drivers/mfd/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/mfd/core.h>
  17 #include <linux/mfd/cros_ec.h>
  18 #include <linux/suspend.h>
  19 #include <asm/unaligned.h>
  20
  21 #define CROS_EC_DEV_EC_INDEX 0
  22 #define CROS_EC_DEV_PD_INDEX 1
  23
  24 static struct cros_ec_platform ec_p = {
  25         .ec_name = CROS_EC_DEV_NAME,
  26         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
  27 };
  28
  29 static struct cros_ec_platform pd_p = {
  30         .ec_name = CROS_EC_DEV_PD_NAME,
  31         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
  32 };
  33
  34 static const struct mfd_cell ec_cell = {
  35         .name = "cros-ec-dev",
  36         .platform_data = &ec_p,
  37         .pdata_size = sizeof(ec_p),
  38 };
  39
  40 static const struct mfd_cell ec_pd_cell = {
  41         .name = "cros-ec-dev",
  42         .platform_data = &pd_p,
  43         .pdata_size = sizeof(pd_p),
  44 };
  45
  46 static irqreturn_t ec_irq_thread(int irq, void *data)
  47 {
  48         struct cros_ec_device *ec_dev = data;
  49         bool wake_event = true;
  50         int ret;
  51
  52         ret = cros_ec_get_next_event(ec_dev, &wake_event);
  53
  54         /*
  55          * Signal only if wake host events or any interrupt if
  56          * cros_ec_get_next_event() returned an error (default value for
  57          * wake_event is true)
  58          */
  59         if (wake_event && device_may_wakeup(ec_dev->dev))
  60                 pm_wakeup_event(ec_dev->dev, 0);
  61
  62         if (ret > 0)
  63                 blocking_notifier_call_chain(&ec_dev->event_notifier,
  64                                              0, ec_dev);
  65         return IRQ_HANDLED;
  66 }
  67
  68 static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
  69 {
  70         int ret;
  71         struct {
  72                 struct cros_ec_command msg;
  73                 union {
  74                         struct ec_params_host_sleep_event req0;
  75                         struct ec_params_host_sleep_event_v1 req1;
  76                         struct ec_response_host_sleep_event_v1 resp1;
  77                 } u;
  78         } __packed buf;
  79
  80         memset(&buf, 0, sizeof(buf));
  81
  82         if (ec_dev->host_sleep_v1) {
  83                 buf.u.req1.sleep_event = sleep_event;
  84                 buf.u.req1.suspend_params.sleep_timeout_ms =
  85                                 EC_HOST_SLEEP_TIMEOUT_DEFAULT;
  86
  87                 buf.msg.outsize = sizeof(buf.u.req1);
  88                 if ((sleep_event == HOST_SLEEP_EVENT_S3_RESUME) ||
  89                     (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
  90                         buf.msg.insize = sizeof(buf.u.resp1);
  91
  92                 buf.msg.version = 1;
  93
  94         } else {
  95                 buf.u.req0.sleep_event = sleep_event;
  96                 buf.msg.outsize = sizeof(buf.u.req0);
  97         }
  98
  99         buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
 100
 101         ret = cros_ec_cmd_xfer(ec_dev, &buf.msg);
 102
 103         /* For now, report failure to transition to S0ix with a warning. */
 104         if (ret >= 0 && ec_dev->host_sleep_v1 &&
 105             (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
 106                 WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
 107                           EC_HOST_RESUME_SLEEP_TIMEOUT,
 108                           "EC detected sleep transition timeout. Total slp_s0 transitions: %d",
 109                           buf.u.resp1.resume_response.sleep_transitions &
 110                           EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
 111
 112         return ret;
 113 }
 114
 115 int cros_ec_register(struct cros_ec_device *ec_dev)
 116 {
 117         struct device *dev = ec_dev->dev;
 118         int err = 0;
 119
 120         BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
 121
 122         ec_dev->max_request = sizeof(struct ec_params_hello);
 123         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
 124         ec_dev->max_passthru = 0;
 125
 126         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
 127         if (!ec_dev->din)
 128                 return -ENOMEM;
 129
 130         ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
 131         if (!ec_dev->dout)
 132                 return -ENOMEM;
 133
 134         mutex_init(&ec_dev->lock);
 135
 136         err = cros_ec_query_all(ec_dev);
 137         if (err) {
 138                 dev_err(dev, "Cannot identify the EC: error %d\n", err);
 139                 return err;
 140         }
 141
 142         if (ec_dev->irq) {
 143                 err = devm_request_threaded_irq(dev, ec_dev->irq, NULL,
 144                                 ec_irq_thread, IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 145                                 "chromeos-ec", ec_dev);
 146                 if (err) {
 147                         dev_err(dev, "Failed to request IRQ %d: %d",
 148                                 ec_dev->irq, err);
 149                         return err;
 150                 }
 151         }
 152
 153         err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell,
 154                                    1, NULL, ec_dev->irq, NULL);
 155         if (err) {
 156                 dev_err(dev,
 157                         "Failed to register Embedded Controller subdevice %d\n",
 158                         err);
 159                 return err;
 160         }
 161
 162         if (ec_dev->max_passthru) {
 163                 /*
 164                  * Register a PD device as well on top of this device.
