include/linux/extcon.h

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