drivers/platform/chrome/cros_ec.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ChromeOS EC multi-function device
   4  *
   5  * Copyright (C) 2012 Google, Inc
   6  *
   7  * The ChromeOS EC multi function device is used to mux all the requests
   8  * to the EC device for its multiple features: keyboard controller,
   9  * battery charging and regulator control, firmware update.
  10  */
  11
  12 #include <linux/of_platform.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_data/cros_ec_commands.h>
  17 #include <linux/platform_data/cros_ec_proto.h>
  18 #include <linux/suspend.h>
  19
  20 #include "cros_ec.h"
  21
  22 #define CROS_EC_DEV_EC_INDEX 0
  23 #define CROS_EC_DEV_PD_INDEX 1
  24
  25 static struct cros_ec_platform ec_p = {
  26         .ec_name = CROS_EC_DEV_NAME,
  27         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
  28 };
  29
  30 static struct cros_ec_platform pd_p = {
  31         .ec_name = CROS_EC_DEV_PD_NAME,
  32         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
  33 };
  34
  35 static irqreturn_t ec_irq_handler(int irq, void *data)
  36 {
  37         struct cros_ec_device *ec_dev = data;
  38
  39         ec_dev->last_event_time = cros_ec_get_time_ns();
  40
  41         return IRQ_WAKE_THREAD;
  42 }
  43
  44 /**
  45  * cros_ec_handle_event() - process and forward pending events on EC
  46  * @ec_dev: Device with events to process.
  47  *
  48  * Call this function in a loop when the kernel is notified that the EC has
  49  * pending events.
  50  *
  51  * Return: true if more events are still pending and this function should be
  52  * called again.
  53  */
  54 bool cros_ec_handle_event(struct cros_ec_device *ec_dev)
  55 {
  56         bool wake_event;
  57         bool ec_has_more_events;
  58         int ret;
  59
  60         ret = cros_ec_get_next_event(ec_dev, &wake_event, &ec_has_more_events);
  61
  62         /*
  63          * Signal only if wake host events or any interrupt if
  64          * cros_ec_get_next_event() returned an error (default value for
  65          * wake_event is true)
  66          */
  67         if (wake_event && device_may_wakeup(ec_dev->dev))
  68                 pm_wakeup_event(ec_dev->dev, 0);
  69
  70         if (ret > 0)
  71                 blocking_notifier_call_chain(&ec_dev->event_notifier,
  72                                              0, ec_dev);
  73
  74         return ec_has_more_events;
  75 }
  76 EXPORT_SYMBOL(cros_ec_handle_event);
  77
  78 static irqreturn_t ec_irq_thread(int irq, void *data)
  79 {
  80         struct cros_ec_device *ec_dev = data;
  81         bool ec_has_more_events;
  82
  83         do {
  84                 ec_has_more_events = cros_ec_handle_event(ec_dev);
  85         } while (ec_has_more_events);
  86
  87         return IRQ_HANDLED;
  88 }
  89
  90 static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
  91 {
  92         int ret;
  93         struct {
  94                 struct cros_ec_command msg;
  95                 union {
  96                         struct ec_params_host_sleep_event req0;
  97                         struct ec_params_host_sleep_event_v1 req1;
  98                         struct ec_response_host_sleep_event_v1 resp1;
  99                 } u;
 100         } __packed buf;
 101
 102         memset(&buf, 0, sizeof(buf));
 103
 104         if (ec_dev->host_sleep_v1) {
 105                 buf.u.req1.sleep_event = sleep_event;
 106                 buf.u.req1.suspend_params.sleep_timeout_ms =
 107                                 EC_HOST_SLEEP_TIMEOUT_DEFAULT;
 108
 109                 buf.msg.outsize = sizeof(buf.u.req1);
 110                 if ((sleep_event == HOST_SLEEP_EVENT_S3_RESUME) ||
 111                     (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
 112                         buf.msg.insize = sizeof(buf.u.resp1);
 113
 114                 buf.msg.version = 1;
 115
 116         } else {
 117                 buf.u.req0.sleep_event = sleep_event;
 118                 buf.msg.outsize = sizeof(buf.u.req0);
 119         }
 120
 121         buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
 122
 123         ret = cros_ec_cmd_xfer_status(ec_dev, &buf.msg);
 124
 125         /* For now, report failure to transition to S0ix with a warning. */
 126         if (ret >= 0 && ec_dev->host_sleep_v1 &&
 127             (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME)) {
 128                 ec_dev->last_resume_result =
 129                         buf.u.resp1.resume_response.sleep_transitions;
 130
 131                 WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
 132                           EC_HOST_RESUME_SLEEP_TIMEOUT,
 133                           "EC detected sleep transition timeout. Total slp_s0 transitions: %d",
 134                           buf.u.resp1.resume_response.sleep_transitions &
 135                           EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
 136         }
 137
 138         return ret;
 139 }
 140
 141 static int cros_ec_ready_event(struct notifier_block *nb,
 142                                unsigned long queued_during_suspend,
 143                                void *_notify)
 144 {
 145         struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
 146                                                      notifier_ready);
 147         u32 host_event = cros_ec_get_host_event(ec_dev);
 148
 149         if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
 150                 mutex_lock(&ec_dev->lock);
 151                 cros_ec_query_all(ec_dev);
 152                 mutex_unlock(&ec_dev->lock);
 153                 return NOTIFY_OK;
 154         }
 155
 156         return NOTIFY_DONE;
 157 }
 158
 159 /**
 160  * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
 161  * @ec_dev: Device to register.
