drivers/platform/chrome/cros_usbpd_notify.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2020 Google LLC
   4  *
   5  * This driver serves as the receiver of cros_ec PD host events.
   6  */
   7
   8 #include <linux/acpi.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_data/cros_ec_proto.h>
  11 #include <linux/platform_data/cros_usbpd_notify.h>
  12 #include <linux/platform_device.h>
  13
  14 #define DRV_NAME "cros-usbpd-notify"
  15 #define DRV_NAME_PLAT_ACPI "cros-usbpd-notify-acpi"
  16 #define ACPI_DRV_NAME "GOOG0003"
  17
  18 static BLOCKING_NOTIFIER_HEAD(cros_usbpd_notifier_list);
  19
  20 struct cros_usbpd_notify_data {
  21         struct device *dev;
  22         struct cros_ec_device *ec;
  23         struct notifier_block nb;
  24 };
  25
  26 /**
  27  * cros_usbpd_register_notify - Register a notifier callback for PD events.
  28  * @nb: Notifier block pointer to register
  29  *
  30  * On ACPI platforms this corresponds to host events on the ECPD
  31  * "GOOG0003" ACPI device. On non-ACPI platforms this will filter mkbp events
  32  * for USB PD events.
  33  *
  34  * Return: 0 on success or negative error code.
  35  */
  36 int cros_usbpd_register_notify(struct notifier_block *nb)
  37 {
  38         return blocking_notifier_chain_register(&cros_usbpd_notifier_list,
  39                                                 nb);
  40 }
  41 EXPORT_SYMBOL_GPL(cros_usbpd_register_notify);
  42
  43 /**
  44  * cros_usbpd_unregister_notify - Unregister notifier callback for PD events.
  45  * @nb: Notifier block pointer to unregister
  46  *
  47  * Unregister a notifier callback that was previously registered with
  48  * cros_usbpd_register_notify().
  49  */
  50 void cros_usbpd_unregister_notify(struct notifier_block *nb)
  51 {
  52         blocking_notifier_chain_unregister(&cros_usbpd_notifier_list, nb);
  53 }
  54 EXPORT_SYMBOL_GPL(cros_usbpd_unregister_notify);
  55
  56 /**
  57  * cros_ec_pd_command - Send a command to the EC.
  58  *
  59  * @ec_dev: EC device
  60  * @command: EC command
  61  * @outdata: EC command output data
  62  * @outsize: Size of outdata
  63  * @indata: EC command input data
  64  * @insize: Size of indata
  65  *
  66  * Return: >= 0 on success, negative error number on failure.
  67  */
  68 static int cros_ec_pd_command(struct cros_ec_device *ec_dev,
  69                               int command,
  70                               uint8_t *outdata,
  71                               int outsize,
  72                               uint8_t *indata,
  73                               int insize)
  74 {
  75         struct cros_ec_command *msg;
  76         int ret;
  77
  78         msg = kzalloc(sizeof(*msg) + max(insize, outsize), GFP_KERNEL);
  79         if (!msg)
  80                 return -ENOMEM;
  81
  82         msg->command = command;
  83         msg->outsize = outsize;
  84         msg->insize = insize;
  85
  86         if (outsize)
  87                 memcpy(msg->data, outdata, outsize);
  88
  89         ret = cros_ec_cmd_xfer_status(ec_dev, msg);
  90         if (ret < 0)
  91                 goto error;
  92
  93         if (insize)
  94                 memcpy(indata, msg->data, insize);
  95 error:
  96         kfree(msg);
  97         return ret;
  98 }
  99
 100 static void cros_usbpd_get_event_and_notify(struct device  *dev,
 101                                             struct cros_ec_device *ec_dev)
 102 {
 103         struct ec_response_host_event_status host_event_status;
 104         u32 event = 0;
 105         int ret;
 106
 107         /*
 108          * We still send a 0 event out to older devices which don't
 109          * have the updated device heirarchy.
 110          */
 111         if (!ec_dev) {
 112                 dev_dbg(dev,
 113                         "EC device inaccessible; sending 0 event status.\n");
 114                 goto send_notify;
 115         }
 116
 117         /* Check for PD host events on EC. */
 118         ret = cros_ec_pd_command(ec_dev, EC_CMD_PD_HOST_EVENT_STATUS,
 119                                  NULL, 0,
 120                                  (uint8_t *)&host_event_status,
 121                                  sizeof(host_event_status));
 122         if (ret < 0) {
 123                 dev_warn(dev, "Can't get host event status (err: %d)\n", ret);
 124                 goto send_notify;
 125         }
 126
 127         event = host_event_status.status;
 128
 129 send_notify:
 130         blocking_notifier_call_chain(&cros_usbpd_notifier_list, event, NULL);
 131 }
 132
 133 #ifdef CONFIG_ACPI
 134
 135 static void cros_usbpd_notify_acpi(acpi_handle device, u32 event, void *data)
 136 {
 137         struct cros_usbpd_notify_data *pdnotify = data;
 138
 139         cros_usbpd_get_event_and_notify(pdnotify->dev, pdnotify->ec);
 140 }
 141
 142 static int cros_usbpd_notify_probe_acpi(struct platform_device *pdev)
 143 {
 144         struct cros_usbpd_notify_data *pdnotify;
 145         struct device *dev = &pdev->dev;
 146         struct acpi_device *adev;
 147         struct cros_ec_device *ec_dev;
 148         acpi_status status;
 149
 150         adev = ACPI_COMPANION(dev);
 151
 152         pdnotify = devm_kzalloc(dev, sizeof(*pdnotify), GFP_KERNEL);
 153         if (!pdnotify)
 154                 return -ENOMEM;
 155
 156         /* Get the EC device pointer needed to talk to the EC. */
 157         ec_dev = dev_get_drvdata(dev->parent);
 158         if (!ec_dev) {
 159                 /*
 160                  * We continue even for older devices which don't have the
 161                  * correct device heirarchy, namely, GOOG0003 is a child
 162                  * of GOOG0004.
