path: root/drivers/counter/counter-sysfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Generic Counter sysfs interface
 * Copyright (C) 2020 William Breathitt Gray
 */
#include <linux/counter.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/kstrtox.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/types.h>

#include "counter-sysfs.h"

static inline struct counter_device *counter_from_dev(struct device *dev)
{
	return container_of(dev, struct counter_device, dev);
}

/**
 * struct counter_attribute - Counter sysfs attribute
 * @dev_attr:	device attribute for sysfs
 * @l:		node to add Counter attribute to attribute group list
 * @comp:	Counter component callbacks and data
 * @scope:	Counter scope of the attribute
 * @parent:	pointer to the parent component
 */
struct counter_attribute {
	struct device_attribute dev_attr;
	struct list_head l;

	struct counter_comp comp;
	enum counter_scope scope;
	void *parent;
};

#define to_counter_attribute(_dev_attr) \
	container_of(_dev_attr, struct counter_attribute, dev_attr)

/**
 * struct counter_attribute_group - container for attribute group
 * @name:	name of the attribute group
 * @attr_list:	list to keep track of created attributes
 * @num_attr:	number of attributes
 */
struct counter_attribute_group {
	const char *name;
	struct list_head attr_list;
	size_t num_attr;
};

static const char *const counter_function_str[] = {
	[COUNTER_FUNCTION_INCREASE] = "increase",
	[COUNTER_FUNCTION_DECREASE] = "decrease",
	[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
	[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
	[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
	[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
	[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
	[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
};

static const char *const counter_signal_value_str[] = {
	[COUNTER_SIGNAL_LEVEL_LOW] = "low",
	[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
};

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"
};

static const char *const counter_count_direction_str[] = {
	[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
	[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
};

static const char *const counter_count_mode_str[] = {
	[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"
};

static const char *const counter_signal_polarity_str[] = {
	[COUNTER_SIGNAL_POLARITY_POSITIVE] = "positive",
	[COUNTER_SIGNAL_POLARITY_NEGATIVE] = "negative"
};

static ssize_t counter_comp_u8_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	const struct counter_attribute *const a = to_counter_attribute(attr);
	struct counter_device *const counter = counter_from_dev(dev);
	int err;
	u8 data = 0;

	switch (a->scope) {
	case COUNTER_SCOPE_DEVICE:
		err = a->comp.device_u8_read(counter, &data);
		break;
	case COUNTER_SCOPE_SIGNAL:
		err = a->comp.signal_u8_read(counter, a->parent, &data);
		break;
	case COUNTER_SCOPE_COUNT:
		err = a->comp.count_u8_read(counter, a->parent, &data);
		break;
	default:
		return -EINVAL;
	}
	if (err < 0)
		return err;

	if (a->comp.type == COUNTER_COMP_BOOL)
		/* data should already be boolean but ensure just to be safe */
		data = !!data;

	return sysfs_emit(buf, "%u\n", (unsigned int)data);
}

static ssize_t counter_comp_u8_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t len)
{
	const struct counter_attribute *const a = to_counter_attribute(attr);
	struct counter_device *const counter = counter_from_dev(dev);
	int err;
	bool bool_data = 0;
	u8 data = 0;

	if (a