[PATCH v3 0/5] Add SW_TABLET_MODE support for AMD SFH convertibles

[PATCH v3 0/5] Add SW_TABLET_MODE support for AMD SFH convertibles

[Basavaraj Natikar]

Add SW_TABLET_MODE support for AMD convertibles whose operating mode
(laptop or tablet) is reported by the Sensor Fusion Hub.

Patches 1 and 2 are preparation: the first tracks the MP2 version
explicitly and the second serializes access to the shared emp2 pointer.
The third adds a way to read the operating mode. The fourth registers an
auxiliary device when the sensor is present, and the fifth is a small
input driver that binds to it and reports the posture to userspace.
Keeping the input handling in its own driver avoids pulling input/evdev
into the sensor transport driver.

Changes in v3:
- Destroy the tablet-mode auxiliary device before the hardware teardown
  in .remove(), instead of from a devres action that runs afterwards,
  closing a use-after-teardown window (Sashiko review).
- Move the Makefile entry to its correct alphabetical position
  (Dmitry Torokhov).

Changes in v2 (address the Sashiko review of v1):
- Read the operating-mode register only on confirmed MP2 v2, by tracking
  the MP2 version explicitly. On v1.0 that register overlaps the 64-bit
  DMA address programmed through C2P, so the earlier unconditional read
  could return DMA bits instead of the operating mode.
- Serialize the shared emp2 pointer and all exported readers under a
  mutex, so a concurrent unbind can no longer free the device while a
  reader is still dereferencing it.
- Publish emp2 only after initialization has populated the client data,
  and clear it early on the MP2 v2 remove path instead of from a
  prematurely registered devres action; this removes both the
  publish-before-init data race and the unconditional global clear on a
  probe failure.
- Destroy the tablet-mode auxiliary device and release its id on removal,
  and allocate the id dynamically so multiple instances cannot collide.
- Report the initial tablet-mode state before registering the input
  device, so userspace never observes a stale default posture.
- Rename the error variable from 'rc' to 'error' to follow the
  input-subsystem convention.

v2: https://lore.kernel.org/all/20260803145801.3801862-1-Basavaraj.Natikar@amd.com/
v1: https://lore.kernel.org/all/20260721174422.3109166-1-Basavaraj.Natikar@amd.com/

Basavaraj Natikar (5):
  HID: amd_sfh: Track MP2 version explicitly
  HID: amd_sfh: Serialize access to the shared emp2 pointer
  HID: amd_sfh: Add accessor to read the operating-mode sensor
  HID: amd_sfh: Register tablet-mode auxiliary device
  Input: misc: Add AMD SFH tablet-mode switch driver

 MAINTAINERS                                   |  1 +
 drivers/hid/amd-sfh-hid/Kconfig               |  1 +
 drivers/hid/amd-sfh-hid/amd_sfh_client.c      | 16 ++++
 drivers/hid/amd-sfh-hid/amd_sfh_common.h      | 13 +++
 drivers/hid/amd-sfh-hid/amd_sfh_pcie.c        | 63 ++++++++++++++-
 .../amd-sfh-hid/sfh1_1/amd_sfh_interface.c    | 39 +++++++++
 .../amd-sfh-hid/sfh1_1/amd_sfh_interface.h    |  1 -
 drivers/input/misc/Kconfig                    | 15 ++++
 drivers/input/misc/Makefile                   |  1 +
 drivers/input/misc/amd_sfh_tabletmode.c       | 81 +++++++++++++++++++
 include/linux/amd-pmf-io.h                    | 14 ++++
 11 files changed, 240 insertions(+), 5 deletions(-)
 create mode 100644 drivers/input/misc/amd_sfh_tabletmode.c

-- 
2.34.1

[PATCH v3 1/5] HID: amd_sfh: Track MP2 version explicitly

[Basavaraj Natikar]

The MP2 version is currently known only implicitly, from whether an ops
pointer was stored in the PCI driver_data. Subsequent changes need to
act on the MP2 version directly, for example to read the operating-mode
register only on confirmed MP2 v2.

