Re: [PATCH V2] hwmon: (ibmpowernv) Add min/max attributes and current sensors

[Guenter Roeck]

On 05/01/2017 09:35 PM, Shilpasri G Bhat wrote:
> Hi Guenter,
>
> On 04/28/2017 06:59 PM, Guenter Roeck wrote:
> > On 04/27/2017 10:59 PM, Shilpasri G Bhat wrote:
> > > Add support for adding min/max values for the inband sensors copied by
> > > OCC to main memory. And also add current(mA) sensors to the list.
> > >
> > > Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
> > > ---
> > > Changes from V1:
> > > - Add functions to get min and max attribute strings
> > > - Add function 'populate_sensor' to fill in the 'struct sensor_data'
> > >   for each sensor.
> > >
> > >  drivers/hwmon/ibmpowernv.c | 96 +++++++++++++++++++++++++++++++++++++---------
> > >  1 file changed, 77 insertions(+), 19 deletions(-)
> > >
> > > diff --git a/drivers/hwmon/ibmpowernv.c b/drivers/hwmon/ibmpowernv.c
> > > index 6d2e660..d59262c 100644
> > > --- a/drivers/hwmon/ibmpowernv.c
> > > +++ b/drivers/hwmon/ibmpowernv.c
> > > @@ -50,6 +50,7 @@ enum sensors {
> > >      TEMP,
> > >      POWER_SUPPLY,
> > >      POWER_INPUT,
> > > +    CURRENT,
> > >      MAX_SENSOR_TYPE,
> > >  };
> > >
> > > @@ -65,7 +66,8 @@ enum sensors {
> > >      {"fan", "ibm,opal-sensor-cooling-fan"},
> > >      {"temp", "ibm,opal-sensor-amb-temp"},
> > >      {"in", "ibm,opal-sensor-power-supply"},
> > > -    {"power", "ibm,opal-sensor-power"}
> > > +    {"power", "ibm,opal-sensor-power"},
> > > +    {"curr"}, /* Follows newer device tree compatible ibm,opal-sensor */
> >
> > Following up on a previous e-mail, this really _is_ odd. Any chance to fix it
> > in the firmware and have current sensors return "ibm,opal-sensor-current" ?
>
> Okay will drop "curr' sensor till we resolve this in the firmware.
>
> > >  };
> > >
> > >  struct sensor_data {
> > > @@ -287,6 +289,7 @@ static int populate_attr_groups(struct platform_device *pdev)
> > >      opal = of_find_node_by_path("/ibm,opal/sensors");
> > >      for_each_child_of_node(opal, np) {
> > >          const char *label;
> > > +        int len;
> > >
> > >          if (np->name == NULL)
> > >              continue;
> > > @@ -298,10 +301,14 @@ static int populate_attr_groups(struct platform_device
> > > *pdev)
> > >          sensor_groups[type].attr_count++;
> > >
> > >          /*
> > > -         * add a new attribute for labels
> > > +         * add attributes for labels, min and max
> > >           */
> > >          if (!of_property_read_string(np, "label", &label))
> > >              sensor_groups[type].attr_count++;
> > > +        if (of_find_property(np, "sensor-data-min", &len))
> > > +            sensor_groups[type].attr_count++;
> > > +        if (of_find_property(np, "sensor-data-max", &len))
> > > +            sensor_groups[type].attr_count++;
> > >      }
> > >
> > >      of_node_put(opal);
> > > @@ -337,6 +344,49 @@ static void create_hwmon_attr(struct sensor_data *sdata,
> > > const char *attr_name,
> > >      sdata->dev_attr.show = show;
> > >  }
> > >
> > > +static void populate_sensor(struct sensor_data *sdata, int od, int hd, int sid,
> > > +                const char *attr_name, enum sensors type,
> > > +                const struct attribute_group *pgroup,
> > > +                ssize_t (*show)(struct device *dev,
> > > +                        struct device_attribute *attr,
> > > +                        char *buf))
> > > +{
> > > +    sdata->id = sid;
> > > +    sdata->type = type;
> > > +    sdata->opal_index = od;
> > > +    sdata->hwmon_index = hd;
> > > +    create_hwmon_attr(sdata, attr_name, show);
> > > +    pgroup->attrs[sensor_groups[type].attr_count++] = &sdata->dev_attr.attr;
> > > +}
> > > +
> > > +static char *get_max_attr(enum sensors type)
> > > +{
> > > +    switch (type) {
> > > +    case POWER_INPUT:
> > > +        return "input_highest";
> > > +    case TEMP:
> > > +        return "max";
> > > +    default:
> > > +        break;
> > > +    }
> > > +
> > > +    return "highest";
> >
> > This is a bit confusing. Why not 'return "highest";' in the default case above ?
> >
> > Also, is this correct for type == POWER_SUPPLY, ie is it "highest" vs. "max" ?
> >
> > Kind of odd that the firmware reports "highest/lowest" in some cases
> > and "max/min" in others. Guess there is nothing we can do about that,
> > just a note.
>
> Firmware has min/max values for all sensors, but I had mapped them as
> highest/lowest to add reset_history attribute in the later patches.

