OSCL-LXR linux-6.0.1/​drivers/​platform/​surface/​aggregator/​core.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Surface Serial Hub (SSH) driver for communication with the Surface/System
  * Aggregator Module (SSAM/SAM).
  *
  * Provides access to a SAM-over-SSH connected EC via a controller device.
  * Handles communication via requests as well as enabling, disabling, and
  * relaying of events.
  *
  * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com>
  */
 
 #include <linux/acpi.h>
 #include <linux/atomic.h>
 #include <linux/completion.h>
 #include <linux/gpio/consumer.h>
 #include <linux/kernel.h>
 #include <linux/kref.h>
 #include <linux/module.h>
 #include <linux/pm.h>
 #include <linux/serdev.h>
 #include <linux/sysfs.h>
 
 #include <linux/surface_aggregator/controller.h>
 #include <linux/surface_aggregator/device.h>
 
 #include "bus.h"
 #include "controller.h"
 
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
 
 /* -- Static controller reference. ------------------------------------------ */
 
 /*
  * Main controller reference. The corresponding lock must be held while
  * accessing (reading/writing) the reference.
  */
 static struct ssam_controller *__ssam_controller;
 static DEFINE_SPINLOCK(__ssam_controller_lock);
 
 /**
  * ssam_get_controller() - Get reference to SSAM controller.
  *
  * Returns a reference to the SSAM controller of the system or %NULL if there
  * is none, it hasn't been set up yet, or it has already been unregistered.
  * This function automatically increments the reference count of the
  * controller, thus the calling party must ensure that ssam_controller_put()
  * is called when it doesn't need the controller any more.
  */
 struct ssam_controller *ssam_get_controller(void)
 {
     struct ssam_controller *ctrl;
 
     spin_lock(&__ssam_controller_lock);
 
     ctrl = __ssam_controller;
     if (!ctrl)
         goto out;
 
     if (WARN_ON(!kref_get_unless_zero(&ctrl->kref)))
         ctrl = NULL;
 
 out:
     spin_unlock(&__ssam_controller_lock);
     return ctrl;
 }
 EXPORT_SYMBOL_GPL(ssam_get_controller);
 
 /**
  * ssam_try_set_controller() - Try to set the main controller reference.
  * @ctrl: The controller to which the reference should point.
  *
  * Set the main controller reference to the given pointer if the reference
  * hasn't been set already.
  *
  * Return: Returns zero on success or %-EEXIST if the reference has already
  * been set.
  */
 static int ssam_try_set_controller(struct ssam_controller *ctrl)
 {
     int status = 0;
 
     spin_lock(&__ssam_controller_lock);
     if (!__ssam_controller)
         __ssam_controller = ctrl;
     else
         status = -EEXIST;
     spin_unlock(&__ssam_controller_lock);
 
     return status;
 }
 
 /**
  * ssam_clear_controller() - Remove/clear the main controller reference.
  *
  * Clears the main controller reference, i.e. sets it to %NULL. This function
  * should be called before the controller is shut down.
  */
 static void ssam_clear_controller(void)
 {
     spin_lock(&__ssam_controller_lock);
     __ssam_controller = NULL;
     spin_unlock(&__ssam_controller_lock);
 }
 
 /**
  * ssam_client_link() - Link an arbitrary client device to the controller.
  * @c: The controller to link to.
  * @client: The client device.
  *
  * Link an arbitrary client device to the controller by creating a device link
  * between it as consumer and the controller device as provider. This function
  * can be used for non-SSAM devices (or SSAM devices not registered as child
  * under the controller) to guarantee that the controller is valid for as long
  * as the driver of the client device is bound, and that proper suspend and
  * resume ordering is guaranteed.
  *
  * The device link does not have to be destructed manually. It is removed
  * automatically once the driver of the client device unbinds.
  *
  * Return: Returns zero on success, %-ENODEV if the controller is not ready or
  * going to be removed soon, or %-ENOMEM if the device link could not be
  * created for other reasons.
  */
 int ssam_client_link(struct ssam_controller *c, struct device *client)
 {
     const u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER;
     struct device_link *link;
     struct device *ctrldev;
 
     ssam_controller_statelock(c);
 
     if (c->state != SSAM_CONTROLLER_STARTED) {
         ssam_controller_stateunlock(c);
         return -ENODEV;
     }
 
     ctrldev = ssam_controller_device(c);
     if (!ctrldev) {
         ssam_controller_stateunlock(c);
         return -ENODEV;
     }
 
     link = device_link_add(client, ctrldev, flags);
     if (!link) {
         ssam_controller_stateunlock(c);
         return -ENOMEM;
     }
 
