linux-surface/patches/5.14/0005-surface-sam.patch

From 93c1103857ae9557a867a378268c76d8d52dba09 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sun, 10 Oct 2021 01:27:17 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Add support for
 Surface Laptop Studio

Add support for the Surface Laptop Studio.

In contrast to previous Surface Laptop models, this one has its HID
devices attached to target ID 1 (instead of 2). It also has a couple
more of them, including a new notifier for when the pen is stashed /
taken out of its place, a "Sys Control" device, and two other
unidentified HID devices with unknown usages.

Battery and performance profile interfaces remain the same.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../surface/surface_aggregator_registry.c     | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 4428c4330229..1679811eff50 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -77,6 +77,42 @@ static const struct software_node ssam_node_bas_dtx = {
 	.parent = &ssam_node_root,
 };
 
+/* HID keyboard (TID1). */
+static const struct software_node ssam_node_hid_tid1_keyboard = {
+	.name = "ssam:01:15:01:01:00",
+	.parent = &ssam_node_root,
+};
+
+/* HID pen stash (TID1; pen taken / stashed away evens). */
+static const struct software_node ssam_node_hid_tid1_penstash = {
+	.name = "ssam:01:15:01:02:00",
+	.parent = &ssam_node_root,
+};
+
+/* HID touchpad (TID1). */
+static const struct software_node ssam_node_hid_tid1_touchpad = {
+	.name = "ssam:01:15:01:03:00",
+	.parent = &ssam_node_root,
+};
+
+/* HID device instance 6 (TID1, unknown HID device). */
+static const struct software_node ssam_node_hid_tid1_iid6 = {
+	.name = "ssam:01:15:01:06:00",
+	.parent = &ssam_node_root,
+};
+
+/* HID device instance 7 (TID1, unknown HID device). */
+static const struct software_node ssam_node_hid_tid1_iid7 = {
+	.name = "ssam:01:15:01:07:00",
+	.parent = &ssam_node_root,
+};
+
+/* HID system controls (TID1). */
+static const struct software_node ssam_node_hid_tid1_sysctrl = {
+	.name = "ssam:01:15:01:08:00",
+	.parent = &ssam_node_root,
+};
+
 /* HID keyboard. */
 static const struct software_node ssam_node_hid_main_keyboard = {
 	.name = "ssam:01:15:02:01:00",
@@ -159,6 +195,21 @@ static const struct software_node *ssam_node_group_sl3[] = {
 	NULL,
 };
 
+/* Devices for Surface Laptop Studio. */
+static const struct software_node *ssam_node_group_sls[] = {
+	&ssam_node_root,
+	&ssam_node_bat_ac,
+	&ssam_node_bat_main,
+	&ssam_node_tmp_pprof,
+	&ssam_node_hid_tid1_keyboard,
+	&ssam_node_hid_tid1_penstash,
+	&ssam_node_hid_tid1_touchpad,
+	&ssam_node_hid_tid1_iid6,
+	&ssam_node_hid_tid1_iid7,
+	&ssam_node_hid_tid1_sysctrl,
+	NULL,
+};
+
 /* Devices for Surface Laptop Go. */
 static const struct software_node *ssam_node_group_slg1[] = {
 	&ssam_node_root,
@@ -507,6 +558,9 @@ static const struct acpi_device_id ssam_platform_hub_match[] = {
 	/* Surface Laptop Go 1 */
 	{ "MSHW0118", (unsigned long)ssam_node_group_slg1 },
 
+	/* Surface Laptop Studio */
+	{ "MSHW0123", (unsigned long)ssam_node_group_sls },
+
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, ssam_platform_hub_match);
-- 
2.33.1

From 8cf31537f7ad6798f881b0cb65e32a6bb5dc787c Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sun, 10 Oct 2021 15:07:42 +0200
Subject: [PATCH] HID: surface-hid: Use correct event registry for managing HID
 events

Fix a timeout error caused by using the wrong registry for some devices,
preventing the driver to probe and manage events correctly.

Until now, we have only ever seen the REG-category registry being used
on devices addressed with target ID 2. In fact, we have only ever seen
Surface Aggregator Module (SAM) HID devices with target ID 2. For those
devices, the registry also has to be addressed with target ID 2.

Some devices, like the new Surface Laptop Studio, however, address their
HID devices on target ID 1. As a result of this, any target ID 2
commands time out. This includes event management commands addressed to
the target ID 2 REG-category registry. For these devices, the registry
has to be addressed via target ID 1 instead.

We therefore assume that the target ID of the registry to be used
depends on the target ID of the respective device. Implement this
accordingly.

Fixes: b05ff1002a5c1 ("HID: Add support for Surface Aggregator Module HID transport")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/hid/surface-hid/surface_hid.c         | 2 +-
 include/linux/surface_aggregator/controller.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/surface-hid/surface_hid.c b/drivers/hid/surface-hid/surface_hid.c
index a3a70e4f3f6c..daa452367c0b 100644
--- a/drivers/hid/surface-hid/surface_hid.c
+++ b/drivers/hid/surface-hid/surface_hid.c
@@ -209,7 +209,7 @@ static int surface_hid_probe(struct ssam_device *sdev)
 
 	shid->notif.base.priority = 1;
 	shid->notif.base.fn = ssam_hid_event_fn;
-	shid->notif.event.reg = SSAM_EVENT_REGISTRY_REG;
+	shid->notif.event.reg = SSAM_EVENT_REGISTRY_REG(sdev->uid.target);
 	shid->notif.event.id.target_category = sdev->uid.category;
 	shid->notif.event.id.instance = sdev->uid.instance;
 	shid->notif.event.mask = SSAM_EVENT_MASK_STRICT;
diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h
index 068e1982ad37..74bfdffaf7b0 100644
--- a/include/linux/surface_aggregator/controller.h
+++ b/include/linux/surface_aggregator/controller.h
@@ -792,8 +792,8 @@ enum ssam_event_mask {
 #define SSAM_EVENT_REGISTRY_KIP	\
 	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_KIP, 0x02, 0x27, 0x28)
 
-#define SSAM_EVENT_REGISTRY_REG \
-	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, 0x02, 0x01, 0x02)
+#define SSAM_EVENT_REGISTRY_REG(tid)\
+	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, tid, 0x01, 0x02)
 
 /**
  * enum ssam_event_notifier_flags - Flags for event notifiers.
-- 
2.33.1

From e37ee323ec827c2ef5ad30f7105203715afc76f4 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sun, 10 Oct 2021 19:48:10 +0200
Subject: [PATCH] HID: surface-hid: Allow driver matching for target ID 1
 devices

Until now we have only ever seen HID devices with target ID 2. The new
Surface Laptop Studio however uses HID devices with target ID 1. Allow
matching this driver to those as well.

Fixes: b05ff1002a5c1 ("HID: Add support for Surface Aggregator Module HID transport")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/hid/surface-hid/surface_hid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/surface-hid/surface_hid.c b/drivers/hid/surface-hid/surface_hid.c
index daa452367c0b..d4aa8c81903a 100644
--- a/drivers/hid/surface-hid/surface_hid.c
+++ b/drivers/hid/surface-hid/surface_hid.c
@@ -230,7 +230,7 @@ static void surface_hid_remove(struct ssam_device *sdev)
 }
 
 static const struct ssam_device_id surface_hid_match[] = {
-	{ SSAM_SDEV(HID, 0x02, SSAM_ANY_IID, 0x00) },
+	{ SSAM_SDEV(HID, SSAM_ANY_TID, SSAM_ANY_IID, 0x00) },
 	{ },
 };
 MODULE_DEVICE_TABLE(ssam, surface_hid_match);
-- 
2.33.1

From 00dbcbeeae4d15358e9af0e9a4cee711f09e896d Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 2 Jun 2021 03:34:06 +0200
Subject: [PATCH] platform/surface: aggregator: Make client device removal more
 generic

Currently, there are similar functions defined in the Aggregator
Registry and the controller core.

