Message-ID: <1381742769.2034.26.camel@rzhang1-mobl4>
Subject: Re: [PATCHv4 2/9] Thermal: Create sensor level APIs
From: Zhang Rui <rui.zhang@intel.com>
To: Durgadoss R <durgadoss.r@intel.com>
Cc: eduardo.valentin@ti.com, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, hongbo.zhang@freescale.com,
        wni@nvidia.com
Date: Mon, 14 Oct 2013 17:26:09 +0800
In-Reply-To: <1380652688-5787-3-git-send-email-durgadoss.r@intel.com>
References: <1380652688-5787-1-git-send-email-durgadoss.r@intel.com>
	 <1380652688-5787-3-git-send-email-durgadoss.r@intel.com>
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On Wed, 2013-10-02 at 00:08 +0530, Durgadoss R wrote:
> This patch creates sensor level APIs, in the
> generic thermal framework.
> 
> A Thermal sensor is a piece of hardware that can report
> temperature of the spot in which it is placed. A thermal
> sensor driver reads the temperature from this sensor
> and reports it out. This kind of driver can be in
> any subsystem. If the sensor needs to participate
> in platform thermal management, the corresponding
> driver can use the APIs introduced in this patch, to
> register(or unregister) with the thermal framework.
> 
> Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
> ---
>  drivers/thermal/thermal_core.c |  284 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/thermal.h        |   29 ++++
>  2 files changed, 313 insertions(+)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 8c5131d..8c46567 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -45,13 +45,16 @@ MODULE_LICENSE("GPL v2");
>  
>  static DEFINE_IDR(thermal_tz_idr);
>  static DEFINE_IDR(thermal_cdev_idr);
> +static DEFINE_IDR(thermal_sensor_idr);
>  static DEFINE_MUTEX(thermal_idr_lock);
>  
>  static LIST_HEAD(thermal_tz_list);
> +static LIST_HEAD(thermal_sensor_list);
>  static LIST_HEAD(thermal_cdev_list);
>  static LIST_HEAD(thermal_governor_list);
>  
>  static DEFINE_MUTEX(thermal_list_lock);
> +static DEFINE_MUTEX(sensor_list_lock);
>  static DEFINE_MUTEX(thermal_governor_lock);
>  
>  static struct thermal_governor *__find_governor(const char *name)
> @@ -463,6 +466,103 @@ static void thermal_zone_device_check(struct work_struct *work)
>  #define to_thermal_zone(_dev) \
>  	container_of(_dev, struct thermal_zone_device, device)
>  
> +#define to_thermal_sensor(_dev) \
> +	container_of(_dev, struct thermal_sensor, device)
> +
> +static ssize_t
> +sensor_name_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct thermal_sensor *ts = to_thermal_sensor(dev);
> +
> +	return sprintf(buf, "%s\n", ts->name);
> +}
> +
> +static ssize_t
> +sensor_temp_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int ret;
> +	long val;
> +	struct thermal_sensor *ts = to_thermal_sensor(dev);
> +
> +	ret = ts->ops->get_temp(ts, &val);
> +
> +	return ret ? ret : sprintf(buf, "%ld\n", val);
> +}
> +
> +static ssize_t
> +hyst_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int indx, ret;
> +	long val;
> +	struct thermal_sensor *ts = to_thermal_sensor(dev);
> +
> +	if (!sscanf(attr->attr.name, "threshold%d_hyst", &indx))
> +		return -EINVAL;
> +
> +	ret = ts->ops->get_hyst(ts, indx, &val);
> +
> +	return ret ? ret : sprintf(buf, "%ld\n", val);
> +}
> +
> +static ssize_t
> +hyst_store(struct device *dev, struct device_attribute *attr,
> +				   const char *buf, size_t count)
> +{
> +	int indx, ret;
> +	long val;
> +	struct thermal_sensor *ts = to_thermal_sensor(dev);
> +
> +	if (!ts->ops->set_hyst)
> +		return -EPERM;
> +
> +	if (!sscanf(attr->attr.name, "threshold%d_hyst", &indx))
> +		return -EINVAL;
> +
> +	if (kstrtol(buf, 10, &val))
> +		return -EINVAL;
> +
> +	ret = ts->ops->set_hyst(ts, indx, val);
> +
> +	return ret ? ret : count;
> +}
> +
> +static ssize_t
> +threshold_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int indx, ret;
> +	long val;
> +	struct thermal_sensor *ts = to_thermal_sensor(dev);
> +
> +	if (!sscanf(attr->attr.name, "threshold%d", &indx))
> +		return -EINVAL;
> +
> +	ret = ts->ops->get_threshold(ts, indx, &val);
> +
> +	return ret ? ret : sprintf(buf, "%ld\n", val);
> +}
> +
> +static ssize_t
> +threshold_store(struct device *dev, struct device_attribute *attr,
> +				   const char *buf, size_t count)
> +{
> +	int indx, ret;
> +	long val;
> +	struct thermal_sensor *ts = to_thermal_sensor(dev);
> +
> +	if (!ts->ops->set_threshold)
> +		return -EPERM;
> +
> +	if (!sscanf(attr->attr.name, "threshold%d", &indx))
> +		return -EINVAL;
> +
> +	if (kstrtol(buf, 10, &val))
> +		return -EINVAL;
> +
> +	ret = ts->ops->set_threshold(ts, indx, val);
> +
> +	return ret ? ret : count;
> +}
> +
>  static ssize_t
>  type_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> @@ -772,6 +872,10 @@ 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);
>  
> +/* Thermal sensor attributes */
> +static DEVICE_ATTR(sensor_name, 0444, sensor_name_show, NULL);