 163                  */
 164                 dev_warn(dev, "Couldn't get Chrome EC device pointer.\n");
 165         }
 166
 167         pdnotify->dev = dev;
 168         pdnotify->ec = ec_dev;
 169
 170         status = acpi_install_notify_handler(adev->handle,
 171                                              ACPI_ALL_NOTIFY,
 172                                              cros_usbpd_notify_acpi,
 173                                              pdnotify);
 174         if (ACPI_FAILURE(status)) {
 175                 dev_warn(dev, "Failed to register notify handler %08x\n",
 176                          status);
 177                 return -EINVAL;
 178         }
 179
 180         return 0;
 181 }
 182
 183 static int cros_usbpd_notify_remove_acpi(struct platform_device *pdev)
 184 {
 185         struct device *dev = &pdev->dev;
 186         struct acpi_device *adev = ACPI_COMPANION(dev);
 187
 188         acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
 189                                    cros_usbpd_notify_acpi);
 190
 191         return 0;
 192 }
 193
 194 static const struct acpi_device_id cros_usbpd_notify_acpi_device_ids[] = {
 195         { ACPI_DRV_NAME, 0 },
 196         { }
 197 };
 198 MODULE_DEVICE_TABLE(acpi, cros_usbpd_notify_acpi_device_ids);
 199
 200 static struct platform_driver cros_usbpd_notify_acpi_driver = {
 201         .driver = {
 202                 .name = DRV_NAME_PLAT_ACPI,
 203                 .acpi_match_table = cros_usbpd_notify_acpi_device_ids,
 204         },
 205         .probe = cros_usbpd_notify_probe_acpi,
 206         .remove = cros_usbpd_notify_remove_acpi,
 207 };
 208
 209 #endif /* CONFIG_ACPI */
 210
 211 static int cros_usbpd_notify_plat(struct notifier_block *nb,
 212                                   unsigned long queued_during_suspend,
 213                                   void *data)
 214 {
 215         struct cros_usbpd_notify_data *pdnotify = container_of(nb,
 216                         struct cros_usbpd_notify_data, nb);
 217         struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
 218         u32 host_event = cros_ec_get_host_event(ec_dev);
 219
 220         if (!host_event)
 221                 return NOTIFY_DONE;
 222
 223         if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU)) {
 224                 cros_usbpd_get_event_and_notify(pdnotify->dev, ec_dev);
 225                 return NOTIFY_OK;
 226         }
 227         return NOTIFY_DONE;
 228 }
 229
 230 static int cros_usbpd_notify_probe_plat(struct platform_device *pdev)
 231 {
 232         struct device *dev = &pdev->dev;
 233         struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
 234         struct cros_usbpd_notify_data *pdnotify;
 235         int ret;
 236
 237         pdnotify = devm_kzalloc(dev, sizeof(*pdnotify), GFP_KERNEL);
 238         if (!pdnotify)
 239                 return -ENOMEM;
 240
 241         pdnotify->dev = dev;
 242         pdnotify->ec = ecdev->ec_dev;
 243         pdnotify->nb.notifier_call = cros_usbpd_notify_plat;
 244
 245         dev_set_drvdata(dev, pdnotify);
 246
 247         ret = blocking_notifier_chain_register(&ecdev->ec_dev->event_notifier,
 248                                                &pdnotify->nb);
 249         if (ret < 0) {
 250                 dev_err(dev, "Failed to register notifier\n");
 251                 return ret;
 252         }
 253
 254         return 0;
 255 }
 256
 257 static int cros_usbpd_notify_remove_plat(struct platform_device *pdev)
 258 {
 259         struct device *dev = &pdev->dev;
 260         struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
 261         struct cros_usbpd_notify_data *pdnotify =
 262                 (struct cros_usbpd_notify_data *)dev_get_drvdata(dev);
 263
 264         blocking_notifier_chain_unregister(&ecdev->ec_dev->event_notifier,
 265                                            &pdnotify->nb);
 266
 267         return 0;
 268 }
 269
 270 static struct platform_driver cros_usbpd_notify_plat_driver = {
 271         .driver = {
 272                 .name = DRV_NAME,
 273         },
 274         .probe = cros_usbpd_notify_probe_plat,
 275         .remove = cros_usbpd_notify_remove_plat,
 276 };
 277
 278 static int __init cros_usbpd_notify_init(void)
 279 {
 280         int ret;
 281
 282         ret = platform_driver_register(&cros_usbpd_notify_plat_driver);
 283         if (ret < 0)
 284                 return ret;
 285
 286 #ifdef CONFIG_ACPI
 287         platform_driver_register(&cros_usbpd_notify_acpi_driver);
 288 #endif
 289         return 0;
 290 }
 291
 292 static void __exit cros_usbpd_notify_exit(void)
 293 {
 294 #ifdef CONFIG_ACPI
 295         platform_driver_unregister(&cros_usbpd_notify_acpi_driver);
 296 #endif
 297         platform_driver_unregister(&cros_usbpd_notify_plat_driver);
 298 }
 299
 300 module_init(cros_usbpd_notify_init);
 301 module_exit(cros_usbpd_notify_exit);
 302
 303 MODULE_LICENSE("GPL");
 304 MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
 305 MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
 306 MODULE_ALIAS("platform:" DRV_NAME);