Make client device removal more generic and export it. We can then use
this function later on to remove client devices from device hubs as well
as the controller and avoid re-defining similar things.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/aggregator/bus.c  | 24 ++++++++--------------
 drivers/platform/surface/aggregator/bus.h  |  3 ---
 drivers/platform/surface/aggregator/core.c |  3 ++-
 include/linux/surface_aggregator/device.h  |  9 ++++++++
 4 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c
index 0169677c243e..eaa8626baead 100644
--- a/drivers/platform/surface/aggregator/bus.c
+++ b/drivers/platform/surface/aggregator/bus.c
@@ -376,27 +376,19 @@ static int ssam_remove_device(struct device *dev, void *_data)
 }
 
 /**
- * ssam_controller_remove_clients() - Remove SSAM client devices registered as
- * direct children under the given controller.
- * @ctrl: The controller to remove all direct clients for.
+ * ssam_remove_clients() - Remove SSAM client devices registered as direct
+ * children under the given parent device.
+ * @dev: The (parent) device to remove all direct clients for.
  *
- * Remove all SSAM client devices registered as direct children under the
- * given controller. Note that this only accounts for direct children of the
- * controller device. This does not take care of any client devices where the
- * parent device has been manually set before calling ssam_device_add. Refer
- * to ssam_device_add()/ssam_device_remove() for more details on those cases.
- *
- * To avoid new devices being added in parallel to this call, the main
- * controller lock (not statelock) must be held during this (and if
- * necessary, any subsequent deinitialization) call.
+ * Remove all SSAM client devices registered as direct children under the given
+ * device. Note that this only accounts for direct children of the device.
+ * Refer to ssam_device_add()/ssam_device_remove() for more details.
  */
-void ssam_controller_remove_clients(struct ssam_controller *ctrl)
+void ssam_remove_clients(struct device *dev)
 {
-	struct device *dev;
-
-	dev = ssam_controller_device(ctrl);
 	device_for_each_child_reverse(dev, NULL, ssam_remove_device);
 }
+EXPORT_SYMBOL_GPL(ssam_remove_clients);
 
 /**
  * ssam_bus_register() - Register and set-up the SSAM client device bus.
diff --git a/drivers/platform/surface/aggregator/bus.h b/drivers/platform/surface/aggregator/bus.h
index ed032c2cbdb2..6964ee84e79c 100644
--- a/drivers/platform/surface/aggregator/bus.h
+++ b/drivers/platform/surface/aggregator/bus.h
@@ -12,14 +12,11 @@
 
 #ifdef CONFIG_SURFACE_AGGREGATOR_BUS
 
-void ssam_controller_remove_clients(struct ssam_controller *ctrl);
-
 int ssam_bus_register(void);
 void ssam_bus_unregister(void);
 
 #else /* CONFIG_SURFACE_AGGREGATOR_BUS */
 
-static inline void ssam_controller_remove_clients(struct ssam_controller *ctrl) {}
 static inline int ssam_bus_register(void) { return 0; }
 static inline void ssam_bus_unregister(void) {}
 
diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
index 279d9df19c01..124df0100a9f 100644
--- a/drivers/platform/surface/aggregator/core.c
+++ b/drivers/platform/surface/aggregator/core.c
@@ -22,6 +22,7 @@
 #include <linux/sysfs.h>
 
 #include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/device.h>
 
 #include "bus.h"
 #include "controller.h"
@@ -742,7 +743,7 @@ static void ssam_serial_hub_remove(struct serdev_device *serdev)
 	ssam_controller_lock(ctrl);
 
 	/* Remove all client devices. */
-	ssam_controller_remove_clients(ctrl);
+	ssam_remove_clients(&serdev->dev);
 
 	/* Act as if suspending to silence events. */
 	status = ssam_ctrl_notif_display_off(ctrl);
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index f636c5310321..cc257097eb05 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -319,6 +319,15 @@ void ssam_device_driver_unregister(struct ssam_device_driver *d);
 		      ssam_device_driver_unregister)
 
 
+/* -- Helpers for controller and hub devices. ------------------------------- */
+
+#ifdef CONFIG_SURFACE_AGGREGATOR_BUS
+void ssam_remove_clients(struct device *dev);
+#else /* CONFIG_SURFACE_AGGREGATOR_BUS */
+static inline void ssam_remove_clients(struct device *dev) {}
+#endif /* CONFIG_SURFACE_AGGREGATOR_BUS */
+
+
 /* -- Helpers for client-device requests. ----------------------------------- */
 
 /**
-- 
2.33.1

From f0aaf21cefd42ce8f828d54a11207d72fea9e579 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 27 Oct 2021 02:06:38 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Use generic client
 removal function

Use generic client removal function introduced in the previous commit
instead of defining our own one.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../surface/surface_aggregator_registry.c     | 24 ++++---------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 1679811eff50..d63f975bfd4c 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -249,20 +249,6 @@ static int ssam_uid_from_string(const char *str, struct ssam_device_uid *uid)
 	return 0;
 }
 
-static int ssam_hub_remove_devices_fn(struct device *dev, void *data)
-{
-	if (!is_ssam_device(dev))
-		return 0;
-
-	ssam_device_remove(to_ssam_device(dev));
-	return 0;
-}
-
-static void ssam_hub_remove_devices(struct device *parent)
-{
-	device_for_each_child_reverse(parent, NULL, ssam_hub_remove_devices_fn);
-}
-
 static int ssam_hub_add_device(struct device *parent, struct ssam_controller *ctrl,
 			       struct fwnode_handle *node)
 {
@@ -308,7 +294,7 @@ static int ssam_hub_add_devices(struct device *parent, struct ssam_controller *c
 
 	return 0;
 err:
-	ssam_hub_remove_devices(parent);
+	ssam_remove_clients(parent);
 	return status;
 }
 
@@ -405,7 +391,7 @@ static void ssam_base_hub_update_workfn(struct work_struct *work)
 	if (hub->state == SSAM_BASE_HUB_CONNECTED)
 		status = ssam_hub_add_devices(&hub->sdev->dev, hub->sdev->ctrl, node);
 	else
-		ssam_hub_remove_devices(&hub->sdev->dev);
+		ssam_remove_clients(&hub->sdev->dev);
 
 	if (status)
 		dev_err(&hub->sdev->dev, "failed to update base-hub devices: %d\n", status);
@@ -487,7 +473,7 @@ static int ssam_base_hub_probe(struct ssam_device *sdev)
 err:
 	ssam_notifier_unregister(sdev->ctrl, &hub->notif);
 	cancel_delayed_work_sync(&hub->update_work);
-	ssam_hub_remove_devices(&sdev->dev);
+	ssam_remove_clients(&sdev->dev);
 	return status;
 }
 
@@ -499,7 +485,7 @@ static void ssam_base_hub_remove(struct ssam_device *sdev)
 
 	ssam_notifier_unregister(sdev->ctrl, &hub->notif);
 	cancel_delayed_work_sync(&hub->update_work);
-	ssam_hub_remove_devices(&sdev->dev);
+	ssam_remove_clients(&sdev->dev);
 }
 
 static const struct ssam_device_id ssam_base_hub_match[] = {
@@ -613,7 +599,7 @@ static int ssam_platform_hub_remove(struct platform_device *pdev)
 {
 	const struct software_node **nodes = platform_get_drvdata(pdev);
 
-	ssam_hub_remove_devices(&pdev->dev);
+	ssam_remove_clients(&pdev->dev);
 	set_secondary_fwnode(&pdev->dev, NULL);
 	software_node_unregister_node_group(nodes);
 	return 0;
-- 
2.33.1

From e86647069fa14e01aff6a31583743f271d666d95 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 27 Oct 2021 02:07:33 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Rename device
 registration function

Rename the device registration function to better align names with the
newly introduced device removal function.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/surface_aggregator_registry.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index d63f975bfd4c..2e0d3a808d47 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -274,8 +274,8 @@ static int ssam_hub_add_device(struct device *parent, struct ssam_controller *ct
 	return status;
 }
 
-static int ssam_hub_add_devices(struct device *parent, struct ssam_controller *ctrl,
-				struct fwnode_handle *node)
+static int ssam_hub_register_clients(struct device *parent, struct ssam_controller *ctrl,
+				     struct fwnode_handle *node)
 {
 	struct fwnode_handle *child;
 	int status;
@@ -389,7 +389,7 @@ static void ssam_base_hub_update_workfn(struct work_struct *work)
 	hub->state = state;
 
 	if (hub->state == SSAM_BASE_HUB_CONNECTED)
-		status = ssam_hub_add_devices(&hub->sdev->dev, hub->sdev->ctrl, node);
+		status = ssam_hub_register_clients(&hub->sdev->dev, hub->sdev->ctrl, node);
 	else
 		ssam_remove_clients(&hub->sdev->dev);
 
@@ -585,7 +585,7 @@ static int ssam_platform_hub_probe(struct platform_device *pdev)
 
 	set_secondary_fwnode(&pdev->dev, root);
 
-	status = ssam_hub_add_devices(&pdev->dev, ctrl, root);
+	status = ssam_hub_register_clients(&pdev->dev, ctrl, root);
 	if (status) {
 		set_secondary_fwnode(&pdev->dev, NULL);
 		software_node_unregister_node_group(nodes);
-- 
2.33.1

From 88d3d04fcfc74c04cb2b406f6b68cd589cfc5d63 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 00:24:47 +0200
Subject: [PATCH] platform/surface: aggregator: Allow devices to be marked as
 hot-removed

Some SSAM devices, notably keyboard and touchpad on the Surface Book 3
and Surface Pro 8, can be hot-removed. When this occurs, communication
with the device may fail and time out. This timeout may unnecessarily
block and slow down device removal and even cause issues when the
devices are detached and re-attached quickly. Thus, communication should
generally be avoided once hot-removal is detected.

