On Thu, 2020-11-19 at 16:39 +0100, Hans de Goede wrote: > Hi, > > On 11/13/20 7:58 AM, Dmitry Torokhov wrote: > > 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" > > So that results in a symlink under /dev, right ? That seems like > it is not really compatible with how most modern userspace discovers > hw (through udev). Although I guess code using udev could still > lookup the symlink in the udev per device data, this just not feel > like a good way forward. We can tag it, the metadata will be readable in where we need it, through libudev, so that's not a big bother.
