drivers/usb/notify/host_notify_class.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  drivers/usb/notify/host_notify_class.c
 *
 * Copyright (C) 2011-2020 Samsung, Inc.
 * Author: Dongrak Shin <dongrak.shin@samsung.com>
 *
 */

 /* usb notify layer v3.5 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/host_notify.h>
#if defined(CONFIG_USB_HW_PARAM)
#include <linux/usb_notify.h>
#endif

struct notify_data {
	struct class *host_notify_class;
	atomic_t device_count;
	struct mutex host_notify_lock;
};

static struct notify_data host_notify;

static ssize_t mode_show(
	struct device *dev, struct device_attribute *attr, char *buf)
{
	struct host_notify_dev *ndev = (struct host_notify_dev *)
		dev_get_drvdata(dev);
	char *mode;

	switch (ndev->mode) {
	case NOTIFY_HOST_MODE:
		mode = "HOST";
		break;
	case NOTIFY_PERIPHERAL_MODE:
		mode = "PERIPHERAL";
		break;
	case NOTIFY_TEST_MODE:
		mode = "TEST";
		break;
	case NOTIFY_NONE_MODE:
	default:
		mode = "NONE";
		break;
	}

	return snprintf(buf, sizeof(mode)+1, "%s\n", mode);
}

static ssize_t mode_store(
		struct device *dev, struct device_attribute *attr,
		const char *buf, size_t size)
{
	struct host_notify_dev *ndev = (struct host_notify_dev *)
		dev_get_drvdata(dev);

	char *mode;
	size_t ret = -ENOMEM;
	int sret = 0;

	if (size < strlen(buf))
		goto error;
	mode = kzalloc(size+1, GFP_KERNEL);
	if (!mode)
		goto error;

	sret = sscanf(buf, "%s", mode);
	if (sret != 1)
		goto error1;

	if (ndev->set_mode) {
		pr_info("host_notify: set mode %s\n", mode);
		if (!strncmp(mode, "HOST", 4))
			ndev->set_mode(NOTIFY_SET_ON);
		else if (!strncmp(mode, "NONE", 4))
			ndev->set_mode(NOTIFY_SET_OFF);
	}
	ret = size;
error1:
	kfree(mode);
error:
	return ret;
}

static ssize_t booster_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct host_notify_dev *ndev = (struct host_notify_dev *)
		dev_get_drvdata(dev);
	char *booster;

	switch (ndev->booster) {
	case NOTIFY_POWER_ON:
		booster = "ON";
		break;
	case NOTIFY_POWER_OFF:
	default:
		booster = "OFF";
		break;
	}

	pr_info("host_notify: read booster %s\n", booster);
	return snprintf(buf,  sizeof(booster)+1, "%s\n", booster);
}

static ssize_t booster_store(
		struct device *dev, struct device_attribute *attr,
		const char *buf, size_t size)
{
	struct host_notify_dev *ndev = (struct host_notify_dev *)
		dev_get_drvdata(dev);

	char *booster;
	size_t ret = -ENOMEM;
	int sret = 0;

	if (size < strlen(buf))
		goto error;
	booster = kzalloc(size+1, GFP_KERNEL);
	if (!booster)
		goto error;

	sret = sscanf(buf, "%s", booster);
	if (sret != 1)
		goto error1;

	if (ndev->set_booster) {
		pr_info("host_notify: set booster %s\n", booster);
		if (!strncmp(booster, "ON", 2)) {
			ndev->set_booster(NOTIFY_SET_ON);
			ndev->mode = NOTIFY_TEST_MODE;
		} else if (!strncmp(booster, "OFF", 3)) {
			ndev->set_booster(NOTIFY_SET_OFF);
			ndev->mode = NOTIFY_NONE_MODE;
		}
	}
	ret = size;
error1:
	kfree(booster);
error:
	return ret;
}

static DEVICE_ATTR_RW(mode);
static DEVICE_ATTR_RW(booster);

static struct attribute *host_notify_attrs[] = {
	&dev_attr_mode.attr,
	&dev_attr_booster.attr,
	NULL,
};

static struct attribute_group host_notify_attr_grp = {
	.attrs = host_notify_attrs,
};

char *host_state_string(int type)
{
	switch (type) {
	case NOTIFY_HOST_NONE:			return "none";
	case NOTIFY_HOST_ADD:			return "add";
	case NOTIFY_HOST_REMOVE:		return "remove";
	case NOTIFY_HOST_OVERCURRENT:	return "overcurrent";
	case NOTIFY_HOST_LOWBATT:		return "lowbatt";
	case NOTIFY_HOST_BLOCK:			return "block";
	case NOTIFY_HOST_SOURCE:		return "source";
	case NOTIFY_HOST_SINK:			return "sink";
	case NOTIFY_HOST_UNKNOWN:
	default:	return "unknown";
	}
}

static int check_state_type(int state)
{
	int ret = 0;

	switch (state) {
	case NOTIFY_HOST_ADD:
	case NOTIFY_HOST_REMOVE:
	case NOTIFY_HOST_BLOCK:
		ret = NOTIFY_HOST_STATE;
		break;
	case NOTIFY_HOST_OVERCURRENT:
	case NOTIFY_HOST_LOWBATT:
	case NOTIFY_HOST_SOURCE:
	case NOTIFY_HOST_SINK:
		ret = NOTIFY_POWER_STATE;
		break;
	case NOTIFY_HOST_NONE:
	case NOTIFY_HOST_UNKNOWN:
	default:
		ret = NOTIFY_UNKNOWN_STATE;
		break;
	}
	return ret;
}

