include/linux/serdev.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   4  */
   5 #ifndef _LINUX_SERDEV_H
   6 #define _LINUX_SERDEV_H
   7
   8 #include <linux/types.h>
   9 #include <linux/device.h>
  10 #include <linux/termios.h>
  11 #include <linux/delay.h>
  12
  13 struct serdev_controller;
  14 struct serdev_device;
  15
  16 /*
  17  * serdev device structures
  18  */
  19
  20 /**
  21  * struct serdev_device_ops - Callback operations for a serdev device
  22  * @receive_buf:        Function called with data received from device;
  23  *                      returns number of bytes accepted; may sleep.
  24  * @write_wakeup:       Function called when ready to transmit more data; must
  25  *                      not sleep.
  26  */
  27 struct serdev_device_ops {
  28         int (*receive_buf)(struct serdev_device *, const unsigned char *, size_t);
  29         void (*write_wakeup)(struct serdev_device *);
  30 };
  31
  32 /**
  33  * struct serdev_device - Basic representation of an serdev device
  34  * @dev:        Driver model representation of the device.
  35  * @nr:         Device number on serdev bus.
  36  * @ctrl:       serdev controller managing this device.
  37  * @ops:        Device operations.
  38  * @write_comp  Completion used by serdev_device_write() internally
  39  * @write_lock  Lock to serialize access when writing data
  40  */
  41 struct serdev_device {
  42         struct device dev;
  43         int nr;
  44         struct serdev_controller *ctrl;
  45         const struct serdev_device_ops *ops;
  46         struct completion write_comp;
  47         struct mutex write_lock;
  48 };
  49
  50 static inline struct serdev_device *to_serdev_device(struct device *d)
  51 {
  52         return container_of(d, struct serdev_device, dev);
  53 }
  54
  55 /**
  56  * struct serdev_device_driver - serdev slave device driver
  57  * @driver:     serdev device drivers should initialize name field of this
  58  *              structure.
  59  * @probe:      binds this driver to a serdev device.
  60  * @remove:     unbinds this driver from the serdev device.
  61  */
  62 struct serdev_device_driver {
  63         struct device_driver driver;
  64         int     (*probe)(struct serdev_device *);
  65         void    (*remove)(struct serdev_device *);
  66 };
  67
  68 static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
  69 {
  70         return container_of(d, struct serdev_device_driver, driver);
  71 }
  72
  73 enum serdev_parity {
  74         SERDEV_PARITY_NONE,
  75         SERDEV_PARITY_EVEN,
  76         SERDEV_PARITY_ODD,
  77 };
  78
  79 /*
  80  * serdev controller structures
  81  */
  82 struct serdev_controller_ops {
  83         int (*write_buf)(struct serdev_controller *, const unsigned char *, size_t);
  84         void (*write_flush)(struct serdev_controller *);
  85         int (*write_room)(struct serdev_controller *);
  86         int (*open)(struct serdev_controller *);
  87         void (*close)(struct serdev_controller *);
  88         void (*set_flow_control)(struct serdev_controller *, bool);
  89         int (*set_parity)(struct serdev_controller *, enum serdev_parity);
  90         unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
  91         void (*wait_until_sent)(struct serdev_controller *, long);
  92         int (*get_tiocm)(struct serdev_controller *);
  93         int (*set_tiocm)(struct serdev_controller *, unsigned int, unsigned int);
  94 };
  95
  96 /**
  97  * struct serdev_controller - interface to the serdev controller
  98  * @dev:        Driver model representation of the device.
  99  * @nr:         number identifier for this controller/bus.
 100  * @serdev:     Pointer to slave device for this controller.
 101  * @ops:        Controller operations.