     /*
      * Return -ENODEV if supplier driver is on its way to be removed. In
      * this case, the controller won't be around for much longer and the
      * device link is not going to save us any more, as unbinding is
      * already in progress.
      */
     if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND) {
         ssam_controller_stateunlock(c);
         return -ENODEV;
     }
 
     ssam_controller_stateunlock(c);
     return 0;
 }
 EXPORT_SYMBOL_GPL(ssam_client_link);
 
 /**
  * ssam_client_bind() - Bind an arbitrary client device to the controller.
  * @client: The client device.
  *
  * Link an arbitrary client device to the controller by creating a device link
  * between it as consumer and the main controller device as provider. This
  * function can be used for non-SSAM devices to guarantee that the controller
  * returned by this function is valid for as long as the driver of the client
  * device is bound, and that proper suspend and resume ordering is guaranteed.
  *
  * This function does essentially the same as ssam_client_link(), except that
  * it first fetches the main controller reference, then creates the link, and
  * finally returns this reference. Note that this function does not increment
  * the reference counter of the controller, as, due to the link, the
  * controller lifetime is assured as long as the driver of the client device
  * is bound.
  *
  * It is not valid to use the controller reference obtained by this method
  * outside of the driver bound to the client device at the time of calling
  * this function, without first incrementing the reference count of the
  * controller via ssam_controller_get(). Even after doing this, care must be
  * taken that requests are only submitted and notifiers are only
  * (un-)registered when the controller is active and not suspended. In other
  * words: The device link only lives as long as the client driver is bound and
  * any guarantees enforced by this link (e.g. active controller state) can
  * only be relied upon as long as this link exists and may need to be enforced
  * in other ways afterwards.
  *
  * The created device link does not have to be destructed manually. It is
  * removed automatically once the driver of the client device unbinds.
  *
  * Return: Returns the controller on success, an error pointer with %-ENODEV
  * if the controller is not present, not ready or going to be removed soon, or
  * %-ENOMEM if the device link could not be created for other reasons.
  */
 struct ssam_controller *ssam_client_bind(struct device *client)
 {
     struct ssam_controller *c;
     int status;
 
     c = ssam_get_controller();
     if (!c)
         return ERR_PTR(-ENODEV);
 
     status = ssam_client_link(c, client);
 
     /*
      * Note that we can drop our controller reference in both success and
      * failure cases: On success, we have bound the controller lifetime
      * inherently to the client driver lifetime, i.e. it the controller is
      * now guaranteed to outlive the client driver. On failure, we're not
      * going to use the controller any more.
      */
     ssam_controller_put(c);
 
     return status >= 0 ? c : ERR_PTR(status);
 }
 EXPORT_SYMBOL_GPL(ssam_client_bind);
 
 
 /* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */
 
 static int ssam_receive_buf(struct serdev_device *dev, const unsigned char *buf,
                 size_t n)
 {
     struct ssam_controller *ctrl;
 
     ctrl = serdev_device_get_drvdata(dev);
     return ssam_controller_receive_buf(ctrl, buf, n);
 }
 
 static void ssam_write_wakeup(struct serdev_device *dev)
 {
     ssam_controller_write_wakeup(serdev_device_get_drvdata(dev));
 }
 
 static const struct serdev_device_ops ssam_serdev_ops = {
     .receive_buf = ssam_receive_buf,
     .write_wakeup = ssam_write_wakeup,
 };
 
