linux/drivers/hwmon/scpi-hwmon.c
Sudeep Holla cef03d7e66 hwmon: (scpi) skip unsupported sensors properly
Currently it's assumed that firmware exports only the class of sensors
supported by the driver. However with newer firmware or SCPI protocol
revision, support for newer classes of sensors can be present.

The driver fails to probe with the following warning if an unsupported
class of sensor is encountered in the firmware.

sysfs: cannot create duplicate filename
	'/devices/platform/scpi/scpi:sensors/hwmon/hwmon0/'
------------[ cut here ]------------
WARNING: at fs/sysfs/dir.c:31
Modules linked in:

CPU: 0 PID: 6 Comm: kworker/u12:0 Not tainted 4.3.0-rc7 #137
Hardware name: ARM Juno development board (r0) (DT)
Workqueue: deferwq deferred_probe_work_func
PC is at sysfs_warn_dup+0x54/0x78
LR is at sysfs_warn_dup+0x54/0x78

This patch fixes the above issue by skipping through the unsupported
class of SCPI sensors.

Fixes: 68acc77a2d ("hwmon: Support thermal zones registration for SCP temperature sensors")
Fixes: ea98b29a05 ("hwmon: Support sensors exported via ARM SCP interface")
Cc: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2015-11-16 09:59:50 -08:00

