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         struct {
  79                 struct cros_ec_command msg;
  80                 struct ec_params_host_sleep_event req;
  81         } __packed buf;
  82
  83         memset(&buf, 0, sizeof(buf));
  84
  85         buf.req.sleep_event = sleep_event;
  86
  87         buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
  88         buf.msg.version = 0;
  89         buf.msg.outsize = sizeof(buf.req);
  90
  91         return cros_ec_cmd_xfer(ec_dev, &buf.msg);
  92 }
  93
  94 int cros_ec_register(struct cros_ec_device *ec_dev)
  95 {
  96         struct device *dev = ec_dev->dev;
  97         int err = 0;
  98
  99         BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
 100
 101         ec_dev->max_request = sizeof(struct ec_params_hello);
 102         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
 103         ec_dev->max_passthru = 0;
 104
 105         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
 106         if (!ec_dev->din)
 107                 return -ENOMEM;
 108
 109         ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
 110         if (!ec_dev->dout)
 111                 return -ENOMEM;
 112
 113         mutex_init(&ec_dev->lock);
 114
 115         err = cros_ec_query_all(ec_dev);
 116         if (err) {
 117                 dev_err(dev, "Cannot identify the EC: error %d\n", err);
 118                 return err;
 119         }
 120
 121         if (ec_dev->irq) {
 122                 err = devm_request_threaded_irq(dev, ec_dev->irq, NULL,
 123                                 ec_irq_thread, IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 124                                 "chromeos-ec", ec_dev);
 125                 if (err) {
 126                         dev_err(dev, "Failed to request IRQ %d: %d",
 127                                 ec_dev->irq, err);
 128                         return err;
 129                 }
 130         }
 131
 132         err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
 133                               NULL, ec_dev->irq, NULL);
 134         if (err) {
 135                 dev_err(dev,
 136                         "Failed to register Embedded Controller subdevice %d\n",
 137                         err);
 138                 return err;
 139         }
 140
 141         if (ec_dev->max_passthru) {
 142                 /*
 143                  * Register a PD device as well on top of this device.
 144                  * We make the following assumptions:
 145                  * - behind an EC, we have a pd
 146                  * - only one device added.
 147                  * - the EC is responsive at init time (it is not true for a
 148                  *   sensor hub.
 149                  */
 150                 err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
 151                                       &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
 152                 if (err) {
 153                         dev_err(dev,
 154                                 "Failed to register Power Delivery subdevice %d\n",
 155                                 err);
 156                         return err;
 157                 }
 158         }
 159
 160         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 161                 err = devm_of_platform_populate(dev);
 162                 if (err) {
 163                         mfd_remove_devices(dev);
 164                         dev_err(dev, "Failed to register sub-devices\n");
 165                         return err;
 166                 }
 167         }
 168
 169         /*
 170          * Clear sleep event - this will fail harmlessly on platforms that
 171          * don't implement the sleep event host command.
 172          */
 173         err = cros_ec_sleep_event(ec_dev, 0);
 174         if (err < 0)
 175                 dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
 176                         err);
 177
 178         dev_info(dev, "Chrome EC device registered\n");
 179
 180         return 0;
 181 }
 182 EXPORT_SYMBOL(cros_ec_register);
 183
 184 int cros_ec_remove(struct cros_ec_device *ec_dev)
 185 {
 186         mfd_remove_devices(ec_dev->dev);
 187
 188         return 0;
 189 }
 190 EXPORT_SYMBOL(cros_ec_remove);
 191
 192 #ifdef CONFIG_PM_SLEEP
 193 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 194 {
 195         struct device *dev = ec_dev->dev;
 196         int ret;
 197         u8 sleep_event;
 198
 199         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 200                       HOST_SLEEP_EVENT_S3_SUSPEND :
 201                       HOST_SLEEP_EVENT_S0IX_SUSPEND;
 202
 203         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 204         if (ret < 0)
 205                 dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
 206                         ret);
 207
 208         if (device_may_wakeup(dev))
 209                 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
 210
 211         disable_irq(ec_dev->irq);
 212         ec_dev->was_wake_device = ec_dev->wake_enabled;
 213         ec_dev->suspended = true;
 214
 215         return 0;
 216 }
 217 EXPORT_SYMBOL(cros_ec_suspend);
 218
 219 static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
 220 {
 221         while (cros_ec_get_next_event(ec_dev, NULL) > 0)
 222                 blocking_notifier_call_chain(&ec_dev->event_notifier,
 223                                              1, ec_dev);
 224 }
 225
 226 int cros_ec_resume(struct cros_ec_device *ec_dev)
 227 {
 228         int ret;
 229         u8 sleep_event;
 230
 231         ec_dev->suspended = false;
 232         enable_irq(ec_dev->irq);
 233
 234         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 235                       HOST_SLEEP_EVENT_S3_RESUME :
 236                       HOST_SLEEP_EVENT_S0IX_RESUME;
 237
 238         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 239         if (ret < 0)
 240                 dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
 241                         ret);
 242
 243         if (ec_dev->wake_enabled) {
 244                 disable_irq_wake(ec_dev->irq);
 245                 ec_dev->wake_enabled = 0;
 246         }
 247         /*
 248          * Let the mfd devices know about events that occur during
 249          * suspend. This way the clients know what to do with them.
 250          */
 251         cros_ec_report_events_during_suspend(ec_dev);
 252
 253
 254         return 0;
 255 }
 256 EXPORT_SYMBOL(cros_ec_resume);
 257
 258 #endif
 259
 260 MODULE_LICENSE("GPL");
 261 MODULE_DESCRIPTION("ChromeOS EC core driver");