On Thu, Nov 12, 2020 at 10:50:12AM +0100, Hans de Goede wrote: > Hi, > > On 11/12/20 7:23 AM, Dmitry Torokhov wrote: > > On Wed, Oct 07, 2020 at 11:51:05AM +0200, Hans de Goede wrote: > >> Hi, > >> > >> On 10/7/20 10:36 AM, Jonathan Cameron wrote: > >>> On Mon, 5 Oct 2020 22:04:27 -0400 > >>> Mark Pearson <markpearson@xxxxxxxxxx> wrote: > >>> > >>>> Adding Nitin, lead for this feature, to the thread > >>> > >>> +CC linux-input and Dmitry for reasons that will become clear below. > >>>> > >>>> 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. > >>> > >>> My first thought on this is it sounds more like a key than a sensor > >>> (simple proximity sensors fall into this category as well.) > > > > [ sorry for sitting on this thread for so long ] > > > > So I think the important question here is if we only ever want yes/no > > answer, or if we can consider adjusting behavior of the system based on > > the "closeness" of an object to the device, in which case I think IIO is > > more flexible. > > > > FWIW in Chrome OS land we name IIO proximity sensors using a scheme > > "proximity-lte", "proximity-wifi", "proximity-wifi-left", > > "proximity-wifi-right", etc, and then userspace implements various > > policies (SAR, etc) based off it. > > Interesting, so 2 questions: > > 1. So your encoding the location in the sensor's parent-device name > instead of using a new sysfs attribute for this ? I think it depends on the kernel we use and architecture. On x86 I think we rely on udev, like this: https://chromium.googlesource.com/chromiumos/overlays/board-overlays/+/master/overlay-nocturne/chromeos-base/chromeos-bsp-nocturne/files/udev/99-cros-sx-proximity.rules DEVPATH=="*/pci0000:00/0000:00:15.1/*", SYMLINK+="proximity-wifi-right" DEVPATH=="*/pci0000:00/0000:00:19.1/*", SYMLINK+="proximity-wifi-left" ATTR{events/in_proximity1_USE_CS1_thresh_either_en}="1" 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"; }; > > 2. Do these sensors just give a boolean value atm, or do they already > report a range ? IIRC one of the objections from the iio folks in > the Lenovo case was that booleans are not really a good fit for iio > (IIRC they also said we could still use iio for this). One of the sensors we use is sx9310 that I believe can report range, but I think we configure them to trigger when a threshold is crossed. Events are handled by our powerd: https://chromium.googlesource.com/chromiumos/platform2/+/master/power_manager/powerd/system/sar_watcher.cc > > Perhaps you can provide an URL to the kernel code implementing these ? drivers/iio/proximity/sx9310.c Also sx932x - https://lore.kernel.org/patchwork/patch/1005708/ Thanks. -- Dmitry
