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/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  */
  51 enum 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 };
  73 extern const char extcon_cable_name[][CABLE_NAME_MAX + 1];
  74
  75 struct 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  */
 113 struct 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  */
 149 struct 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  */
 169 struct 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  */
 183 extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
 184 extern void extcon_dev_unregister(struct extcon_dev *edev);
 185 extern 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  */
 193 static inline u32 extcon_get_state(struct extcon_dev *edev)
 194 {
 195         return edev->state;
 196 }
 197
 198 extern int extcon_set_state(struct extcon_dev *edev, u32 state);
 199 extern 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  */
 206 extern int extcon_find_cable_index(struct extcon_dev *sdev,
 207                                    const char *cable_name);
 208 extern int extcon_get_cable_state_(struct extcon_dev *edev, int cable_index);
 209 extern int extcon_set_cable_state_(struct extcon_dev *edev, int cable_index,
 210                                    bool cable_state);
 211
 212 extern int extcon_get_cable_state(struct extcon_dev *edev,
 213                                   const char *cable_name);
 214 extern 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  */
 223 extern 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);
 227 extern 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  */
 236 extern int extcon_register_notifier(struct extcon_dev *edev,
 237                                     struct notifier_block *nb);
 238 extern int extcon_unregister_notifier(struct extcon_dev *edev,
 239                                       struct notifier_block *nb);
 240 #else /* CONFIG_EXTCON */
 241 static inline int extcon_dev_register(struct extcon_dev *edev,
 242                                       struct device *dev)
 243 {
 244         return 0;
 245 }
 246
 247 static inline void extcon_dev_unregister(struct extcon_dev *edev) { }
 248
 249 static inline u32 extcon_get_state(struct extcon_dev *edev)
 250 {
 251         return 0;
 252 }
 253
 254 static inline int extcon_set_state(struct extcon_dev *edev, u32 state)
 255 {
 256         return 0;
 257 }
 258
 259 static inline int extcon_update_state(struct extcon_dev *edev, u32 mask,
 260                                        u32 state)
 261 {
 262         return 0;
 263 }
 264
 265 static inline int extcon_find_cable_index(struct extcon_dev *edev,
 266                                           const char *cable_name)
 267 {
 268         return 0;
 269 }
 270
 271 static inline int extcon_get_cable_state_(struct extcon_dev *edev,
 272                                           int cable_index)
 273 {
 274         return 0;
 275 }
 276
 277 static inline int extcon_set_cable_state_(struct extcon_dev *edev,
 278                                           int cable_index, bool cable_state)
 279 {
 280         return 0;
 281 }
 282
 283 static inline int extcon_get_cable_state(struct extcon_dev *edev,
 284                         const char *cable_name)
 285 {
 286         return 0;
 287 }
 288
 289 static inline int extcon_set_cable_state(struct extcon_dev *edev,
 290                         const char *cable_name, int state)
 291 {
 292         return 0;
 293 }
 294
 295 static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 296 {
 297         return NULL;
 298 }
 299
 300 static inline int extcon_register_notifier(struct extcon_dev *edev,
 301                                            struct notifier_block *nb)
 302 {
 303         return 0;
 304 }
 305
 306 static inline int extcon_unregister_notifier(struct extcon_dev *edev,
 307                                              struct notifier_block *nb)
 308 {
 309         return 0;
 310 }
 311
 312 static 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
 320 static 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__ */