While we already remove a device as soon as we detect its hot-removal,
the corresponding device driver may still attempt to communicate with
the device during teardown. This is especially critical as communication
failure may also extend to event disablement.

Add a flag to allow marking devices as hot-removed. This can then be
used during client driver teardown to check if any communication
attemtps should be avoided.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/aggregator/bus.c | 33 +++++++++++++++
 include/linux/surface_aggregator/device.h | 50 +++++++++++++++++++++--
 2 files changed, 80 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c
index eaa8626baead..9cb6337f2b35 100644
--- a/drivers/platform/surface/aggregator/bus.c
+++ b/drivers/platform/surface/aggregator/bus.c
@@ -390,6 +390,39 @@ void ssam_remove_clients(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(ssam_remove_clients);
 
+static int ssam_mark_device_hot_removed(struct device *dev, void *_data)
+{
+	struct ssam_device *sdev = to_ssam_device(dev);
+
+	if (is_ssam_device(dev))
+		ssam_device_mark_hot_removed(sdev);
+
+	return 0;
+}
+
+/**
+ * ssam_hot_remove_clients() - Remove SSAM client devices registered as direct
+ * children under the given parent device and mark them as hot-removed.
+ * @dev: The (parent) device to remove all direct clients for.
+ *
+ * Remove all SSAM client devices registered as direct children under the given
+ * device.
+ *
+ * Note that this only accounts for direct children of the device. Refer to
+ * ssam_device_add()/ssam_device_remove() for more details.
+ */
+void ssam_hot_remove_clients(struct device *dev)
+{
+	/* Mark devices as hot-removed before we remove any */
+	device_for_each_child_reverse(dev, NULL, ssam_mark_device_hot_removed);
+
+	ssam_remove_clients(dev);
+}
+EXPORT_SYMBOL_GPL(ssam_hot_remove_clients);
+
+
+/* -- Bus registration. ----------------------------------------------------- */
+
 /**
  * ssam_bus_register() - Register and set-up the SSAM client device bus.
  */
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index cc257097eb05..b474a9baab42 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -148,17 +148,30 @@ struct ssam_device_uid {
 #define SSAM_SDEV(cat, tid, iid, fun) \
 	SSAM_DEVICE(SSAM_DOMAIN_SERIALHUB, SSAM_SSH_TC_##cat, tid, iid, fun)
 
+/*
+ * enum ssam_device_flags - Flags for SSAM client devices.
+ * @SSAM_DEVICE_HOT_REMOVED_BIT:
+ *	The device has been hot-removed. Further communication with it may time
+ *	out and should be avoided.
+ */
+enum ssam_device_flags {
+	SSAM_DEVICE_HOT_REMOVED_BIT = 0,
+};
+
 /**
  * struct ssam_device - SSAM client device.
- * @dev:  Driver model representation of the device.
- * @ctrl: SSAM controller managing this device.
- * @uid:  UID identifying the device.
+ * @dev:   Driver model representation of the device.
+ * @ctrl:  SSAM controller managing this device.
+ * @uid:   UID identifying the device.
+ * @flags: Device state flags, see &enum ssam_device_flags.
  */
 struct ssam_device {
 	struct device dev;
 	struct ssam_controller *ctrl;
 
 	struct ssam_device_uid uid;
+
+	unsigned long flags;
 };
 
 /**
@@ -240,6 +253,35 @@ struct ssam_device *ssam_device_alloc(struct ssam_controller *ctrl,
 int ssam_device_add(struct ssam_device *sdev);
 void ssam_device_remove(struct ssam_device *sdev);
 
+/**
+ * ssam_device_mark_hot_removed() - Mark the given device as hot-removed.
+ * @sdev: The device to mark as hot-removed.
+ *
+ * Mark the device as having been hot-removed. This signals drivers using the
+ * device that communication with the device should be avoided and may lead to
+ * timeouts.
+ */
+static inline void ssam_device_mark_hot_removed(struct ssam_device *sdev)
+{
+	dev_dbg(&sdev->dev, "marking device as hot-removed\n");
+	set_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
+}
+
+/**
+ * ssam_device_is_hot_removed() - Check if the given device has been
+ * hot-removed.
+ * @sdev: The device to check.
+ *
+ * Checks if the given device has been marked as hot-removed. See
+ * ssam_device_mark_hot_removed() for more details.
+ *
+ * Return: Returns ``true`` if the device has been marked as hot-removed.
+ */
+static inline bool ssam_device_is_hot_removed(struct ssam_device *sdev)
+{
+	return test_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
+}
+
 /**
  * ssam_device_get() - Increment reference count of SSAM client device.
  * @sdev: The device to increment the reference count of.
@@ -323,8 +365,10 @@ void ssam_device_driver_unregister(struct ssam_device_driver *d);
 
 #ifdef CONFIG_SURFACE_AGGREGATOR_BUS
 void ssam_remove_clients(struct device *dev);
+void ssam_hot_remove_clients(struct device *dev);
 #else /* CONFIG_SURFACE_AGGREGATOR_BUS */
 static inline void ssam_remove_clients(struct device *dev) {}
+static inline void ssam_hot_remove_clients(struct device *dev) {}
 #endif /* CONFIG_SURFACE_AGGREGATOR_BUS */
 
 
-- 
2.33.1

From d74f2c3b78911fb6cb98c23f345c03d01f84f148 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 00:48:22 +0200
Subject: [PATCH] platform/surface: aggregator: Allow notifiers to avoid
 communication on unregistering

When SSAM client devices have been (physically) hot-removed,
communication attempts with those devices may fail and time out. This
can even extend to event notifiers, due to which timeouts may occur
during device removal, slowing down that process.

Add a flag to the notifier unregister function that allows skipping
communication with the EC to prevent this. Furthermore, add wrappers for
registering and unregistering notifiers belonging to SSAM client devices
that automatically check if the device has been marked as hot-removed
and communication should be avoided.

Note that non-SSAM client devices can generally not be hot-removed, so
also add a convenience wrapper for those, defaulting to allow
communication.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../driver-api/surface_aggregator/client.rst  |  6 +-
 .../platform/surface/aggregator/controller.c  | 53 ++++++++++------
 include/linux/surface_aggregator/controller.h | 24 +++++++-
 include/linux/surface_aggregator/device.h     | 60 +++++++++++++++++++
 4 files changed, 122 insertions(+), 21 deletions(-)

diff --git a/Documentation/driver-api/surface_aggregator/client.rst b/Documentation/driver-api/surface_aggregator/client.rst
index e519d374c378..27f95abdbe99 100644
--- a/Documentation/driver-api/surface_aggregator/client.rst
+++ b/Documentation/driver-api/surface_aggregator/client.rst
@@ -17,6 +17,8 @@
 .. |SSAM_DEVICE| replace:: :c:func:`SSAM_DEVICE`
 .. |ssam_notifier_register| replace:: :c:func:`ssam_notifier_register`
 .. |ssam_notifier_unregister| replace:: :c:func:`ssam_notifier_unregister`
+.. |ssam_device_notifier_register| replace:: :c:func:`ssam_device_notifier_register`
+.. |ssam_device_notifier_unregister| replace:: :c:func:`ssam_device_notifier_unregister`
 .. |ssam_request_sync| replace:: :c:func:`ssam_request_sync`
 .. |ssam_event_mask| replace:: :c:type:`enum ssam_event_mask <ssam_event_mask>`
 
@@ -312,7 +314,9 @@ Handling Events
 To receive events from the SAM EC, an event notifier must be registered for
 the desired event via |ssam_notifier_register|. The notifier must be
 unregistered via |ssam_notifier_unregister| once it is not required any
-more.
+more. For |ssam_device| type clients, the |ssam_device_notifier_register| and
+|ssam_device_notifier_unregister| wrappers should be preferred as they properly
+handle hot-removal of client devices.
 
