drivers/mfd/cros_ec.c

   1 /*
   2  * ChromeOS EC multi-function device
   3  *
   4  * Copyright (C) 2012 Google, Inc
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * The ChromeOS EC multi function device is used to mux all the requests
  16  * to the EC device for its multiple features: keyboard controller,
  17  * battery charging and regulator control, firmware update.
  18  */
  19
  20 #include <linux/of_platform.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/slab.h>
  23 #include <linux/module.h>
  24 #include <linux/mfd/core.h>
  25 #include <linux/mfd/cros_ec.h>
  26 #include <linux/suspend.h>
  27 #include <asm/unaligned.h>
  28
  29 #define CROS_EC_DEV_EC_INDEX 0
  30 #define CROS_EC_DEV_PD_INDEX 1
  31
  32 static struct cros_ec_platform ec_p = {
  33         .ec_name = CROS_EC_DEV_NAME,
  34         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
  35 };
  36
  37 static struct cros_ec_platform pd_p = {
  38         .ec_name = CROS_EC_DEV_PD_NAME,
  39         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
  40 };
  41
  42 static const struct mfd_cell ec_cell = {
  43         .name = "cros-ec-dev",
  44         .platform_data = &ec_p,
  45         .pdata_size = sizeof(ec_p),
  46 };
  47
  48 static const struct mfd_cell ec_pd_cell = {
  49         .name = "cros-ec-dev",
  50         .platform_data = &pd_p,
  51         .pdata_size = sizeof(pd_p),
  52 };
  53
  54 static irqreturn_t ec_irq_thread(int irq, void *data)
  55 {
  56         struct cros_ec_device *ec_dev = data;
  57         bool wake_event = true;
  58         int ret;
  59
  60         ret = cros_ec_get_next_event(ec_dev, &wake_event);
  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         return IRQ_HANDLED;
  74 }
  75
  76 static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
  77 {
  78         int ret;
  79         struct {
  80                 struct cros_ec_command msg;
  81                 union {
  82                         struct ec_params_host_sleep_event req0;
  83                         struct ec_params_host_sleep_event_v1 req1;
  84                         struct ec_response_host_sleep_event_v1 resp1;
  85                 } u;
  86         } __packed buf;
  87
  88         memset(&buf, 0, sizeof(buf));
  89
  90         if (ec_dev->host_sleep_v1) {
  91                 buf.u.req1.sleep_event = sleep_event;
  92                 buf.u.req1.suspend_params.sleep_timeout_ms =
  93                                 EC_HOST_SLEEP_TIMEOUT_DEFAULT;
  94
  95                 buf.msg.outsize = sizeof(buf.u.req1);
  96                 if ((sleep_event == HOST_SLEEP_EVENT_S3_RESUME) ||
  97                     (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
  98                         buf.msg.insize = sizeof(buf.u.resp1);
  99
 100                 buf.msg.version = 1;
 101
 102         } else {
 103                 buf.u.req0.sleep_event = sleep_event;
 104                 buf.msg.outsize = sizeof(buf.u.req0);
 105         }
 106
 107         buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
 108
 109         ret = cros_ec_cmd_xfer(ec_dev, &buf.msg);
 110
 111         /* For now, report failure to transition to S0ix with a warning. */
 112         if (ret >= 0 && ec_dev->host_sleep_v1 &&
 113             (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
 114                 WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
 115                           EC_HOST_RESUME_SLEEP_TIMEOUT,
 116                           "EC detected sleep transition timeout. Total slp_s0 transitions: %d",
 117                           buf.u.resp1.resume_response.sleep_transitions &
 118                           EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
 119
 120         return ret;
 121 }
 122
 123 int cros_ec_register(struct cros_ec_device *ec_dev)
 124 {
 125         struct device *dev = ec_dev->dev;
 126         int err = 0;
 127
 128         BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
 129
 130         ec_dev->max_request = sizeof(struct ec_params_hello);
 131         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
 132         ec_dev->max_passthru = 0;
 133
 134         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
 135         if (!ec_dev->din)
 136                 return -ENOMEM;
 137
 138         ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
 139         if (!ec_dev->dout)
 140                 return -ENOMEM;
 141
 142         mutex_init(&ec_dev->lock);
 143
 144         err = cros_ec_query_all(ec_dev);
 145         if (err) {
 146                 dev_err(dev, "Cannot identify the EC: error %d\n", err);
 147                 return err;
 148         }
 149
 150         if (ec_dev->irq) {
 151                 err = devm_request_threaded_irq(dev, ec_dev->irq, NULL,
 152                                 ec_irq_thread, IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 153                                 "chromeos-ec", ec_dev);
 154                 if (err) {
 155                         dev_err(dev, "Failed to request IRQ %d: %d",
 156                                 ec_dev->irq, err);
 157                         return err;
 158                 }
 159         }
 160
 161         err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell,
 162                                    1, NULL, ec_dev->irq, NULL);
 163         if (err) {
 164                 dev_err(dev,
 165                         "Failed to register Embedded Controller subdevice %d\n",
 166                         err);
 167                 return err;
 168         }
 169
 170         if (ec_dev->max_passthru) {
 171                 /*
 172                  * Register a PD device as well on top of this device.