 162  *
 163  * Before calling this, allocate a pointer to a new device and then fill
 164  * in all the fields up to the --private-- marker.
 165  *
 166  * Return: 0 on success or negative error code.
 167  */
 168 int cros_ec_register(struct cros_ec_device *ec_dev)
 169 {
 170         struct device *dev = ec_dev->dev;
 171         int err = 0;
 172
 173         BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
 174
 175         ec_dev->max_request = sizeof(struct ec_params_hello);
 176         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
 177         ec_dev->max_passthru = 0;
 178
 179         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
 180         if (!ec_dev->din)
 181                 return -ENOMEM;
 182
 183         ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
 184         if (!ec_dev->dout)
 185                 return -ENOMEM;
 186
 187         mutex_init(&ec_dev->lock);
 188
 189         err = cros_ec_query_all(ec_dev);
 190         if (err) {
 191                 dev_err(dev, "Cannot identify the EC: error %d\n", err);
 192                 return err;
 193         }
 194
 195         if (ec_dev->irq > 0) {
 196                 err = devm_request_threaded_irq(dev, ec_dev->irq,
 197                                                 ec_irq_handler,
 198                                                 ec_irq_thread,
 199                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 200                                                 "chromeos-ec", ec_dev);
 201                 if (err) {
 202                         dev_err(dev, "Failed to request IRQ %d: %d",
 203                                 ec_dev->irq, err);
 204                         return err;
 205                 }
 206         }
 207
 208         /* Register a platform device for the main EC instance */
 209         ec_dev->ec = platform_device_register_data(ec_dev->dev, "cros-ec-dev",
 210                                         PLATFORM_DEVID_AUTO, &ec_p,
 211                                         sizeof(struct cros_ec_platform));
 212         if (IS_ERR(ec_dev->ec)) {
 213                 dev_err(ec_dev->dev,
 214                         "Failed to create CrOS EC platform device\n");
 215                 return PTR_ERR(ec_dev->ec);
 216         }
 217
 218         if (ec_dev->max_passthru) {
 219                 /*
 220                  * Register a platform device for the PD behind the main EC.
 221                  * We make the following assumptions:
 222                  * - behind an EC, we have a pd
 223                  * - only one device added.
 224                  * - the EC is responsive at init time (it is not true for a
 225                  *   sensor hub).
 226                  */
 227                 ec_dev->pd = platform_device_register_data(ec_dev->dev,
 228                                         "cros-ec-dev",
 229                                         PLATFORM_DEVID_AUTO, &pd_p,
 230                                         sizeof(struct cros_ec_platform));
 231                 if (IS_ERR(ec_dev->pd)) {
 232                         dev_err(ec_dev->dev,
 233                                 "Failed to create CrOS PD platform device\n");
 234                         platform_device_unregister(ec_dev->ec);
 235                         return PTR_ERR(ec_dev->pd);
 236                 }
 237         }
 238
 239         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 240                 err = devm_of_platform_populate(dev);
 241                 if (err) {
 242                         platform_device_unregister(ec_dev->pd);
 243                         platform_device_unregister(ec_dev->ec);
 244                         dev_err(dev, "Failed to register sub-devices\n");
 245                         return err;
 246                 }
 247         }
 248
 249         /*
 250          * Clear sleep event - this will fail harmlessly on platforms that
 251          * don't implement the sleep event host command.
