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"); 422