[RFC PATCH 04/11] thermal: use dev.groups to manage always present tz attributes

[Eduardo Valentin <edubezval@gmail.com>]

Thermal zones attributes are all being created using
device_create_file(). This has the disadvantage of making the code
complicated and sometimes we may miss the cleanup of them.

This patch starts to move the thermal zone sysfs attributes to the
dev.groups, so Linux device core manage them for us. For now, this patch
only moves those attributes are always present regardless of thermal
zone condition.

This change has also the advantage of cleaning up the thermal zone
parameters sysfs entries that are left unclean after device
registration.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
---
 drivers/thermal/thermal_core.c | 86 ++++++++++++++++--------------------------
 1 file changed, 33 insertions(+), 53 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 2227264..0a7d918 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -989,42 +989,46 @@ create_s32_tzp_attr(slope);
 create_s32_tzp_attr(offset);
 #undef create_s32_tzp_attr
 
+/*
+ * These are thermal zone device attributes that will always be present.
+ * All the attributes created for tzp (create_s32_tzp_attr) also are always
+ * present on the sysfs interface.
+ */
 static DEVICE_ATTR(type, 0444, type_show, NULL);
 static DEVICE_ATTR(temp, 0444, temp_show, NULL);
-static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
-static DEVICE_ATTR(passive, S_IRUGO | S_IWUSR, passive_show, passive_store);
 static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR, policy_show, policy_store);
 static DEVICE_ATTR(available_policies, S_IRUGO, available_policies_show, NULL);
-static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
 static DEVICE_ATTR(sustainable_power, S_IWUSR | S_IRUGO, sustainable_power_show,
 		   sustainable_power_store);
 
-static struct device_attribute *dev_tzp_attrs[] = {
-	&dev_attr_sustainable_power,
-	&dev_attr_k_po,
-	&dev_attr_k_pu,
-	&dev_attr_k_i,
-	&dev_attr_k_d,
-	&dev_attr_integral_cutoff,
-	&dev_attr_slope,
-	&dev_attr_offset,
-};
-
-static int create_tzp_attrs(struct device *dev)
-{
-	int i;
+/* These thermal zone device attributes are created based on conditions */
+static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
+static DEVICE_ATTR(passive, S_IRUGO | S_IWUSR, passive_show, passive_store);
+static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
 
-	for (i = 0; i < ARRAY_SIZE(dev_tzp_attrs); i++) {
-		int ret;
-		struct device_attribute *dev_attr = dev_tzp_attrs[i];
+static struct attribute *thermal_zone_dev_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_temp.attr,
+	&dev_attr_policy.attr,
+	&dev_attr_available_policies.attr,
+	&dev_attr_sustainable_power.attr,
+	&dev_attr_k_po.attr,
+	&dev_attr_k_pu.attr,
+	&dev_attr_k_i.attr,
+	&dev_attr_k_d.attr,
+	&dev_attr_integral_cutoff.attr,
+	&dev_attr_slope.attr,
+	&dev_attr_offset.attr,
+};
 
-		ret = device_create_file(dev, dev_attr);
-		if (ret)
-			return ret;
-	}
+static struct attribute_group thermal_zone_attribute_group = {
+	.attrs = thermal_zone_dev_attrs,
+};
 
-	return 0;
-}
+static const struct attribute_group *thermal_zone_attribute_groups[] = {
+	&thermal_zone_attribute_group,
+	NULL
+};
 
 /**
  * power_actor_get_max_power() - get the maximum power that a cdev can consume
@@ -1846,6 +1850,9 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
 	tz->trips = trips;
 	tz->passive_delay = passive_delay;
 	tz->polling_delay = polling_delay;
+
+	/* Add nodes that are always present via .groups */
+	tz->device.groups = thermal_zone_attribute_groups;
 	/* A new thermal zone needs to be updated anyway. */
 	atomic_set(&tz->need_update, 1);
 
@@ -1892,29 +1899,6 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
 			goto unregister;
 	}
 
-	result = device_create_file(&tz->device, &dev_attr_type);
-	if (result)
-		goto unregister;
-
-	result = device_create_file(&tz->device, &dev_attr_temp);
-	if (result)
-		goto unregister;
-
-	/* Create policy attribute */
-	result = device_create_file(&tz->device, &dev_attr_policy);
-	if (result)
-		goto unregister;
-
-	/* Create available_policies attribute */
-	result = device_create_file(&tz->device, &dev_attr_available_policies);
-	if (result)
-		goto unregister;
-
-	/* Add thermal zone params */
-	result = create_tzp_attrs(&tz->device);
-	if (result)
-		goto unregister;
-
 	/* Update 'this' zone's governor information */
 	mutex_lock(&thermal_governor_lock);
 
@@ -2009,12 +1993,8 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz)
 
 	thermal_zone_device_set_polling(tz, 0);
 
-	device_remove_file(&tz->device, &dev_attr_type);
-	device_remove_file(&tz->device, &dev_attr_temp);
 	if (tz->ops->get_mode)
 		device_remove_file(&tz->device, &dev_attr_mode);
-	device_remove_file(&tz->device, &dev_attr_policy);
-	device_remove_file(&tz->device, &dev_attr_available_policies);
 	remove_trip_attrs(tz);
 	thermal_set_governor(tz, NULL);
 
-- 
2.1.4