 Event notifiers are registered by providing (at minimum) a callback to call
 in case an event has been received, the registry specifying how the event
diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c
index b8c377b3f932..dc0f22be2630 100644
--- a/drivers/platform/surface/aggregator/controller.c
+++ b/drivers/platform/surface/aggregator/controller.c
@@ -2199,16 +2199,26 @@ static int ssam_nf_refcount_enable(struct ssam_controller *ctrl,
 }
 
 /**
- * ssam_nf_refcount_disable_free() - Disable event for reference count entry if it is
- * no longer in use and free the corresponding entry.
+ * ssam_nf_refcount_disable_free() - Disable event for reference count entry if
+ * it is no longer in use and free the corresponding entry.
  * @ctrl:  The controller to disable the event on.
  * @entry: The reference count entry for the event to be disabled.
  * @flags: The flags used for enabling the event on the EC.
+ * @ec:    Flag specifying if the event should actually be disabled on the EC.
  *
- * If the reference count equals zero, i.e. the event is no longer requested by
- * any client, the event will be disabled and the corresponding reference count
- * entry freed. The reference count entry must not be used any more after a
- * call to this function.
+ * If ``ec`` equals ``true`` and the reference count equals zero (i.e.  the
+ * event is no longer requested by any client), the specified event will be
+ * disabled on the EC via the corresponding request.
+ *
+ * If ``ec`` equals ``false``, no request will be sent to the EC and the event
+ * can be considered in a detached state (i.e. no longer used but still
+ * enabled). Disabling an event via this method may be required for
+ * hot-removable devices, where event disable requests may time out after the
+ * device has been physically removed.
+ *
+ * In both cases, if the reference count equals zero, the corresponding
+ * reference count entry will be freed. The reference count entry must not be
+ * used any more after a call to this function.
  *
  * Also checks if the flags used for disabling the event match the flags used
  * for enabling the event and warns if they do not (regardless of reference
@@ -2223,7 +2233,7 @@ static int ssam_nf_refcount_enable(struct ssam_controller *ctrl,
  * returns the status of the event-enable EC command.
  */
 static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl,
-					 struct ssam_nf_refcount_entry *entry, u8 flags)
+					 struct ssam_nf_refcount_entry *entry, u8 flags, bool ec)
 {
 	const struct ssam_event_registry reg = entry->key.reg;
 	const struct ssam_event_id id = entry->key.id;
@@ -2232,8 +2242,9 @@ static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl,
 
 	lockdep_assert_held(&nf->lock);
 
-	ssam_dbg(ctrl, "disabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n",
-		 reg.target_category, id.target_category, id.instance, entry->refcount);
+	ssam_dbg(ctrl, "%s event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n",
+		 ec ? "disabling" : "detaching", reg.target_category, id.target_category,
+		 id.instance, entry->refcount);
 
 	if (entry->flags != flags) {
 		ssam_warn(ctrl,
@@ -2242,7 +2253,7 @@ static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl,
 			  id.instance);
 	}
 
-	if (entry->refcount == 0) {
+	if (ec && entry->refcount == 0) {
 		status = ssam_ssh_event_disable(ctrl, reg, id, flags);
 		kfree(entry);
 	}
@@ -2322,20 +2333,26 @@ int ssam_notifier_register(struct ssam_controller *ctrl, struct ssam_event_notif
 EXPORT_SYMBOL_GPL(ssam_notifier_register);
 
 /**
- * ssam_notifier_unregister() - Unregister an event notifier.
- * @ctrl: The controller the notifier has been registered on.
- * @n:    The event notifier to unregister.
+ * __ssam_notifier_unregister() - Unregister an event notifier.
+ * @ctrl:    The controller the notifier has been registered on.
+ * @n:       The event notifier to unregister.
+ * @disable: Whether to disable the corresponding event on the EC.
  *
  * Unregister an event notifier. Decrement the usage counter of the associated
  * SAM event if the notifier is not marked as an observer. If the usage counter
- * reaches zero, the event will be disabled.
+ * reaches zero and ``disable`` equals ``true``, the event will be disabled.
+ *
+ * Useful for hot-removable devices, where communication may fail once the
+ * device has been physically removed. In that case, specifying ``disable`` as
+ * ``false`` avoids communication with the EC.
  *
  * Return: Returns zero on success, %-ENOENT if the given notifier block has
  * not been registered on the controller. If the given notifier block was the
  * last one associated with its specific event, returns the status of the
  * event-disable EC-command.
  */
-int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n)
+int __ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n,
+			       bool disable)
 {
 	u16 rqid = ssh_tc_to_rqid(n->event.id.target_category);
 	struct ssam_nf_refcount_entry *entry;
@@ -2373,7 +2390,7 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_not
 			goto remove;
 		}
 
-		status = ssam_nf_refcount_disable_free(ctrl, entry, n->event.flags);
+		status = ssam_nf_refcount_disable_free(ctrl, entry, n->event.flags, disable);
 	}
 
 remove:
@@ -2383,7 +2400,7 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_not
 
 	return status;
 }
-EXPORT_SYMBOL_GPL(ssam_notifier_unregister);
+EXPORT_SYMBOL_GPL(__ssam_notifier_unregister);
 
 /**
  * ssam_controller_event_enable() - Enable the specified event.
@@ -2477,7 +2494,7 @@ int ssam_controller_event_disable(struct ssam_controller *ctrl,
 		return -ENOENT;
 	}
 
-	status = ssam_nf_refcount_disable_free(ctrl, entry, flags);
+	status = ssam_nf_refcount_disable_free(ctrl, entry, flags, true);
 
 	mutex_unlock(&nf->lock);
 	return status;
diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h
index 74bfdffaf7b0..50a2b4926c06 100644
--- a/include/linux/surface_aggregator/controller.h
+++ b/include/linux/surface_aggregator/controller.h
@@ -835,8 +835,28 @@ struct ssam_event_notifier {
 int ssam_notifier_register(struct ssam_controller *ctrl,
 			   struct ssam_event_notifier *n);
 
-int ssam_notifier_unregister(struct ssam_controller *ctrl,
-			     struct ssam_event_notifier *n);
+int __ssam_notifier_unregister(struct ssam_controller *ctrl,
+			       struct ssam_event_notifier *n, bool disable);
+
+/**
+ * ssam_notifier_unregister() - Unregister an event notifier.
+ * @ctrl:    The controller the notifier has been registered on.
+ * @n:       The event notifier to unregister.
+ *
+ * Unregister an event notifier. Decrement the usage counter of the associated
+ * SAM event if the notifier is not marked as an observer. If the usage counter
+ * reaches zero, the event will be disabled.
+ *
+ * Return: Returns zero on success, %-ENOENT if the given notifier block has
+ * not been registered on the controller. If the given notifier block was the
+ * last one associated with its specific event, returns the status of the
+ * event-disable EC-command.
+ */
+static inline int ssam_notifier_unregister(struct ssam_controller *ctrl,
+					   struct ssam_event_notifier *n)
+{
+	return __ssam_notifier_unregister(ctrl, n, true);
+}
 
 int ssam_controller_event_enable(struct ssam_controller *ctrl,
 				 struct ssam_event_registry reg,
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index b474a9baab42..76e6300b07d5 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -474,4 +474,64 @@ static inline void ssam_hot_remove_clients(struct device *dev) {}
 				    sdev->uid.instance, ret);		\
 	}
 
+
+/* -- Helpers for client-device notifiers. ---------------------------------- */
+
+/**
+ * ssam_device_notifier_register() - Register an event notifier for the
+ * specified client device.
+ * @sdev: The device the notifier should be registered on.
+ * @n:    The event notifier to register.
+ *
+ * Register an event notifier. Increment the usage counter of the associated
+ * SAM event if the notifier is not marked as an observer. If the event is not
+ * marked as an observer and is currently not enabled, it will be enabled
+ * during this call. If the notifier is marked as an observer, no attempt will
+ * be made at enabling any event and no reference count will be modified.
+ *
+ * Notifiers marked as observers do not need to be associated with one specific
+ * event, i.e. as long as no event matching is performed, only the event target
+ * category needs to be set.
+ *
+ * Return: Returns zero on success, %-ENOSPC if there have already been
+ * %INT_MAX notifiers for the event ID/type associated with the notifier block
+ * registered, %-ENOMEM if the corresponding event entry could not be
+ * allocated, %-ENODEV if the device is marked as hot-removed. If this is the
+ * first time that a notifier block is registered for the specific associated
+ * event, returns the status of the event-enable EC-command.
+ */
+static inline int ssam_device_notifier_register(struct ssam_device *sdev,
+						struct ssam_event_notifier *n)
+{
+	if (ssam_device_is_hot_removed(sdev))
+		return -ENODEV;
+
+	return ssam_notifier_register(sdev->ctrl, n);
+}
+
+/**
+ * ssam_device_notifier_unregister() - Unregister an event notifier for the
+ * specified client device.
+ * @sdev: The device the notifier has been registered on.
+ * @n:    The event notifier to unregister.
+ *
+ * Unregister an event notifier. Decrement the usage counter of the associated
+ * SAM event if the notifier is not marked as an observer. If the usage counter
+ * reaches zero, the event will be disabled.
+ *
+ * In case the device has been marked as hot-removed, the event will not be
+ * disabled on the EC, as in those cases any attempt at doing so may time out.
+ *
+ * Return: Returns zero on success, %-ENOENT if the given notifier block has
+ * not been registered on the controller. If the given notifier block was the
+ * last one associated with its specific event, returns the status of the
+ * event-disable EC-command.
+ */
+static inline int ssam_device_notifier_unregister(struct ssam_device *sdev,
+						  struct ssam_event_notifier *n)
+{
+	return __ssam_notifier_unregister(sdev->ctrl, n,
+					  !ssam_device_is_hot_removed(sdev));
+}
+
 #endif /* _LINUX_SURFACE_AGGREGATOR_DEVICE_H */
-- 
2.33.1