Track the MP2 version explicitly so that version-specific behaviour can
be gated on it, and leave it unset for generations that do not require
such handling.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
---
 drivers/hid/amd-sfh-hid/amd_sfh_common.h | 6 ++++++
 drivers/hid/amd-sfh-hid/amd_sfh_pcie.c   | 9 +++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_common.h b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
index 78f830c133e5..68586f08ab23 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_common.h
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
@@ -35,6 +35,11 @@ enum cmd_id {
 	STOP_ALL_SENSORS = 8,
 };
 
+enum amd_mp2_version {
+	MP2_VER_V2 = 1,
+	MP2_VER_1_1 = 2,
+};
+
 struct amd_mp2_sensor_info {
 	u8 sensor_idx;
 	u32 period;
@@ -64,6 +69,7 @@ struct amd_mp2_dev {
 	struct mutex lock;
 	u8 init_done;
 	u8 rver;
+	u8 mp2_ver;
 };
 
 struct amd_mp2_ops {
diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
index 4b81cebdc335..92801ca38957 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
@@ -285,6 +285,7 @@ static void mp2_select_ops(struct amd_mp2_dev *privdata)
 	switch (acs) {
 	case V2_STATUS:
 		privdata->mp2_ops = &amd_sfh_ops_v2;
+		privdata->mp2_ver = MP2_VER_V2;
 		break;
 	default:
 		privdata->mp2_ops = &amd_sfh_ops;
@@ -471,8 +472,9 @@ static int amd_mp2_pci_probe(struct pci_dev *pdev, const struct pci_device_id *i
 	if (rc)
 		return rc;
 
-	privdata->sfh1_1_ops = (const struct amd_sfh1_1_ops *)id->driver_data;
-	if (privdata->sfh1_1_ops) {
+	privdata->mp2_ver = (enum amd_mp2_version)id->driver_data;
+	if (privdata->mp2_ver >= MP2_VER_1_1) {
+		privdata->sfh1_1_ops = &sfh1_1_ops;
 		if (boot_cpu_data.x86 >= 0x1A)
 			privdata->rver = 1;
 
@@ -540,8 +542,7 @@ static SIMPLE_DEV_PM_OPS(amd_mp2_pm_ops, amd_mp2_pci_suspend,
 
 static const struct pci_device_id amd_mp2_pci_tbl[] = {
 	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2) },
-	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2_1_1),
-	  .driver_data = (kernel_ulong_t)&sfh1_1_ops },
+	{ PCI_DEVICE_DATA(AMD, MP2_1_1, MP2_VER_1_1) },
 	{ }
 };
 MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);
-- 
2.34.1

[PATCH v3 2/5] HID: amd_sfh: Serialize access to the shared emp2 pointer

[Basavaraj Natikar]

The SFH accessors reach the device through a file-global emp2 pointer
that is published at probe and cleared on remove. amd_get_sfh_info() is
exported and called from other modules on unrelated threads, so a reader
can observe a non-NULL emp2 and then race a concurrent unbind that clears
it and frees the device.

Serialize the emp2 publish/clear and all readers under a mutex, so a
reader either sees a live device for the whole access or sees NULL.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
---
 drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c b/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c
index 837d59e7a661..dd2720bae65c 100644
--- a/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c
+++ b/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c
@@ -8,12 +8,14 @@
  * Author: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
  */
 #include <linux/amd-pmf-io.h>
+#include <linux/cleanup.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/iopoll.h>
 