 165                  * We make the following assumptions:
 166                  * - behind an EC, we have a pd
 167                  * - only one device added.
 168                  * - the EC is responsive at init time (it is not true for a
 169                  *   sensor hub.
 170                  */
 171                 err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
 172                                       &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
 173                 if (err) {
 174                         dev_err(dev,
 175                                 "Failed to register Power Delivery subdevice %d\n",
 176                                 err);
 177                         return err;
 178                 }
 179         }
 180
 181         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 182                 err = devm_of_platform_populate(dev);
 183                 if (err) {
 184                         mfd_remove_devices(dev);
 185                         dev_err(dev, "Failed to register sub-devices\n");
 186                         return err;
 187                 }
 188         }
 189
 190         /*
 191          * Clear sleep event - this will fail harmlessly on platforms that
 192          * don't implement the sleep event host command.
 193          */
 194         err = cros_ec_sleep_event(ec_dev, 0);
 195         if (err < 0)
 196                 dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
 197                         err);
 198
 199         dev_info(dev, "Chrome EC device registered\n");
 200
 201         return 0;
 202 }
 203 EXPORT_SYMBOL(cros_ec_register);
 204
 205 #ifdef CONFIG_PM_SLEEP
 206 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 207 {
 208         struct device *dev = ec_dev->dev;
 209         int ret;
 210         u8 sleep_event;
 211
 212         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 213                       HOST_SLEEP_EVENT_S3_SUSPEND :
 214                       HOST_SLEEP_EVENT_S0IX_SUSPEND;
 215
 216         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 217         if (ret < 0)
 218                 dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
 219                         ret);
 220
 221         if (device_may_wakeup(dev))
 222                 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
 223
 224         disable_irq(ec_dev->irq);
 225         ec_dev->was_wake_device = ec_dev->wake_enabled;
 226         ec_dev->suspended = true;
 227
 228         return 0;
 229 }
 230 EXPORT_SYMBOL(cros_ec_suspend);
 231
 232 static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
 233 {
 234         while (ec_dev->mkbp_event_supported &&
 235                cros_ec_get_next_event(ec_dev, NULL) > 0)
 236                 blocking_notifier_call_chain(&ec_dev->event_notifier,
 237                                              1, ec_dev);
 238 }
 239
 240 int cros_ec_resume(struct cros_ec_device *ec_dev)
 241 {
 242         int ret;
 243         u8 sleep_event;
 244
 245         ec_dev->suspended = false;
 246         enable_irq(ec_dev->irq);
 247
 248         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 249                       HOST_SLEEP_EVENT_S3_RESUME :
 250                       HOST_SLEEP_EVENT_S0IX_RESUME;
 251
 252         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 253         if (ret < 0)
 254                 dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
 255                         ret);
 256
 257         if (ec_dev->wake_enabled) {
 258                 disable_irq_wake(ec_dev->irq);
 259                 ec_dev->wake_enabled = 0;
 260         }
 261         /*
 262          * Let the mfd devices know about events that occur during
 263          * suspend. This way the clients know what to do with them.
 264          */
 265         cros_ec_report_events_during_suspend(ec_dev);
 266
 267
 268         return 0;
 269 }
 270 EXPORT_SYMBOL(cros_ec_resume);
 271
 272 #endif
 273
 274 MODULE_LICENSE("GPL");
 275 MODULE_DESCRIPTION("ChromeOS EC core driver");