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counter: Introduce the Generic Counter interface

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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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
William Breathitt Gray 2019-04-02 15:30:36 +09:00 committed by Greg Kroah-Hartman
parent 7df95299b9
commit 0040a390d2
8 changed files with 2148 additions and 0 deletions
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8
MAINTAINERS
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@ -4054,6 +4054,14 @@ 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

2
drivers/Kconfig
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@ -230,4 +230,6 @@ source "drivers/slimbus/Kconfig"
source "drivers/interconnect/Kconfig"
source "drivers/counter/Kconfig"
endmenu

1
drivers/Makefile
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@ -187,3 +187,4 @@ obj-$(CONFIG_UNISYS_VISORBUS) += visorbus/
obj-$(CONFIG_SIOX) += siox/
obj-$(CONFIG_GNSS) += gnss/
obj-$(CONFIG_INTERCONNECT) += interconnect/
obj-$(CONFIG_COUNTER) += counter/

10
drivers/counter/Kconfig Normal file
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@ -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.

5
drivers/counter/Makefile Normal file
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@ -0,0 +1,5 @@
#
# Makefile for Counter devices
#
obj-$(CONFIG_COUNTER) += counter.o

1567
drivers/counter/counter.c Normal file
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510
include/linux/counter.h Normal file
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@ -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_ */

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include/linux/counter_enum.h Normal file
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@ -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_ */