 #include "amd_sfh_interface.h"
 
 static struct amd_mp2_dev *emp2;
+static DEFINE_MUTEX(emp2_lock);
 
 static int amd_sfh_wait_response(struct amd_mp2_dev *mp2, u8 sid, u32 cmd_id)
 {
@@ -78,12 +80,14 @@ static struct amd_mp2_ops amd_sfh_ops = {
 
 void sfh_deinit_emp2(void)
 {
+	guard(mutex)(&emp2_lock);
 	emp2 = NULL;
 }
 
 void sfh_interface_init(struct amd_mp2_dev *mp2)
 {
 	mp2->mp2_ops = &amd_sfh_ops;
+	guard(mutex)(&emp2_lock);
 	emp2 = mp2;
 }
 
@@ -160,6 +164,8 @@ static int amd_sfh_als_info(u32 *ambient_light)
 
 int amd_get_sfh_info(struct amd_sfh_info *sfh_info, enum sfh_message_type op)
 {
+	guard(mutex)(&emp2_lock);
+
 	if (sfh_info) {
 		switch (op) {
 		case MT_HPD:
-- 
2.34.1

[PATCH v3 3/5] HID: amd_sfh: Add accessor to read the operating-mode sensor

[Basavaraj Natikar]

Allow other drivers to query the operating mode (laptop or tablet)
reported by the Sensor Fusion Hub. This is the interface used by the
tablet-mode switch driver to report the device posture to userspace.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
---
 drivers/hid/amd-sfh-hid/amd_sfh_client.c      | 16 +++++++++
 drivers/hid/amd-sfh-hid/amd_sfh_common.h      |  5 +++
 drivers/hid/amd-sfh-hid/amd_sfh_pcie.c        |  4 +++
 .../amd-sfh-hid/sfh1_1/amd_sfh_interface.c    | 33 +++++++++++++++++++
 .../amd-sfh-hid/sfh1_1/amd_sfh_interface.h    |  1 -
 include/linux/amd-pmf-io.h                    | 14 ++++++++
 6 files changed, 72 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_client.c b/drivers/hid/amd-sfh-hid/amd_sfh_client.c
index 96ae792beeb6..ae6add0b9ce3 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_client.c
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_client.c
@@ -383,3 +383,19 @@ int amd_sfh_hid_client_deinit(struct amd_mp2_dev *privdata)
 
 	return 0;
 }
+
+bool amd_sfh_op_idx_enabled(struct amd_mp2_dev *mp2)
+{
+	struct amdtp_cl_data *cl = mp2->cl_data;
+	int i;
+
+	if (!cl)
+		return false;
+
+	for (i = 0; i < cl->num_hid_devices; i++)
+		if (cl->sensor_idx[i] == op_idx &&
+		    READ_ONCE(cl->sensor_sts[i]) == SENSOR_ENABLED)
+			return true;
+
+	return false;
+}
diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_common.h b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
index 68586f08ab23..0ca3254151ac 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_common.h
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
@@ -106,4 +106,9 @@ static inline u64 amd_get_p2c_val(struct amd_mp2_dev *mp2, u32 idx)
 {
 	return mp2->rver == 1 ? AMD_P2C_MSG_V1(idx) :  AMD_P2C_MSG(idx);
 }
+
+bool amd_sfh_op_idx_enabled(struct amd_mp2_dev *mp2);
+void sfh_set_emp2(struct amd_mp2_dev *mp2);
+void sfh_deinit_emp2(void);
+
 #endif
diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
index 92801ca38957..4b1cd260410d 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
@@ -251,6 +251,8 @@ int amd_mp2_get_sensor_num(struct amd_mp2_dev *privdata, u8 *sensor_id)
 static void amd_mp2_pci_remove(void *privdata)
 {
 	struct amd_mp2_dev *mp2 = privdata;
+
+	sfh_deinit_emp2();
 	amd_sfh_hid_client_deinit(privdata);
 	mp2->mp2_ops->stop_all(mp2);
 	pcim_intx(mp2->pdev, false);
@@ -419,6 +421,7 @@ static void sfh_init_work(struct work_struct *work)
 		return;
 	}
 
