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-ctl",
  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-ctl",
  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         int ret;
  58
  59         if (device_may_wakeup(ec_dev->dev))
  60                 pm_wakeup_event(ec_dev->dev, 0);
  61
  62         ret = cros_ec_get_next_event(ec_dev);
  63         if (ret > 0)
  64                 blocking_notifier_call_chain(&ec_dev->event_notifier,
  65                                              0, ec_dev);
  66         return IRQ_HANDLED;
  67 }
  68
  69 static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
  70 {
  71         struct {
  72                 struct cros_ec_command msg;
  73                 struct ec_params_host_sleep_event req;
  74         } __packed buf;
  75
  76         memset(&buf, 0, sizeof(buf));
  77
  78         buf.req.sleep_event = sleep_event;
  79
  80         buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
  81         buf.msg.version = 0;
  82         buf.msg.outsize = sizeof(buf.req);
  83
  84         return cros_ec_cmd_xfer(ec_dev, &buf.msg);
  85 }
  86
  87 int cros_ec_register(struct cros_ec_device *ec_dev)
  88 {
  89         struct device *dev = ec_dev->dev;
  90         int err = 0;
  91
  92         BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
  93
  94         ec_dev->max_request = sizeof(struct ec_params_hello);
  95         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
  96         ec_dev->max_passthru = 0;
  97
  98         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
  99         if (!ec_dev->din)
 100                 return -ENOMEM;
 101
 102         ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
 103         if (!ec_dev->dout)
 104                 return -ENOMEM;
 105
 106         mutex_init(&ec_dev->lock);
 107
 108         cros_ec_query_all(ec_dev);
 109
 110         if (ec_dev->irq) {
 111                 err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
 112                                            IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 113                                            "chromeos-ec", ec_dev);
 114                 if (err) {
 115                         dev_err(dev, "Failed to request IRQ %d: %d",
 116                                 ec_dev->irq, err);
 117                         return err;
 118                 }
 119         }
 120
 121         err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
 122                               NULL, ec_dev->irq, NULL);
 123         if (err) {
 124                 dev_err(dev,
 125                         "Failed to register Embedded Controller subdevice %d\n",
 126                         err);
 127                 goto fail_mfd;
 128         }
 129
 130         if (ec_dev->max_passthru) {
 131                 /*
 132                  * Register a PD device as well on top of this device.
 133                  * We make the following assumptions:
 134                  * - behind an EC, we have a pd
 135                  * - only one device added.
 136                  * - the EC is responsive at init time (it is not true for a
 137                  *   sensor hub.
 138                  */
 139                 err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
 140                                       &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
 141                 if (err) {
 142                         dev_err(dev,
 143                                 "Failed to register Power Delivery subdevice %d\n",
 144                                 err);
 145                         goto fail_mfd;
 146                 }
 147         }
 148
 149         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 150                 err = devm_of_platform_populate(dev);
 151                 if (err) {
 152                         mfd_remove_devices(dev);
 153                         dev_err(dev, "Failed to register sub-devices\n");
 154                         goto fail_mfd;
 155                 }
 156         }
 157
 158         /*
 159          * Clear sleep event - this will fail harmlessly on platforms that
 160          * don't implement the sleep event host command.
 161          */
 162         err = cros_ec_sleep_event(ec_dev, 0);
 163         if (err < 0)
 164                 dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
 165                         err);
 166
 167         dev_info(dev, "Chrome EC device registered\n");
 168
 169         cros_ec_acpi_install_gpe_handler(dev);
 170
 171         return 0;
 172
 173 fail_mfd:
 174         if (ec_dev->irq)
 175                 free_irq(ec_dev->irq, ec_dev);
 176         return err;
 177 }
 178 EXPORT_SYMBOL(cros_ec_register);
 179
 180 int cros_ec_remove(struct cros_ec_device *ec_dev)
 181 {
 182         mfd_remove_devices(ec_dev->dev);
 183
 184         cros_ec_acpi_remove_gpe_handler();
 185
 186         if (ec_dev->irq)
 187                 free_irq(ec_dev->irq, ec_dev);
 188
 189         return 0;
 190 }
 191 EXPORT_SYMBOL(cros_ec_remove);
 192
 193 #ifdef CONFIG_PM_SLEEP
 194 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 195 {
 196         struct device *dev = ec_dev->dev;
 197         int ret;
 198         u8 sleep_event;
 199
 200         if (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) {
 201                 sleep_event = HOST_SLEEP_EVENT_S3_SUSPEND;
 202         } else {
 203                 sleep_event = HOST_SLEEP_EVENT_S0IX_SUSPEND;
 204
 205                 /* Clearing the GPE status for any pending event */
 206                 cros_ec_acpi_clear_gpe();
 207         }
 208
 209         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 210         if (ret < 0)
 211                 dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
 212                         ret);
 213
 214         if (device_may_wakeup(dev))
 215                 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
 216
 217         disable_irq(ec_dev->irq);
 218         ec_dev->was_wake_device = ec_dev->wake_enabled;
 219         ec_dev->suspended = true;
 220
 221         return 0;
 222 }
 223 EXPORT_SYMBOL(cros_ec_suspend);
 224
 225 static void cros_ec_drain_events(struct cros_ec_device *ec_dev)
 226 {
 227         while (cros_ec_get_next_event(ec_dev) > 0)
 228                 blocking_notifier_call_chain(&ec_dev->event_notifier,
 229                                              1, ec_dev);
 230 }
 231
 232 int cros_ec_resume(struct cros_ec_device *ec_dev)
 233 {
 234         int ret;
 235         u8 sleep_event;
 236
 237         ec_dev->suspended = false;
 238         enable_irq(ec_dev->irq);
 239
 240         sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
 241                       HOST_SLEEP_EVENT_S3_RESUME :
 242                       HOST_SLEEP_EVENT_S0IX_RESUME;
 243
 244         ret = cros_ec_sleep_event(ec_dev, sleep_event);
 245         if (ret < 0)
 246                 dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
 247                         ret);
 248
 249         /*
 250          * In some cases, we need to distinguish between events that occur
 251          * during suspend if the EC is not a wake source. For example,
 252          * keypresses during suspend should be discarded if it does not wake
 253          * the system.
 254          *
 255          * If the EC is not a wake source, drain the event queue and mark them
 256          * as "queued during suspend".
 257          */
 258         if (ec_dev->wake_enabled) {
 259                 disable_irq_wake(ec_dev->irq);
 260                 ec_dev->wake_enabled = 0;
 261         } else {
 262                 cros_ec_drain_events(ec_dev);
 263         }
 264
 265         return 0;
 266 }
 267 EXPORT_SYMBOL(cros_ec_resume);
 268
 269 #endif
 270
 271 MODULE_LICENSE("GPL");
 272 MODULE_DESCRIPTION("ChromeOS EC core driver");