On Fri, 2021-04-16 at 13:13 +0200, Hans de Goede wrote: > Hi, > > On 4/16/21 12:45 PM, Bastien Nocera wrote: > > Hey, > > > > On Mon, 2021-04-05 at 22:42 +0200, Hans de Goede wrote: > > > Add an entry to Documentation/ABI/testing/sysfs-bus-iio for > > > the new device label sysfs-attribute support. > > > > > > And document the standardized labels which may be used with > > > proximity > > > sensors to hint userspace about the intended use of the sensor. > > > > > > Using labels to differentiate between the multiple proximity > > > sensors > > > which a modern laptop/tablet may have was discussed in this > > > thread: > > > https://lore.kernel.org/linux-iio/9f9b0ff6-3bf1-63c4-eb36-901cecd7c4d9@xxxxxxxxxx/ > > > > > > As mentioned there the "proximity-wifi*" labels are already being > > > used > > > in this manner on some chromebooks, see e.g.: > > > arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi > > > arch/arm64/boot/dts/qcom/sc7180-trogdor-lte-sku.dtsi > > > > > > And the "proximity-palmrest" and "proximity-lap" labels are > > > intended > > > to be used with the lap and palmrest sensors found in recent > > > Lenovo > > > ThinkPad models. > > > > > > Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> > > > Cc: Mark Pearson <mpearson@xxxxxxxxxx> > > > Cc: Bastien Nocera <hadess@xxxxxxxxxx> > > > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > > > --- > > > Changes in v2: > > > - Drop the too generic: > > > What: /sys/bus/iio/devices/iio:deviceX/in_*_label > > > What: /sys/bus/iio/devices/iio:deviceX/out_*_label > > > lines from the newly added documentation, if/when we start > > > using channel-labels with proximity sensors then those should > > > get a separate in_proximityX_label documentation. > > > --- > > > Documentation/ABI/testing/sysfs-bus-iio | 39 > > > +++++++++++++++++++++++++ > > > 1 file changed, 39 insertions(+) > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio > > > b/Documentation/ABI/testing/sysfs-bus-iio > > > index d957f5da5c04..7379e40d862d 100644 > > > --- a/Documentation/ABI/testing/sysfs-bus-iio > > > +++ b/Documentation/ABI/testing/sysfs-bus-iio > > > @@ -33,6 +33,45 @@ Description: > > > Description of the physical chip / device for > > > device > > > X. > > > Typically a part number. > > > > > > +What: /sys/bus/iio/devices/iio:deviceX/label > > > +KernelVersion: 5.8 > > > +Contact: linux-iio@xxxxxxxxxxxxxxx > > > +Description: > > > + Optional symbolic label for a device. > > > + This is useful for userspace to be able to better > > > identify an > > > + individual device. > > > + > > > + The contents of the label are free-form, but > > > there > > > are some > > > + standardized uses: > > > + > > > + For proximity sensors which give the proximity > > > (of a > > > person) to > > > + a certain wlan or wwan antenna the following > > > standardized labels > > > + are used: > > > + > > > + * "proximity-wifi" > > > + * "proximity-lte" > > > + * "proximity-wifi-lte" > > > + * "proximity-wifi-left" > > > + * "proximity-wifi-right" > > > > Could we avoid having "lte" in the label names? Do we have a way to > > communicate that some of those labels are deprecated and should be > > avoided? > > > > I would use "wwan" instead of "lte" here, and just mention > > "proximity- > > wifi-lte" as a synonym for "proximity-wifi-wwan". > > the "lte" postfix is currently in use on ChromeOS, which is why > I chose it here. I'm fine with adding some text that new drivers > should use -wwan, although I wonder how this will work with > separate mmwave and normal 5g antennas as such keeping lte for > both 4g + regular 5g might actually be better and then the separate > mmwave antennas can use a -mmwave postfix. LTE isn't 4G or 5G, so it's already a misnomer. I also doubt that any end-user cares what actual technology is being used in the antennas, I just wanted to avoid us having to add another name to the list when folks realise that LTE support is long gone from their devices. > > Dmitry IIRC you brought up the use of these labels in a previous > discussion. Do you have anything to add here ? Is ChromeOS > already doing anything wrt SAR for mmwave antennas? > > > > > > + > > > + These are used to indicate to userspace that > > > these > > > proximity > > > + sensors may be used to tune transmit power to > > > ensure > > > that > > > + Specific Absorption Rate (SAR) limits are > > > honored. > > > + The "-left" and "-right" labels are for devices > > > with > > > multiple > > > + antennas. > > > + > > > + In some laptops/tablets the standardized > > > proximity > > > sensor labels > > > + instead indicate proximity to a specific part of > > > the > > > device: > > > + > > > + * "proximity-palmrest" indicates proximity to the > > > keyboard's palmrest > > > + * "proximity-palmrest-left" indicates proximity > > > to > > > the left part of the palmrest > > > + * "proximity-palmrest-right" indicates proximity > > > to > > > the right part of the palmrest > > > + * "proximity-lap" indicates the device is being > > > used > > > on someone's lap > > > + > > > + Note "proximity-lap" is special in that its value > > > may > > > be > > > + calculated by firmware from other sensor > > > readings, > > > rather then > > > + being a raw sensor reading. > > > > I don't think that this is needed. I would expect that this sensor > > would have a "0" minimum and "1" maximum value, which makes it > > clear > > that the sensor value is synthesised. > > IIO typically exports real sensor readings, not these kind of > synthesized values so IMHO it is good to mention this in the docs. > > > Maybe this special case should be mentioned (if that's needed), > > rather > > than pointing out that this particular sensor might be special > > (they > > could all be, depending on how the system is implemented after > > all). > > > > Did you think about where you wanted the sensor's threshold to be > > exported? Still in udev/hwdb? > > AFAIK the plan was for the driver to export this as a IIO sysfs > attribute, Documentation/ABI/testing/sysfs-bus-iio > already has: > > What: /sys/.../events/in_proximity0_thresh_falling_value > What: /sys/.../events/in_proximity0_thresh_rising_value > > Those are intended for the trigger interface, but IIRC I think the > plan was to also use these on a device without trigger support > to advertise the recommended threshold to be used by userspace. > > Jonathan ? > > Regards, > > Hans > > > > > > > > > > Cheers > > > > > + > > > What: /sys/bus/iio/devices/iio:deviceX/current_timestam > > > p_cl > > > ock > > > KernelVersion: 4.5 > > > Contact: linux-iio@xxxxxxxxxxxxxxx > > > > >
