path: root/drivers/extcon/extcon.c

/*
 *  drivers/extcon/extcon.c - External Connector (extcon) framework.
 *
 *  External connector (extcon) class driver
 *
 * Copyright (C) 2015 Samsung Electronics
 * Author: Chanwoo Choi <cw00.choi@samsung.com>
 *
 * Copyright (C) 2012 Samsung Electronics
 * Author: Donggeun Kim <dg77.kim@samsung.com>
 * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
 *
 * based on android/drivers/switch/switch_class.c
 * Copyright (C) 2008 Google, Inc.
 * Author: Mike Lockwood <lockwood@android.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/extcon.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/sysfs.h>

#define SUPPORTED_CABLE_MAX	32
#define CABLE_NAME_MAX		30

static const char *extcon_name[] =  {
	[EXTCON_NONE]		= "NONE",

	/* USB external connector */
	[EXTCON_USB]		= "USB",
	[EXTCON_USB_HOST]	= "USB-HOST",

	/* Charger external connector */
	[EXTCON_TA]		= "TA",
	[EXTCON_FAST_CHARGER]	= "FAST-CHARGER",
	[EXTCON_SLOW_CHARGER]	= "SLOW-CHARGER",
	[EXTCON_CHARGE_DOWNSTREAM] = "CHARGE-DOWNSTREAM",

	/* Audio/Video external connector */
	[EXTCON_LINE_IN]	= "LINE-IN",
	[EXTCON_LINE_OUT]	= "LINE-OUT",
	[EXTCON_MICROPHONE]	= "MICROPHONE",
	[EXTCON_HEADPHONE]	= "HEADPHONE",

	[EXTCON_HDMI]		= "HDMI",
	[EXTCON_MHL]		= "MHL",
	[EXTCON_DVI]		= "DVI",
	[EXTCON_VGA]		= "VGA",
	[EXTCON_SPDIF_IN]	= "SPDIF-IN",
	[EXTCON_SPDIF_OUT]	= "SPDIF-OUT",
	[EXTCON_VIDEO_IN]	= "VIDEO-IN",
	[EXTCON_VIDEO_OUT]	= "VIDEO-OUT",

	/* Etc external connector */
	[EXTCON_DOCK]		= "DOCK",
	[EXTCON_JIG]		= "JIG",
	[EXTCON_MECHANICAL]	= "MECHANICAL",

	NULL,
};

static struct class *extcon_class;
#if defined(CONFIG_ANDROID)
static struct class_compat *switch_class;
#endif /* CONFIG_ANDROID */

static LIST_HEAD(extcon_dev_list);
static DEFINE_MUTEX(extcon_dev_list_lock);

/**
 * check_mutually_exclusive - Check if new_state violates mutually_exclusive
 *			      condition.
 * @edev:	the extcon device
 * @new_state:	new cable attach status for @edev
 *
 * Returns 0 if nothing violates. Returns the index + 1 for the first
 * violated condition.
 */
static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
{
	int i = 0;

	if (!edev->mutually_exclusive)
		return 0;

	for (i = 0; edev->mutually_exclusive[i]; i++) {
		int weight;
		u32 correspondants = new_state & edev->mutually_exclusive[i];

		/* calculate the total number of bits set */
		weight = hweight32(correspondants);
		if (weight > 1)
			return i + 1;
	}

	return 0;
}

static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id)
{
	int i;

	/* Find the the index of extcon cable in edev->supported_cable */
	for (i = 0; i < edev->max_supported; i++) {
		if (edev->supported_cable[i] == id)
			return i;
	}

	return -EINVAL;
}

static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
{
	unsigned int id = EXTCON_NONE;
	int i = 0;

	if (edev->max_supported == 0)
		return -EINVAL;

	/* Find the the number of extcon cable */
	while (extcon_name[i]) {
		if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
			id = i;
			break;
		}
	}

	if (id == EXTCON_NONE)
		return -EINVAL;

	return find_cable_index_by_id(edev, id);
}

static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
{
	if (((prev >> idx) & 0x1) != ((new >> idx) & 0x1)) {
		*attached = new ? true : false;
		return true;
	}

	return false;
}

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	int i, count = 0;
	struct extcon_dev *edev = dev_get_drvdata(dev);

	if (edev->print_state) {
		int ret = edev->print_state(edev, buf);

		if (ret >= 0)
			return ret;
		/* Use default if failed */
	}

	if (edev->max_supported == 0)
		return sprintf(buf, "%u\n", edev->state);

	for (i = 0; i < edev->