 102  */
 103 struct serdev_controller {
 104         struct device           dev;
 105         unsigned int            nr;
 106         struct serdev_device    *serdev;
 107         const struct serdev_controller_ops *ops;
 108 };
 109
 110 static inline struct serdev_controller *to_serdev_controller(struct device *d)
 111 {
 112         return container_of(d, struct serdev_controller, dev);
 113 }
 114
 115 static inline void *serdev_device_get_drvdata(const struct serdev_device *serdev)
 116 {
 117         return dev_get_drvdata(&serdev->dev);
 118 }
 119
 120 static inline void serdev_device_set_drvdata(struct serdev_device *serdev, void *data)
 121 {
 122         dev_set_drvdata(&serdev->dev, data);
 123 }
 124
 125 /**
 126  * serdev_device_put() - decrement serdev device refcount
 127  * @serdev      serdev device.
 128  */
 129 static inline void serdev_device_put(struct serdev_device *serdev)
 130 {
 131         if (serdev)
 132                 put_device(&serdev->dev);
 133 }
 134
 135 static inline void serdev_device_set_client_ops(struct serdev_device *serdev,
 136                                               const struct serdev_device_ops *ops)
 137 {
 138         serdev->ops = ops;
 139 }
 140
 141 static inline
 142 void *serdev_controller_get_drvdata(const struct serdev_controller *ctrl)
 143 {
 144         return ctrl ? dev_get_drvdata(&ctrl->dev) : NULL;
 145 }
 146
 147 static inline void serdev_controller_set_drvdata(struct serdev_controller *ctrl,
 148                                                void *data)
 149 {
 150         dev_set_drvdata(&ctrl->dev, data);
 151 }
 152
 153 /**
 154  * serdev_controller_put() - decrement controller refcount
 155  * @ctrl        serdev controller.
 156  */
 157 static inline void serdev_controller_put(struct serdev_controller *ctrl)
 158 {
 159         if (ctrl)
 160                 put_device(&ctrl->dev);
 161 }
 162
 163 struct serdev_device *serdev_device_alloc(struct serdev_controller *);
 164 int serdev_device_add(struct serdev_device *);
 165 void serdev_device_remove(struct serdev_device *);
 166
 167 struct serdev_controller *serdev_controller_alloc(struct device *, size_t);
 168 int serdev_controller_add(struct serdev_controller *);
 169 void serdev_controller_remove(struct serdev_controller *);
 170
 171 static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl)
 172 {
 173         struct serdev_device *serdev = ctrl->serdev;
 174
 175         if (!serdev || !serdev->ops->write_wakeup)
 176                 return;
 177
 178         serdev->ops->write_wakeup(serdev);
 179 }
 180
 181 static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
 182                                               const unsigned char *data,
 183                                               size_t count)
 184 {
 185         struct serdev_device *serdev = ctrl->serdev;
 186
 187         if (!serdev || !serdev->ops->receive_buf)
 188                 return 0;
 189
 190         return serdev->ops->receive_buf(serdev, data, count);
 191 }
 192
 193 #if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
 194
 195 int serdev_device_open(struct serdev_device *);
 196 void serdev_device_close(struct serdev_device *);
 197 int devm_serdev_device_open(struct device *, struct serdev_device *);
 198 unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
 199 void serdev_device_set_flow_control(struct serdev_device *, bool);
 200 int serdev_device_write_buf(struct serdev_device *, const unsigned char *, size_t);
 201 void serdev_device_wait_until_sent(struct serdev_device *, long);
 202 int serdev_device_get_tiocm(struct serdev_device *);
 203 int serdev_device_set_tiocm(struct serdev_device *, int, int);
 204 void serdev_device_write_wakeup(struct serdev_device *);
 205 int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, long);
 206 void serdev_device_write_flush(struct serdev_device *);
 207 int serdev_device_write_room(struct serdev_device *);
 208
 209 /*
 210  * serdev device driver functions
 211  */
 212 int __serdev_device_driver_register(struct serdev_device_driver *, struct module *);
 213 #define serdev_device_driver_register(sdrv) \
 214         __serdev_device_driver_register(sdrv, THIS_MODULE)
