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

[Aisheng Dong <aisheng.dong@nxp.com>]

Hi Eduardo & Rui,

> From: Anson Huang
> Sent: Tuesday, June 11, 2019 8:37 PM
>
> > From: Aisheng Dong
> > Sent: Tuesday, June 11, 2019 7:47 PM
> > 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.
> 

The API change seems good to me. 
But since this is a core changes, we need your inputs to confirm whether this approach
is ok to you.

So please tell us whether you're fine with this approach.

Regards
Dong Aisheng

> Thanks,
> Anson
> 
> >
> > > From: Anson.Huang@nxp.com [mailto:Anson.Huang@nxp.com]
> > > 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@nxp.com>
> > > ---
> > > 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