Not sure I am parsing that correctly. Does the firmware report highest/lowest
or min/max ? reset_history only makes sense if the chip supports highest/lowest.

In case you plan to implement highest/lowest in software ... please don't.
Highest/lowest attributes must only be provided if the history is delivered
by the chip. If the chip does not support highest/lowest values, user
space can implement it, but we definitely don't want any workers or
similar in the kernel to do it.

Thanks,
Guenter

> Will change "TEMP" to highest/lowest to keep consistency.
>
> Thanks and Regards,
> Shilpa
>
> > > +}
> > > +
> > > +static char *get_min_attr(enum sensors type)
> > > +{
> > > +    switch (type) {
> > > +    case POWER_INPUT:
> > > +        return "input_lowest";
> > > +    case TEMP:
> > > +        return "min";
> > > +    default:
> > > +        break;
> > > +    }
> > > +
> > > +    return "lowest";
> >
> > Same here.
> >
> > > +}
> > > +
> > >  /*
> > >   * Iterate through the device tree for each child of 'sensors' node, create
> > >   * a sysfs attribute file, the file is named by translating the DT node name
> > > @@ -365,6 +415,7 @@ static int create_device_attrs(struct platform_device *pdev)
> > >      for_each_child_of_node(opal, np) {
> > >          const char *attr_name;
> > >          u32 opal_index;
> > > +        u32 hwmon_index;
> > >          const char *label;
> > >
> > >          if (np->name == NULL)
> > > @@ -386,9 +437,6 @@ static int create_device_attrs(struct platform_device *pdev)
> > >              continue;
> > >          }
> > >
> > > -        sdata[count].id = sensor_id;
> > > -        sdata[count].type = type;
> > > -
> > >          /*
> > >           * If we can not parse the node name, it means we are
> > >           * running on a newer device tree. We can just forget
> > > @@ -401,14 +449,12 @@ static int create_device_attrs(struct platform_device
> > > *pdev)
> > >              opal_index = INVALID_INDEX;
> > >          }
> > >
> > > -        sdata[count].opal_index = opal_index;
> > > -        sdata[count].hwmon_index =
> > > -            get_sensor_hwmon_index(&sdata[count], sdata, count);
> > > -
> > > -        create_hwmon_attr(&sdata[count], attr_name, show_sensor);
> > > -
> > > -        pgroups[type]->attrs[sensor_groups[type].attr_count++] =
> > > -                &sdata[count++].dev_attr.attr;
> > > +        hwmon_index = get_sensor_hwmon_index(&sdata[count], sdata,
> > > +                             count);
> > > +        populate_sensor(&sdata[count], opal_index, hwmon_index,
> > > +                sensor_id, attr_name, type, pgroups[type],
> > > +                show_sensor);
> > > +        count++;
> > >
> > >          if (!of_property_read_string(np, "label", &label)) {
> > >              /*
> > > @@ -417,16 +463,28 @@ static int create_device_attrs(struct platform_device
> > > *pdev)
> > >               * attribute. They are related to the same
> > >               * sensor.
> > >               */
> > > -            sdata[count].type = type;
> > > -            sdata[count].opal_index = sdata[count - 1].opal_index;
> > > -            sdata[count].hwmon_index = sdata[count - 1].hwmon_index;
> > >
> > >              make_sensor_label(np, &sdata[count], label);
> > > +            populate_sensor(&sdata[count], opal_index, hwmon_index,
> > > +                    sensor_id, "label", type, pgroups[type],
> > > +                    show_label);
> > > +            count++;
> > > +        }
> > >
> > > -            create_hwmon_attr(&sdata[count], "label", show_label);
> > > +        if (!of_property_read_u32(np, "sensor-data-max", &sensor_id)) {
> > > +            attr_name = get_max_attr(type);
> > > +            populate_sensor(&sdata[count], opal_index, hwmon_index,
> > > +                    sensor_id, attr_name, type,
> > > +                    pgroups[type], show_sensor);
> > > +            count++;
> > > +        }
> > >
> > > -            pgroups[type]->attrs[sensor_groups[type].attr_count++] =
> > > -                &sdata[count++].dev_attr.attr;
> > > +        if (!of_property_read_u32(np, "sensor-data-min", &sensor_id)) {
> > > +            attr_name = get_min_attr(type);
> > > +            populate_sensor(&sdata[count], opal_index, hwmon_index,
> > > +                    sensor_id, attr_name, type,
> > > +                    pgroups[type], show_sensor);
> > > +            count++;
> > >          }
> > >      }
>
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