thermal: int340x: Mode setting with new OS handshake

With the new OS handshake introduced by commit: "c7ff2976 ("thermal:
int340x: Update OS policy capability handshake")", the "enabled" thermal
zone mode doesn't work in the same way as previously.

The "enabled" mode fails with -EINVAL when the new handshake is used.

To address this issue, when the new OS UUID mask is set:

 - When the mode is "enabled", return 0 as the firmware already has the
   latest policy mask.

 - When the mode is "disabled", update the firmware with the UUID mask
   of zero.

This way, the firmware can take over the thermal control.

Also reset the OS UUID mask, which allows user space to update with new
set of policies.

Fixes: c7ff2976 ("thermal: int340x: Update OS policy capability handshake")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Changelog edits, removed unneeded parens ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/thermal/intel/int340x_thermal/int3400_thermal.c

@@ -194,12 +194,31 @@ static int int3400_thermal_run_osc(acpi_handle handle, char *uuid_str, int *enab
 	return result;
 }
 
+static int set_os_uuid_mask(struct int3400_thermal_priv *priv, u32 mask)
+{
+	int cap = 0;
+
+	/*
+	 * Capability bits:
+	 * Bit 0: set to 1 to indicate DPTF is active
+	 * Bi1 1: set to 1 to active cooling is supported by user space daemon
+	 * Bit 2: set to 1 to passive cooling is supported by user space daemon
+	 * Bit 3: set to 1 to critical trip is handled by user space daemon
+	 */
+	if (mask)
+		cap = (priv->os_uuid_mask << 1) | 0x01;
+
+	return int3400_thermal_run_osc(priv->adev->handle,
+				       "b23ba85d-c8b7-3542-88de-8de2ffcfd698",
+				       &cap);
+}
+
 static ssize_t current_uuid_store(struct device *dev,
 				  struct device_attribute *attr,
 				  const char *buf, size_t count)
 {
 	struct int3400_thermal_priv *priv = dev_get_drvdata(dev);
-	int i;
+	int ret, i;
 
 	for (i = 0; i < INT3400_THERMAL_MAXIMUM_UUID; ++i) {
 		if (!strncmp(buf, int3400_thermal_uuids[i],
@@ -231,19 +250,7 @@ static ssize_t current_uuid_store(struct device *dev,
 	}
 
 	if (priv->os_uuid_mask) {
-		int cap, ret;
-
-		/*
-		 * Capability bits:
-		 * Bit 0: set to 1 to indicate DPTF is active
-		 * Bi1 1: set to 1 to active cooling is supported by user space daemon
-		 * Bit 2: set to 1 to passive cooling is supported by user space daemon
-		 * Bit 3: set to 1 to critical trip is handled by user space daemon
-		 */
-		cap = ((priv->os_uuid_mask << 1) | 0x01);
-		ret = int3400_thermal_run_osc(priv->adev->handle,
-					      "b23ba85d-c8b7-3542-88de-8de2ffcfd698",
-					      &cap);
+		ret = set_os_uuid_mask(priv, priv->os_uuid_mask);
 		if (ret)
 			return ret;
 	}
@@ -469,17 +476,26 @@ static int int3400_thermal_change_mode(struct thermal_zone_device *thermal,
 	if (mode != thermal->mode) {
 		int enabled;
 
+		enabled = mode == THERMAL_DEVICE_ENABLED;
+
+		if (priv->os_uuid_mask) {
+			if (!enabled) {
+				priv->os_uuid_mask = 0;
+				result = set_os_uuid_mask(priv, priv->os_uuid_mask);
+			}
+			goto eval_odvp;
+		}
+
 		if (priv->current_uuid_index < 0 ||
 		    priv->current_uuid_index >= INT3400_THERMAL_MAXIMUM_UUID)
 			return -EINVAL;
 
-		enabled = (mode == THERMAL_DEVICE_ENABLED);
 		result = int3400_thermal_run_osc(priv->adev->handle,
 						 int3400_thermal_uuids[priv->current_uuid_index],
 						 &enabled);
 	}
 
-
+eval_odvp:
 	evaluate_odvp(priv);
 
 	return result;