Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1446088

Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by iio_hwmon

Show all headers | View raw

On 18/07/2016 14:24, Jonathan Cameron wrote:
> On 15/07/16 10:59, Quentin Schulz wrote:
>> Currently, iio_hwmon only exposes values of the IIO channels it can read
>> but no label by channel is exposed.
>>
>> This adds exposition of sysfs files containing label for IIO channels it
>> can read based on extended_name field of the iio_chan_spec of the channel.
>> If the extended_name field is empty, the sysfs file is not created by
>> iio_hwmon.
> Hmm. This is not the intent of extended name at all.  That exists to add
> a small amount of information to an constructed IIO channel name.
> Typically it's used to indicate physically wired stuff like:
> 
> in_voltage0_vdd_raw for cases where that channel of the ADC is hard wired
> to the vdd.  In this particular case the use might actually work as the
> vdd makes it clear it's a voltage - in general that's not the case.
> 
> Use of extended_name at all in IIO is only done after extensive review.
> It adds nasty custom ABI to a device, so the gain has to be considerable
> to use it.
> 
> When I read your original suggestion of adding labels, I was expecting the
> use of datasheet_name.  That has the advantage of being well defined by
> the datasheet (if not it should not be provided) + not being used in
> the construction of the IIO channel related attributes.  However, that
> may still not correspond well to the expected labelling in hwmon.

Good to know for extend_name use cases. While doing further testing, I
noticed the extend_name is also appended to the sysfs filename.. which
is definitely not what we want.

I've checked for datasheet_name and it is only used to be compared to
adc_channel_label from iio_map structure. Same for adc_channel_label
(which has to be the same as datasheet_name of the iio_chan_spec it is
linked to). So I could use this instead of extend_name to put a label on
a channel.
However, I thought of it to be more a way to identify the hardware in
the datasheet more than giving users a hint on what it is. That's what
"git grep adc_channel_label" told me. It's definitely better to use
datasheet_name over extend_name for channel labeling but I don't know if
it's really the good variable to use for labeling? In my understanding
of datasheet_name, in my case it would be more "temp_gpadc" than "SoC
temperature", that's what I mean.

> Thinking more on this, the label is going to often be a function of how
> the board is wired up...  Perhaps it should be a characteristic of the
> channel_map (hence from DT or similar) rather than part of the IIO driver
> itself?

Hmm.. I would not put a property in the DT only for labeling.

[...]

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v2 0/4] add support for Allwinner SoCs ADC Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-15 12:10 +0200
  [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-15 12:10 +0200
    Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-07-18 15:10 +0200
      Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-19 14:10 +0200
    Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Jonathan Cameron <jic23@kernel.org> - 2016-07-19 07:40 +0200
      Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Lee Jones <lee.jones@linaro.org> - 2016-07-19 09:40 +0200
        Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Jonathan Cameron <jic23@kernel.org> - 2016-07-20 17:10 +0200
          Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Lee Jones <lee.jones@linaro.org> - 2016-07-21 14:20 +0200
            Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-07-21 22:10 +0200
              Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Lee Jones <lee.jones@linaro.org> - 2016-07-22 16:00 +0200
                Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Jonathan Cameron <jic23@kernel.org> - 2016-07-23 13:00 +0200
                Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-07-25 12:00 +0200
      Re: [PATCH v2 3/4] mfd: add support for Allwinner SoCs ADC Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-19 10:40 +0200
  [PATCH v2 1/4] hwmon: iio_hwmon: defer probe when no channel is found Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-15 12:10 +0200
    Re: [v2,1/4] hwmon: iio_hwmon: defer probe when no channel is found Guenter Roeck <linux@roeck-us.net> - 2016-07-16 19:10 +0200
      Re: [v2,1/4] hwmon: iio_hwmon: defer probe when no channel is found Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-07-18 12:10 +0200
        Re: [v2,1/4] hwmon: iio_hwmon: defer probe when no channel is found Guenter Roeck <linux@roeck-us.net> - 2016-07-18 15:30 +0200
  [PATCH v2 4/4] hwmon: iio: add label for channels read by iio_hwmon Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-15 12:10 +0200
    Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by  iio_hwmon Guenter Roeck <linux@roeck-us.net> - 2016-07-15 16:10 +0200
      Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by  iio_hwmon Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-15 16:40 +0200
        Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by  iio_hwmon Guenter Roeck <linux@roeck-us.net> - 2016-07-16 05:00 +0200
    Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by  iio_hwmon Jonathan Cameron <jic23@kernel.org> - 2016-07-19 07:40 +0200
      Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by  iio_hwmon Quentin Schulz <quentin.schulz@free-electrons.com> - 2016-07-19 09:00 +0200
        Re: [PATCH v2 4/4] hwmon: iio: add label for channels read by  iio_hwmon Jonathan Cameron <jic23@kernel.org> - 2016-07-20 16:50 +0200

csiph-web