[PATCH v3 2/3] platform/x86: thinkpad_acpi: Add support for palm sensor

[Mark Pearson <markpearson@lenovo.com>]

Use input device event support for notifying userspace of palm sensor
state changes

Co-developed-by: Nitin Joshi <njoshi1@lenovo.com>
Signed-off-by: Nitin Joshi <njoshi1@lenovo.com>
Signed-off-by: Mark Pearson <markpearson@lenovo.com>
---
Changes in V2:
 - Update commit message to be correct

Changes in V3:
 - remove unnecessary global state variable
 - clean up error handling code
 - set dangling pointer to null

 drivers/platform/x86/thinkpad_acpi.c | 95 +++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index eae3579f106f..3cb07c12a705 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -4013,6 +4013,7 @@ static bool hotkey_notify_usrevent(const u32 hkey,
 }
 
 static void thermal_dump_all_sensors(void);
+static void palmsensor_refresh(void);
 
 static bool hotkey_notify_6xxx(const u32 hkey,
 				 bool *send_acpi_ev,
@@ -4079,8 +4080,8 @@ static bool hotkey_notify_6xxx(const u32 hkey,
 
 	case TP_HKEY_EV_PALM_DETECTED:
 	case TP_HKEY_EV_PALM_UNDETECTED:
-		/* palm detected hovering the keyboard, forward to user-space
-		 * via netlink for consumption */
+		/* palm detected  - pass on to event handler */
+		palmsensor_refresh();
 		return true;
 
 	default:
@@ -9918,6 +9919,92 @@ static struct ibm_struct dytc_driver_data = {
 	.exit = dytc_exit,
 };
 
+/*************************************************************************
+ * Proximity sensor subdriver
+ */
+
+#define PALMSENSOR_PRESENT_BIT 0 /* Determine if psensor present */
+#define PALMSENSOR_ON_BIT      1 /* psensor status */
+
+struct input_dev *tpacpi_sw_dev;
+bool has_palmsensor;
+
+static int palmsensor_get(bool *present, bool *state)
+{
+	acpi_handle psensor_handle;
+	int output;
+
+	if (ACPI_FAILURE(acpi_get_handle(hkey_handle, "GPSS", &psensor_handle)))
+		return -ENODEV;
+	if (!acpi_evalf(psensor_handle, &output, NULL, "d"))
+		return -EIO;
+
+	*present = output & BIT(PALMSENSOR_PRESENT_BIT) ? true : false;
+	*state = output & BIT(PALMSENSOR_ON_BIT) ? true : false;
+	return 0;
+}
+
+static void palmsensor_refresh(void)
+{
+	bool state;
+	int err;
+
+	if (has_palmsensor) {
+		err = palmsensor_get(&has_palmsensor, &state);
+		if (err)
+			return;
+		input_report_switch(tpacpi_sw_dev, SW_PALMREST_PROXIMITY, state);
+		input_sync(tpacpi_sw_dev);
+	}
+}
+
+static int tpacpi_proxsensor_init(struct ibm_init_struct *iibm)
+{
+	int palm_err, err;
+	bool palm_state;
+
+	palm_err = palmsensor_get(&has_palmsensor, &palm_state);
+	/* If support isn't available (ENODEV) then quit, but don't return an error */
+	if (palm_err == -ENODEV)
+		return 1;
+
+	/* Otherwise, if there was an error return it */
+	if (palm_err && (palm_err != ENODEV))
+		return palm_err;
+
+	if (has_palmsensor) {
+		tpacpi_sw_dev = input_allocate_device();
+		if (!tpacpi_sw_dev)
+			return -ENOMEM;
+		tpacpi_sw_dev->name = "Thinkpad proximity switches";
+		tpacpi_sw_dev->phys = TPACPI_DRVR_NAME "/input1";
+		tpacpi_sw_dev->id.bustype = BUS_HOST;
+		tpacpi_sw_dev->id.vendor = thinkpad_id.vendor;
+		tpacpi_sw_dev->id.product = TPACPI_HKEY_INPUT_PRODUCT;
+		tpacpi_sw_dev->id.version = TPACPI_HKEY_INPUT_VERSION;
+		tpacpi_sw_dev->dev.parent = &tpacpi_pdev->dev;
+
+		input_set_capability(tpacpi_sw_dev, EV_SW, SW_PALMREST_PROXIMITY);
+		input_report_switch(tpacpi_sw_dev, SW_PALMREST_PROXIMITY, palm_state);
+		err = input_register_device(tpacpi_sw_dev);
+		if (err) {
+			input_free_device(tpacpi_sw_dev);
+			tpacpi_sw_dev = NULL;
+			return 0;
+		}
+	}
+	return 1;
+}
+
+static void proxsensor_exit(void)
+{
+	input_unregister_device(tpacpi_sw_dev);
+}
+
+static struct ibm_struct proxsensor_driver_data = {
+	.name = "proximity-sensor",
+	.exit = proxsensor_exit,
+};
 /****************************************************************************
  ****************************************************************************
  *
@@ -10411,6 +10498,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
 		.init = tpacpi_dytc_init,
 		.data = &dytc_driver_data,
 	},
+	{
+		.init = tpacpi_proxsensor_init,
+		.data = &proxsensor_driver_data,
+	},
 };
 
 static int __init set_ibm_param(const char *val, const struct kernel_param *kp)
-- 
2.28.0