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