this attribute is under sensorX/ directory, thus I think "name" is clear
enough.
what do you think?

> +static DEVICE_ATTR(temp_input, 0444, sensor_temp_show, NULL);
> +
what about "temp"? to be consistent with the current naming.

>  /* sys I/F for cooling device */
>  #define to_cooling_device(_dev)	\
>  	container_of(_dev, struct thermal_cooling_device, device)
> @@ -1585,6 +1689,186 @@ static void remove_trip_attrs(struct thermal_zone_device *tz)
>  	kfree(tz->trip_hyst_attrs);
>  }
>  
> + /**
> + * enable_sensor_thresholds - create sysfs nodes for thresholdX
IMO, this name is confusing. It looks like that you are enabling the
sensor hardware here.
so why not "thermal_sensor_sysfs_add", and you can add the "name" and
"temp" attribute in this function as well.

> + * @ts:		the thermal sensor
> + * @count:	Number of thresholds supported by sensor hardware
> + *
> + * 'Thresholds' are temperatures programmed into the sensor hardware,
> + * on crossing which the sensor can generate an interrupt.
> + */
> +static int enable_sensor_thresholds(struct thermal_sensor *ts, int count)
> +{
> +	int i;
> +	int size = sizeof(struct thermal_attr) * count;
> +
> +	ts->thresh_attrs = devm_kzalloc(&ts->device, size, GFP_KERNEL);
> +	if (!ts->thresh_attrs)
> +		return -ENOMEM;
> +
> +	if (ts->ops->get_hyst) {
> +		ts->hyst_attrs = devm_kzalloc(&ts->device, size, GFP_KERNEL);
> +		if (!ts->hyst_attrs)
> +			return -ENOMEM;
> +	}
> +
I do not think you can use devm_kzalloc here.