 173                  * We make the following assumptions:
 174                  * - behind an EC, we have a pd
 175                  * - only one device added.
 176                  * - the EC is responsive at init time (it is not true for a
 177                  *   sensor hub.
 178                  */
 179                 err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
 180                                       &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
 181                 if (err) {
 182                         dev_err(dev,
 183                                 "Failed to register Power Delivery subdevice %d\n",
 184                                 err);
 185                         return err;
 186                 }
 187         }
 188
 189         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 190                 err = devm_of_platform_populate(dev);
 191                 if (err) {
 192                         mfd_remove_devices(dev);
 193                         dev_err(dev, "Failed to register sub-devices\n");
 194                         return err;
 195                 }
 196         }
 197
 198         /*
 199          * Clear sleep event - this will fail harmlessly on platforms that
 200          * don't implement the sleep event host command.
 201          */
 202         err = cros_ec_sleep_event(ec_dev, 0);
 203         if (err < 0)
 204                 dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
 205                         err);
 206
 207         dev_info(dev, "Chrome EC device registered\n");
 208
 209         return 0;
 210 }
 211 EXPORT_SYMBOL(cros_ec_register);
 212
 213 #ifdef CONFIG_PM_SLEEP
 214 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 215 {
 216         struct device *dev = ec_dev->dev;
 217         int ret;
 218         u8 sleep_event;
 219
 220         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 221                       HOST_SLEEP_EVENT_S3_SUSPEND :
 222                       HOST_SLEEP_EVENT_S0IX_SUSPEND;
 223
 224         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 225         if (ret < 0)
 226                 dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
 227                         ret);
 228
 229         if (device_may_wakeup(dev))
 230                 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
 231
 232         disable_irq(ec_dev->irq);
 233         ec_dev->was_wake_device = ec_dev->wake_enabled;
 234         ec_dev->suspended = true;
 235
 236         return 0;
 237 }
 238 EXPORT_SYMBOL(cros_ec_suspend);
 239
 240 static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
 241 {
 242         while (ec_dev->mkbp_event_supported &&
 243                cros_ec_get_next_event(ec_dev, NULL) > 0)
 244                 blocking_notifier_call_chain(&ec_dev->event_notifier,
 245                                              1, ec_dev);
 246 }
 247
 248 int cros_ec_resume(struct cros_ec_device *ec_dev)
 249 {
 250         int ret;
 251         u8 sleep_event;
 252
 253         ec_dev->suspended = false;
 254         enable_irq(ec_dev->irq);
 255
 256         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 257                       HOST_SLEEP_EVENT_S3_RESUME :
 258                       HOST_SLEEP_EVENT_S0IX_RESUME;
 259
 260         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 261         if (ret < 0)
 262                 dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
 263                         ret);
 264
 265         if (ec_dev->wake_enabled) {
 266                 disable_irq_wake(ec_dev->irq);
 267                 ec_dev->wake_enabled = 0;
 268         }
 269         /*
 270          * Let the mfd devices know about events that occur during
 271          * suspend. This way the clients know what to do with them.
 272          */
 273         cros_ec_report_events_during_suspend(ec_dev);
 274
 275
 276         return 0;
 277 }
 278 EXPORT_SYMBOL(cros_ec_resume);
 279
 280 #endif
 281
 282 MODULE_LICENSE("GPL");
 283 MODULE_DESCRIPTION("ChromeOS EC core driver");