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

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Date:   Sun, 19 Nov 2017 18:38:35 +0100
From:   Gabriele Mazzotta <gabriele.mzt@...il.com>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     Kiernan Hager <kah.listaddress@...il.com>,
        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>,
        Marek Vasut <marex@...x.de>,
        "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

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.

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);
>>  }
>>
>