> +	ts->thresholds = count;
> +
> +	/* Create threshold attributes */
> +	for (i = 0; i < count; i++) {
> +		snprintf(ts->thresh_attrs[i].name, THERMAL_NAME_LENGTH,
> +						 "threshold%d", i);
> +
> +		sysfs_attr_init(&ts->thresh_attrs[i].attr.attr);
> +		ts->thresh_attrs[i].attr.attr.name = ts->thresh_attrs[i].name;
> +		ts->thresh_attrs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
> +		ts->thresh_attrs[i].attr.show = threshold_show;
> +		ts->thresh_attrs[i].attr.store = threshold_store;
> +
> +		device_create_file(&ts->device, &ts->thresh_attrs[i].attr);
> +
> +		/* Create threshold_hyst attributes */
> +		if (!ts->ops->get_hyst)
> +			continue;
> +
> +		snprintf(ts->hyst_attrs[i].name, THERMAL_NAME_LENGTH,
> +						 "threshold%d_hyst", i);
> +
> +		sysfs_attr_init(&ts->hyst_attrs[i].attr.attr);
> +		ts->hyst_attrs[i].attr.attr.name = ts->hyst_attrs[i].name;
> +		ts->hyst_attrs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
> +		ts->hyst_attrs[i].attr.show = hyst_show;
> +		ts->hyst_attrs[i].attr.store = hyst_store;
> +
> +		device_create_file(&ts->device, &ts->hyst_attrs[i].attr);
> +	}
> +	return 0;
> +}
> +
> +/**
> + * thermal_sensor_register - register a new thermal sensor
> + * @name:	name of the thermal sensor
> + * @count:	Number of thresholds supported by hardware
> + * @ops:	standard thermal sensor callbacks
> + * @devdata:	private device data
> + *
> + * On Success returns a thermal sensor reference, otherwise:
> + * -EINVAL for invalid parameters,
> + * -ENOMEM for insufficient memory cases,
> +*/
> +struct thermal_sensor *thermal_sensor_register(const char *name, int count,
> +			struct thermal_sensor_ops *ops, void *devdata)
> +{
> +	struct thermal_sensor *ts;
> +	int ret;
> +
> +	if (!name || (name && strlen(name) >= THERMAL_NAME_LENGTH))
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!ops || !ops->get_temp)
> +		return ERR_PTR(-EINVAL);
> +
> +	ts = kzalloc(sizeof(*ts), GFP_KERNEL);
> +	if (!ts)
> +		return ERR_PTR(-ENOMEM);
> +
> +	idr_init(&ts->idr);
> +	ret = get_idr(&thermal_sensor_idr, &thermal_idr_lock, &ts->id);
> +	if (ret)
> +		goto exit_free;
> +
> +	strlcpy(ts->name, name, sizeof(ts->name));
> +	ts->ops = ops;
> +	ts->devdata = devdata;
> +	ts->device.class = &thermal_class;
> +
> +	dev_set_name(&ts->device, "sensor%d", ts->id);
> +	ret = device_register(&ts->device);
> +	if (ret)
> +		goto exit_idr;
> +
> +	ret = device_create_file(&ts->device, &dev_attr_sensor_name);
> +	if (ret)
> +		goto exit_unregister;
> +
> +	ret = device_create_file(&ts->device, &dev_attr_temp_input);
> +	if (ret)
> +		goto exit_name;
> +
> +	if (count > 0 && ts->ops->get_threshold) {
> +		ret = enable_sensor_thresholds(ts, count);
> +		if (ret)
> +			goto exit_temp;
> +	}
> +
> +	/* Add this sensor to the global list of sensors */
> +	mutex_lock(&sensor_list_lock);
> +	list_add_tail(&ts->node, &thermal_sensor_list);
> +	mutex_unlock(&sensor_list_lock);
> +
> +	return ts;
> +
> +exit_temp:
> +	device_remove_file(&ts->device, &dev_attr_temp_input);
> +exit_name:
> +	device_remove_file(&ts->device, &dev_attr_sensor_name);
> +exit_unregister:
> +	device_unregister(&ts->device);
> +exit_idr:
> +	release_idr(&thermal_sensor_idr, &thermal_idr_lock, ts->id);
> +exit_free:
> +	kfree(ts);
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL(thermal_sensor_register);
> +
> +/**
> + * remove_thermal_zone - removes the sysfs nodes for given sensor

