thermal: hwmon: move hwmon support to single file

In order to improve code organization, this patch
moves the hwmon sysfs support to a file named
thermal_hwmon. This helps to add extra support
for hwmon without scrambling the code.

In order to do this move, the hwmon list head is now
using its own locking. Before, the list used
the global thermal locking. Also, some minor changes
in the code were required, as recommended by checkpatch.pl.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>

1 files changed, 269 insertions, 0 deletions

diff --git a/drivers/thermal/thermal_hwmon.c b/drivers/thermal/thermal_hwmon.c
new file mode 100644
index 000000000000..fdb07199d9c2
--- /dev/null
+++ b/drivers/thermal/thermal_hwmon.c
@@ -0,0 +1,269 @@
+/*
+ *  thermal_hwmon.c - Generic Thermal Management hwmon support.
+ *
+ *  Code based on Intel thermal_core.c. Copyrights of the original code:
+ *  Copyright (C) 2008 Intel Corp
+ *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
+ *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
+ *
+ *  Copyright (C) 2013 Texas Instruments
+ *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
+ *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+#include <linux/hwmon.h>
+#include <linux/thermal.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include "thermal_hwmon.h"
+
+/* hwmon sys I/F */
+/* thermal zone devices with the same type share one hwmon device */
+struct thermal_hwmon_device {
+	char type[THERMAL_NAME_LENGTH];
+	struct device *device;
+	int count;
+	struct list_head tz_list;
+	struct list_head node;
+};
+
+struct thermal_hwmon_attr {
+	struct device_attribute attr;
+	char name[16];
+};
+
+/* one temperature input for each thermal zone */
+struct thermal_hwmon_temp {
+	struct list_head hwmon_node;
+	struct thermal_zone_device *tz;
+	struct thermal_hwmon_attr temp_input;	/* hwmon sys attr */
+	struct thermal_hwmon_attr temp_crit;	/* hwmon sys attr */
+};
+
+static LIST_HEAD(thermal_hwmon_list);
+
+static DEFINE_MUTEX(thermal_hwmon_list_lock);
+
+static ssize_t
+name_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_hwmon_device *hwmon = dev_get_drvdata(dev);
+	return sprintf(buf, "%s\n", hwmon->type);
+}
+static DEVICE_ATTR(name, 0444, name_show, NULL);
+
+static ssize_t
+temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	long temperature;
+	int ret;
+	struct thermal_hwmon_attr *hwmon_attr
+			= container_of(attr, struct thermal_hwmon_attr, attr);
+	struct thermal_hwmon_temp *temp
+			= container_of(hwmon_attr, struct thermal_hwmon_temp,
+				       temp_input);
+	struct thermal_zone_device *tz = temp->tz;
+
+	ret = thermal_zone_get_temp(tz, &temperature);
+
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%ld\n", temperature);
+}
+
+static ssize_t
+temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_hwmon_attr *hwmon_attr
+			= container_of(attr, struct thermal_hwmon_attr, attr);
+	struct thermal_hwmon_temp *temp
+			= container_of(hwmon_attr, struct thermal_hwmon_temp,
+				       temp_crit);
+	struct thermal_zone_device *tz = temp->tz;
+	long temperature;
+	int ret;
+
+	ret = tz->ops->get_trip_temp(tz, 0, &temperature);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%ld\n", temperature);
+}
+
+
+static struct thermal_hwmon_device *
+thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
+{
+	struct thermal_hwmon_device *hwmon;
+
+	mutex_lock(&thermal_hwmon_list_lock);
+	list_for_each_entry(hwmon, &thermal_hwmon_list, node)
+		if (!strcmp(hwmon->type, tz->type)) {
+			mutex_unlock(&thermal_hwmon_list_lock);
+			return hwmon;
+		}
+	mutex_unlock(&thermal_hwmon_list_lock);
+
+	return NULL;
+}
+
+/* Find the temperature input matching a given thermal zone */
+static struct thermal_hwmon_temp *
+thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
