On Mon, 23 Nov 2020 13:16:20 +0100 Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 11/20/20 10:59 AM, Jonathan Cameron wrote: > > On Thu, 19 Nov 2020 16:39:07 +0100 > > Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > >>>>>>>> On 2020-10-03 10:02 a.m., Hans de Goede wrote: > >>>>>>>>> Hi All, > >>>>>>>>> > >>>>>>>>> Modern laptops can have various sensors which are kinda > >>>>>>>>> like proximity sensors, but not really (they are more > >>>>>>>>> specific in which part of the laptop the user is > >>>>>>>>> proximate to). > >>>>>>>>> > >>>>>>>>> Specifically modern Thinkpad's have 2 readings which we > >>>>>>>>> want to export to userspace, and I'm wondering if we > >>>>>>>>> could use the IIO framework for this since these readings > >>>>>>>>> are in essence sensor readings: > >>>>>>>>> > >>>>>>>>> 1. These laptops have a sensor in the palm-rests to > >>>>>>>>> check if a user is physically proximate to the device's > >>>>>>>>> palm-rests. This info will be used by userspace for WWAN > >>>>>>>>> functionality to control the transmission level safely. > >>>>>>>>> > >>>>>>>>> A patch adding a thinkpad_acpi specific sysfs API for this > >>>>>>>>> is currently pending: > >>>>>>>>> https://patchwork.kernel.org/patch/11722127/ > >>>>>>>>> > >>>>>>>>> But I'm wondering if it would not be better to use > >>>>>>>>> IIO to export this info. > > <snip> > > >>> On newer ARM we use "label" attribute in DTS: > >>> > >>> arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi > >>> > >>> ap_sar_sensor: proximity@28 { > >>> compatible = "semtech,sx9310"; > >>> reg = <0x28>; > >>> #io-channel-cells = <1>; > >>> pinctrl-names = "default"; > >>> pinctrl-0 = <&p_sensor_int_l>; > >>> > >>> interrupt-parent = <&tlmm>; > >>> interrupts = <24 IRQ_TYPE_LEVEL_LOW>; > >>> > >>> vdd-supply = <&pp3300_a>; > >>> svdd-supply = <&pp1800_prox>; > >>> > >>> status = "disabled"; > >>> label = "proximity-wifi"; > >>> }; > >> > >> Hmm, interesting. I did not know iio-devices could > >> have a label sysfs attribute (nor that that could be > >> set through device-tree). I was thinking about adding > >> an in_proximity_location sysfs attribute. But using > >> labels (and standardizing a set of label names) will > >> work nicely too. > > > > It's fairly new. Note we also have per channel labels > > though they are 'very new'. Might be handy if the sensors > > appear as a single device despite being spread over the > > laptop. > > Interesting, the thinkpad_acpi stuff currently has 2 > proximity(ish) sensors: > > 1. Laptop is close to (on) someones lap > 2. Someone's arms are resting on or close to the palmrest > > Ideally we would indeed register 1 iio-dev with separate > channels for this, rather then having to register 2 > (and the future maybe even more) iio-devs for this. > > Can you give a pointer to docs / examples of using a > label per channel ? Docs if done with DT binding are at: https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/?h=testing&id=7f79711533a96b02e1e24e2e36a29b08734e36e2 ABI Docs https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/?h=testing&id=3079188f821cfbdbb0b12f668335931a87eb14c6 An example using it directly rather than via DT (it's not really DT related though in some cases the label may come from there) https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/?h=testing&id=1f4877218f7e2c2b914aeb69a8a0f47d59c74717 Those will probably be in Linux-next later this week. Jonathan > > >> Is there a know set of labels which ChromeOS is currently > >> using? If we are going to use labels for this it would > >> be good IMHO to define a set of standard labels for > >> this in say Documentation/ABI/testing/sysfs-bus-iio-labels. > > > > If you do want to do this, please just put it under sysfs-bus-iio > > doc. I want this to be in the top level doc. > > Ok, ack. > > Dmitry, can you perhaps dig up a full-list of labels > which ChromeOS is currently using to identify > proximity sensors for e.g. SAR related use? > > Regards, > > Hans >
