Re: [PATCH v3 2/3] iio: adc128s052: add ACPI _HID AANT1280

From: Andy Shevchenko
Date: Fri Oct 26 2018 - 08:12:35 EST

On Fri, Oct 26, 2018 at 11:13:01AM +0100, Dan O'Donovan wrote:
> On 10/25/2018 06:46 PM, Andy Shevchenko wrote:
> > On Thu, Oct 25, 2018 at 04:35:41PM +0100, Dan O'Donovan wrote:

> >> + { "AANT1280", 2 }, /* ADC124S021 compatible ACPI ID */

> > Looking how driver is organized and what ACPI can provide I would highly
> > recommend to look forward to PTYP field for utilization of the type of the HW.

> > Maybe it would not work with published BIOSes, but would be good for the future
> > (in that case anybody can utilize that _HID + PTYP pair on their platforms).

> Thanks Andy for your review and feedback. Your _HID + PTYP suggestion sounds
> interesting, but I couldn't find any information in the ACPI spec or elsewhere
> about how/when/where to use it.

I stand corrected, it's not in the spec, rather de facto use of it in some
cases, see below.

> It isn't used in the UP Squared ACPI tables.
> Do you have any links or other information you could share about it? Thanks!

As far as I can find the following code in the kernel and thus real ACPI tables
in the wild that utilize it.

drivers/acpi/dptf/dptf_power.c:84: status = acpi_evaluate_integer(acpi_dev->handle, "PTYP", NULL, &ptype);
drivers/platform/x86/intel_cht_int33fe.c:101: status = acpi_evaluate_integer(ACPI_HANDLE(dev), "PTYP", NULL, &ptyp);
drivers/thermal/int340x_thermal/int3403_thermal.c:237: status = acpi_evaluate_integer(priv->adev->handle, "PTYP",

With Best Regards,
Andy Shevchenko