drivers/tty/serdev/core.c

   1 /*
   2  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   3  *
   4  * Based on drivers/spmi/spmi.c:
   5  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 and
   9  * only version 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/errno.h>
  18 #include <linux/idr.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/of_device.h>
  23 #include <linux/serdev.h>
  24 #include <linux/slab.h>
  25
  26 static bool is_registered;
  27 static DEFINE_IDA(ctrl_ida);
  28
  29 static void serdev_device_release(struct device *dev)
  30 {
  31         struct serdev_device *serdev = to_serdev_device(dev);
  32         kfree(serdev);
  33 }
  34
  35 static const struct device_type serdev_device_type = {
  36         .release        = serdev_device_release,
  37 };
  38
  39 static void serdev_ctrl_release(struct device *dev)
  40 {
  41         struct serdev_controller *ctrl = to_serdev_controller(dev);
  42         ida_simple_remove(&ctrl_ida, ctrl->nr);
  43         kfree(ctrl);
  44 }
  45
  46 static const struct device_type serdev_ctrl_type = {
  47         .release        = serdev_ctrl_release,
  48 };
  49
  50 static int serdev_device_match(struct device *dev, struct device_driver *drv)
  51 {
  52         /* TODO: ACPI and platform matching */
  53         return of_driver_match_device(dev, drv);
  54 }
  55
  56 static int serdev_uevent(struct device *dev, struct kobj_uevent_env *env)
  57 {
  58         /* TODO: ACPI and platform modalias */
  59         return of_device_uevent_modalias(dev, env);
  60 }
  61
  62 /**
  63  * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
  64  * @serdev:     serdev_device to be added
  65  */
  66 int serdev_device_add(struct serdev_device *serdev)
  67 {
  68         struct device *parent = serdev->dev.parent;
  69         int err;
  70
  71         dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
  72
  73         err = device_add(&serdev->dev);
  74         if (err < 0) {
  75                 dev_err(&serdev->dev, "Can't add %s, status %d\n",
  76                         dev_name(&serdev->dev), err);
  77                 goto err_device_add;
  78         }
  79
  80         dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
  81
  82 err_device_add:
  83         return err;
  84 }
  85 EXPORT_SYMBOL_GPL(serdev_device_add);
  86
  87 /**
  88  * serdev_device_remove(): remove an serdev device
  89  * @serdev:     serdev_device to be removed
  90  */
  91 void serdev_device_remove(struct serdev_device *serdev)
  92 {
  93         device_unregister(&serdev->dev);
  94 }
  95 EXPORT_SYMBOL_GPL(serdev_device_remove);
  96
  97 int serdev_device_open(struct serdev_device *serdev)
  98 {
  99         struct serdev_controller *ctrl = serdev->ctrl;
 100
 101         if (!ctrl || !ctrl->ops->open)
 102                 return -EINVAL;
 103
 104         return ctrl->ops->open(ctrl);
 105 }
 106 EXPORT_SYMBOL_GPL(serdev_device_open);
 107
 108 void serdev_device_close(struct serdev_device *serdev)
 109 {
 110         struct serdev_controller *ctrl = serdev->ctrl;
 111
 112         if (!ctrl || !ctrl->ops->close)
 113                 return;
 114
 115         ctrl->ops->close(ctrl);
 116 }
 117 EXPORT_SYMBOL_GPL(serdev_device_close);
 118
 119 int serdev_device_write_buf(struct serdev_device *serdev,
 120                             const unsigned char *buf, size_t count)
 121 {
 122         struct serdev_controller *ctrl = serdev->ctrl;
 123
 124         if (!ctrl || !ctrl->ops->write_buf)
 125                 return -EINVAL;
 126
 127         return ctrl->ops->write_buf(ctrl, buf, count);
 128 }
 129 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 130
 131 void serdev_device_write_flush(struct serdev_device *serdev)