 
 /* -- SysFS and misc. ------------------------------------------------------- */
 
 static int ssam_log_firmware_version(struct ssam_controller *ctrl)
 {
     u32 version, a, b, c;
     int status;
 
     status = ssam_get_firmware_version(ctrl, &version);
     if (status)
         return status;
 
     a = (version >> 24) & 0xff;
     b = ((version >> 8) & 0xffff);
     c = version & 0xff;
 
     ssam_info(ctrl, "SAM firmware version: %u.%u.%u\n", a, b, c);
     return 0;
 }
 
 static ssize_t firmware_version_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
 {
     struct ssam_controller *ctrl = dev_get_drvdata(dev);
     u32 version, a, b, c;
     int status;
 
     status = ssam_get_firmware_version(ctrl, &version);
     if (status < 0)
         return status;
 
     a = (version >> 24) & 0xff;
     b = ((version >> 8) & 0xffff);
     c = version & 0xff;
 
     return sysfs_emit(buf, "%u.%u.%u\n", a, b, c);
 }
 static DEVICE_ATTR_RO(firmware_version);
 
 static struct attribute *ssam_sam_attrs[] = {
     &dev_attr_firmware_version.attr,
     NULL
 };
 
 static const struct attribute_group ssam_sam_group = {
     .name = "sam",
     .attrs = ssam_sam_attrs,
 };
 
 
 /* -- ACPI based device setup. ---------------------------------------------- */
 
 static acpi_status ssam_serdev_setup_via_acpi_crs(struct acpi_resource *rsc,
                           void *ctx)
 {
     struct serdev_device *serdev = ctx;
     struct acpi_resource_uart_serialbus *uart;
     bool flow_control;
     int status = 0;
 
     if (!serdev_acpi_get_uart_resource(rsc, &uart))
         return AE_OK;
 
     /* Set up serdev device. */
     serdev_device_set_baudrate(serdev, uart->default_baud_rate);
 
     /* serdev currently only supports RTSCTS flow control. */
     if (uart->flow_control & (~((u8)ACPI_UART_FLOW_CONTROL_HW))) {
         dev_warn(&serdev->dev, "setup: unsupported flow control (value: %#04x)\n",
              uart->flow_control);
     }
 
     /* Set RTSCTS flow control. */
     flow_control = uart->flow_control & ACPI_UART_FLOW_CONTROL_HW;
     serdev_device_set_flow_control(serdev, flow_control);
 
     /* serdev currently only supports EVEN/ODD parity. */
     switch (uart->parity) {
     case ACPI_UART_PARITY_NONE:
         status = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
         break;
     case ACPI_UART_PARITY_EVEN:
         status = serdev_device_set_parity(serdev, SERDEV_PARITY_EVEN);
         break;
     case ACPI_UART_PARITY_ODD:
         status = serdev_device_set_parity(serdev, SERDEV_PARITY_ODD);
         break;
     default:
         dev_warn(&serdev->dev, "setup: unsupported parity (value: %#04x)\n",
              uart->parity);
         break;
     }
 
     if (status) {
         dev_err(&serdev->dev, "setup: failed to set parity (value: %#04x, error: %d)\n",
             uart->parity, status);
         return AE_ERROR;
     }
 
     /* We've found the resource and are done. */
     return AE_CTRL_TERMINATE;
 }
 
 static acpi_status ssam_serdev_setup_via_acpi(acpi_handle handle,
                           struct serdev_device *serdev)
 {
     return acpi_walk_resources(handle, METHOD_NAME__CRS,
                    ssam_serdev_setup_via_acpi_crs, serdev);
 }
 
 
 /* -- Power management. ----------------------------------------------------- */
 
 static void ssam_serial_hub_shutdown(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * Try to disable notifiers, signal display-off and D0-exit, ignore any
      * errors.
      *
      * Note: It has not been established yet if this is actually
      * necessary/useful for shutdown.
      */
 
     status = ssam_notifier_disable_registered(c);
     if (status) {
         ssam_err(c, "pm: failed to disable notifiers for shutdown: %d\n",
              status);
     }
 
     status = ssam_ctrl_notif_display_off(c);
     if (status)
         ssam_err(c, "pm: display-off notification failed: %d\n", status);
 
     status = ssam_ctrl_notif_d0_exit(c);
     if (status)
         ssam_err(c, "pm: D0-exit notification failed: %d\n", status);
 }
 