 252          */
 253         err = cros_ec_sleep_event(ec_dev, 0);
 254         if (err < 0)
 255                 dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
 256                         err);
 257
 258         if (ec_dev->mkbp_event_supported) {
 259                 /*
 260                  * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
 261                  * event.
 262                  */
 263                 ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
 264                 err = blocking_notifier_chain_register(&ec_dev->event_notifier,
 265                                                       &ec_dev->notifier_ready);
 266                 if (err)
 267                         return err;
 268         }
 269
 270         dev_info(dev, "Chrome EC device registered\n");
 271
 272         return 0;
 273 }
 274 EXPORT_SYMBOL(cros_ec_register);
 275
 276 /**
 277  * cros_ec_unregister() - Remove a ChromeOS EC.
 278  * @ec_dev: Device to unregister.
 279  *
 280  * Call this to deregister a ChromeOS EC, then clean up any private data.
 281  *
 282  * Return: 0 on success or negative error code.
 283  */
 284 int cros_ec_unregister(struct cros_ec_device *ec_dev)
 285 {
 286         if (ec_dev->pd)
 287                 platform_device_unregister(ec_dev->pd);
 288         platform_device_unregister(ec_dev->ec);
 289
 290         return 0;
 291 }
 292 EXPORT_SYMBOL(cros_ec_unregister);
 293
 294 #ifdef CONFIG_PM_SLEEP
 295 /**
 296  * cros_ec_suspend() - Handle a suspend operation for the ChromeOS EC device.
 297  * @ec_dev: Device to suspend.
 298  *
 299  * This can be called by drivers to handle a suspend event.
 300  *
 301  * Return: 0 on success or negative error code.
 302  */
 303 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 304 {
 305         struct device *dev = ec_dev->dev;
 306         int ret;
 307         u8 sleep_event;
 308
 309         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 310                       HOST_SLEEP_EVENT_S3_SUSPEND :
 311                       HOST_SLEEP_EVENT_S0IX_SUSPEND;
 312
 313         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 314         if (ret < 0)
 315                 dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
 316                         ret);
 317
 318         if (device_may_wakeup(dev))
 319                 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
 320
 321         disable_irq(ec_dev->irq);
 322         ec_dev->was_wake_device = ec_dev->wake_enabled;
 323         ec_dev->suspended = true;
 324
 325         return 0;
 326 }
 327 EXPORT_SYMBOL(cros_ec_suspend);
 328
 329 static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
 330 {
 331         while (ec_dev->mkbp_event_supported &&
 332                cros_ec_get_next_event(ec_dev, NULL, NULL) > 0)
 333                 blocking_notifier_call_chain(&ec_dev->event_notifier,
 334                                              1, ec_dev);
 335 }
 336
 337 /**
 338  * cros_ec_resume() - Handle a resume operation for the ChromeOS EC device.
 339  * @ec_dev: Device to resume.
 340  *
 341  * This can be called by drivers to handle a resume event.
 342  *
 343  * Return: 0 on success or negative error code.
 344  */
 345 int cros_ec_resume(struct cros_ec_device *ec_dev)
 346 {
 347         int ret;
 348         u8 sleep_event;
 349
 350         ec_dev->suspended = false;
 351         enable_irq(ec_dev->irq);
 352
 353         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 354                       HOST_SLEEP_EVENT_S3_RESUME :
 355                       HOST_SLEEP_EVENT_S0IX_RESUME;
 356
 357         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 358         if (ret < 0)
 359                 dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
 360                         ret);
 361
 362         if (ec_dev->wake_enabled) {
 363                 disable_irq_wake(ec_dev->irq);
 364                 ec_dev->wake_enabled = 0;
 365         }
 366         /*
 367          * Let the mfd devices know about events that occur during
 368          * suspend. This way the clients know what to do with them.
 369          */
 370         cros_ec_report_events_during_suspend(ec_dev);
 371
 372
 373         return 0;
 374 }
 375 EXPORT_SYMBOL(cros_ec_resume);
 376
 377 #endif
 378
 379 MODULE_LICENSE("GPL");
 380 MODULE_DESCRIPTION("ChromeOS EC core driver");