linux/include/linux/extcon.h
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   1/*
   2 *  External connector (extcon) class driver
   3 *
   4 * Copyright (C) 2012 Samsung Electronics
   5 * Author: Donggeun Kim <dg77.kim@samsung.com>
   6 * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
   7 *
   8 * based on switch class driver
   9 * Copyright (C) 2008 Google, Inc.
  10 * Author: Mike Lockwood <lockwood@android.com>
  11 *
  12 * This software is licensed under the terms of the GNU General Public
  13 * License version 2, as published by the Free Software Foundation, and
  14 * may be copied, distributed, and modified under those terms.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21*/
  22
  23#ifndef __LINUX_EXTCON_H__
  24#define __LINUX_EXTCON_H__
  25
  26#include <linux/device.h>
  27#include <linux/notifier.h>
  28#include <linux/sysfs.h>
  29
  30#define SUPPORTED_CABLE_MAX     32
  31#define CABLE_NAME_MAX          30
  32
  33/*
  34 * The standard cable name is to help support general notifier
  35 * and notifiee device drivers to share the common names.
  36 * Please use standard cable names unless your notifier device has
  37 * a very unique and abnormal cable or
  38 * the cable type is supposed to be used with only one unique
  39 * pair of notifier/notifiee devices.
  40 *
  41 * Please add any other "standard" cables used with extcon dev.
  42 *
  43 * You may add a dot and number to specify version or specification
  44 * of the specific cable if it is required. (e.g., "Fast-charger.18"
  45 * and "Fast-charger.10" for 1.8A and 1.0A chargers)
  46 * However, the notifiee and notifier should be able to handle such
  47 * string and if the notifiee can negotiate the protocol or identify,
  48 * you don't need such convention. This convention is helpful when
  49 * notifier can distinguish but notifiee cannot.
  50 */
  51enum extcon_cable_name {
  52        EXTCON_USB = 0,
  53        EXTCON_USB_HOST,
  54        EXTCON_TA, /* Travel Adaptor */
  55        EXTCON_FAST_CHARGER,
  56        EXTCON_SLOW_CHARGER,
  57        EXTCON_CHARGE_DOWNSTREAM, /* Charging an external device */
  58        EXTCON_HDMI,
  59        EXTCON_MHL,
  60        EXTCON_DVI,
  61        EXTCON_VGA,
  62        EXTCON_DOCK,
  63        EXTCON_LINE_IN,
  64        EXTCON_LINE_OUT,
  65        EXTCON_MIC_IN,
  66        EXTCON_HEADPHONE_OUT,
  67        EXTCON_SPDIF_IN,
  68        EXTCON_SPDIF_OUT,
  69        EXTCON_VIDEO_IN,
  70        EXTCON_VIDEO_OUT,
  71        EXTCON_MECHANICAL,
  72};
  73extern const char extcon_cable_name[][CABLE_NAME_MAX + 1];
  74
  75struct extcon_cable;
  76
  77/**
  78 * struct extcon_dev - An extcon device represents one external connector.
  79 * @name:       The name of this extcon device. Parent device name is used
  80 *              if NULL.
  81 * @supported_cable:    Array of supported cable names ending with NULL.
  82 *                      If supported_cable is NULL, cable name related APIs
  83 *                      are disabled.
  84 * @mutually_exclusive: Array of mutually exclusive set of cables that cannot
  85 *                      be attached simultaneously. The array should be
  86 *                      ending with NULL or be NULL (no mutually exclusive
  87 *                      cables). For example, if it is { 0x7, 0x30, 0}, then,
  88 *                      {0, 1}, {0, 1, 2}, {0, 2}, {1, 2}, or {4, 5} cannot
  89 *                      be attached simulataneously. {0x7, 0} is equivalent to
  90 *                      {0x3, 0x6, 0x5, 0}. If it is {0xFFFFFFFF, 0}, there
  91 *                      can be no simultaneous connections.
  92 * @print_name: An optional callback to override the method to print the
  93 *              name of the extcon device.
  94 * @print_state:        An optional callback to override the method to print the
  95 *              status of the extcon device.
