On Fri, 12 Feb 2021 19:58:47 +0100 Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 2/12/21 7:46 PM, Jonathan Cameron wrote: > > On Sun, 7 Feb 2021 13:37:19 +0100 > > Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > > >> Add an entry to Documentation/ABI/testing/sysfs-bus-iio for > >> the new device and channel 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 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> > >> --- > >> Documentation/ABI/testing/sysfs-bus-iio | 41 +++++++++++++++++++++++++ > >> 1 file changed, 41 insertions(+) > >> > >> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio > >> index 35289d47d6cb..f2f090f8bd2f 100644 > >> --- a/Documentation/ABI/testing/sysfs-bus-iio > >> +++ b/Documentation/ABI/testing/sysfs-bus-iio > >> @@ -33,6 +33,47 @@ Description: > >> Description of the physical chip / device for device X. > >> Typically a part number. > >> > >> +What: /sys/bus/iio/devices/iio:deviceX/label > >> +What: /sys/bus/iio/devices/iio:deviceX/in_*_label > >> +What: /sys/bus/iio/devices/iio:deviceX/out_*_label > > > > I was a bit in two minds about this from an organizational point of view. > > 1) Whether to separate the general label where position tends to make sense > > from the channel labels. May be something we want to do in future but we can probably > > let that go for now. > > 2) Whether to allow such broad wild cards for the channels. > > Whilst in theory any channel can have a label we normally only document ABI > > that actually exists (mostly to know what we might break if we change anything :) > > Still I can't see any way we can change this without breakage so in this > > one case let's let the broad wild card go in. > > > > This comes unstuck on the fact it overlaps with existing more specific Docs. > > > > So can you pull the channel part out of here for v2. > > /sys/bus/iio/devices/iio:deviceX/in_voltageY_label > > /sys/bus/iio/devices/iio:deviceX/in_anglY_label > > The problem is that these labels may either be used on a whole device, > which is certainly the case with the accelerometers in patch 2/2 where > the x y and z channels obviously all are either "accel-base" or > "accel-display". > > Where as for proximity sensors the labels could be either applied at the > device level, or at a channel level. > > The existing chromebook proximity usage is applying a label for this > at the device level. > > This does mean that atm all users of this are using device-level labels; Not at all, but some (possibly all?) are separately documented in two existing entries. The generic version you propose overlaps with them and that is what I'd like to avoid. We could group these into the same 'catch all' element, but I suspect the text will just grow too large over time, so I'd like to keep them as broken up as possible. What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_label What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_label What: /sys/bus/iio/devices/iio:deviceX/in_anglY_label > and maybe I'm reading too much in your request. I guess that for now > I can just drop these lines for v2 : > > What: /sys/bus/iio/devices/iio:deviceX/in_*_label > What: /sys/bus/iio/devices/iio:deviceX/out_*_label > > Is that what you have in mind ? > > Or do you want me to split this up in a proximity sensor case and an > accel case, and group both cases together with other proximity / accel > sensor attributes ? Yes, that would be ideal for the cases where we have separate channel labels, but if we aren't using them today, lets introduce them when they are needed. Jonathan > > Regards, > > Hans > > > > > > Jonathan > >> +KernelVersion: 5.8 > >> +Contact: linux-iio@xxxxxxxxxxxxxxx > >> +Description: > >> + Optional symbolic label for a device or a channel. > >> + This is useful for userspace to be able to better identify an > >> + individual device or channel. > >> + > >> + 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" > >> + > >> + 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. > >> + > >> What: /sys/bus/iio/devices/iio:deviceX/current_timestamp_clock > >> KernelVersion: 4.5 > >> Contact: linux-iio@xxxxxxxxxxxxxxx > > >