+			  const struct thermal_zone_device *tz)
+{
+	struct thermal_hwmon_temp *temp;
+
+	mutex_lock(&thermal_hwmon_list_lock);
+	list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
+		if (temp->tz == tz) {
+			mutex_unlock(&thermal_hwmon_list_lock);
+			return temp;
+		}
+	mutex_unlock(&thermal_hwmon_list_lock);
+
+	return NULL;
+}
+
+int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
+{
+	struct thermal_hwmon_device *hwmon;
+	struct thermal_hwmon_temp *temp;
+	int new_hwmon_device = 1;
+	int result;
+
+	hwmon = thermal_hwmon_lookup_by_type(tz);
+	if (hwmon) {
+		new_hwmon_device = 0;
+		goto register_sys_interface;
+	}
+
+	hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&hwmon->tz_list);
+	strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
+	hwmon->device = hwmon_device_register(NULL);
+	if (IS_ERR(hwmon->device)) {
+		result = PTR_ERR(hwmon->device);
+		goto free_mem;
+	}
+	dev_set_drvdata(hwmon->device, hwmon);
+	result = device_create_file(hwmon->device, &dev_attr_name);
+	if (result)
+		goto free_mem;
+
+ register_sys_interface:
+	temp = kzalloc(sizeof(*temp), GFP_KERNEL);
+	if (!temp) {
+		result = -ENOMEM;
+		goto unregister_name;
+	}
+
+	temp->tz = tz;
+	hwmon->count++;
+
+	snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
+		 "temp%d_input", hwmon->count);
+	temp->temp_input.attr.attr.name = temp->temp_input.name;
+	temp->temp_input.attr.attr.mode = 0444;
+	temp->temp_input.attr.show = temp_input_show;
+	sysfs_attr_init(&temp->temp_input.attr.attr);
+	result = device_create_file(hwmon->device, &temp->temp_input.attr);
+	if (result)
+		goto free_temp_mem;
+
+	if (tz->ops->get_crit_temp) {
+		unsigned long temperature;
+		if (!tz->ops->get_crit_temp(tz, &temperature)) {
+			snprintf(temp->temp_crit.name,
+				 sizeof(temp->temp_crit.name),
+				"temp%d_crit", hwmon->count);
+			temp->temp_crit.attr.attr.name = temp->temp_crit.name;
+			temp->temp_crit.attr.attr.mode = 0444;
+			temp->temp_crit.attr.show = temp_crit_show;
+			sysfs_attr_init(&temp->temp_crit.attr.attr);
+			result = device_create_file(hwmon->device,
+						    &temp->temp_crit.attr);
+			if (result)
+				goto unregister_input;
+		}
+	}
+
+	mutex_lock(&thermal_hwmon_list_lock);
+	if (new_hwmon_device)
+		list_add_tail(&hwmon->node, &thermal_hwmon_list);
+	list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
+	mutex_unlock(&thermal_hwmon_list_lock);
+
+	return 0;
+
+ unregister_input:
+	device_remove_file(hwmon->device, &temp->temp_input.attr);
+ free_temp_mem:
+	kfree(temp);
+ unregister_name:
+	if (new_hwmon_device) {
+		device_remove_file(hwmon->device, &dev_attr_name);
+		hwmon_device_unregister(hwmon->device);
+	}
+ free_mem:
+	if (new_hwmon_device)
+		kfree(hwmon);
+
+	return result;
+}
+
+void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
+{
+	struct thermal_hwmon_device *hwmon;
+	struct thermal_hwmon_temp *temp;
+
+	hwmon = thermal_hwmon_lookup_by_type(tz);
+	if (unlikely(!hwmon)) {
+		/* Should never happen... */
+		dev_dbg(&tz->device, "hwmon device lookup failed!\n");
+		return;
+	}
+
+	temp = thermal_hwmon_lookup_temp(hwmon, tz);
+	if (unlikely(!temp)) {
+		/* Should never happen... */
+		dev_dbg(&tz->device, "temperature input lookup failed!\n");
+		return;
+	}
+
+	device_remove_file(hwmon->device, &temp->temp_input.attr);
+	if (tz->ops->get_crit_temp)
+		device_remove_file(hwmon->device, &temp->temp_crit.attr);
+
+	mutex_lock(&thermal_hwmon_list_lock);
+	list_del(&temp->hwmon_node);
+	kfree(temp);
+	if (!list_empty(&hwmon->tz_list)) {
+		mutex_unlock(&thermal_hwmon_list_lock);
+		return;
+	}
+	list_del(&hwmon->node);
+	mutex_unlock(&thermal_hwmon_list_lock);
+
+	device_remove_file(hwmon->device, &dev_attr_name);
+	hwmon_device_unregister(hwmon->device);
+	kfree(hwmon);
+}