 #ifdef CONFIG_PM_SLEEP
 
 static int ssam_serial_hub_pm_prepare(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * Try to signal display-off, This will quiesce events.
      *
      * Note: Signaling display-off/display-on should normally be done from
      * some sort of display state notifier. As that is not available,
      * signal it here.
      */
 
     status = ssam_ctrl_notif_display_off(c);
     if (status)
         ssam_err(c, "pm: display-off notification failed: %d\n", status);
 
     return status;
 }
 
 static void ssam_serial_hub_pm_complete(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * Try to signal display-on. This will restore events.
      *
      * Note: Signaling display-off/display-on should normally be done from
      * some sort of display state notifier. As that is not available,
      * signal it here.
      */
 
     status = ssam_ctrl_notif_display_on(c);
     if (status)
         ssam_err(c, "pm: display-on notification failed: %d\n", status);
 }
 
 static int ssam_serial_hub_pm_suspend(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * Try to signal D0-exit, enable IRQ wakeup if specified. Abort on
      * error.
      */
 
     status = ssam_ctrl_notif_d0_exit(c);
     if (status) {
         ssam_err(c, "pm: D0-exit notification failed: %d\n", status);
         goto err_notif;
     }
 
     status = ssam_irq_arm_for_wakeup(c);
     if (status)
         goto err_irq;
 
     WARN_ON(ssam_controller_suspend(c));
     return 0;
 
 err_irq:
     ssam_ctrl_notif_d0_entry(c);
 err_notif:
     ssam_ctrl_notif_display_on(c);
     return status;
 }
 
 static int ssam_serial_hub_pm_resume(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     WARN_ON(ssam_controller_resume(c));
 
     /*
      * Try to disable IRQ wakeup (if specified) and signal D0-entry. In
      * case of errors, log them and try to restore normal operation state
      * as far as possible.
      *
      * Note: Signaling display-off/display-on should normally be done from
      * some sort of display state notifier. As that is not available,
      * signal it here.
      */
 
     ssam_irq_disarm_wakeup(c);
 
     status = ssam_ctrl_notif_d0_entry(c);
     if (status)
         ssam_err(c, "pm: D0-entry notification failed: %d\n", status);
 
     return 0;
 }
 
 static int ssam_serial_hub_pm_freeze(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * During hibernation image creation, we only have to ensure that the
      * EC doesn't send us any events. This is done via the display-off
      * and D0-exit notifications. Note that this sets up the wakeup IRQ
      * on the EC side, however, we have disabled it by default on our side
      * and won't enable it here.
      *
      * See ssam_serial_hub_poweroff() for more details on the hibernation
      * process.
      */
 
     status = ssam_ctrl_notif_d0_exit(c);
     if (status) {
         ssam_err(c, "pm: D0-exit notification failed: %d\n", status);
         ssam_ctrl_notif_display_on(c);
         return status;
     }
 
     WARN_ON(ssam_controller_suspend(c));
     return 0;
 }
 
 static int ssam_serial_hub_pm_thaw(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     WARN_ON(ssam_controller_resume(c));
 
     status = ssam_ctrl_notif_d0_entry(c);
     if (status)
         ssam_err(c, "pm: D0-exit notification failed: %d\n", status);
 
     return status;
 }
 
 static int ssam_serial_hub_pm_poweroff(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * When entering hibernation and powering off the system, the EC, at
      * least on some models, may disable events. Without us taking care of
      * that, this leads to events not being enabled/restored when the
      * system resumes from hibernation, resulting SAM-HID subsystem devices
      * (i.e. keyboard, touchpad) not working, AC-plug/AC-unplug events being
      * gone, etc.
      *
      * To avoid these issues, we disable all registered events here (this is
      * likely not actually required) and restore them during the drivers PM
      * restore callback.
      *
      * Wakeup from the EC interrupt is not supported during hibernation,
      * so don't arm the IRQ here.
      */
 
     status = ssam_notifier_disable_registered(c);
     if (status) {
         ssam_err(c, "pm: failed to disable notifiers for hibernation: %d\n",
              status);
         return status;
     }
 
     status = ssam_ctrl_notif_d0_exit(c);
     if (status) {
         ssam_err(c, "pm: D0-exit notification failed: %d\n", status);
         ssam_notifier_restore_registered(c);
         return status;
     }
 
     WARN_ON(ssam_controller_suspend(c));
     return 0;
 }
 
 static int ssam_serial_hub_pm_restore(struct device *dev)
 {
     struct ssam_controller *c = dev_get_drvdata(dev);
     int status;
 