  96 * @dev:        Device of this extcon. Do not provide at register-time.
  97 * @state:      Attach/detach state of this extcon. Do not provide at
  98 *              register-time
  99 * @nh: Notifier for the state change events from this extcon
 100 * @entry:      To support list of extcon devices so that users can search
 101 *              for extcon devices based on the extcon name.
 102 * @lock:
 103 * @max_supported:      Internal value to store the number of cables.
 104 * @extcon_dev_type:    Device_type struct to provide attribute_groups
 105 *                      customized for each extcon device.
 106 * @cables:     Sysfs subdirectories. Each represents one cable.
 107 *
 108 * In most cases, users only need to provide "User initializing data" of
 109 * this struct when registering an extcon. In some exceptional cases,
 110 * optional callbacks may be needed. However, the values in "internal data"
 111 * are overwritten by register function.
 112 */
 113struct extcon_dev {
 114        /* --- Optional user initializing data --- */
 115        const char      *name;
 116        const char **supported_cable;
 117        const u32       *mutually_exclusive;
 118
 119        /* --- Optional callbacks to override class functions --- */
 120        ssize_t (*print_name)(struct extcon_dev *edev, char *buf);
 121        ssize_t (*print_state)(struct extcon_dev *edev, char *buf);
 122
 123        /* --- Internal data. Please do not set. --- */
 124        struct device   *dev;
 125        u32             state;
 126        struct raw_notifier_head nh;
 127        struct list_head entry;
 128        spinlock_t lock; /* could be called by irq handler */
 129        int max_supported;
 130
 131        /* /sys/class/extcon/.../cable.n/... */
 132        struct device_type extcon_dev_type;
 133        struct extcon_cable *cables;
 134        /* /sys/class/extcon/.../mutually_exclusive/... */
 135        struct attribute_group attr_g_muex;
 136        struct attribute **attrs_muex;
 137        struct device_attribute *d_attrs_muex;
 138};
 139
 140/**
 141 * struct extcon_cable  - An internal data for each cable of extcon device.
 142 * @edev:       The extcon device
 143 * @cable_index:        Index of this cable in the edev
 144 * @attr_g:     Attribute group for the cable
 145 * @attr_name:  "name" sysfs entry
 146 * @attr_state: "state" sysfs entry
 147 * @attrs:      Array pointing to attr_name and attr_state for attr_g
 148 */
 149struct extcon_cable {
 150        struct extcon_dev *edev;
 151        int cable_index;
 152
 153        struct attribute_group attr_g;
 154        struct device_attribute attr_name;
 155        struct device_attribute attr_state;
 156
 157        struct attribute *attrs[3]; /* to be fed to attr_g.attrs */
 158};
 159
 160/**
 161 * struct extcon_specific_cable_nb - An internal data for
 162 *                              extcon_register_interest().
 163 * @internal_nb:        a notifier block bridging extcon notifier and cable notifier.
 164 * @user_nb:    user provided notifier block for events from a specific cable.
 165 * @cable_index:        the target cable.
 166 * @edev:       the target extcon device.
 167 * @previous_value:     the saved previous event value.
 168 */
 169struct extcon_specific_cable_nb {
 170        struct notifier_block internal_nb;
 171        struct notifier_block *user_nb;
 172        int cable_index;
 173        struct extcon_dev *edev;
 174        unsigned long previous_value;
 175};
 176
 177#if IS_ENABLED(CONFIG_EXTCON)
 178
 179/*
 180 * Following APIs are for notifiers or configurations.
 181 * Notifiers are the external port and connection devices.
 182 */
 183extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
 184extern void extcon_dev_unregister(struct extcon_dev *edev);
 185extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
 186
 187/*
 188 * get/set/update_state access the 32b encoded state value, which represents
 189 * states of all possible cables of the multistate port. For example, if one
 190 * calls extcon_set_state(edev, 0x7), it may mean that all the three cables
 191 * are attached to the port.
 192 */
 193static inline u32 extcon_get_state(struct extcon_dev *edev)
 194{
 195        return edev->state;
 196}
 197
 198extern int extcon_set_state(struct extcon_dev *edev, u32 state);
 199extern int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state);
 200
 201/*
 202 * get/set_cable_state access each bit of the 32b encoded state value.
