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