linux-stable/include/linux/counter_enum.h
William Breathitt Gray 0040a390d2 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>
2019-04-25 21:33:37 +02:00

45 lines
1.4 KiB
C

/* 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_ */