+	sfh_set_emp2(mp2);
 	amd_sfh_clear_intr(mp2);
 	mp2->init_done = 1;
 }
@@ -448,6 +451,7 @@ static int amd_mp2_pci_probe(struct pci_dev *pdev, const struct pci_device_id *i
 
 	privdata->pdev = pdev;
 	dev_set_drvdata(&pdev->dev, privdata);
+
 	rc = pcim_enable_device(pdev);
 	if (rc)
 		return rc;
diff --git a/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c b/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c
index dd2720bae65c..097c5513ccd8 100644
--- a/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c
+++ b/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.c
@@ -84,6 +84,12 @@ void sfh_deinit_emp2(void)
 	emp2 = NULL;
 }
 
+void sfh_set_emp2(struct amd_mp2_dev *mp2)
+{
+	guard(mutex)(&emp2_lock);
+	emp2 = mp2;
+}
+
 void sfh_interface_init(struct amd_mp2_dev *mp2)
 {
 	mp2->mp2_ops = &amd_sfh_ops;
@@ -91,6 +97,31 @@ void sfh_interface_init(struct amd_mp2_dev *mp2)
 	emp2 = mp2;
 }
 
+static int amd_sfh_op_mode_info(u32 *op_mode)
+{
+	struct sfh_op_mode mode;
+	bool present;
+
+	if (!op_mode)
+		return -EINVAL;
+	if (!emp2)
+		return -ENODEV;
+
+	present = emp2->sfh1_1_ops ? emp2->dev_en.is_sra_present
+				   : (emp2->mp2_ver == MP2_VER_V2 &&
+				      amd_sfh_op_idx_enabled(emp2));
+	if (!present)
+		return -ENODEV;
+
+	mode.val = readl(emp2->mmio + amd_get_c2p_val(emp2, 3));
+	dev_dbg(&emp2->pdev->dev, "op-mode: %s (mode=%u)\n",
+		mode.op_mode.mode == SFH_MODE_TABLET ? "tablet" : "laptop",
+		mode.op_mode.mode);
+	*op_mode = mode.op_mode.mode;
+
+	return 0;
+}
+
 static int amd_sfh_mode_info(u32 *platform_type, u32 *laptop_placement)
 {
 	struct sfh_op_mode mode;
@@ -175,6 +206,8 @@ int amd_get_sfh_info(struct amd_sfh_info *sfh_info, enum sfh_message_type op)
 		case MT_SRA:
 			return amd_sfh_mode_info(&sfh_info->platform_type,
 						 &sfh_info->laptop_placement);
+		case MT_OP_MODE:
+			return amd_sfh_op_mode_info(&sfh_info->op_mode);
 		}
 	}
 	return -EINVAL;
diff --git a/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.h b/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.h
index 665c99ad779f..56258c4d1b3a 100644
--- a/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.h
+++ b/drivers/hid/amd-sfh-hid/sfh1_1/amd_sfh_interface.h
@@ -185,7 +185,6 @@ struct sfh_op_mode {
 };
 
 void sfh_interface_init(struct amd_mp2_dev *mp2);
-void sfh_deinit_emp2(void);
 void amd_sfh1_1_set_desc_ops(struct amd_mp2_ops *mp2_ops);
 int amd_sfh_float_to_int(u32 flt32_val);
 #endif
diff --git a/include/linux/amd-pmf-io.h b/include/linux/amd-pmf-io.h
index 55198d2875cc..dc59c43bd8f2 100644
--- a/include/linux/amd-pmf-io.h
+++ b/include/linux/amd-pmf-io.h
@@ -19,11 +19,13 @@
  * @MT_HPD: Message ID to know the Human presence info from MP2 FW
  * @MT_ALS: Message ID to know the Ambient light info from MP2 FW
  * @MT_SRA: Message ID to know the SRA data from MP2 FW
+ * @MT_OP_MODE: Message ID to know the operating-mode (tablet/laptop) info
  */
 enum sfh_message_type {
 	MT_HPD,
 	MT_ALS,
 	MT_SRA,
+	MT_OP_MODE,
 };
 
