[PATCH v6] platform/x86: thinkpad-acpi: Add support for new hotkey for camera shutter switch

[Nitin Joshi <nitjoshi@gmail.com>]

New Lenovo Thinkpad models, e.g. the 'X9-14 Gen 1' and 'X9-15 Gen 1'
has new shortcut on F9 key i.e to switch camera shutter and it
send a new 0x131b hkey event when F9 key is pressed.

This commit adds support for new hkey 0x131b.

Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Nitin Joshi <nitjoshi@gmail.com>
---
Changes in v6:
* Fix sparse error.
Changes in v5:
* Incorporated review comments for consistency.
Changes in v4:
* Renamed macro from METHOD_ERR to GCES_NO_SHUTTER_DEVICE.
Changes in v3:
* Avoid wasteful get_camera_shutter() calls and Minor changes based on review comments to make
  code more readable.
Changes in v2:
* Added ASL method to get camera shutter status and send it to userspace.
---
 drivers/platform/x86/thinkpad_acpi.c | 43 +++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 5790095c175e..080063395082 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -182,6 +182,7 @@ enum tpacpi_hkey_event_t {
 						   * directly in the sparse-keymap.
 						   */
 	TP_HKEY_EV_AMT_TOGGLE		= 0x131a, /* Toggle AMT on/off */
+	TP_HKEY_EV_CAMERASHUTTER_TOGGLE = 0x131b, /* Toggle Camera Shutter */
 	TP_HKEY_EV_DOUBLETAP_TOGGLE	= 0x131c, /* Toggle trackpoint doubletap on/off */
 	TP_HKEY_EV_PROFILE_TOGGLE	= 0x131f, /* Toggle platform profile in 2024 systems */
 	TP_HKEY_EV_PROFILE_TOGGLE2	= 0x1401, /* Toggle platform profile in 2025 + systems */
@@ -2250,6 +2251,25 @@ static void tpacpi_input_send_tabletsw(void)
 	}
 }
 
+#define GCES_NO_SHUTTER_DEVICE BIT(31)
+
+static int get_camera_shutter(void)
+{
+	acpi_handle gces_handle;
+	int output;
+
+	if (ACPI_FAILURE(acpi_get_handle(hkey_handle, "GCES", &gces_handle)))
+		return -ENODEV;
+
+	if (!acpi_evalf(gces_handle, &output, NULL, "dd", 0))
+		return -EIO;
+
+	if (output & GCES_NO_SHUTTER_DEVICE)
+		return -ENODEV;
+
+	return output;
+}
+
 static bool tpacpi_input_send_key(const u32 hkey, bool *send_acpi_ev)
 {
 	bool known_ev;
@@ -3303,7 +3323,7 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 	const struct key_entry *keymap;
 	bool radiosw_state  = false;
 	bool tabletsw_state = false;
-	int hkeyv, res, status;
+	int hkeyv, res, status, camera_shutter_state;
 
 	vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_HKEY,
 			"initializing hotkey subdriver\n");
@@ -3467,6 +3487,12 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 	if (res)
 		return res;
 
+	camera_shutter_state = get_camera_shutter();
+	if (camera_shutter_state >= 0) {
+		input_set_capability(tpacpi_inputdev, EV_SW, SW_CAMERA_LENS_COVER);
+		input_report_switch(tpacpi_inputdev, SW_CAMERA_LENS_COVER, camera_shutter_state);
+	}
+
 	if (tp_features.hotkey_wlsw) {
 		input_set_capability(tpacpi_inputdev, EV_SW, SW_RFKILL_ALL);
 		input_report_switch(tpacpi_inputdev,
@@ -11161,6 +11187,8 @@ static struct platform_driver tpacpi_hwmon_pdriver = {
  */
 static bool tpacpi_driver_event(const unsigned int hkey_event)
 {
+	int camera_shutter_state;
+
 	switch (hkey_event) {
 	case TP_HKEY_EV_BRGHT_UP:
 	case TP_HKEY_EV_BRGHT_DOWN:
@@ -11236,6 +11264,19 @@ static bool tpacpi_driver_event(const unsigned int hkey_event)
 		else
 			dytc_control_amt(!dytc_amt_active);
 
+		return true;
+	case TP_HKEY_EV_CAMERASHUTTER_TOGGLE:
+		camera_shutter_state = get_camera_shutter();
+		if (camera_shutter_state < 0) {
+			pr_err("Error retrieving camera shutter state after shutter event\n");
+			return true;
+		}
+		mutex_lock(&tpacpi_inputdev_send_mutex);
+
+		input_report_switch(tpacpi_inputdev, SW_CAMERA_LENS_COVER, camera_shutter_state);
+		input_sync(tpacpi_inputdev);
+
+		mutex_unlock(&tpacpi_inputdev_send_mutex);
 		return true;
 	case TP_HKEY_EV_DOUBLETAP_TOGGLE:
 		tp_features.trackpoint_doubletap = !tp_features.trackpoint_doubletap;
-- 
2.43.0