From c737f87cc26eaa28a6d44637478cf0835d395a94 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 01:20:49 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Use client device
 wrappers for notifier registration

Use newly introduced client device wrapper functions for notifier
registration and deregistration.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/surface_aggregator_registry.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 2e0d3a808d47..64c83b846907 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -459,7 +459,7 @@ static int ssam_base_hub_probe(struct ssam_device *sdev)
 
 	ssam_device_set_drvdata(sdev, hub);
 
-	status = ssam_notifier_register(sdev->ctrl, &hub->notif);
+	status = ssam_device_notifier_register(sdev, &hub->notif);
 	if (status)
 		return status;
 
@@ -471,7 +471,7 @@ static int ssam_base_hub_probe(struct ssam_device *sdev)
 	return 0;
 
 err:
-	ssam_notifier_unregister(sdev->ctrl, &hub->notif);
+	ssam_device_notifier_unregister(sdev, &hub->notif);
 	cancel_delayed_work_sync(&hub->update_work);
 	ssam_remove_clients(&sdev->dev);
 	return status;
@@ -483,7 +483,7 @@ static void ssam_base_hub_remove(struct ssam_device *sdev)
 
 	sysfs_remove_group(&sdev->dev.kobj, &ssam_base_hub_group);
 
-	ssam_notifier_unregister(sdev->ctrl, &hub->notif);
+	ssam_device_notifier_unregister(sdev, &hub->notif);
 	cancel_delayed_work_sync(&hub->update_work);
 	ssam_remove_clients(&sdev->dev);
 }
-- 
2.33.1

From 8f2340e6b616e25cdf4e9f8a75ec95287172f918 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 01:08:29 +0200
Subject: [PATCH] power/supply: surface_charger: Add support for hot-removal

In cases of hot-removal, further communication with the device should be
avoided as it may fail and time out.

Use the client device wrapper functions to register and unregister the
notifiers as those check during unregistration if the device has been
marked as hot-removed and handle this case appropriately.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/power/supply/surface_charger.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/power/supply/surface_charger.c b/drivers/power/supply/surface_charger.c
index a060c36c7766..9a3525c32aca 100644
--- a/drivers/power/supply/surface_charger.c
+++ b/drivers/power/supply/surface_charger.c
@@ -69,6 +69,9 @@ static int spwr_ac_update_unlocked(struct spwr_ac_device *ac)
 	__le32 old = ac->state;
 	int status;
 
+	if (ssam_device_is_hot_removed(ac->sdev))
+		return -ENODEV;
+
 	lockdep_assert_held(&ac->lock);
 
 	status = ssam_retry(ssam_bat_get_psrc, ac->sdev, &ac->state);
@@ -103,7 +106,6 @@ static int spwr_ac_recheck(struct spwr_ac_device *ac)
 static u32 spwr_notify_ac(struct ssam_event_notifier *nf, const struct ssam_event *event)
 {
 	struct spwr_ac_device *ac;
-	int status;
 
 	ac = container_of(nf, struct spwr_ac_device, notif);
 
@@ -121,8 +123,12 @@ static u32 spwr_notify_ac(struct ssam_event_notifier *nf, const struct ssam_even
 
 	switch (event->command_id) {
 	case SAM_EVENT_CID_BAT_ADP:
-		status = spwr_ac_recheck(ac);
-		return ssam_notifier_from_errno(status) | SSAM_NOTIF_HANDLED;
+		/*
+		 * Any errors here should not be critical and logged in the
+		 * corresponding functions, so ignore them.
+		 */
+		spwr_ac_recheck(ac);
+		return SSAM_NOTIF_HANDLED;
 
 	default:
 		return 0;
@@ -216,7 +222,7 @@ static int spwr_ac_register(struct spwr_ac_device *ac)
 	if (IS_ERR(ac->psy))
 		return PTR_ERR(ac->psy);
 
-	return ssam_notifier_register(ac->sdev->ctrl, &ac->notif);
+	return ssam_device_notifier_register(ac->sdev, &ac->notif);
 }
 
 
@@ -251,7 +257,7 @@ static void surface_ac_remove(struct ssam_device *sdev)
 {
 	struct spwr_ac_device *ac = ssam_device_get_drvdata(sdev);
 
-	ssam_notifier_unregister(sdev->ctrl, &ac->notif);
+	ssam_device_notifier_unregister(sdev, &ac->notif);
 }
 
 static const struct spwr_psy_properties spwr_psy_props_adp1 = {
-- 
2.33.1

From c7ee552c8c906928968838f8d5798d495bddea35 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 01:15:34 +0200
Subject: [PATCH] power/supply: surface_battery: Add support for hot-removal

In cases of hot-removal, further communication with the device should be
avoided as it may fail and time out.

Use the client device wrapper functions to register and unregister the
notifiers as those check during unregistration if the device has been
marked as hot-removed and handle this case appropriately.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/power/supply/surface_battery.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/surface_battery.c b/drivers/power/supply/surface_battery.c
index 5ec2e6bb2465..ebf1f96e9a89 100644
--- a/drivers/power/supply/surface_battery.c
+++ b/drivers/power/supply/surface_battery.c
@@ -156,6 +156,9 @@ static bool spwr_battery_present(struct spwr_battery_device *bat)
 {
 	lockdep_assert_held(&bat->lock);
 
+	if (ssam_device_is_hot_removed(bat->sdev))
+		return false;
+
 	return le32_to_cpu(bat->sta) & SAM_BATTERY_STA_PRESENT;
 }
 
@@ -245,6 +248,9 @@ static int spwr_battery_update_bix_unlocked(struct spwr_battery_device *bat)
 
 	lockdep_assert_held(&bat->lock);
 
+	if (ssam_device_is_hot_removed(bat->sdev))
+		return 0;
+
 	status = spwr_battery_load_sta(bat);
 	if (status)
 		return status;
@@ -802,7 +808,7 @@ static int spwr_battery_register(struct spwr_battery_device *bat)
 	if (IS_ERR(bat->psy))
 		return PTR_ERR(bat->psy);
 
-	return ssam_notifier_register(bat->sdev->ctrl, &bat->notif);
+	return ssam_device_notifier_register(bat->sdev, &bat->notif);
 }
 
 
@@ -837,7 +843,7 @@ static void surface_battery_remove(struct ssam_device *sdev)
 {
 	struct spwr_battery_device *bat = ssam_device_get_drvdata(sdev);
 
-	ssam_notifier_unregister(sdev->ctrl, &bat->notif);
+	ssam_device_notifier_unregister(sdev, &bat->notif);
 	cancel_delayed_work_sync(&bat->update_work);
 }
 
-- 
2.33.1

From 585bb3af623931c535785688993097083e273865 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 01:33:02 +0200
Subject: [PATCH] HID: surface-hid: Add support for hot-removal

Add support for hot-removal of SSAM HID client devices.

Once a device has been hot-removed, further communication with it should
be avoided as it may fail and time out. While the device will be removed
as soon as we detect hot-removal, communication may still occur during
teardown, especially when unregistering notifiers.