 /**
@@ -44,12 +46,24 @@ enum sfh_hpd_info {
  * @user_present: Populates the user presence information
  * @platform_type: Operating modes (clamshell, flat, tent, etc.)
  * @laptop_placement: Device states (ontable, onlap, outbag)
+ * @op_mode: Operating-mode field (see enum sfh_dev_mode); used for tablet detection
  */
 struct amd_sfh_info {
 	u32 ambient_light;
 	u8 user_present;
 	u32 platform_type;
 	u32 laptop_placement;
+	u32 op_mode;
+};
+
+/**
+ * enum sfh_dev_mode - SFH operating-mode field (sfh_op_mode.mode, bits 0-2)
+ * @SFH_MODE_LAPTOP: Device is in laptop/clamshell posture
+ * @SFH_MODE_TABLET: Device is in tablet posture
+ */
+enum sfh_dev_mode {
+	SFH_MODE_LAPTOP	= 1,
+	SFH_MODE_TABLET	= 3,
 };
 
 enum laptop_placement {
-- 
2.34.1

[PATCH v3 4/5] HID: amd_sfh: Register tablet-mode auxiliary device

[Basavaraj Natikar]

Register an auxiliary device when the operating-mode sensor is present,
so a dedicated input driver can bind to it and report the device
posture. This keeps the input handling out of the sensor transport
driver.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
---
 drivers/hid/amd-sfh-hid/Kconfig          |  1 +
 drivers/hid/amd-sfh-hid/amd_sfh_common.h |  2 +
 drivers/hid/amd-sfh-hid/amd_sfh_pcie.c   | 50 ++++++++++++++++++++++++
 3 files changed, 53 insertions(+)

diff --git a/drivers/hid/amd-sfh-hid/Kconfig b/drivers/hid/amd-sfh-hid/Kconfig
index 3291786a5ee6..d86d83ffebd7 100644
--- a/drivers/hid/amd-sfh-hid/Kconfig
+++ b/drivers/hid/amd-sfh-hid/Kconfig
@@ -6,6 +6,7 @@ menu "AMD SFH HID Support"
 config AMD_SFH_HID
 	tristate "AMD Sensor Fusion Hub"
 	depends on X86
+	select AUXILIARY_BUS
 	help
 	  If you say yes to this option, support will be included for the
 	  AMD Sensor Fusion Hub.
diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_common.h b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
index 0ca3254151ac..f8c6b7fc34fb 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_common.h
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
@@ -10,6 +10,7 @@
 #ifndef AMD_SFH_COMMON_H
 #define AMD_SFH_COMMON_H
 
+#include <linux/auxiliary_bus.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
 #include "amd_sfh_hid.h"
@@ -70,6 +71,7 @@ struct amd_mp2_dev {
 	u8 init_done;
 	u8 rver;
 	u8 mp2_ver;
+	struct auxiliary_device *tm_auxdev;
 };
 
 struct amd_mp2_ops {
diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
index 4b1cd260410d..1405167aa369 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
@@ -8,11 +8,13 @@
  *	    Basavaraj Natikar <Basavaraj.Natikar@amd.com>
  */
 
+#include <linux/auxiliary_bus.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/devm-helpers.h>
 #include <linux/dma-mapping.h>
 #include <linux/dmi.h>
+#include <linux/idr.h>
 #include <linux/interrupt.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/iopoll.h>
@@ -389,6 +391,51 @@ static const struct attribute_group *amd_sfh_groups[] = {
 	NULL,
 };
 