     /*
      * Ignore but log errors, try to restore state as much as possible in
      * case of failures. See ssam_serial_hub_poweroff() for more details on
      * the hibernation process.
      */
 
     WARN_ON(ssam_controller_resume(c));
 
     status = ssam_ctrl_notif_d0_entry(c);
     if (status)
         ssam_err(c, "pm: D0-entry notification failed: %d\n", status);
 
     ssam_notifier_restore_registered(c);
     return 0;
 }
 
 static const struct dev_pm_ops ssam_serial_hub_pm_ops = {
     .prepare  = ssam_serial_hub_pm_prepare,
     .complete = ssam_serial_hub_pm_complete,
     .suspend  = ssam_serial_hub_pm_suspend,
     .resume   = ssam_serial_hub_pm_resume,
     .freeze   = ssam_serial_hub_pm_freeze,
     .thaw     = ssam_serial_hub_pm_thaw,
     .poweroff = ssam_serial_hub_pm_poweroff,
     .restore  = ssam_serial_hub_pm_restore,
 };
 
 #else /* CONFIG_PM_SLEEP */
 
 static const struct dev_pm_ops ssam_serial_hub_pm_ops = { };
 
 #endif /* CONFIG_PM_SLEEP */
 
 
 /* -- Device/driver setup. -------------------------------------------------- */
 
 static const struct acpi_gpio_params gpio_ssam_wakeup_int = { 0, 0, false };
 static const struct acpi_gpio_params gpio_ssam_wakeup     = { 1, 0, false };
 
 static const struct acpi_gpio_mapping ssam_acpi_gpios[] = {
     { "ssam_wakeup-int-gpio", &gpio_ssam_wakeup_int, 1 },
     { "ssam_wakeup-gpio",     &gpio_ssam_wakeup,     1 },
     { },
 };
 
 static int ssam_serial_hub_probe(struct serdev_device *serdev)
 {
     struct acpi_device *ssh = ACPI_COMPANION(&serdev->dev);
     struct ssam_controller *ctrl;
     acpi_status astatus;
     int status;
 
     if (gpiod_count(&serdev->dev, NULL) < 0)
         return -ENODEV;
 
     status = devm_acpi_dev_add_driver_gpios(&serdev->dev, ssam_acpi_gpios);
     if (status)
         return status;
 
     /* Allocate controller. */
     ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
     if (!ctrl)
         return -ENOMEM;
 
     /* Initialize controller. */
     status = ssam_controller_init(ctrl, serdev);
     if (status)
         goto err_ctrl_init;
 
     ssam_controller_lock(ctrl);
 
     /* Set up serdev device. */
     serdev_device_set_drvdata(serdev, ctrl);
     serdev_device_set_client_ops(serdev, &ssam_serdev_ops);
     status = serdev_device_open(serdev);
     if (status)
         goto err_devopen;
 
     astatus = ssam_serdev_setup_via_acpi(ssh->handle, serdev);
     if (ACPI_FAILURE(astatus)) {
         status = -ENXIO;
         goto err_devinit;
     }
 
     /* Start controller. */
     status = ssam_controller_start(ctrl);
     if (status)
         goto err_devinit;
 
     ssam_controller_unlock(ctrl);
 
     /*
      * Initial SAM requests: Log version and notify default/init power
      * states.
      */
     status = ssam_log_firmware_version(ctrl);
     if (status)
         goto err_initrq;
 
     status = ssam_ctrl_notif_d0_entry(ctrl);
     if (status)
         goto err_initrq;
 
     status = ssam_ctrl_notif_display_on(ctrl);
     if (status)
         goto err_initrq;
 
     status = sysfs_create_group(&serdev->dev.kobj, &ssam_sam_group);
     if (status)
         goto err_initrq;
 
     /* Set up IRQ. */
     status = ssam_irq_setup(ctrl);
     if (status)
         goto err_irq;
 
     /* Finally, set main controller reference. */
     status = ssam_try_set_controller(ctrl);
     if (WARN_ON(status))    /* Currently, we're the only provider. */
         goto err_mainref;
 
