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 <asm/unaligned.h>
  27
  28 #define CROS_EC_DEV_EC_INDEX 0
  29 #define CROS_EC_DEV_PD_INDEX 1
  30
  31 static struct cros_ec_platform ec_p = {
  32         .ec_name = CROS_EC_DEV_NAME,
  33         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
  34 };
  35
  36 static struct cros_ec_platform pd_p = {
  37         .ec_name = CROS_EC_DEV_PD_NAME,
  38         .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
  39 };
  40
  41 static const struct mfd_cell ec_cell = {
  42         .name = "cros-ec-ctl",
  43         .platform_data = &ec_p,
  44         .pdata_size = sizeof(ec_p),
  45 };
  46
  47 static const struct mfd_cell ec_pd_cell = {
  48         .name = "cros-ec-ctl",
  49         .platform_data = &pd_p,
  50         .pdata_size = sizeof(pd_p),
  51 };
  52
  53 static irqreturn_t ec_irq_thread(int irq, void *data)
  54 {
  55         struct cros_ec_device *ec_dev = data;
  56         int ret;
  57
  58         if (device_may_wakeup(ec_dev->dev))
  59                 pm_wakeup_event(ec_dev->dev, 0);
  60
  61         ret = cros_ec_get_next_event(ec_dev);
  62         if (ret > 0)
  63                 blocking_notifier_call_chain(&ec_dev->event_notifier,
  64                                              0, ec_dev);
  65         return IRQ_HANDLED;
  66 }
  67
  68 int cros_ec_register(struct cros_ec_device *ec_dev)
  69 {
  70         struct device *dev = ec_dev->dev;
  71         int err = 0;
  72
  73         BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
  74
  75         ec_dev->max_request = sizeof(struct ec_params_hello);
  76         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
  77         ec_dev->max_passthru = 0;
  78
  79         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
  80         if (!ec_dev->din)
  81                 return -ENOMEM;
  82
  83         ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
  84         if (!ec_dev->dout)
  85                 return -ENOMEM;
  86
  87         mutex_init(&ec_dev->lock);
  88
  89         cros_ec_query_all(ec_dev);
  90
  91         if (ec_dev->irq) {
  92                 err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
  93                                            IRQF_TRIGGER_LOW | IRQF_ONESHOT,
  94                                            "chromeos-ec", ec_dev);
  95                 if (err) {
  96                         dev_err(dev, "Failed to request IRQ %d: %d",
  97                                 ec_dev->irq, err);
  98                         return err;
  99                 }
 100         }
 101
 102         err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
 103                               NULL, ec_dev->irq, NULL);
 104         if (err) {
 105                 dev_err(dev,
 106                         "Failed to register Embedded Controller subdevice %d\n",
 107                         err);
 108                 goto fail_mfd;
 109         }
 110
 111         if (ec_dev->max_passthru) {
 112                 /*
 113                  * Register a PD device as well on top of this device.
 114                  * We make the following assumptions:
 115                  * - behind an EC, we have a pd
 116                  * - only one device added.
 117                  * - the EC is responsive at init time (it is not true for a
 118                  *   sensor hub.
 119                  */
 120                 err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
 121                                       &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
 122                 if (err) {
 123                         dev_err(dev,
 124                                 "Failed to register Power Delivery subdevice %d\n",
 125                                 err);
 126                         goto fail_mfd;
 127                 }
 128         }
 129
 130         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 131                 err = of_platform_populate(dev->of_node, NULL, NULL, dev);
 132                 if (err) {
 133                         mfd_remove_devices(dev);
 134                         dev_err(dev, "Failed to register sub-devices\n");
 135                         goto fail_mfd;
 136                 }
 137         }
 138
 139         dev_info(dev, "Chrome EC device registered\n");
 140
 141         return 0;
 142
 143 fail_mfd:
 144         if (ec_dev->irq)
 145                 free_irq(ec_dev->irq, ec_dev);
 146         return err;
 147 }
 148 EXPORT_SYMBOL(cros_ec_register);
 149
 150 int cros_ec_remove(struct cros_ec_device *ec_dev)
 151 {
 152         mfd_remove_devices(ec_dev->dev);
 153
 154         return 0;
 155 }
 156 EXPORT_SYMBOL(cros_ec_remove);
 157
 158 #ifdef CONFIG_PM_SLEEP
 159 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 160 {
 161         struct device *dev = ec_dev->dev;
 162
 163         if (device_may_wakeup(dev))
 164                 ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
 165
 166         disable_irq(ec_dev->irq);
 167         ec_dev->was_wake_device = ec_dev->wake_enabled;
 168
 169         return 0;
 170 }
 171 EXPORT_SYMBOL(cros_ec_suspend);
 172
 173 static void cros_ec_drain_events(struct cros_ec_device *ec_dev)
 174 {
 175         while (cros_ec_get_next_event(ec_dev) > 0)
 176                 blocking_notifier_call_chain(&ec_dev->event_notifier,
 177                                              1, ec_dev);
 178 }
 179
 180 int cros_ec_resume(struct cros_ec_device *ec_dev)
 181 {
 182         enable_irq(ec_dev->irq);
 183
 184         /*
 185          * In some cases, we need to distinguish between events that occur
 186          * during suspend if the EC is not a wake source. For example,
 187          * keypresses during suspend should be discarded if it does not wake
 188          * the system.
 189          *
 190          * If the EC is not a wake source, drain the event queue and mark them
 191          * as "queued during suspend".
 192          */
 193         if (ec_dev->wake_enabled) {
 194                 disable_irq_wake(ec_dev->irq);
 195                 ec_dev->wake_enabled = 0;
 196         } else {
 197                 cros_ec_drain_events(ec_dev);
 198         }
 199
 200         return 0;
 201 }
 202 EXPORT_SYMBOL(cros_ec_resume);
 203
 204 #endif
 205
 206 MODULE_LICENSE("GPL");
 207 MODULE_DESCRIPTION("ChromeOS EC core driver");