Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

From	John Garry <john.garry@huawei.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning
Date	2017-06-30 11:40 +0200
Message-ID	<tY0z7-3Ia-13@gated-at.bofh.it> (permalink)
References	(6 earlier) <tSHnv-5OL-97@gated-at.bofh.it> <tSUXo-63M-7@gated-at.bofh.it> <tSXBT-7N5-5@gated-at.bofh.it> <tXKkG-1nd-49@gated-at.bofh.it> <tY065-3v8-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On 30/06/2017 10:05, Mika Westerberg wrote:
> On Thu, Jun 29, 2017 at 05:16:15PM +0100, John Garry wrote:
>> On 16/06/2017 12:24, Rafael J. Wysocki wrote:
>>>>>>>>>
>>>>>>>>> It causes acpi_default_enumeration() to be called but it should be fine
>>>>>>>>> as we are dealing with platform device anyway.
>>>>>>>
>>>>>>> I do not quite understand how declaring such MFD cell above would make sure
>>>>>>> that the LPC probe is called before the IPMI device is enumerated...
>>>>>
>>>>> In fact it may be that it is not sufficient in this case because the
>>>>> ACPI core might enumerate child devices before the LPC driver even gets
>>>>> a chance to probe so you would need to add also scan handler to the
>>>>> child devices and mark them already enumerated or something like that.
>>> Or extend the special I2C/SPI handling to them.
>>>
>>
>> For this, is it possible to just configure the ACPI table so we spoof that
>> the LPC slave (IPI0001), is an i2c/spi slave? Could we just add a resource
>> of type ACPI_RESOURCE_TYPE_SERIAL_BUS, and common serial bus type i2c/spi to
>> solve this?
>
> But is the device connected to a I2C or SPI bus? If not, then it does
> not make much sense to declare it as I2C or SPI slave. Instead it should
> be platform device which is the type we use when there is no explicit
> bus specified in ACPI.
>

No, it's not a SPI nor an I2C bus. I actually would say that my idea is 
generally wrong, as the ACPI definition is not a real reflection of the 
bus/slave.

However, Rafael did suggest extending special I2C/SPI handling to them. 
In this case, I don't see how the LPC slave can be identified like an 
I2C or SPI slave is.

Thanks,
John

> .
>

Thread

Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning John Garry <john.garry@huawei.com> - 2017-06-29 18:20 +0200
  Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-30 11:10 +0200
    Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning John Garry <john.garry@huawei.com> - 2017-06-30 11:40 +0200
      Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning "Rafael J. Wysocki" <rafael@kernel.org> - 2017-06-30 15:00 +0200

csiph-web