+static DEFINE_IDA(sfh_tm_ida);
+
+static void amd_sfh_maybe_register_tm(struct amd_mp2_dev *mp2)
+{
+	struct auxiliary_device *adev;
+	bool present;
+	int id;
+
+	if (mp2->tm_auxdev)
+		return;
+
+	present = mp2->sfh1_1_ops ? mp2->dev_en.is_sra_present
+				  : (mp2->mp2_ver == MP2_VER_V2 &&
+				     amd_sfh_op_idx_enabled(mp2));
+	if (!present)
+		return;
+
+	id = ida_alloc(&sfh_tm_ida, GFP_KERNEL);
+	if (id < 0)
+		return;
+
+	adev = auxiliary_device_create(&mp2->pdev->dev, KBUILD_MODNAME,
+				       "tabletmode", NULL, id);
+	if (!adev) {
+		ida_free(&sfh_tm_ida, id);
+		dev_warn(&mp2->pdev->dev, "tabletmode auxdev create failed\n");
+		return;
+	}
+
+	mp2->tm_auxdev = adev;
+}
+
+static void amd_sfh_unregister_tm(struct amd_mp2_dev *mp2)
+{
+	int id;
+
+	if (!mp2->tm_auxdev)
+		return;
+
+	id = mp2->tm_auxdev->id;
+	auxiliary_device_destroy(mp2->tm_auxdev);
+	mp2->tm_auxdev = NULL;
+	ida_free(&sfh_tm_ida, id);
+}
+
 static void sfh1_1_init_work(struct work_struct *work)
 {
 	struct amd_mp2_dev *mp2 = container_of(work, struct amd_mp2_dev, work);
@@ -405,6 +452,7 @@ static void sfh1_1_init_work(struct work_struct *work)
 	if (rc)
 		dev_warn(&mp2->pdev->dev, "failed to update sysfs group\n");
 
+	amd_sfh_maybe_register_tm(mp2);
 }
 
 static void sfh_init_work(struct work_struct *work)
@@ -424,6 +472,7 @@ static void sfh_init_work(struct work_struct *work)
 	sfh_set_emp2(mp2);
 	amd_sfh_clear_intr(mp2);
 	mp2->init_done = 1;
+	amd_sfh_maybe_register_tm(mp2);
 }
 
 static void amd_sfh_remove(struct pci_dev *pdev)
@@ -431,6 +480,7 @@ static void amd_sfh_remove(struct pci_dev *pdev)
 	struct amd_mp2_dev *mp2 = pci_get_drvdata(pdev);
 
 	flush_work(&mp2->work);
+	amd_sfh_unregister_tm(mp2);
 	if (mp2->init_done)
 		mp2->mp2_ops->remove(mp2);
 }
-- 
2.34.1

[PATCH v3 5/5] Input: misc: Add AMD SFH tablet-mode switch driver

[Basavaraj Natikar]

Report whether an AMD convertible is in laptop or tablet mode using the
operating-mode sensor provided by the Sensor Fusion Hub, and expose it
to userspace as SW_TABLET_MODE, so userspace can react to the device
being folded into tablet posture.

Cc: Helge Bahmann <hcb@chaoticmind.net>
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 MAINTAINERS                             |  1 +
 drivers/input/misc/Kconfig              | 15 +++++
 drivers/input/misc/Makefile             |  1 +
 drivers/input/misc/amd_sfh_tabletmode.c | 81 +++++++++++++++++++++++++
 4 files changed, 98 insertions(+)
 create mode 100644 drivers/input/misc/amd_sfh_tabletmode.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 5114e6db7307..30b429eb9286 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1301,6 +1301,7 @@ L:	linux-input@vger.kernel.org
 S:	Maintained
 F:	Documentation/hid/amd-sfh*
 F:	drivers/hid/amd-sfh-hid/
+F:	drivers/input/misc/amd_sfh_tabletmode.c
 
 AMD SPI DRIVER
 M:	Raju Rangoju <Raju.Rangoju@amd.com>
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 1f6c57dba030..5b76be31f687 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -899,6 +899,21 @@ config INPUT_SOC_BUTTON_ARRAY
 	  To compile this driver as a module, choose M here: the
 	  module will be called soc_button_array.
 
