diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
index 822907dcc845..99066aa8d97b 100644
--- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
+++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
@@ -50,6 +50,7 @@ detailed description):
 	- WAN enable and disable
 	- UWB enable and disable
 	- LCD Shadow (PrivacyGuard) enable and disable
+	- Lap mode sensor
 
 A compatibility table by model and feature is maintained on the web
 site, http://ibm-acpi.sf.net/. I appreciate any success or failure
@@ -1432,6 +1433,20 @@ The first command ensures the best viewing angle and the latter one turns
 on the feature, restricting the viewing angles.
 
 
+DYTC Lapmode sensor
+------------------
+
+sysfs: dytc_lapmode
+
+Newer thinkpads and mobile workstations have the ability to determine if
+the device is in deskmode or lapmode. This feature is used by user space
+to decide if WWAN transmission can be increased to maximum power and is
+also useful for understanding the different thermal modes available as
+they differ between desk and lap mode.
+
+The property is read-only. If the platform doesn't have support the sysfs
+class is not created.
+
 EXPERIMENTAL: UWB
 -----------------
 
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 0f6fceda5fc0..7fee3c1c2418 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -4030,8 +4030,8 @@ static bool hotkey_notify_6xxx(const u32 hkey,
 		return true;
 	case TP_HKEY_EV_THM_CSM_COMPLETED:
 		pr_debug("EC reports: Thermal Control Command set completed (DYTC)\n");
-		/* recommended action: do nothing, we don't have
-		 * Lenovo ATM information */
+		/* Thermal event - pass on to event handler */
+		tpacpi_driver_event(hkey);
 		return true;
 	case TP_HKEY_EV_THM_TRANSFM_CHANGED:
 		pr_debug("EC reports: Thermal Transformation changed (GMTS)\n");
@@ -9803,6 +9803,105 @@ static struct ibm_struct lcdshadow_driver_data = {
 	.write = lcdshadow_write,
 };
 
+/*************************************************************************
+ * DYTC subdriver, for the Lenovo lapmode feature
+ */
+
+#define DYTC_CMD_GET          2 /* To get current IC function and mode */
+#define DYTC_GET_LAPMODE_BIT 17 /* Set when in lapmode */
+
+static bool dytc_lapmode;
+
+static void dytc_lapmode_notify_change(void)
+{
+	sysfs_notify(&tpacpi_pdev->dev.kobj, NULL, "dytc_lapmode");
+}
+
+static int dytc_command(int command, int *output)
+{
+	acpi_handle dytc_handle;
+
+	if (ACPI_FAILURE(acpi_get_handle(hkey_handle, "DYTC", &dytc_handle))) {
+		/* Platform doesn't support DYTC */
+		return -ENODEV;
+	}
+	if (!acpi_evalf(dytc_handle, output, NULL, "dd", command))
+		return -EIO;
+	return 0;
+}
+
+static int dytc_lapmode_get(bool *state)
+{
+	int output, err;
+
+	err = dytc_command(DYTC_CMD_GET, &output);
+	if (err)
+		return err;
+	*state = output & BIT(DYTC_GET_LAPMODE_BIT) ? true : false;
+	return 0;
+}
+
+static void dytc_lapmode_refresh(void)
+{
+	bool new_state;
+	int err;
+
+	err = dytc_lapmode_get(&new_state);
+	if (err || (new_state == dytc_lapmode))
+		return;
+
+	dytc_lapmode = new_state;
+	dytc_lapmode_notify_change();
+}
+
+/* sysfs lapmode entry */
+static ssize_t dytc_lapmode_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", dytc_lapmode);
+}
+
+static DEVICE_ATTR_RO(dytc_lapmode);
+
+static struct attribute *dytc_attributes[] = {
+	&dev_attr_dytc_lapmode.attr,
+	NULL,
+};
+
+static const struct attribute_group dytc_attr_group = {
+	.attrs = dytc_attributes,
+};
+
+static int tpacpi_dytc_init(struct ibm_init_struct *iibm)
+{
+	int err;
+
+	err = dytc_lapmode_get(&dytc_lapmode);
+	/* If support isn't available (ENODEV) then don't return an error
+	 * but just don't create the sysfs group
+	 */
+	if (err == -ENODEV)
+		return 0;
+	/* For all other errors we can flag the failure */
+	if (err)
+		return err;
+
+	/* Platform supports this feature - create the group */
+	err = sysfs_create_group(&tpacpi_pdev->dev.kobj, &dytc_attr_group);
+	return err;
+}
+
+static void dytc_exit(void)
+{
+	sysfs_remove_group(&tpacpi_pdev->dev.kobj, &dytc_attr_group);
+}
+
+static struct ibm_struct dytc_driver_data = {
+	.name = "dytc",
+	.exit = dytc_exit,
+};
+
 /****************************************************************************
  ****************************************************************************
  *
@@ -9850,6 +9949,10 @@ static void tpacpi_driver_event(const unsigned int hkey_event)
 
 		mutex_unlock(&kbdlight_mutex);
 	}
+
+	if (hkey_event == TP_HKEY_EV_THM_CSM_COMPLETED)
+		dytc_lapmode_refresh();
+
 }
 
 static void hotkey_driver_event(const unsigned int scancode)
@@ -10288,6 +10391,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
 		.init = tpacpi_lcdshadow_init,
 		.data = &lcdshadow_driver_data,
 	},
+	{
+		.init = tpacpi_dytc_init,
+		.data = &dytc_driver_data,
+	},
 };
 
 static int __init set_ibm_param(const char *val, const struct kernel_param *kp)