RE: [PATCH V14 2/5] thermal: of-thermal: add API for getting sensor ID from DT

[Anson Huang]

Hi, Aisheng

> -----Original Message-----
> From: Aisheng Dong
> Sent: Tuesday, June 11, 2019 7:47 PM
> To: Anson Huang <anson.huang@xxxxxxx>; robh+dt@xxxxxxxxxx;
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> Cc: dl-linux-imx <linux-imx@xxxxxxx>
> Subject: RE: [PATCH V14 2/5] thermal: of-thermal: add API for getting sensor
> ID from DT
> 
> Hi Anson,
> 
> The implementation looks good to me.
> A few minor comments on the doc:

This patch is pending for so long and even till now I am NOT sure if everyone is OK for
this change, so I will wait for some comments if there is any, and will improve the doc
together in next version.

Thanks,
Anson

> 
> > From: Anson.Huang@xxxxxxx [mailto:Anson.Huang@xxxxxxx]
> > Sent: Monday, June 10, 2019 10:53 AM
> >
> > On some platforms like i.MX8QXP, the thermal driver needs a real HW
> > sensor ID from DT thermal zone, the HW sensor ID is used to get
> > temperature from SCU firmware, and the virtual sensor ID starting from
> > 0 to N is NOT used at all,
> 
> This API is unware of HW ID or Virtual ID. So we probably no need to
> mention It here.
> 
> > this patch adds new API thermal_zone_of_get_sensor_id() to provide the
> > feature of getting sensor ID from DT thermal zone's node.
> >
> 
> "It's useful for thermal driver to register the specific thermal zone devices
> from DT in a common way."
> 
> > Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
> > ---
> > Changes since V13:
> > 	- add new API into the thermal API doc.
> > ---
> >  Documentation/thermal/sysfs-api.txt |  8 +++++
> >  drivers/thermal/of-thermal.c        | 66
> > ++++++++++++++++++++++++++++---------
> >  include/linux/thermal.h             | 10 ++++++
> >  3 files changed, 68 insertions(+), 16 deletions(-)
> >
> > diff --git a/Documentation/thermal/sysfs-api.txt
> > b/Documentation/thermal/sysfs-api.txt
> > index c3fa500..8d7f1b1 100644
> > --- a/Documentation/thermal/sysfs-api.txt
> > +++ b/Documentation/thermal/sysfs-api.txt
> > @@ -159,6 +159,14 @@ temperature) and throttle appropriate devices.
> >  	for the thermal zone device, which might be useful for platform
> >  	drivers for temperature calculations.
> >
> > +1.1.9 int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
> > +		struct device_node *sensor_np,
> > +		u32 *id)
> > +
> > +	This interface is used to get the sensor id from thermal sensor's
> > +	phandle argument, it might be necessary for some platforms which
> > +	have specific sensor ID rather than virtual ID from 0 - N.
> 
> Does below one look better?
> 
> "This interface is used to get the sensor id from the given thermal zone in DT,
> which might be useful for thermal drivers to register specific thermal zone
> device in a common way."
> 
> > +
> >  1.2 thermal cooling device interface
> >  1.2.1 struct thermal_cooling_device
> > *thermal_cooling_device_register(char
> > *name,
> >  		void *devdata, struct thermal_cooling_device_ops *) diff --git
> > a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c index
> > dc5093b..a53792b 100644
> > --- a/drivers/thermal/of-thermal.c
> > +++ b/drivers/thermal/of-thermal.c
> > @@ -449,6 +449,54 @@ thermal_zone_of_add_sensor(struct device_node
> > *zone,  }
> >
> >  /**
> > + * thermal_zone_of_get_sensor_id - get sensor ID from a DT thermal
> > + zone
> > + * @tz_np: a valid thermal zone device node.
> > + * @sensor_np: a sensor node of a valid sensor device.
> > + * @id: a sensor ID pointer will be passed back.
> 
> the sensor ID returned if success
> 
> > + *
> > + * This function will get sensor ID from a given thermal zone node,
> > + use
> > + * "thermal-sensors" as list name, and get sensor ID from first
> > + phandle's
> > + * argument.
> 
