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

[Basavaraj Natikar <Basavaraj.Natikar@amd.com>]

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