While hot-removal is a surprise event that can happen any time, try to
avoid communication as much as possible once it has been detected to
prevent timeouts that can slow down device removal and cause issues,
e.g. when quickly re-attaching the device.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/hid/surface-hid/surface_hid_core.c | 38 +++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/surface-hid/surface_hid_core.c b/drivers/hid/surface-hid/surface_hid_core.c
index 5571e74abe91..63a7963ed345 100644
--- a/drivers/hid/surface-hid/surface_hid_core.c
+++ b/drivers/hid/surface-hid/surface_hid_core.c
@@ -19,12 +19,30 @@
 #include "surface_hid_core.h"
 
 
+/* -- Utility functions. ---------------------------------------------------- */
+
+static bool surface_hid_is_hot_removed(struct surface_hid_device *shid)
+{
+	/*
+	 * Non-ssam client devices, i.e. platform client devices, cannot be
+	 * hot-removed.
+	 */
+	if (!is_ssam_device(shid->dev))
+		return false;
+
+	return ssam_device_is_hot_removed(to_ssam_device(shid->dev));
+}
+
+
 /* -- Device descriptor access. --------------------------------------------- */
 
 static int surface_hid_load_hid_descriptor(struct surface_hid_device *shid)
 {
 	int status;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_HID,
 			(u8 *)&shid->hid_desc, sizeof(shid->hid_desc));
 	if (status)
@@ -61,6 +79,9 @@ static int surface_hid_load_device_attributes(struct surface_hid_device *shid)
 {
 	int status;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_ATTRS,
 			(u8 *)&shid->attrs, sizeof(shid->attrs));
 	if (status)
@@ -88,9 +109,18 @@ static int surface_hid_start(struct hid_device *hid)
 static void surface_hid_stop(struct hid_device *hid)
 {
 	struct surface_hid_device *shid = hid->driver_data;
+	bool hot_removed;
+
+	/*
+	 * Communication may fail for devices that have been hot-removed. This
+	 * also includes registration of HID events, so we need to check this
+	 * here. Only if the device has not been marked as hot-removed, we can
+	 * safely disable events.
+	 */
+	hot_removed = surface_hid_is_hot_removed(shid);
 
 	/* Note: This call will log errors for us, so ignore them here. */
-	ssam_notifier_unregister(shid->ctrl, &shid->notif);
+	__ssam_notifier_unregister(shid->ctrl, &shid->notif, !hot_removed);
 }
 
 static int surface_hid_open(struct hid_device *hid)
@@ -109,6 +139,9 @@ static int surface_hid_parse(struct hid_device *hid)
 	u8 *buf;
 	int status;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	buf = kzalloc(len, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -126,6 +159,9 @@ static int surface_hid_raw_request(struct hid_device *hid, unsigned char reportn
 {
 	struct surface_hid_device *shid = hid->driver_data;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	if (rtype == HID_OUTPUT_REPORT && reqtype == HID_REQ_SET_REPORT)
 		return shid->ops.output_report(shid, reportnum, buf, len);
 
-- 
2.33.1

From 06fee01ca55ec43027b5bc5fcd3c3f26a63d0c72 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sun, 10 Oct 2021 23:56:23 +0200
Subject: [PATCH] wip! platform/surface: aggregator_registry: Add KIP device
 hub

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../surface/surface_aggregator_registry.c     | 210 +++++++++++++++++-
 1 file changed, 208 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 64c83b846907..e02fe833fde8 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -505,6 +505,200 @@ static struct ssam_device_driver ssam_base_hub_driver = {
 };
 
 
+/* -- SSAM KIP-subsystem hub driver. ---------------------------------------- */
+
+/*
+ * Some devices may need a bit of time to be fully usable after being
+ * (re-)connected. This delay has been determined via experimentation.
+ */
+#define SSAM_KIP_UPDATE_CONNECT_DELAY		msecs_to_jiffies(250)
+
+#define SSAM_EVENT_KIP_CID_CONNECTION		0x2c
+
+enum ssam_kip_hub_state {
+	SSAM_KIP_HUB_UNINITIALIZED,
+	SSAM_KIP_HUB_CONNECTED,
+	SSAM_KIP_HUB_DISCONNECTED,
+};
+
+struct ssam_kip_hub {
+	struct ssam_device *sdev;
+
+	enum ssam_kip_hub_state state;
+	struct delayed_work update_work;
+
+	struct ssam_event_notifier notif;
+};
+
+SSAM_DEFINE_SYNC_REQUEST_R(__ssam_kip_get_connection_state, u8, {
+	.target_category = SSAM_SSH_TC_KIP,
+	.target_id       = 0x01,
+	.command_id      = 0x2c,
+	.instance_id     = 0x00,
+});
+
+static int ssam_kip_get_connection_state(struct ssam_kip_hub *hub, enum ssam_kip_hub_state *state)
+{
+	int status;
+	u8 connected;
+
+	status = ssam_retry(__ssam_kip_get_connection_state, hub->sdev->ctrl, &connected);
+	if (status < 0) {
+		dev_err(&hub->sdev->dev, "failed to query KIP connection state: %d\n", status);
+		return status;
+	}
+
+	*state = connected ? SSAM_KIP_HUB_CONNECTED : SSAM_KIP_HUB_DISCONNECTED;
+	return 0;
+}
+
+static ssize_t ssam_kip_hub_state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ssam_kip_hub *hub = dev_get_drvdata(dev);
+	bool connected = hub->state == SSAM_KIP_HUB_CONNECTED;
+
+	return sysfs_emit(buf, "%d\n", connected);
+}
+
+static struct device_attribute ssam_kip_hub_attr_state =
+	__ATTR(state, 0444, ssam_kip_hub_state_show, NULL);
+
+static struct attribute *ssam_kip_hub_attrs[] = {
+	&ssam_kip_hub_attr_state.attr,
+	NULL,
+};
+
+static const struct attribute_group ssam_kip_hub_group = {
+	.attrs = ssam_kip_hub_attrs,
+};
+
+static void ssam_kip_hub_update_workfn(struct work_struct *work)
+{
+	struct ssam_kip_hub *hub = container_of(work, struct ssam_kip_hub, update_work.work);
+	struct fwnode_handle *node = dev_fwnode(&hub->sdev->dev);
+	enum ssam_kip_hub_state state;
+	int status = 0;
+
+	status = ssam_kip_get_connection_state(hub, &state);
+	if (status)
+		return;
+
+	if (hub->state == state)
+		return;
+	hub->state = state;
+
+	if (hub->state == SSAM_KIP_HUB_CONNECTED)
+		status = ssam_hub_register_clients(&hub->sdev->dev, hub->sdev->ctrl, node);
+	else
+		ssam_remove_clients(&hub->sdev->dev);
+
+	if (status)
+		dev_err(&hub->sdev->dev, "failed to update KIP-hub devices: %d\n", status);
+}
+
+static u32 ssam_kip_hub_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
+{
+	struct ssam_kip_hub *hub = container_of(nf, struct ssam_kip_hub, notif);
+	unsigned long delay;
+
+	if (event->command_id != SSAM_EVENT_KIP_CID_CONNECTION)
+		return 0;	/* Return "unhandled". */
+
+	if (event->length < 1) {
+		dev_err(&hub->sdev->dev, "unexpected payload size: %u\n", event->length);
+		return 0;
+	}
+
+	/*
+	 * Delay update when KIP devices are being connected to give devices/EC
+	 * some time to set up.
+	 */
+	delay = event->data[0] ? SSAM_KIP_UPDATE_CONNECT_DELAY : 0;
+
+	schedule_delayed_work(&hub->update_work, delay);
+
+	return SSAM_NOTIF_HANDLED;
+}
+
+static int __maybe_unused ssam_kip_hub_resume(struct device *dev)
+{
+	struct ssam_kip_hub *hub = dev_get_drvdata(dev);
+
+	schedule_delayed_work(&hub->update_work, 0);
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(ssam_kip_hub_pm_ops, NULL, ssam_kip_hub_resume);
+
+static int ssam_kip_hub_probe(struct ssam_device *sdev)
+{
+	struct ssam_kip_hub *hub;
+	int status;
+
+	hub = devm_kzalloc(&sdev->dev, sizeof(*hub), GFP_KERNEL);
+	if (!hub)
+		return -ENOMEM;
+
+	hub->sdev = sdev;
+	hub->state = SSAM_KIP_HUB_UNINITIALIZED;
+
+	hub->notif.base.priority = INT_MAX;  /* This notifier should run first. */
+	hub->notif.base.fn = ssam_kip_hub_notif;
+	hub->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
+	hub->notif.event.id.target_category = SSAM_SSH_TC_KIP,
+	hub->notif.event.id.instance = 0,
+	hub->notif.event.mask = SSAM_EVENT_MASK_TARGET;
+	hub->notif.event.flags = SSAM_EVENT_SEQUENCED;
+
+	INIT_DELAYED_WORK(&hub->update_work, ssam_kip_hub_update_workfn);
+
+	ssam_device_set_drvdata(sdev, hub);
+
+	status = ssam_device_notifier_register(sdev, &hub->notif);
+	if (status)
+		return status;
+
+	status = sysfs_create_group(&sdev->dev.kobj, &ssam_kip_hub_group);
+	if (status)
+		goto err;
+
+	schedule_delayed_work(&hub->update_work, 0);
+	return 0;
+
+err:
+	ssam_device_notifier_unregister(sdev, &hub->notif);
+	cancel_delayed_work_sync(&hub->update_work);
+	ssam_remove_clients(&sdev->dev);
+	return status;
+}
+
+static void ssam_kip_hub_remove(struct ssam_device *sdev)
+{
+	struct ssam_kip_hub *hub = ssam_device_get_drvdata(sdev);
+
+	sysfs_remove_group(&sdev->dev.kobj, &ssam_kip_hub_group);
+
+	ssam_device_notifier_unregister(sdev, &hub->notif);
+	cancel_delayed_work_sync(&hub->update_work);
+	ssam_remove_clients(&sdev->dev);
+}
+
+static const struct ssam_device_id ssam_kip_hub_match[] = {
+	{ SSAM_SDEV(KIP, 0x01, 0x00, 0x00) },
+	{ },
+};
+
+static struct ssam_device_driver ssam_kip_hub_driver = {
+	.probe = ssam_kip_hub_probe,
+	.remove = ssam_kip_hub_remove,
+	.match_table = ssam_kip_hub_match,
+	.driver = {
+		.name = "surface_kip_hub",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.pm = &ssam_kip_hub_pm_ops,
+	},
+};
+
+
 /* -- SSAM platform/meta-hub driver. ---------------------------------------- */
 