int host_state_notify(struct host_notify_dev *ndev, int state)
{
	int type = 0;

	if (!ndev->dev) {
		pr_err("host_notify: %s ndev->dev is NULL\n", __func__);
		return -ENXIO;
	}

	mutex_lock(&host_notify.host_notify_lock);

	pr_info("host_notify: ndev name=%s: state=%s\n",
		ndev->name, host_state_string(state));

	type = check_state_type(state);

	if (type == NOTIFY_HOST_STATE) {
		if (ndev->host_state != state) {
			pr_info("host_notify: host_state (%s->%s)\n",
				host_state_string(ndev->host_state),
				host_state_string(state));
			ndev->host_state = state;
			ndev->host_change = 1;
			kobject_uevent(&ndev->dev->kobj, KOBJ_CHANGE);
			ndev->host_change = 0;
#if defined(CONFIG_USB_HW_PARAM)
			if (state == NOTIFY_HOST_ADD)
				inc_hw_param_host(ndev, USB_CCIC_OTG_USE_COUNT);
#endif
		}
	} else if (type == NOTIFY_POWER_STATE) {
		if (ndev->power_state != state) {
			pr_info("host_notify: power_state (%s->%s)\n",
				host_state_string(ndev->power_state),
				host_state_string(state));
			ndev->power_state = state;
			ndev->power_change = 1;
			kobject_uevent(&ndev->dev->kobj, KOBJ_CHANGE);
			ndev->power_change = 0;
#if defined(CONFIG_USB_HW_PARAM)
			if (state == NOTIFY_HOST_OVERCURRENT)
				inc_hw_param_host(ndev, USB_CCIC_OVC_COUNT);
#endif
		}
	} else {
		ndev->host_state = state;
		ndev->power_state = state;
	}

	mutex_unlock(&host_notify.host_notify_lock);
	return 0;
}
EXPORT_SYMBOL_GPL(host_state_notify);

static int
host_notify_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct host_notify_dev *ndev = (struct host_notify_dev *)
		dev_get_drvdata(dev);
	char *state;
	int state_type;

	if (!ndev) {
		/* this happens when the device is first created */
		return 0;
	}

	if (ndev->host_change)
		state_type = ndev->host_state;
	else if (ndev->power_change)
		state_type = ndev->power_state;
	else
		state_type = NOTIFY_HOST_NONE;

	switch (state_type) {
	case NOTIFY_HOST_ADD:
		state = "ADD";
		break;
	case NOTIFY_HOST_REMOVE:
		state = "REMOVE";
		break;
	case NOTIFY_HOST_OVERCURRENT:
		state = "OVERCURRENT";
		break;
	case NOTIFY_HOST_LOWBATT:
		state = "LOWBATT";
		break;
	case NOTIFY_HOST_BLOCK:
		state = "BLOCK";
		break;
	case NOTIFY_HOST_SOURCE:
		state = "SOURCE";
		break;
	case NOTIFY_HOST_SINK:
		state = "SINK";
		break;
	case NOTIFY_HOST_UNKNOWN:
		state = "UNKNOWN";
		break;
	case NOTIFY_HOST_NONE:
	default:
		return 0;
	}
	if (add_uevent_var(env, "DEVNAME=%s", ndev->dev->kobj.name))
		return -ENOMEM;
	if (add_uevent_var(env, "STATE=%s", state))
		return -ENOMEM;
	return 0;
}

static int create_notify_class(void)
{
	if (!host_notify.host_notify_class) {
		host_notify.host_notify_class
			= class_create(THIS_MODULE, "host_notify");
		if (IS_ERR(host_notify.host_notify_class))
			return PTR_ERR(host_notify.host_notify_class);
		atomic_set(&host_notify.device_count, 0);
		mutex_init(&host_notify.host_notify_lock);
		host_notify.host_notify_class->dev_uevent = host_notify_uevent;
	}

	return 0;
}

int host_notify_dev_register(struct host_notify_dev *ndev)
{
	int ret;

	if (!host_notify.host_notify_class) {
		ret = create_notify_class();
		if (ret < 0)
			return ret;
	}

	ndev->index = atomic_inc_return(&host_notify.device_count);
	ndev->dev = device_create(host_notify.host_notify_class, NULL,
		MKDEV(0, ndev->index), NULL, "%s", ndev->name);
	if (IS_ERR(ndev->dev))
		return PTR_ERR(ndev->dev);

	ret = sysfs_create_group(&ndev->dev->kobj, &host_notify_attr_grp);
	if (ret < 0) {
		device_destroy(host_notify.host_notify_class,
				MKDEV(0, ndev->index));
		return ret;
	}

	dev_set_drvdata(ndev->dev, ndev);
	ndev->host_state = NOTIFY_HOST_NONE;
	ndev->power_state = NOTIFY_HOST_SINK;
	return 0;
}
EXPORT_SYMBOL_GPL(host_notify_dev_register);

void host_notify_dev_unregister(struct host_notify_dev *ndev)
{
	ndev->host_state = NOTIFY_HOST_NONE;
	ndev->power_state = NOTIFY_HOST_SINK;
	sysfs_remove_group(&ndev->dev->kobj, &host_notify_attr_grp);
	dev_set_drvdata(ndev->dev, NULL);
	device_destroy(host_notify.host_notify_class, MKDEV(0, ndev->index));
	ndev->dev = NULL;
}
EXPORT_SYMBOL_GPL(host_notify_dev_unregister);

int notify_class_init(void)
{
	return create_notify_class();
}

void notify_class_exit(void)
{
	class_destroy(host_notify.host_notify_class);
}