state container
+ * @ops: callbacks from driver
+ * @signals: array of Signals
+ * @num_signals: number of Signals specified in @signals
+ * @counts: array of Counts
+ * @num_counts: number of Counts specified in @counts
+ * @ext: optional array of Counter device extensions
+ * @num_ext: number of Counter device extensions specified in @ext
+ * @priv: optional private data supplied by driver
+ */
+struct counter_device {
+ const char *name;
+ struct device *parent;
+ struct counter_device_state *device_state;
+
+ const struct counter_ops *ops;
+
+ struct counter_signal *signals;
+ size_t num_signals;
+ struct counter_count *counts;
+ size_t num_counts;
+
+ const struct counter_device_ext *ext;
+ size_t num_ext;
+
+ void *priv;
+};
+
+enum counter_signal_level {
+ COUNTER_SIGNAL_LEVEL_LOW = 0,
+ COUNTER_SIGNAL_LEVEL_HIGH
+};
+
+enum counter_signal_value_type {
+ COUNTER_SIGNAL_LEVEL = 0
+};
+
+enum counter_count_value_type {
+ COUNTER_COUNT_POSITION = 0,
+};
+
+void counter_signal_read_value_set(struct counter_signal_read_value *const val,
+ const enum counter_signal_value_type type,
+ void *const data);
+void counter_count_read_value_set(struct counter_count_read_value *const val,
+ const enum counter_count_value_type type,
+ void *const data);
+int counter_count_write_value_get(void *const data,
+ const enum counter_count_value_type type,
+ const struct counter_count_write_value *const val);
+
+int counter_register(struct counter_device *const counter);
+void counter_unregister(struct counter_device *const counter);
+int devm_counter_register(struct device *dev,
+ struct counter_device *const counter);
+void devm_counter_unregister(struct device *dev,
+ struct counter_device *const counter);
+
+#endif /* _COUNTER_H_ */
diff --git a/include/linux/counter_enum.h b/include/linux/counter_enum.h
new file mode 100644
index 000000000000..9f917298a88f
--- /dev/null
+++ b/include/linux/counter_enum.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter interface enum functions
+ * Copyright (C) 2018 William Breathitt Gray
+ */
+#ifndef _COUNTER_ENUM_H_
+#define _COUNTER_ENUM_H_
+
+#include <linux/types.h>
+
+struct counter_device;
+struct counter_signal;
+struct counter_count;
+
+ssize_t counter_signal_enum_read(struct counter_device *counter,
+ struct counter_signal *signal, void *priv,
+ char *buf);
+ssize_t counter_signal_enum_write(struct counter_device *counter,
+ struct counter_signal *signal, void *priv,
+ const char *buf, size_t len);
+
+ssize_t counter_signal_enum_available_read(struct counter_device *counter,
+ struct counter_signal *signal,
+ void *priv, char *buf);
+
+ssize_t counter_count_enum_read(struct counter_device *counter,
+ struct counter_count *count, void *priv,
+ char *buf);
+ssize_t counter_count_enum_write(struct counter_device *counter,
+ struct counter_count *count, void *priv,
+ const char *buf, size_t len);
+
+ssize_t counter_count_enum_available_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, char *buf);
+
+ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
+ char *buf);
+ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
+ const char *buf, size_t len);
+
+ssize_t counter_device_enum_available_read(struct counter_device *counter,
+ void *priv, char *buf);
+
+#endif /* _COUNTER_ENUM_H_ */
--
2.21.0