 static const struct acpi_device_id ssam_platform_hub_match[] = {
@@ -624,18 +818,30 @@ static int __init ssam_device_hub_init(void)
 
 	status = platform_driver_register(&ssam_platform_hub_driver);
 	if (status)
-		return status;
+		goto err_platform;
 
 	status = ssam_device_driver_register(&ssam_base_hub_driver);
 	if (status)
-		platform_driver_unregister(&ssam_platform_hub_driver);
+		goto err_base;
+
+	status = ssam_device_driver_register(&ssam_kip_hub_driver);
+	if (status)
+		goto err_kip;
 
+	return 0;
+
+err_kip:
+	ssam_device_driver_unregister(&ssam_base_hub_driver);
+err_base:
+	platform_driver_unregister(&ssam_platform_hub_driver);
+err_platform:
 	return status;
 }
 module_init(ssam_device_hub_init);
 
 static void __exit ssam_device_hub_exit(void)
 {
+	ssam_device_driver_unregister(&ssam_kip_hub_driver);
 	ssam_device_driver_unregister(&ssam_base_hub_driver);
 	platform_driver_unregister(&ssam_platform_hub_driver);
 }
-- 
2.33.1

From 275eff5a992506073188eddb09bfa2c0cfa838e5 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 03:19:20 +0200
Subject: [PATCH] wip! platform/surface: Add KIP tablet-mode switch

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/Kconfig              |   8 +
 drivers/platform/surface/Makefile             |   1 +
 .../surface/surface_kip_tablet_switch.c       | 242 ++++++++++++++++++
 3 files changed, 251 insertions(+)
 create mode 100644 drivers/platform/surface/surface_kip_tablet_switch.c

diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig
index 3105f651614f..133ebb84bd2d 100644
--- a/drivers/platform/surface/Kconfig
+++ b/drivers/platform/surface/Kconfig
@@ -152,6 +152,14 @@ config SURFACE_HOTPLUG
 	  Select M or Y here, if you want to (fully) support hot-plugging of
 	  dGPU devices on the Surface Book 2 and/or 3 during D3cold.
 
+config SURFACE_KIP_TABLET_SWITCH
+	tristate "Surface KIP Tablet-Mode Switch Driver"
+	depends on SURFACE_AGGREGATOR
+	depends on SURFACE_AGGREGATOR_BUS
+	depends on INPUT
+	help
+	  TODO
+
 config SURFACE_PLATFORM_PROFILE
 	tristate "Surface Platform Profile Driver"
 	depends on SURFACE_AGGREGATOR_REGISTRY
diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile
index 32889482de55..6d9291c993c4 100644
--- a/drivers/platform/surface/Makefile
+++ b/drivers/platform/surface/Makefile
@@ -14,5 +14,6 @@ obj-$(CONFIG_SURFACE_AGGREGATOR_REGISTRY) += surface_aggregator_registry.o
 obj-$(CONFIG_SURFACE_DTX)		+= surface_dtx.o
 obj-$(CONFIG_SURFACE_GPE)		+= surface_gpe.o
 obj-$(CONFIG_SURFACE_HOTPLUG)		+= surface_hotplug.o
+obj-$(CONFIG_SURFACE_KIP_TABLET_SWITCH)	+= surface_kip_tablet_switch.o
 obj-$(CONFIG_SURFACE_PLATFORM_PROFILE)	+= surface_platform_profile.o
 obj-$(CONFIG_SURFACE_PRO3_BUTTON)	+= surfacepro3_button.o
diff --git a/drivers/platform/surface/surface_kip_tablet_switch.c b/drivers/platform/surface/surface_kip_tablet_switch.c
new file mode 100644
index 000000000000..87055f13bf9c
--- /dev/null
+++ b/drivers/platform/surface/surface_kip_tablet_switch.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Surface System Aggregator Module (SSAM) tablet mode switch via KIP
+ * subsystem.
+ *
+ * Copyright (C) 2021 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/device.h>
+
+#define SSAM_EVENT_KIP_CID_LID_STATE		0x1d
+
+enum ssam_kip_lid_state {
+	SSAM_KIP_LID_STATE_DISCONNECTED   = 0x01,
+	SSAM_KIP_LID_STATE_CLOSED         = 0x02,
+	SSAM_KIP_LID_STATE_LAPTOP         = 0x03,
+	SSAM_KIP_LID_STATE_FOLDED_CANVAS  = 0x04,
+	SSAM_KIP_LID_STATE_FOLDED_BACK    = 0x05,
+};
+
+struct ssam_kip_sw {
+	struct ssam_device *sdev;
+
+	enum ssam_kip_lid_state state;
+	struct work_struct update_work;
+	struct input_dev *mode_switch;
+
+	struct ssam_event_notifier notif;
+};
+
+SSAM_DEFINE_SYNC_REQUEST_R(__ssam_kip_get_lid_state, u8, {
+	.target_category = SSAM_SSH_TC_KIP,
+	.target_id       = 0x01,
+	.command_id      = 0x1d,
+	.instance_id     = 0x00,
+});
+
+static int ssam_kip_get_lid_state(struct ssam_kip_sw *sw, enum ssam_kip_lid_state *state)
+{
+	int status;
+	u8 raw;
+
+	status = ssam_retry(__ssam_kip_get_lid_state, sw->sdev->ctrl, &raw);
+	if (status < 0) {
+		dev_err(&sw->sdev->dev, "failed to query KIP lid state: %d\n", status);
+		return status;
+	}
+
+	*state = raw;
+	return 0;
+}
+
+static const char* ssam_kip_lid_state_str(enum ssam_kip_lid_state state)
+{
+	switch (state) {
+	case SSAM_KIP_LID_STATE_DISCONNECTED:
+		return "disconnected";
+
+	case SSAM_KIP_LID_STATE_CLOSED:
+		return "closed";
+
+	case SSAM_KIP_LID_STATE_LAPTOP:
+		return "laptop";
+
+	case SSAM_KIP_LID_STATE_FOLDED_CANVAS:
+		return "folded-canvas";
+
+	case SSAM_KIP_LID_STATE_FOLDED_BACK:
+		return "folded-back";
+
+	default:
+		return "<unknown>";
+	}
+}
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ssam_kip_sw *sw = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", ssam_kip_lid_state_str(sw->state));
+}
+static DEVICE_ATTR_RO(state);
+
+static struct attribute *ssam_kip_sw_attrs[] = {
+	&dev_attr_state.attr,
+	NULL,
+};
+
+static const struct attribute_group ssam_kip_sw_group = {
+	.attrs = ssam_kip_sw_attrs,
+};
+
+static void ssam_kip_sw_update_workfn(struct work_struct *work)
+{
+	struct ssam_kip_sw *sw = container_of(work, struct ssam_kip_sw, update_work);
+	enum ssam_kip_lid_state state;
+	int tablet, status;
+
+	status = ssam_kip_get_lid_state(sw, &state);
+	if (status)
+		return;
+
+	if (sw->state == state)
+		return;
+
+	sw->state = state;
+
+	/* Send SW_TABLET_MODE event. */
+	tablet = state != SSAM_KIP_LID_STATE_LAPTOP;
+	input_report_switch(sw->mode_switch, SW_TABLET_MODE, tablet);
+	input_sync(sw->mode_switch);
+}
+
+static u32 ssam_kip_sw_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
+{
+	struct ssam_kip_sw *sw = container_of(nf, struct ssam_kip_sw, notif);
+
+	if (event->command_id != SSAM_EVENT_KIP_CID_LID_STATE)
+		return 0;	/* Return "unhandled". */
+
+	if (event->length < 1) {
+		dev_err(&sw->sdev->dev, "unexpected payload size: %u\n", event->length);
+		return 0;
+	}
+
+	schedule_work(&sw->update_work);
+
+	return SSAM_NOTIF_HANDLED;
+}
+
+static int __maybe_unused ssam_kip_sw_resume(struct device *dev)
+{
+	struct ssam_kip_sw *sw = dev_get_drvdata(dev);
+
+	schedule_work(&sw->update_work);
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(ssam_kip_sw_pm_ops, NULL, ssam_kip_sw_resume);
+
+static int ssam_kip_sw_probe(struct ssam_device *sdev)
+{
+	struct ssam_kip_sw *sw;
+	int tablet, status;
+
+	sw = devm_kzalloc(&sdev->dev, sizeof(*sw), GFP_KERNEL);
+	if (!sw)
+		return -ENOMEM;
+
+	sw->sdev = sdev;
+	INIT_WORK(&sw->update_work, ssam_kip_sw_update_workfn);
+
+	ssam_device_set_drvdata(sdev, sw);
+
+	/* Get initial state. */
+	status = ssam_kip_get_lid_state(sw, &sw->state);
+	if (status)
+		return status;
+
+	/* Set up tablet mode switch. */
+	sw->mode_switch = devm_input_allocate_device(&sdev->dev);
+	if (!sw->mode_switch)
+		return -ENOMEM;
+
+	sw->mode_switch->name = "Microsoft Surface KIP Tablet Mode Switch";
+	sw->mode_switch->phys = "ssam/01:0e:01:00:01/input0";
+	sw->mode_switch->id.bustype = BUS_HOST;
+	sw->mode_switch->dev.parent = &sdev->dev;
+
+	tablet = sw->state != SSAM_KIP_LID_STATE_LAPTOP;
+	input_set_capability(sw->mode_switch, EV_SW, SW_TABLET_MODE);
+	input_report_switch(sw->mode_switch, SW_TABLET_MODE, tablet);
+
+	status = input_register_device(sw->mode_switch);
+	if (status)
+		return status;
+
+	/* Set up notifier. */
+	sw->notif.base.priority = 0;
+	sw->notif.base.fn = ssam_kip_sw_notif;
+	sw->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
+	sw->notif.event.id.target_category = SSAM_SSH_TC_KIP,
+	sw->notif.event.id.instance = 0,
+	sw->notif.event.mask = SSAM_EVENT_MASK_TARGET;
+	sw->notif.event.flags = SSAM_EVENT_SEQUENCED;
+
+	status = ssam_device_notifier_register(sdev, &sw->notif);
+	if (status)
+		return status;
+
+	status = sysfs_create_group(&sdev->dev.kobj, &ssam_kip_sw_group);
+	if (status)
+		goto err;
+
+	/* We might have missed events during setup, so check again. */
+	schedule_work(&sw->update_work);
+	return 0;
+
+err:
+	ssam_device_notifier_unregister(sdev, &sw->notif);
+	cancel_work_sync(&sw->update_work);
+	return status;
+}
+
+static void ssam_kip_sw_remove(struct ssam_device *sdev)
+{
+	struct ssam_kip_sw *sw = ssam_device_get_drvdata(sdev);
+
+	sysfs_remove_group(&sdev->dev.kobj, &ssam_kip_sw_group);
+
+	ssam_device_notifier_unregister(sdev, &sw->notif);
+	cancel_work_sync(&sw->update_work);
+}
+
+static const struct ssam_device_id ssam_kip_sw_match[] = {
+	{ SSAM_SDEV(KIP, 0x01, 0x00, 0x01) },
+	{ },
+};
+MODULE_DEVICE_TABLE(ssam, ssam_kip_sw_match);
+
+static struct ssam_device_driver ssam_kip_sw_driver = {
+	.probe = ssam_kip_sw_probe,
+	.remove = ssam_kip_sw_remove,
+	.match_table = ssam_kip_sw_match,
+	.driver = {
+		.name = "surface_kip_tablet_mode_switch",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.pm = &ssam_kip_sw_pm_ops,
+	},
+};
+module_ssam_device_driver(ssam_kip_sw_driver);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("Tablet mode switch driver for Surface devices using KIP subsystem");
+MODULE_LICENSE("GPL");
-- 
2.33.1

