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