> "This function will get sensor ID from a given thermal zone node and the
> sensor get must match the temperature providers @sensor_np."
> 
> Regards
> Dong Aisheng
> 
> > + *
> > + * Return: 0 on success, proper error code otherwise.
> > + */
> > +
> > +int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
> > +				  struct device_node *sensor_np,
> > +				  u32 *id)
> > +{
> > +	struct of_phandle_args sensor_specs;
> > +	int ret;
> > +
> > +	ret = of_parse_phandle_with_args(tz_np,
> > +					 "thermal-sensors",
> > +					 "#thermal-sensor-cells",
> > +					 0,
> > +					 &sensor_specs);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (sensor_specs.np != sensor_np) {
> > +		of_node_put(sensor_specs.np);
> > +		return -ENODEV;
> > +	}
> > +
> > +	if (sensor_specs.args_count >= 1) {
> > +		*id = sensor_specs.args[0];
> > +		WARN(sensor_specs.args_count > 1,
> > +		     "%pOFn: too many cells in sensor specifier %d\n",
> > +		     sensor_specs.np, sensor_specs.args_count);
> > +	} else {
> > +		*id = 0;
> > +	}
> > +
> > +	of_node_put(sensor_specs.np);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(thermal_zone_of_get_sensor_id);
> > +
> > +/**
> >   * thermal_zone_of_sensor_register - registers a sensor to a DT thermal
> zone
> >   * @dev: a valid struct device pointer of a sensor device. Must contain
> >   *       a valid .of_node, for the sensor node.
> > @@ -499,36 +547,22 @@ thermal_zone_of_sensor_register(struct device
> > *dev, int sensor_id, void *data,
> >  	sensor_np = of_node_get(dev->of_node);
> >
> >  	for_each_available_child_of_node(np, child) {
> > -		struct of_phandle_args sensor_specs;
> >  		int ret, id;
> >
> >  		/* For now, thermal framework supports only 1 sensor per
> zone */
> > -		ret = of_parse_phandle_with_args(child, "thermal-sensors",
> > -						 "#thermal-sensor-cells",
> > -						 0, &sensor_specs);
> > +		ret = thermal_zone_of_get_sensor_id(child, sensor_np, &id);
> >  		if (ret)
> >  			continue;
> >
> > -		if (sensor_specs.args_count >= 1) {
> > -			id = sensor_specs.args[0];
> > -			WARN(sensor_specs.args_count > 1,
> > -			     "%pOFn: too many cells in sensor specifier %d\n",
> > -			     sensor_specs.np, sensor_specs.args_count);
> > -		} else {
> > -			id = 0;
> > -		}
> > -
> > -		if (sensor_specs.np == sensor_np && id == sensor_id) {
> > +		if (id == sensor_id) {
> >  			tzd = thermal_zone_of_add_sensor(child, sensor_np,
> >  							 data, ops);
> >  			if (!IS_ERR(tzd))
> >  				tzd->ops->set_mode(tzd,
> THERMAL_DEVICE_ENABLED);
> >
> > -			of_node_put(sensor_specs.np);
> >  			of_node_put(child);
> >  			goto exit;
> >  		}
> > -		of_node_put(sensor_specs.np);
> >  	}
> >  exit:
> >  	of_node_put(sensor_np);
> > diff --git a/include/linux/thermal.h b/include/linux/thermal.h index
> > 15a4ca5..5edffe6 100644
> > --- a/include/linux/thermal.h
> > +++ b/include/linux/thermal.h
> > @@ -375,6 +375,9 @@ struct thermal_trip {
> >
> >  /* Function declarations */
> >  #ifdef CONFIG_THERMAL_OF
> > +int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
> > +				  struct device_node *sensor_np,
> > +				  u32 *id);
> >  struct thermal_zone_device *
> >  thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
> >  				const struct thermal_zone_of_device_ops
> *ops); @@
> > -386,6 +389,13 @@ struct thermal_zone_device
> > *devm_thermal_zone_of_sensor_register(
> >  void devm_thermal_zone_of_sensor_unregister(struct device *dev,
> >  					    struct thermal_zone_device *tz);
> #else
> > +
> > +static int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
> > +					 struct device_node *sensor_np,
> > +					 u32 *id)
> > +{
> > +	return -ENOENT;
> > +}
> >  static inline struct thermal_zone_device *
> > thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
> >  				const struct thermal_zone_of_device_ops
> *ops)
> > --
> > 2.7.4