 132 {
 133         struct serdev_controller *ctrl = serdev->ctrl;
 134
 135         if (!ctrl || !ctrl->ops->write_flush)
 136                 return;
 137
 138         ctrl->ops->write_flush(ctrl);
 139 }
 140 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 141
 142 int serdev_device_write_room(struct serdev_device *serdev)
 143 {
 144         struct serdev_controller *ctrl = serdev->ctrl;
 145
 146         if (!ctrl || !ctrl->ops->write_room)
 147                 return 0;
 148
 149         return serdev->ctrl->ops->write_room(ctrl);
 150 }
 151 EXPORT_SYMBOL_GPL(serdev_device_write_room);
 152
 153 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 154 {
 155         struct serdev_controller *ctrl = serdev->ctrl;
 156
 157         if (!ctrl || !ctrl->ops->set_baudrate)
 158                 return 0;
 159
 160         return ctrl->ops->set_baudrate(ctrl, speed);
 161
 162 }
 163 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 164
 165 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 166 {
 167         struct serdev_controller *ctrl = serdev->ctrl;
 168
 169         if (!ctrl || !ctrl->ops->set_flow_control)
 170                 return;
 171
 172         ctrl->ops->set_flow_control(ctrl, enable);
 173 }
 174 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 175
 176 static int serdev_drv_probe(struct device *dev)
 177 {
 178         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 179
 180         return sdrv->probe(to_serdev_device(dev));
 181 }
 182
 183 static int serdev_drv_remove(struct device *dev)
 184 {
 185         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 186
 187         sdrv->remove(to_serdev_device(dev));
 188         return 0;
 189 }
 190
 191 static ssize_t modalias_show(struct device *dev,
 192                              struct device_attribute *attr, char *buf)
 193 {
 194         ssize_t len = of_device_get_modalias(dev, buf, PAGE_SIZE - 2);
 195         buf[len] = '\n';
 196         buf[len+1] = 0;
 197         return len+1;
 198 }
 199
 200 static struct device_attribute serdev_device_attrs[] = {
 201         __ATTR_RO(modalias),
 202         __ATTR_NULL
 203 };
 204
 205 static struct bus_type serdev_bus_type = {
 206         .name           = "serial",
 207         .match          = serdev_device_match,
 208         .probe          = serdev_drv_probe,
 209         .remove         = serdev_drv_remove,
 210         .uevent         = serdev_uevent,
 211         .dev_attrs      = serdev_device_attrs,
 212 };
 213
 214 /**
 215  * serdev_controller_alloc() - Allocate a new serdev device
 216  * @ctrl:       associated controller
 217  *
 218  * Caller is responsible for either calling serdev_device_add() to add the
 219  * newly allocated controller, or calling serdev_device_put() to discard it.
 220  */
 221 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 222 {
 223         struct serdev_device *serdev;
 224
 225         serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 226         if (!serdev)
 227                 return NULL;
 228
 229         serdev->ctrl = ctrl;
 230         ctrl->serdev = serdev;
 231         device_initialize(&serdev->dev);
 232         serdev->dev.parent = &ctrl->dev;
 233         serdev->dev.bus = &serdev_bus_type;
 234         serdev->dev.type = &serdev_device_type;
 235         return serdev;
 236 }
 237 EXPORT_SYMBOL_GPL(serdev_device_alloc);
 238
 239 /**
 240  * serdev_controller_alloc() - Allocate a new serdev controller
 241  * @parent:     parent device
 242  * @size:       size of private data
 243  *
 244  * Caller is responsible for either calling serdev_controller_add() to add the
 245  * newly allocated controller, or calling serdev_controller_put() to discard it.
