include/linux/serdev.h

   1 /*
   2  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 and
   6  * only version 2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13 #ifndef _LINUX_SERDEV_H
  14 #define _LINUX_SERDEV_H
  15
  16 #include <linux/types.h>
  17 #include <linux/device.h>
  18 #include <linux/termios.h>
  19 #include <linux/delay.h>
  20
  21 struct serdev_controller;
  22 struct serdev_device;
  23
  24 /*
  25  * serdev device structures
  26  */
  27
  28 /**
  29  * struct serdev_device_ops - Callback operations for a serdev device
  30  * @receive_buf:        Function called with data received from device;
  31  *                      returns number of bytes accepted; may sleep.
  32  * @write_wakeup:       Function called when ready to transmit more data; must
  33  *                      not sleep.
  34  */
  35 struct serdev_device_ops {
  36         int (*receive_buf)(struct serdev_device *, const unsigned char *, size_t);
  37         void (*write_wakeup)(struct serdev_device *);
  38 };
  39
  40 /**
  41  * struct serdev_device - Basic representation of an serdev device
  42  * @dev:        Driver model representation of the device.
  43  * @nr:         Device number on serdev bus.
  44  * @ctrl:       serdev controller managing this device.
  45  * @ops:        Device operations.
  46  * @write_comp  Completion used by serdev_device_write() internally
  47  * @write_lock  Lock to serialize access when writing data
  48  */
  49 struct serdev_device {
  50         struct device dev;
  51         int nr;
  52         struct serdev_controller *ctrl;
  53         const struct serdev_device_ops *ops;
  54         struct completion write_comp;
  55         struct mutex write_lock;
  56 };
  57
  58 static inline struct serdev_device *to_serdev_device(struct device *d)
  59 {
  60         return container_of(d, struct serdev_device, dev);
  61 }
  62
  63 /**
  64  * struct serdev_device_driver - serdev slave device driver
  65  * @driver:     serdev device drivers should initialize name field of this
  66  *              structure.
  67  * @probe:      binds this driver to a serdev device.
  68  * @remove:     unbinds this driver from the serdev device.
  69  */
  70 struct serdev_device_driver {
  71         struct device_driver driver;
  72         int     (*probe)(struct serdev_device *);
  73         void    (*remove)(struct serdev_device *);
  74 };
  75
  76 static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
  77 {
  78         return container_of(d, struct serdev_device_driver, driver);
  79 }
  80
  81 enum serdev_parity {
  82         SERDEV_PARITY_NONE,
  83         SERDEV_PARITY_EVEN,
  84         SERDEV_PARITY_ODD,
  85 };
  86
  87 /*
  88  * serdev controller structures
  89  */
  90 struct serdev_controller_ops {
  91         int (*write_buf)(struct serdev_controller *, const unsigned char *, size_t);
  92         void (*write_flush)(struct serdev_controller *);
  93         int (*write_room)(struct serdev_controller *);
  94         int (*open)(struct serdev_controller *);
  95         void (*close)(struct serdev_controller *);
  96         void (*set_flow_control)(struct serdev_controller *, bool);
  97         int (*set_parity)(struct serdev_controller *, enum serdev_parity);
  98         unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
  99         void (*wait_until_sent)(struct serdev_controller *, long);
 100         int (*get_tiocm)(struct serdev_controller *);
 101         int (*set_tiocm)(struct serdev_controller *, unsigned int, unsigned int);
 102 };
 103
 104 /**
 105  * struct serdev_controller - interface to the serdev controller
 106  * @dev:        Driver model representation of the device.
 107  * @nr:         number identifier for this controller/bus.
 108  * @serdev:     Pointer to slave device for this controller.
 109  * @ops:        Controller operations.