s/remove_thermal_zone/thermal_sensor_unregister

> + * @ts:	Thermal sensor to be removed.
> + */
> +void thermal_sensor_unregister(struct thermal_sensor *ts)
> +{
> +	int i;
> +	struct thermal_sensor *pos, *next;
> +	bool found = false;
> +
> +	if (!ts)
> +		return;
> +
> +	mutex_lock(&sensor_list_lock);
> +	list_for_each_entry_safe(pos, next, &thermal_sensor_list, node) {
> +		if (pos == ts) {
> +			list_del(&ts->node);
> +			found = true;
> +			break;
> +		}
> +	}
> +	mutex_unlock(&sensor_list_lock);
> +
> +	if (!found)
> +		return;
> +
> +	for (i = 0; i < ts->thresholds; i++) {
> +		device_remove_file(&ts->device, &ts->thresh_attrs[i].attr);
> +		if (ts->ops->get_hyst) {
> +			device_remove_file(&ts->device,
> +					&ts->hyst_attrs[i].attr);
> +		}
> +	}
> +
> +	device_remove_file(&ts->device, &dev_attr_sensor_name);
> +	device_remove_file(&ts->device, &dev_attr_temp_input);
> +
hmmm, I'd prefer you to introduce a separate function for the sysfs
cleanup code. 

thanks,
rui
> +	release_idr(&thermal_sensor_idr, &thermal_idr_lock, ts->id);
> +	idr_destroy(&ts->idr);
> +
> +	device_unregister(&ts->device);
> +
> +	kfree(ts);
> +	return;
> +}
> +EXPORT_SYMBOL(thermal_sensor_unregister);
> +
>  /**
>   * thermal_zone_device_register() - register a new thermal zone device
>   * @type:	the thermal zone device type
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index a386a1c..25fc562 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -58,6 +58,7 @@
>  #define DEFAULT_THERMAL_GOVERNOR       "user_space"
>  #endif
>  
> +struct thermal_sensor;
>  struct thermal_zone_device;
>  struct thermal_cooling_device;
>  
> @@ -139,6 +140,15 @@ struct thermal_cooling_device_ops {
>  	int (*set_cur_state) (struct thermal_cooling_device *, unsigned long);
>  };
>  
> +struct thermal_sensor_ops {
> +	int (*get_temp) (struct thermal_sensor *, long *);
> +	int (*get_trend) (struct thermal_sensor *, int, enum thermal_trend *);
> +	int (*set_threshold) (struct thermal_sensor *, int, long);
> +	int (*get_threshold) (struct thermal_sensor *, int, long *);
> +	int (*set_hyst) (struct thermal_sensor *, int, long);
> +	int (*get_hyst) (struct thermal_sensor *, int, long *);
> +};
> +
>  struct thermal_cooling_device {
>  	int id;
>  	char type[THERMAL_NAME_LENGTH];
> @@ -156,6 +166,21 @@ struct thermal_attr {
>  	char name[THERMAL_NAME_LENGTH];
>  };
>  
> +struct thermal_sensor {
> +	char name[THERMAL_NAME_LENGTH];
> +	int id;
> +	int temp;
> +	int prev_temp;
> +	int thresholds;
> +	void *devdata;
> +	struct idr idr;
> +	struct device device;
> +	struct list_head node;
> +	struct thermal_sensor_ops *ops;
> +	struct thermal_attr *thresh_attrs;
> +	struct thermal_attr *hyst_attrs;
> +};
> +
>  struct thermal_zone_device {
>  	int id;
>  	char type[THERMAL_NAME_LENGTH];
> @@ -248,6 +273,10 @@ struct thermal_instance *get_thermal_instance(struct thermal_zone_device *,
>  void thermal_cdev_update(struct thermal_cooling_device *);
>  void thermal_notify_framework(struct thermal_zone_device *, int);
>  
> +struct thermal_sensor *thermal_sensor_register(const char *, int,
> +				struct thermal_sensor_ops *, void *);
> +void thermal_sensor_unregister(struct thermal_sensor *);
> +
>  #ifdef CONFIG_NET
>  extern int thermal_generate_netlink_event(struct thermal_zone_device *tz,
>  						enum events event);


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