290 lines
7.4 KiB
C

/*
* System Control and Power Interface(SCPI) based hwmon sensor driver
*
* Copyright (C) 2015 ARM Ltd.
* Punit Agrawal <punit.agrawal@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/hwmon.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/scpi_protocol.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/thermal.h>
struct sensor_data {
struct scpi_sensor_info info;
struct device_attribute dev_attr_input;
struct device_attribute dev_attr_label;
char input[20];
char label[20];
};
struct scpi_thermal_zone {
struct list_head list;
int sensor_id;
struct scpi_sensors *scpi_sensors;
struct thermal_zone_device *tzd;
};
struct scpi_sensors {
struct scpi_ops *scpi_ops;
struct sensor_data *data;
struct list_head thermal_zones;
struct attribute **attrs;
struct attribute_group group;
const struct attribute_group *groups[2];
};
static int scpi_read_temp(void *dev, int *temp)
{
struct scpi_thermal_zone *zone = dev;
struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
u32 value;
int ret;
ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
if (ret)
return ret;
*temp = value;
return 0;
}
/* hwmon callback functions */
static ssize_t
scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
struct sensor_data *sensor;
u32 value;
int ret;
sensor = container_of(attr, struct sensor_data, dev_attr_input);
ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
if (ret)
return ret;
return sprintf(buf, "%u\n", value);
}
static ssize_t
scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
{
struct sensor_data *sensor;
sensor = container_of(attr, struct sensor_data, dev_attr_label);
return sprintf(buf, "%s\n", sensor->info.name);
}
static void
unregister_thermal_zones(struct platform_device *pdev,
struct scpi_sensors *scpi_sensors)
{
struct list_head *pos;
list_for_each(pos, &scpi_sensors->thermal_zones) {
struct scpi_thermal_zone *zone;
zone = list_entry(pos, struct scpi_thermal_zone, list);
thermal_zone_of_sensor_unregister(&pdev->dev, zone->tzd);
}
}
static struct thermal_zone_of_device_ops scpi_sensor_ops = {
.get_temp = scpi_read_temp,
};
static int scpi_hwmon_probe(struct platform_device *pdev)
{
u16 nr_sensors, i;
int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
struct scpi_ops *scpi_ops;
struct device *hwdev, *dev = &pdev->dev;
struct scpi_sensors *scpi_sensors;
int ret, idx;
scpi_ops = get_scpi_ops();
if (!scpi_ops)
return -EPROBE_DEFER;
ret = scpi_ops->sensor_get_capability(&nr_sensors);
if (ret)
return ret;
if (!nr_sensors)
return -ENODEV;
scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
if (!scpi_sensors)
return -ENOMEM;
scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
sizeof(*scpi_sensors->data), GFP_KERNEL);
if (!scpi_sensors->data)
return -ENOMEM;
scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
sizeof(*scpi_sensors->attrs), GFP_KERNEL);
if (!scpi_sensors->attrs)
return -ENOMEM;
scpi_sensors->scpi_ops = scpi_ops;
for (i = 0, idx = 0; i < nr_sensors; i++) {
struct sensor_data *sensor = &scpi_sensors->data[idx];
ret = scpi_ops->sensor_get_info(i, &sensor->info);
if (ret)
return ret;
switch (sensor->info.class) {
case TEMPERATURE:
snprintf(sensor->input, sizeof(sensor->input),
"temp%d_input", num_temp + 1);
snprintf(sensor->label, sizeof(sensor->input),
"temp%d_label", num_temp + 1);
num_temp++;
break;
case VOLTAGE:
snprintf(sensor->input, sizeof(sensor->input),
"in%d_input", num_volt);
snprintf(sensor->label, sizeof(sensor->input),
"in%d_label", num_volt);
num_volt++;
break;
case CURRENT:
snprintf(sensor->input, sizeof(sensor->input),
"curr%d_input", num_current + 1);
snprintf(sensor->label, sizeof(sensor->input),
"curr%d_label", num_current + 1);
num_current++;
break;
case POWER:
snprintf(sensor->input, sizeof(sensor->input),
"power%d_input", num_power + 1);
snprintf(sensor->label, sizeof(sensor->input),
"power%d_label", num_power + 1);
num_power++;
break;
default:
continue;
}
sensor->dev_attr_input.attr.mode = S_IRUGO;
sensor->dev_attr_input.show = scpi_show_sensor;
sensor->dev_attr_input.attr.name = sensor->input;
sensor->dev_attr_label.attr.mode = S_IRUGO;
sensor->dev_attr_label.show = scpi_show_label;
sensor->dev_attr_label.attr.name = sensor->label;
scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
idx++;
}
scpi_sensors->group.attrs = scpi_sensors->attrs;
scpi_sensors->groups[0] = &scpi_sensors->group;
platform_set_drvdata(pdev, scpi_sensors);
hwdev = devm_hwmon_device_register_with_groups(dev,
"scpi_sensors", scpi_sensors, scpi_sensors->groups);
if (IS_ERR(hwdev))
return PTR_ERR(hwdev);
/*
* Register the temperature sensors with the thermal framework
* to allow their usage in setting up the thermal zones from
* device tree.
*
* NOTE: Not all temperature sensors maybe used for thermal
* control
*/
INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
for (i = 0; i < nr_sensors; i++) {
struct sensor_data *sensor = &scpi_sensors->data[i];
struct scpi_thermal_zone *zone;
if (sensor->info.class != TEMPERATURE)
continue;
zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
if (!zone) {
ret = -ENOMEM;
goto unregister_tzd;
}
zone->sensor_id = i;
zone->scpi_sensors = scpi_sensors;
zone->tzd = thermal_zone_of_sensor_register(dev,
sensor->info.sensor_id, zone, &scpi_sensor_ops);
/*
* The call to thermal_zone_of_sensor_register returns
* an error for sensors that are not associated with
* any thermal zones or if the thermal subsystem is
* not configured.
*/
if (IS_ERR(zone->tzd)) {
devm_kfree(dev, zone);
continue;
}
list_add(&zone->list, &scpi_sensors->thermal_zones);
}
return 0;
unregister_tzd:
unregister_thermal_zones(pdev, scpi_sensors);
return ret;
}
static int scpi_hwmon_remove(struct platform_device *pdev)
{
struct scpi_sensors *scpi_sensors = platform_get_drvdata(pdev);
unregister_thermal_zones(pdev, scpi_sensors);
return 0;
}
static const struct of_device_id scpi_of_match[] = {
{.compatible = "arm,scpi-sensors"},
{},
};
static struct platform_driver scpi_hwmon_platdrv = {
.driver = {
.name = "scpi-hwmon",
.owner = THIS_MODULE,
.of_match_table = scpi_of_match,
},
.probe = scpi_hwmon_probe,
.remove = scpi_hwmon_remove,
};
module_platform_driver(scpi_hwmon_platdrv);
MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
MODULE_LICENSE("GPL v2");