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authorWilliam Breathitt Gray <vilhelm.gray@gmail.com>2019-04-02 09:30:36 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-25 22:33:37 +0300
commit0040a390d2fde44a03b3a05cf0cdf3e692ece60f (patch)
tree29901e0b8bc3a2e4387509bb35203b6f79f70f59 /include/linux/counter.h
parent7df95299b94a63ec67a6389fc02dc25019a80ee8 (diff)
downloadlinux-0040a390d2fde44a03b3a05cf0cdf3e692ece60f.tar.xz
counter: Introduce the Generic Counter interface
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>
Diffstat (limited to 'include/linux/counter.h')
-rw-r--r--include/linux/counter.h510
1 files changed, 510 insertions, 0 deletions
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_ */