 246  * The allocated private data region may be accessed via
 247  * serdev_controller_get_drvdata()
 248  */
 249 struct serdev_controller *serdev_controller_alloc(struct device *parent,
 250                                               size_t size)
 251 {
 252         struct serdev_controller *ctrl;
 253         int id;
 254
 255         if (WARN_ON(!parent))
 256                 return NULL;
 257
 258         ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 259         if (!ctrl)
 260                 return NULL;
 261
 262         device_initialize(&ctrl->dev);
 263         ctrl->dev.type = &serdev_ctrl_type;
 264         ctrl->dev.bus = &serdev_bus_type;
 265         ctrl->dev.parent = parent;
 266         ctrl->dev.of_node = parent->of_node;
 267         serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 268
 269         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 270         if (id < 0) {
 271                 dev_err(parent,
 272                         "unable to allocate serdev controller identifier.\n");
 273                 serdev_controller_put(ctrl);
 274                 return NULL;
 275         }
 276
 277         ctrl->nr = id;
 278         dev_set_name(&ctrl->dev, "serial%d", id);
 279
 280         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 281         return ctrl;
 282 }
 283 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 284
 285 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 286 {
 287         struct device_node *node;
 288         struct serdev_device *serdev = NULL;
 289         int err;
 290         bool found = false;
 291
 292         for_each_available_child_of_node(ctrl->dev.of_node, node) {
 293                 if (!of_get_property(node, "compatible", NULL))
 294                         continue;
 295
 296                 dev_dbg(&ctrl->dev, "adding child %s\n", node->full_name);
 297
 298                 serdev = serdev_device_alloc(ctrl);
 299                 if (!serdev)
 300                         continue;
 301
 302                 serdev->dev.of_node = node;
 303
 304                 err = serdev_device_add(serdev);
 305                 if (err) {
 306                         dev_err(&serdev->dev,
 307                                 "failure adding device. status %d\n", err);
 308                         serdev_device_put(serdev);
 309                 } else
 310                         found = true;
 311         }
 312         if (!found)
 313                 return -ENODEV;
 314
 315         return 0;
 316 }
 317
 318 /**
 319  * serdev_controller_add() - Add an serdev controller
 320  * @ctrl:       controller to be registered.
 321  *
 322  * Register a controller previously allocated via serdev_controller_alloc() with
 323  * the serdev core.
 324  */
 325 int serdev_controller_add(struct serdev_controller *ctrl)
 326 {
 327         int ret;
 328
 329         /* Can't register until after driver model init */
 330         if (WARN_ON(!is_registered))
 331                 return -EAGAIN;
 332
 333         ret = device_add(&ctrl->dev);
 334         if (ret)
 335                 return ret;
 336
 337         ret = of_serdev_register_devices(ctrl);
 338         if (ret)
 339                 goto out_dev_del;
 340
 341         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 342                 ctrl->nr, &ctrl->dev);
 343         return 0;
 344
 345 out_dev_del:
 346         device_del(&ctrl->dev);
 347         return ret;
 348 };
 349 EXPORT_SYMBOL_GPL(serdev_controller_add);
 350
 351 /* Remove a device associated with a controller */
 352 static int serdev_remove_device(struct device *dev, void *data)
 353 {
 354         struct serdev_device *serdev = to_serdev_device(dev);
 355         if (dev->type == &serdev_device_type)
 356                 serdev_device_remove(serdev);
 357         return 0;
 358 }
 359
 360 /**
 361  * serdev_controller_remove(): remove an serdev controller
 362  * @ctrl:       controller to remove
 363  *
 364  * Remove a serdev controller.  Caller is responsible for calling
 365  * serdev_controller_put() to discard the allocated controller.
 366  */
 367 void serdev_controller_remove(struct serdev_controller *ctrl)
 368 {
 369         int dummy;
 370
 371         if (!ctrl)
 372                 return;
 373
 374         dummy = device_for_each_child(&ctrl->dev, NULL,
 375                                       serdev_remove_device);
 376         device_del(&ctrl->dev);
 377 }
 378 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 379
 380 /**
 381  * serdev_driver_register() - Register client driver with serdev core
 382  * @sdrv:       client driver to be associated with client-device.
 383  *
 384  * This API will register the client driver with the serdev framework.
 385  * It is typically called from the driver's module-init function.
 386  */
 387 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 388 {
 389         sdrv->driver.bus = &serdev_bus_type;
 390         sdrv->driver.owner = owner;
 391
 392         /* force drivers to async probe so I/O is possible in probe */
 393         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 394
 395         return driver_register(&sdrv->driver);
 396 }
 397 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 398
 399 static void __exit serdev_exit(void)
 400 {
 401         bus_unregister(&serdev_bus_type);
 402 }
 403 module_exit(serdev_exit);
 404
 405 static int __init serdev_init(void)
 406 {
 407         int ret;
 408
 409         ret = bus_register(&serdev_bus_type);
 410         if (ret)
 411                 return ret;
 412
 413         is_registered = true;
 414         return 0;
 415 }
 416 /* Must be before serial drivers register */
 417 postcore_initcall(serdev_init);
 418
 419 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 420 MODULE_LICENSE("GPL v2");
 421 MODULE_DESCRIPTION("Serial attached device bus");