linux-kernel - Re: [RFC] iio: light: acpi-als: Enable the light sensor on the Zenbook UX430UQ

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Date:   Mon, 20 Nov 2017 09:51:50 -0700
From:   Kiernan Hager <kah.listaddress@...il.com>
To:     Marek Vasut <marex@...x.de>
Cc:     Gabriele Mazzotta <gabriele.mzt@...il.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        linux-iio@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>
Subject: Re: [RFC] iio: light: acpi-als: Enable the light sensor on the
 Zenbook UX430UQ

On Sun, Nov 19, 2017 at 11:11 AM, Marek Vasut <marex@...x.de> wrote:
> On 11/19/2017 06:38 PM, Gabriele Mazzotta wrote:
>> 2017-11-19 18:03 GMT+01:00 Jonathan Cameron <jic23@...nel.org>:
>>> On Wed, 15 Nov 2017 20:27:54 -0700
>>> Kiernan Hager <kah.listaddress@...il.com> wrote:
>>>
>>>> This makes acpi-als properly enable the light sensor on the Zenbook UX430UQ. I don't know if the checking that I do to make sure that the ACPI method exists is sufficient or if it should disable the sensor when the module is unloaded, so input is appreciated on those matters.
>>>
>>> Please wrap descriptions to around 72 characters (leaves room for indentation
>>> in the email thread :)
>>>
>>> This seems very much like a board specific hack.  I've cc'd people
>>> who have worked on the driver recently and the acpi list.
>>
>> This is indeed board specific. I know many other laptops of the
>> Zenbook line need something similar and if you look at
>> drivers/platform/x86/asus-wmi.c or any other asus-* driver you'll
>> find several quirks to enable various features.
>
> Maybe that's where it should go . EC0 in the ACPI path seems like
> Embedded Controller to me .
>
>> Kiernan, check commit aca234f6378864d85514be558746c0ea6eabfa8e
>> ("asus-wmi: provide access to ALS control") in particular.
>>
>>>>
>>>> Signed-off-by: Kiernan Hager <kah.listaddress@...il.com>
>>>> ---
>>>>  drivers/iio/light/acpi-als.c | 16 ++++++++++++++++
>>>>  1 file changed, 16 insertions(+)
>>>>
>>>> diff --git a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
>>>> index c35e2f8df339..8fd66166f19f 100644
>>>> --- a/drivers/iio/light/acpi-als.c
>>>> +++ b/drivers/iio/light/acpi-als.c
>>>> @@ -179,6 +179,10 @@ static int acpi_als_add(struct acpi_device *device)
>>>>       struct acpi_als *als;
>>>>       struct iio_dev *indio_dev;
>>>>       struct iio_buffer *buffer;
>>>> +     unsigned long long temp_val;
>>>> +     acpi_status status;
>>>> +     struct acpi_object_list arg_list;
>>>> +     union acpi_object arg;
>>>>
>>>>       indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
>>>>       if (!indio_dev)
>>>> @@ -203,6 +207,18 @@ static int acpi_als_add(struct acpi_device *device)
>>>>
>>>>       iio_device_attach_buffer(indio_dev, buffer);
>>>>
>>>> +     arg_list.count = 1;
>>>> +     arg_list.pointer = &arg;
>>>> +     arg.type = ACPI_TYPE_INTEGER;
>>>> +     arg.integer.value = 1;
>>>> +
>>>> +     if (acpi_has_method(als->device->handle, "\\_SB.PCI0.LPCB.EC0.ALSC")) {
>>> So this is poking something on
>>> PCI bus 0
>>> LPC bus B
>>> Somethingbus 0
>>> Ambient light controller.
>>>
>>> I assume there is a better way of establishing this needs to be set?
>>>
>>>> +             status = acpi_evaluate_integer(als->device->handle,
>>>> +                                            "\\_SB.PCI0.LPCB.EC0.ALSC",
>>>> +                                            &arg_list,
>>>> +                                            &temp_val);
>>>> +     }
>>>> +
>>>>       return devm_iio_device_register(&device->dev, indio_dev);
>>>>  }
>>>>
>>>
>
>
> --
> Best regards,
> Marek Vasut

That sounds like a good idea. I'll have a look at that file and
possibly apply my patch to that instead.

Kiernan