 203 * They are used to access the status of each cable based on the cable_name
 204 * or cable_index, which is retrieved by extcon_find_cable_index
 205 */
 206extern int extcon_find_cable_index(struct extcon_dev *sdev,
 207                                   const char *cable_name);
 208extern int extcon_get_cable_state_(struct extcon_dev *edev, int cable_index);
 209extern int extcon_set_cable_state_(struct extcon_dev *edev, int cable_index,
 210                                   bool cable_state);
 211
 212extern int extcon_get_cable_state(struct extcon_dev *edev,
 213                                  const char *cable_name);
 214extern int extcon_set_cable_state(struct extcon_dev *edev,
 215                                  const char *cable_name, bool cable_state);
 216
 217/*
 218 * Following APIs are for notifiees (those who want to be notified)
 219 * to register a callback for events from a specific cable of the extcon.
 220 * Notifiees are the connected device drivers wanting to get notified by
 221 * a specific external port of a connection device.
 222 */
 223extern int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 224                                    const char *extcon_name,
 225                                    const char *cable_name,
 226                                    struct notifier_block *nb);
 227extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb);
 228
 229/*
 230 * Following APIs are to monitor every action of a notifier.
 231 * Registrar gets notified for every external port of a connection device.
 232 * Probably this could be used to debug an action of notifier; however,
 233 * we do not recommend to use this for normal 'notifiee' device drivers who
 234 * want to be notified by a specific external port of the notifier.
 235 */
 236extern int extcon_register_notifier(struct extcon_dev *edev,
 237                                    struct notifier_block *nb);
 238extern int extcon_unregister_notifier(struct extcon_dev *edev,
 239                                      struct notifier_block *nb);
 240#else /* CONFIG_EXTCON */
 241static inline int extcon_dev_register(struct extcon_dev *edev,
 242                                      struct device *dev)
 243{
 244        return 0;
 245}
 246
 247static inline void extcon_dev_unregister(struct extcon_dev *edev) { }
 248
 249static inline u32 extcon_get_state(struct extcon_dev *edev)
 250{
 251        return 0;
 252}
 253
 254static inline int extcon_set_state(struct extcon_dev *edev, u32 state)
 255{
 256        return 0;
 257}
 258
 259static inline int extcon_update_state(struct extcon_dev *edev, u32 mask,
 260                                       u32 state)
 261{
 262        return 0;
 263}
 264
 265static inline int extcon_find_cable_index(struct extcon_dev *edev,
 266                                          const char *cable_name)
 267{
 268        return 0;
 269}
 270
 271static inline int extcon_get_cable_state_(struct extcon_dev *edev,
 272                                          int cable_index)
 273{
 274        return 0;
 275}
 276
 277static inline int extcon_set_cable_state_(struct extcon_dev *edev,
 278                                          int cable_index, bool cable_state)
 279{
 280        return 0;
 281}
 282
 283static inline int extcon_get_cable_state(struct extcon_dev *edev,
 284                        const char *cable_name)
 285{
 286        return 0;
 287}
 288
 289static inline int extcon_set_cable_state(struct extcon_dev *edev,
 290                        const char *cable_name, int state)
 291{
 292        return 0;
 293}
 294
 295static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 296{
 297        return NULL;
 298}
 299
 300static inline int extcon_register_notifier(struct extcon_dev *edev,
 301                                           struct notifier_block *nb)
 302{
 303        return 0;
 304}
 305
 306static inline int extcon_unregister_notifier(struct extcon_dev *edev,
 307                                             struct notifier_block *nb)
 308{
 309        return 0;
 310}
 311
 312static inline int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 313                                           const char *extcon_name,
 314                                           const char *cable_name,
 315                                           struct notifier_block *nb)
 316{
 317        return 0;
 318}
 319
 320static inline int extcon_unregister_interest(struct extcon_specific_cable_nb
 321                                                    *obj)
 322{
 323        return 0;
 324}
 325#endif /* CONFIG_EXTCON */
 326#endif /* __LINUX_EXTCON_H__ */
 327
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