Hi, On 4/16/21 12:56 PM, Bastien Nocera wrote: > On Mon, 2021-04-05 at 22:39 +0200, Hans de Goede wrote: >> Some 2-in-1 laptops / convertibles with 360° (yoga-style) hinges, >> have 2 accelerometers, 1 in their base and 1 in their display. >> >> In many cases the kernel can detect the location of each >> accelerometer >> based on e.g. information from the ACPI tables. >> >> It is important for userspace to know the location of the 2 >> accelerometers. >> Rather then adding a new sysfs-attribute for this we can relay this >> information to userspace by using standardized label strings for >> this. >> This mirrors how this is done for proximity sensors. >> >> This commit documents 2 new standardized label strings for this >> purpose: >> "accel-base" >> "accel-display" > > If we have a combined proximity and accelerometer sensor (which > wouldn't be unheard off with sensor hubs being used), how are multiple > labels, say "proximity-wifi" and "accel-base" documented? Sensor hubs typically use one iio device per sensor, see e.g. how HID-sensors work. And if a device which does not use separate iio-devices per sensor shows up then the plan is to use per channel-labels which are already supported by iio. Regards, Hans >> Note the "base" and "display" suffixes were chosen to match the >> values >> used for the systemd/udev hwdb.d/60-sensor.hwdb file's ACCEL_LOCATION >> property. >> >> 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 | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/Documentation/ABI/testing/sysfs-bus-iio >> b/Documentation/ABI/testing/sysfs-bus-iio >> index 7379e40d862d..b7529bca83f5 100644 >> --- a/Documentation/ABI/testing/sysfs-bus-iio >> +++ b/Documentation/ABI/testing/sysfs-bus-iio >> @@ -72,6 +72,13 @@ Description: >> calculated by firmware from other sensor readings, >> rather then >> being a raw sensor reading. >> >> + For accelerometers used in 2-in-1s with 360° (yoga- >> style) hinges, >> + which have an accelerometer in both their base and >> their display, >> + the following standardized labels are used: >> + >> + * "accel-base" >> + * "accel-display" >> + >> What: /sys/bus/iio/devices/iio:deviceX/current_timestamp_cl >> ock >> KernelVersion: 4.5 >> Contact: linux-iio@xxxxxxxxxxxxxxx > >
