drm/radeon: expose DPM thermal thresholds through sysfs

The hwmon sysfs interface allows exposing temperature limits. The "max"
and "min" thresholds will be exposed as a critical high limit and its
hysteresis value, respectively. This gives the user a better idea of how
well cooling is doing and whether it is sufficient.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_pm.c

@@ -536,6 +536,23 @@ static ssize_t radeon_hwmon_show_temp(struct device *dev,
 	return snprintf(buf, PAGE_SIZE, "%d\n", temp);
 }
 
+static ssize_t radeon_hwmon_show_temp_thresh(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct radeon_device *rdev = ddev->dev_private;
+	int hyst = to_sensor_dev_attr(attr)->index;
+	int temp;
+
+	if (hyst)
+		temp = rdev->pm.dpm.thermal.min_temp;
+	else
+		temp = rdev->pm.dpm.thermal.max_temp;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", temp);
+}
+
 static ssize_t radeon_hwmon_show_name(struct device *dev,
 				      struct device_attribute *attr,
 				      char *buf)
@@ -544,16 +561,37 @@ static ssize_t radeon_hwmon_show_name(struct device *dev,
 }
 
 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, radeon_hwmon_show_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, radeon_hwmon_show_temp_thresh, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IRUGO, radeon_hwmon_show_temp_thresh, NULL, 1);
 static SENSOR_DEVICE_ATTR(name, S_IRUGO, radeon_hwmon_show_name, NULL, 0);
 
 static struct attribute *hwmon_attributes[] = {
 	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
 	&sensor_dev_attr_name.dev_attr.attr,
 	NULL
 };
 
+static umode_t hwmon_attributes_visible(struct kobject *kobj,
+					struct attribute *attr, int index)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct radeon_device *rdev = ddev->dev_private;
+
+	/* Skip limit attributes if DPM is not enabled */
+	if (rdev->pm.pm_method != PM_METHOD_DPM &&
+	    (attr == &sensor_dev_attr_temp1_crit.dev_attr.attr ||
+	     attr == &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr))
+		return 0;
+
+	return attr->mode;
+}
+
 static const struct attribute_group hwmon_attrgroup = {
 	.attrs = hwmon_attributes,
+	.is_visible = hwmon_attributes_visible,
 };
 
 static int radeon_hwmon_init(struct radeon_device *rdev)