 110  */
 111 struct serdev_controller {
 112         struct device           dev;
 113         unsigned int            nr;
 114         struct serdev_device    *serdev;
 115         const struct serdev_controller_ops *ops;
 116 };
 117
 118 static inline struct serdev_controller *to_serdev_controller(struct device *d)
 119 {
 120         return container_of(d, struct serdev_controller, dev);
 121 }
 122
 123 static inline void *serdev_device_get_drvdata(const struct serdev_device *serdev)
 124 {
 125         return dev_get_drvdata(&serdev->dev);
 126 }
 127
 128 static inline void serdev_device_set_drvdata(struct serdev_device *serdev, void *data)
 129 {
 130         dev_set_drvdata(&serdev->dev, data);
 131 }
 132
 133 /**
 134  * serdev_device_put() - decrement serdev device refcount
 135  * @serdev      serdev device.
 136  */
 137 static inline void serdev_device_put(struct serdev_device *serdev)
 138 {
 139         if (serdev)
 140                 put_device(&serdev->dev);
 141 }
 142
 143 static inline void serdev_device_set_client_ops(struct serdev_device *serdev,
 144                                               const struct serdev_device_ops *ops)
 145 {
 146         serdev->ops = ops;
 147 }
 148
 149 static inline
 150 void *serdev_controller_get_drvdata(const struct serdev_controller *ctrl)
 151 {
 152         return ctrl ? dev_get_drvdata(&ctrl->dev) : NULL;
 153 }
 154
 155 static inline void serdev_controller_set_drvdata(struct serdev_controller *ctrl,
 156                                                void *data)
 157 {
 158         dev_set_drvdata(&ctrl->dev, data);
 159 }
 160
 161 /**
 162  * serdev_controller_put() - decrement controller refcount
 163  * @ctrl        serdev controller.
 164  */
 165 static inline void serdev_controller_put(struct serdev_controller *ctrl)
 166 {
 167         if (ctrl)
 168                 put_device(&ctrl->dev);
 169 }
 170
 171 struct serdev_device *serdev_device_alloc(struct serdev_controller *);
 172 int serdev_device_add(struct serdev_device *);
 173 void serdev_device_remove(struct serdev_device *);
 174
 175 struct serdev_controller *serdev_controller_alloc(struct device *, size_t);
 176 int serdev_controller_add(struct serdev_controller *);
 177 void serdev_controller_remove(struct serdev_controller *);
 178
 179 static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl)
 180 {
 181         struct serdev_device *serdev = ctrl->serdev;
 182
 183         if (!serdev || !serdev->ops->write_wakeup)
 184                 return;
 185
 186         serdev->ops->write_wakeup(serdev);
 187 }
 188
 189 static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
 190                                               const unsigned char *data,
 191                                               size_t count)
 192 {
 193         struct serdev_device *serdev = ctrl->serdev;
 194
 195         if (!serdev || !serdev->ops->receive_buf)
 196                 return 0;
 197
 198         return serdev->ops->receive_buf(serdev, data, count);
 199 }
 200
 201 #if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
 202
 203 int serdev_device_open(struct serdev_device *);
 204 void serdev_device_close(struct serdev_device *);
 205 int devm_serdev_device_open(struct device *, struct serdev_device *);
 206 unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
 207 void serdev_device_set_flow_control(struct serdev_device *, bool);
 208 int serdev_device_write_buf(struct serdev_device *, const unsigned char *, size_t);
 209 void serdev_device_wait_until_sent(struct serdev_device *, long);
 210 int serdev_device_get_tiocm(struct serdev_device *);
 211 int serdev_device_set_tiocm(struct serdev_device *, int, int);
 212 void serdev_device_write_wakeup(struct serdev_device *);
 213 int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, unsigned long);
 214 void serdev_device_write_flush(struct serdev_device *);
 215 int serdev_device_write_room(struct serdev_device *);
 216
 217 /*
 218  * serdev device driver functions
 219  */
 220 int __serdev_device_driver_register(struct serdev_device_driver *, struct module *);
 221 #define serdev_device_driver_register(sdrv) \
 222         __serdev_device_driver_register(sdrv, THIS_MODULE)