From b321e78a0435113151c7647986c30b4a2c076ed7 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 27 Oct 2021 22:33:03 +0200
Subject: [PATCH] platform/surface: Add support for the Surface Pro 8

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../surface/surface_aggregator_registry.c     | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index e02fe833fde8..c7baa3771420 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -47,6 +47,12 @@ static const struct software_node ssam_node_hub_base = {
 	.parent = &ssam_node_root,
 };
 
+/* KIP device hub (keyboard cover on Surface Pro 8). */
+static const struct software_node ssam_node_hub_kip = {
+	.name = "ssam:01:0e:01:00:00",
+	.parent = &ssam_node_root,
+};
+
 /* AC adapter. */
 static const struct software_node ssam_node_bat_ac = {
 	.name = "ssam:01:02:01:01:01",
@@ -71,6 +77,12 @@ static const struct software_node ssam_node_tmp_pprof = {
 	.parent = &ssam_node_root,
 };
 
+/* Tablet mode switch via KIP subsystem. */
+static const struct software_node ssam_node_kip_tablet_switch = {
+	.name = "ssam:01:0e:01:00:01",
+	.parent = &ssam_node_root,
+};
+
 /* DTX / detachment-system device (Surface Book 3). */
 static const struct software_node ssam_node_bas_dtx = {
 	.name = "ssam:01:11:01:00:00",
@@ -155,6 +167,30 @@ static const struct software_node ssam_node_hid_base_iid6 = {
 	.parent = &ssam_node_hub_base,
 };
 
+/* HID keyboard (KIP hub). */
+static const struct software_node ssam_node_hid_kip_keyboard = {
+	.name = "ssam:01:15:02:01:00",
+	.parent = &ssam_node_hub_kip,
+};
+
+/* HID pen stash (KIP hub; pen taken / stashed away evens). */
+static const struct software_node ssam_node_hid_kip_penstash = {
+	.name = "ssam:01:15:02:02:00",
+	.parent = &ssam_node_hub_kip,
+};
+
+/* HID touchpad (KIP hub). */
+static const struct software_node ssam_node_hid_kip_touchpad = {
+	.name = "ssam:01:15:02:03:00",
+	.parent = &ssam_node_hub_kip,
+};
+
+/* HID device instance 5 (KIP hub, unknown HID device). */
+static const struct software_node ssam_node_hid_kip_iid5 = {
+	.name = "ssam:01:15:02:05:00",
+	.parent = &ssam_node_hub_kip,
+};
+
 /*
  * Devices for 5th- and 6th-generations models:
  * - Surface Book 2,
@@ -228,6 +264,20 @@ static const struct software_node *ssam_node_group_sp7[] = {
 	NULL,
 };
 
+static const struct software_node *ssam_node_group_sp8[] = {
+	&ssam_node_root,
+	&ssam_node_hub_kip,
+	&ssam_node_bat_ac,
+	&ssam_node_bat_main,
+	&ssam_node_tmp_pprof,
+	&ssam_node_kip_tablet_switch,
+	&ssam_node_hid_kip_keyboard,
+	&ssam_node_hid_kip_penstash,
+	&ssam_node_hid_kip_touchpad,
+	&ssam_node_hid_kip_iid5,
+	NULL,
+};
+
 
 /* -- Device registry helper functions. ------------------------------------- */
 
@@ -714,6 +764,9 @@ static const struct acpi_device_id ssam_platform_hub_match[] = {
 	/* Surface Pro 7+ */
 	{ "MSHW0119", (unsigned long)ssam_node_group_sp7 },
 
+	/* Surface Pro 8 */
+	{ "MSHW0263", (unsigned long)ssam_node_group_sp8 },
+
 	/* Surface Book 2 */
 	{ "MSHW0107", (unsigned long)ssam_node_group_gen5 },
 
-- 
2.33.1