path: root/drivers/extcon/extcon-class.c

/*
 *  drivers/extcon/extcon_class.c
 *
 *  External connector (extcon) class driver
 *
 * 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/slab.h>
#include <linux/sysfs.h>
#include <linux/of.h>

/*
 * extcon_cable_name suggests the standard cable names for commonly used
 * cable types.
 *
 * However, please do not use extcon_cable_name directly for extcon_dev
 * struct's supported_cable pointer unless your device really supports
 * every single port-type of the following cable names. Please choose cable
 * names that are actually used in your extcon device.
 */
const char extcon_cable_name[][CABLE_NAME_MAX + 1] = {
	[EXTCON_USB]		= "USB",
	[EXTCON_USB_HOST]	= "USB-Host",
	[EXTCON_TA]		= "TA",
	[EXTCON_FAST_CHARGER]	= "Fast-charger",
	[EXTCON_SLOW_CHARGER]	= "Slow-charger",
	[EXTCON_CHARGE_DOWNSTREAM]	= "Charge-downstream",
	[EXTCON_HDMI]		= "HDMI",
	[EXTCON_MHL]		= "MHL",
	[EXTCON_DVI]		= "DVI",
	[EXTCON_VGA]		= "VGA",
	[EXTCON_DOCK]		= "Dock",
	[EXTCON_LINE_IN]	= "Line-in",
	[EXTCON_LINE_OUT]	= "Line-out",
	[EXTCON_MIC_IN]		= "Microphone",
	[EXTCON_HEADPHONE_OUT]	= "Headphone",
	[EXTCON_SPDIF_IN]	= "SPDIF-in",
	[EXTCON_SPDIF_OUT]	= "SPDIF-out",
	[EXTCON_VIDEO_IN]	= "Video-in",
	[EXTCON_VIDEO_OUT]	= "Video-out",
	[EXTCON_MECHANICAL]	= "Mechanical",
};

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 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 < SUPPORTED_CABLE_MAX; i++) {
		if (!edev->supported_cable[i])
			break;
		count += sprintf(buf + count, "%s=%d\n",
				 edev->supported_cable[i],
				 !!(edev->state & (1 << i)));
	}

	return count;
}

static ssize_t state_store(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	u32 state;
	ssize_t ret = 0;
	struct extcon_dev *edev = dev_get_drvdata(dev);

	ret = sscanf(buf, "0x%x", &state);
	if (ret == 0)
		ret = -EINVAL;
	else
		ret = extcon_set_state(edev, state);

	if (ret < 0)
		return ret;

	return count;
}
static DEVICE_ATTR_RW(state);

static ssize_t name_show(struct device *dev