+config INPUT_AMD_SFH_TABLETMODE
+	tristate "AMD SFH tablet-mode switch"
+	depends on AMD_SFH_HID
+	select AUXILIARY_BUS
+	help
+	  Expose SW_TABLET_MODE for AMD convertible laptops whose
+	  operation-mode sensor is provided by the AMD Sensor Fusion Hub.
+
+	  Userspace components such as systemd-logind and modern desktop
+	  environments react to SW_TABLET_MODE when the device is folded
+	  into tablet posture.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called amd_sfh_tabletmode.
+
 config INPUT_DRV260X_HAPTICS
 	tristate "TI DRV260X haptics support"
 	depends on INPUT && I2C
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 2281d6803fce..6fab9acf3de3 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_INPUT_AD714X_SPI)		+= ad714x-spi.o
 obj-$(CONFIG_INPUT_ADXL34X)		+= adxl34x.o
 obj-$(CONFIG_INPUT_ADXL34X_I2C)		+= adxl34x-i2c.o
 obj-$(CONFIG_INPUT_ADXL34X_SPI)		+= adxl34x-spi.o
+obj-$(CONFIG_INPUT_AMD_SFH_TABLETMODE)	+= amd_sfh_tabletmode.o
 obj-$(CONFIG_INPUT_APANEL)		+= apanel.o
 obj-$(CONFIG_INPUT_ARIEL_PWRBUTTON)	+= ariel-pwrbutton.o
 obj-$(CONFIG_INPUT_ARIZONA_HAPTICS)	+= arizona-haptics.o
diff --git a/drivers/input/misc/amd_sfh_tabletmode.c b/drivers/input/misc/amd_sfh_tabletmode.c
new file mode 100644
index 000000000000..3931a1c6eb74
--- /dev/null
+++ b/drivers/input/misc/amd_sfh_tabletmode.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD SFH tablet-mode switch driver
+ *
+ * Copyright (c) 2026, Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Author: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
+ */
+
+#include <linux/amd-pmf-io.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/pci_ids.h>
+
+#define POLL_INTERVAL_MS	200
+
+static void sfh_tm_poll(struct input_dev *input)
+{
+	struct amd_sfh_info info = {};
+
+	if (amd_get_sfh_info(&info, MT_OP_MODE))
+		return;
+
+	input_report_switch(input, SW_TABLET_MODE,
+			    info.op_mode == SFH_MODE_TABLET);
+	input_sync(input);
+}
+
+static int sfh_tm_probe(struct auxiliary_device *auxdev,
+			const struct auxiliary_device_id *id)
+{
+	struct device *dev = &auxdev->dev;
+	struct amd_sfh_info info = {};
+	struct input_dev *input;
+	int error;
+
+	error = amd_get_sfh_info(&info, MT_OP_MODE);
+	if (error)
+		return error == -EINVAL ? -ENODEV : error;
+
+	input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	input->name		= "AMD SFH tablet mode switch";
+	input->phys		= "amd-sfh/tabletmode";
+	input->id.bustype	= BUS_HOST;
+	input->id.vendor	= PCI_VENDOR_ID_AMD;
+	input_set_capability(input, EV_SW, SW_TABLET_MODE);
+
+	error = input_setup_polling(input, sfh_tm_poll);
+	if (error)
+		return error;
+	input_set_poll_interval(input, POLL_INTERVAL_MS);
+
+	sfh_tm_poll(input);
+
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static const struct auxiliary_device_id sfh_tm_id_table[] = {
+	{ .name = "amd_sfh.tabletmode" },
+	{}
+};
+MODULE_DEVICE_TABLE(auxiliary, sfh_tm_id_table);
+
+static struct auxiliary_driver sfh_tm_driver = {
+	.name		= "tabletmode",
+	.id_table	= sfh_tm_id_table,
+	.probe		= sfh_tm_probe,
+};
+module_auxiliary_driver(sfh_tm_driver);
+
+MODULE_DESCRIPTION("AMD SFH tablet mode switch");
+MODULE_LICENSE("GPL");
-- 
2.34.1