From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Siddharth Chintamaneni <sidchintamaneni@gmail.com>,
Jarred White <jarredwhite@linux.microsoft.com>,
Andi Shyti <andi.shyti@kernel.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Allen Pais <apais@microsoft.com>,
"rlmenge@gmail.com" <rlmenge@gmail.com>,
"hargar@linux.microsoft.com" <hargar@linux.microsoft.com>,
Jeff Kirsher <jeff.kirsher@microsoft.com>
Subject: Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs
Date: Mon, 9 Nov 2026 14:34:28 +0200 [thread overview]
Message-ID: <avG91GDyffzeuBVg@ashevche-desk.local> (raw)
In-Reply-To: <avBSrChTZTQL2rNj@shikoro>
On Sun, Nov 08, 2026 at 11:45:00AM +0100, Wolfram Sang wrote:
>
> > For Cobalt, the firmware exposes the designware input clock frequency
> > through the ACPI HCLK object.
> > Is there an existing way to retrieve or configure this clock frequency
> > through the ACPI tables, rather than hardcoding it in the driver?
>
> Calling for Andy here for being the designware + ACPI expert.
We don't have the common way, it's unspecified. However, many drivers and some
firmwares adopted the "clock-frequency" property. Unfortunately for I2C it means
the clock of the bus, and not functional clock of the controller. So, I'm
afraid you will need to have your own custom solution. Also makes sense to look
what ARM people do in the same situtions (I know that Qualcomm tries hard to
enable ACPI on laptops, if I was you, I would ask them first).
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-11-09 12:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-04 23:49 Siddharth Chintamaneni
2026-11-05 10:03 ` Andy Shevchenko
2026-11-05 18:03 ` [EXTERNAL] " Jeff Kirsher
[not found] ` <DS1PR21MB4279C556CFB876C5562C7F1182772@DS1PR21MB4279.namprd21.prod.outlook.com>
2026-11-05 21:27 ` Jarred White
2026-11-06 16:30 ` Siddharth Chintamaneni
2026-11-07 0:44 ` Siddharth Chintamaneni
2026-11-08 10:45 ` Wolfram Sang
2026-11-09 12:34 ` Andy Shevchenko [this message]
2026-11-08 10:41 ` Wolfram Sang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=avG91GDyffzeuBVg@ashevche-desk.local \
--to=andriy.shevchenko@linux.intel.com \
--cc=andi.shyti@kernel.org \
--cc=apais@microsoft.com \
--cc=hargar@linux.microsoft.com \
--cc=jarredwhite@linux.microsoft.com \
--cc=jeff.kirsher@microsoft.com \
--cc=lenb@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mika.westerberg@linux.intel.com \
--cc=rafael@kernel.org \
--cc=rlmenge@gmail.com \
--cc=sidchintamaneni@gmail.com \
--cc=wsa+renesas@sang-engineering.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®