 223
 224 /**
 225  * serdev_device_driver_unregister() - unregister an serdev client driver
 226  * @sdrv:       the driver to unregister
 227  */
 228 static inline void serdev_device_driver_unregister(struct serdev_device_driver *sdrv)
 229 {
 230         if (sdrv)
 231                 driver_unregister(&sdrv->driver);
 232 }
 233
 234 #define module_serdev_device_driver(__serdev_device_driver) \
 235         module_driver(__serdev_device_driver, serdev_device_driver_register, \
 236                         serdev_device_driver_unregister)
 237
 238 #else
 239
 240 static inline int serdev_device_open(struct serdev_device *sdev)
 241 {
 242         return -ENODEV;
 243 }
 244 static inline void serdev_device_close(struct serdev_device *sdev) {}
 245 static inline unsigned int serdev_device_set_baudrate(struct serdev_device *sdev, unsigned int baudrate)
 246 {
 247         return 0;
 248 }
 249 static inline void serdev_device_set_flow_control(struct serdev_device *sdev, bool enable) {}
 250 static inline int serdev_device_write_buf(struct serdev_device *serdev,
 251                                           const unsigned char *buf,
 252                                           size_t count)
 253 {
 254         return -ENODEV;
 255 }
 256 static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, long timeout) {}
 257 static inline int serdev_device_get_tiocm(struct serdev_device *serdev)
 258 {
 259         return -ENOTSUPP;
 260 }
 261 static inline int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 262 {
 263         return -ENOTSUPP;
 264 }
 265 static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf,
 266                                       size_t count, unsigned long timeout)
 267 {
 268         return -ENODEV;
 269 }
 270 static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
 271 static inline int serdev_device_write_room(struct serdev_device *sdev)
 272 {
 273         return 0;
 274 }
 275
 276 #define serdev_device_driver_register(x)
 277 #define serdev_device_driver_unregister(x)
 278
 279 #endif /* CONFIG_SERIAL_DEV_BUS */
 280
 281 static inline bool serdev_device_get_cts(struct serdev_device *serdev)
 282 {
 283         int status = serdev_device_get_tiocm(serdev);
 284         return !!(status & TIOCM_CTS);
 285 }
 286
 287 static inline int serdev_device_wait_for_cts(struct serdev_device *serdev, bool state, int timeout_ms)
 288 {
 289         unsigned long timeout;
 290         bool signal;
 291
 292         timeout = jiffies + msecs_to_jiffies(timeout_ms);
 293         while (time_is_after_jiffies(timeout)) {
 294                 signal = serdev_device_get_cts(serdev);
 295                 if (signal == state)
 296                         return 0;
 297                 usleep_range(1000, 2000);
 298         }
 299
 300         return -ETIMEDOUT;
 301 }
 302
 303 static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enable)
 304 {
 305         if (enable)
 306                 return serdev_device_set_tiocm(serdev, TIOCM_RTS, 0);
 307         else
 308                 return serdev_device_set_tiocm(serdev, 0, TIOCM_RTS);
 309 }
 310
 311 int serdev_device_set_parity(struct serdev_device *serdev,
 312                              enum serdev_parity parity);
 313
 314 /*
 315  * serdev hooks into TTY core
 316  */
 317 struct tty_port;
 318 struct tty_driver;
 319
 320 #ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
 321 struct device *serdev_tty_port_register(struct tty_port *port,
 322                                         struct device *parent,
 323                                         struct tty_driver *drv, int idx);
 324 int serdev_tty_port_unregister(struct tty_port *port);
 325 #else
 326 static inline struct device *serdev_tty_port_register(struct tty_port *port,
 327                                            struct device *parent,
 328                                            struct tty_driver *drv, int idx)
 329 {
 330         return ERR_PTR(-ENODEV);
 331 }
 332 static inline int serdev_tty_port_unregister(struct tty_port *port)
 333 {
 334         return -ENODEV;
 335 }
 336 #endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
 337
 338 #endif /*_LINUX_SERDEV_H */