 215
 216 /**
 217  * serdev_device_driver_unregister() - unregister an serdev client driver
 218  * @sdrv:       the driver to unregister
 219  */
 220 static inline void serdev_device_driver_unregister(struct serdev_device_driver *sdrv)
 221 {
 222         if (sdrv)
 223                 driver_unregister(&sdrv->driver);
 224 }
 225
 226 #define module_serdev_device_driver(__serdev_device_driver) \
 227         module_driver(__serdev_device_driver, serdev_device_driver_register, \
 228                         serdev_device_driver_unregister)
 229
 230 #else
 231
 232 static inline int serdev_device_open(struct serdev_device *sdev)
 233 {
 234         return -ENODEV;
 235 }
 236 static inline void serdev_device_close(struct serdev_device *sdev) {}
 237 static inline unsigned int serdev_device_set_baudrate(struct serdev_device *sdev, unsigned int baudrate)
 238 {
 239         return 0;
 240 }
 241 static inline void serdev_device_set_flow_control(struct serdev_device *sdev, bool enable) {}
 242 static inline int serdev_device_write_buf(struct serdev_device *serdev,
 243                                           const unsigned char *buf,
 244                                           size_t count)
 245 {
 246         return -ENODEV;
 247 }
 248 static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, long timeout) {}
 249 static inline int serdev_device_get_tiocm(struct serdev_device *serdev)
 250 {
 251         return -ENOTSUPP;
 252 }
 253 static inline int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 254 {
 255         return -ENOTSUPP;
 256 }
 257 static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf,
 258                                       size_t count, unsigned long timeout)
 259 {
 260         return -ENODEV;
 261 }
 262 static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
 263 static inline int serdev_device_write_room(struct serdev_device *sdev)
 264 {
 265         return 0;
 266 }
 267
 268 #define serdev_device_driver_register(x)
 269 #define serdev_device_driver_unregister(x)
 270
 271 #endif /* CONFIG_SERIAL_DEV_BUS */
 272
 273 static inline bool serdev_device_get_cts(struct serdev_device *serdev)
 274 {
 275         int status = serdev_device_get_tiocm(serdev);
 276         return !!(status & TIOCM_CTS);
 277 }
 278
 279 static inline int serdev_device_wait_for_cts(struct serdev_device *serdev, bool state, int timeout_ms)
 280 {
 281         unsigned long timeout;
 282         bool signal;
 283
 284         timeout = jiffies + msecs_to_jiffies(timeout_ms);
 285         while (time_is_after_jiffies(timeout)) {
 286                 signal = serdev_device_get_cts(serdev);
 287                 if (signal == state)
 288                         return 0;
 289                 usleep_range(1000, 2000);
 290         }
 291
 292         return -ETIMEDOUT;
 293 }
 294
 295 static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enable)
 296 {
 297         if (enable)
 298                 return serdev_device_set_tiocm(serdev, TIOCM_RTS, 0);
 299         else
 300                 return serdev_device_set_tiocm(serdev, 0, TIOCM_RTS);
 301 }
 302
 303 int serdev_device_set_parity(struct serdev_device *serdev,
 304                              enum serdev_parity parity);
 305
 306 /*
 307  * serdev hooks into TTY core
 308  */
 309 struct tty_port;
 310 struct tty_driver;
 311
 312 #ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
 313 struct device *serdev_tty_port_register(struct tty_port *port,
 314                                         struct device *parent,
 315                                         struct tty_driver *drv, int idx);
 316 int serdev_tty_port_unregister(struct tty_port *port);
 317 #else
 318 static inline struct device *serdev_tty_port_register(struct tty_port *port,
 319                                            struct device *parent,
 320                                            struct tty_driver *drv, int idx)
 321 {
 322         return ERR_PTR(-ENODEV);
 323 }
 324 static inline int serdev_tty_port_unregister(struct tty_port *port)
 325 {
 326         return -ENODEV;
 327 }
 328 #endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
 329
 330 #endif /*_LINUX_SERDEV_H */