     /*
      * TODO: The EC can wake up the system via the associated GPIO interrupt
      *       in multiple situations. One of which is the remaining battery
      *       capacity falling below a certain threshold. Normally, we should
      *       use the device_init_wakeup function, however, the EC also seems
      *       to have other reasons for waking up the system and it seems
      *       that Windows has additional checks whether the system should be
      *       resumed. In short, this causes some spurious unwanted wake-ups.
      *       For now let's thus default power/wakeup to false.
      */
     device_set_wakeup_capable(&serdev->dev, true);
     acpi_dev_clear_dependencies(ssh);
 
     return 0;
 
 err_mainref:
     ssam_irq_free(ctrl);
 err_irq:
     sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group);
 err_initrq:
     ssam_controller_lock(ctrl);
     ssam_controller_shutdown(ctrl);
 err_devinit:
     serdev_device_close(serdev);
 err_devopen:
     ssam_controller_destroy(ctrl);
     ssam_controller_unlock(ctrl);
 err_ctrl_init:
     kfree(ctrl);
     return status;
 }
 
 static void ssam_serial_hub_remove(struct serdev_device *serdev)
 {
     struct ssam_controller *ctrl = serdev_device_get_drvdata(serdev);
     int status;
 
     /* Clear static reference so that no one else can get a new one. */
     ssam_clear_controller();
 
     /* Disable and free IRQ. */
     ssam_irq_free(ctrl);
 
     sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group);
     ssam_controller_lock(ctrl);
 
     /* Remove all client devices. */
     ssam_remove_clients(&serdev->dev);
 
     /* Act as if suspending to silence events. */
     status = ssam_ctrl_notif_display_off(ctrl);
     if (status) {
         dev_err(&serdev->dev, "display-off notification failed: %d\n",
             status);
     }
 
     status = ssam_ctrl_notif_d0_exit(ctrl);
     if (status) {
         dev_err(&serdev->dev, "D0-exit notification failed: %d\n",
             status);
     }
 
     /* Shut down controller and remove serdev device reference from it. */
     ssam_controller_shutdown(ctrl);
 
     /* Shut down actual transport. */
     serdev_device_wait_until_sent(serdev, 0);
     serdev_device_close(serdev);
 
     /* Drop our controller reference. */
     ssam_controller_unlock(ctrl);
     ssam_controller_put(ctrl);
 
     device_set_wakeup_capable(&serdev->dev, false);
 }
 
 static const struct acpi_device_id ssam_serial_hub_match[] = {
     { "MSHW0084", 0 },
     { },
 };
 MODULE_DEVICE_TABLE(acpi, ssam_serial_hub_match);
 
 static struct serdev_device_driver ssam_serial_hub = {
     .probe = ssam_serial_hub_probe,
     .remove = ssam_serial_hub_remove,
     .driver = {
         .name = "surface_serial_hub",
         .acpi_match_table = ssam_serial_hub_match,
         .pm = &ssam_serial_hub_pm_ops,
         .shutdown = ssam_serial_hub_shutdown,
         .probe_type = PROBE_PREFER_ASYNCHRONOUS,
     },
 };
 
 
 /* -- Module setup. --------------------------------------------------------- */
 
 static int __init ssam_core_init(void)
 {
     int status;
 
     status = ssam_bus_register();
     if (status)
         goto err_bus;
 
     status = ssh_ctrl_packet_cache_init();
     if (status)
         goto err_cpkg;
 
     status = ssam_event_item_cache_init();
     if (status)
         goto err_evitem;
 
     status = serdev_device_driver_register(&ssam_serial_hub);
     if (status)
         goto err_register;
 
     return 0;
 
 err_register:
     ssam_event_item_cache_destroy();
 err_evitem:
     ssh_ctrl_packet_cache_destroy();
 err_cpkg:
     ssam_bus_unregister();
 err_bus:
     return status;
 }
 subsys_initcall(ssam_core_init);
 
 static void __exit ssam_core_exit(void)
 {
     serdev_device_driver_unregister(&ssam_serial_hub);
     ssam_event_item_cache_destroy();
     ssh_ctrl_packet_cache_destroy();
     ssam_bus_unregister();
 }
 module_exit(ssam_core_exit);
 
 MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
 MODULE_DESCRIPTION("Subsystem and Surface Serial Hub driver for Surface System Aggregator Module");
 MODULE_LICENSE("GPL");

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