Re: [PATCH 1/2] iio: documentation: Document proximity sensor label use

From: Hans de Goede <hdegoede@redhat.com>
To: Bastien Nocera <hadess@hadess.net>, Jonathan Cameron <jic23@kernel.org>
Cc: linux-input@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	linux-iio@vger.kernel.org,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Mark Pearson <mpearson@lenovo.com>
Subject: Re: [PATCH 1/2] iio: documentation: Document proximity sensor label use
Date: Mon, 8 Feb 2021 14:50:26 +0100	[thread overview]
Message-ID: <676c9b71-ffc6-343e-f4ef-b0ec73fdb906@redhat.com> (raw)
In-Reply-To: <2b7a0374f4af5e2113c1d209246b506d7f42ae29.camel@hadess.net>

Hi,

On 2/8/21 2:40 PM, Bastien Nocera wrote:
> On Sun, 2021-02-07 at 13:37 +0100, Hans de Goede 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@redhat.com/
>>
>> 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.
> 
> Both patches in the series look fine to me.

Thank you for checking.

> Is IIO the interface you plan on using to implement the lap detection
> for the thinkpad_acpi driver?

ATM both the lap detection and the palmrest proximity detection are
already available using thinkpad_acpi specific sysfs attributes:

[hans@x1 linux]$ cat /sys/bus/platform/devices/thinkpad_acpi/dytc_lapmode 
0
[hans@x1 linux]$ cat /sys/bus/platform/devices/thinkpad_acpi/palmsensor 
1

Which I think you are already aware of ?  These will not be going
anywhere since dropping these would be a userspace ABI break.

With that said, yes the plan is to extend the thinkpad_acpi driver
to also report lap / palmrest proximity through IIO using these labels.

With the idea being that if other drivers / vendor firmwares also will
export similar readings that those will then also use IIO with these
labels for this, so that there is one unified / driver independent
interface which userspace can use to get these readings.

> If so, don't forget to set the "nearlevel" property as well.

Ack, I'll make sure that you are on the Cc when the patches for this
get posted.

Regards,

Hans