[PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Siddharth Chintamaneni]

Add the MSFT0006 ACPI ID for the DesignWare I2C controller integrated
on Microsoft Cobalt SoCs, along with its 300 MHz input clock description
in acpi_apd.c.

Without an explicit MSFT0006 entry, ACPI device matching falls back to
its _CID (APMC0D0F), which configures a 100 MHz input clock instead of
the controller's actual 300 MHz clock.

Cc: Jarred White <jarredwhite@microsoft.com>
Cc: Jeff Kirsher <jeff.kirsher@microsoft.com>
Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
---
 drivers/acpi/acpi_apd.c                     | 6 ++++++
 drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
index 9fc667d6776c8..a1baa056931c4 100644
--- a/drivers/acpi/acpi_apd.c
+++ b/drivers/acpi/acpi_apd.c
@@ -198,6 +198,11 @@ static const struct apd_device_desc hjmc_i2c_desc = {
 	.fixed_clk_rate = 200 * HZ_PER_MHZ,
 };
 
+static const struct apd_device_desc msft_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 300 * HZ_PER_MHZ,
+};
+
 #endif /* CONFIG_ARM64 */
 
 #endif
@@ -272,6 +277,7 @@ static const struct acpi_device_id acpi_apd_device_ids[] = {
 	{ "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
 	{ "LECA0002", APD_ADDR(leca_spi_desc) },
 	{ "LECA0003", APD_ADDR(leca_i2c_desc) },
+	{ "MSFT0006", APD_ADDR(msft_i2c_desc) },
 	{ "NXP0001", APD_ADDR(nxp_i2c_desc) },
 #endif
 	{ }
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 1da6b0314b6a0..f359d38cc63c7 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -280,6 +280,7 @@ static const struct acpi_device_id dw_i2c_acpi_match[] = {
 	{ .id = "INT3433" },
 	{ .id = "INTC10EF" },
 	{ .id = "LECA0003" },
+	{ .id = "MSFT0006" },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
-- 
2.45.4

Re: [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Andy Shevchenko]

On Wed, Nov 04, 2026 at 11:49:28PM +0000, Siddharth Chintamaneni wrote:
> Add the MSFT0006 ACPI ID for the DesignWare I2C controller integrated
> on Microsoft Cobalt SoCs, along with its 300 MHz input clock description
> in acpi_apd.c.
> 
> Without an explicit MSFT0006 entry, ACPI device matching falls back to
> its _CID (APMC0D0F), which configures a 100 MHz input clock instead of
> the controller's actual 300 MHz clock.

> Cc: Jarred White <jarredwhite@microsoft.com>
> Cc: Jeff Kirsher <jeff.kirsher@microsoft.com>

Move Cc list after the '---' line below. It will reduce the noise in the commit
message and hence Git history.

> Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
> ---

Cc list goes here...

>  drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
>  2 files changed, 7 insertions(+)

Code wise LGTM, I assume MS allocated that HID for the specific device and
we will not see collisions in the future.

-- 
With Best Regards,
Andy Shevchenko

RE: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Jeff Kirsher]

> -----Original Message-----
> From: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
> Sent: Wednesday, November 4, 2026 3:49 PM
> To: Andi Shyti <andi.shyti@kernel.org>; Mika Westerberg
> <mika.westerberg@linux.intel.com>; Rafael J . Wysocki <rafael@kernel.org>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>; Len Brown
> <lenb@kernel.org>; linux-i2c@vger.kernel.org; linux-acpi@vger.kernel.org;
> linux-kernel@vger.kernel.org; Allen Pais <apais@microsoft.com>;
> rlmenge@gmail.com; hargar@linux.microsoft.com; Siddharth Chintamaneni
> <sidchintamaneni@gmail.com>; Jarred White <jarred.white@microsoft.com>;
> Jeff Kirsher <jeff.kirsher@microsoft.com>
> Subject: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006
> for Microsoft Cobalt SoCs
> 
> [You don't often get email from sidchintamaneni@gmail.com. Learn why this is
> important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> Add the MSFT0006 ACPI ID for the DesignWare I2C controller integrated on
> Microsoft Cobalt SoCs, along with its 300 MHz input clock description in
> acpi_apd.c.
> 
> Without an explicit MSFT0006 entry, ACPI device matching falls back to its
> _CID (APMC0D0F), which configures a 100 MHz input clock instead of the
> controller's actual 300 MHz clock.
> 
> Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>

Acked-by: Jeff Kirsher <jeff.kirsher@microsoft.com>

> ---
> Cc: Jarred White <jarredwhite@microsoft.com>
>
>  drivers/acpi/acpi_apd.c                     | 6 ++++++
>  drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c index
> 9fc667d6776c8..a1baa056931c4 100644
> --- a/drivers/acpi/acpi_apd.c
> +++ b/drivers/acpi/acpi_apd.c
> @@ -198,6 +198,11 @@ static const struct apd_device_desc hjmc_i2c_desc =
> {
>         .fixed_clk_rate = 200 * HZ_PER_MHZ,  };
> 
> +static const struct apd_device_desc msft_i2c_desc = {
> +       .setup = acpi_apd_setup,
> +       .fixed_clk_rate = 300 * HZ_PER_MHZ, };
> +
>  #endif /* CONFIG_ARM64 */
> 
>  #endif
> @@ -272,6 +277,7 @@ static const struct acpi_device_id
> acpi_apd_device_ids[] = {
>         { "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
>         { "LECA0002", APD_ADDR(leca_spi_desc) },
>         { "LECA0003", APD_ADDR(leca_i2c_desc) },
> +       { "MSFT0006", APD_ADDR(msft_i2c_desc) },
>         { "NXP0001", APD_ADDR(nxp_i2c_desc) },  #endif
>         { }
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
> b/drivers/i2c/busses/i2c-designware-platdrv.c
> index 1da6b0314b6a0..f359d38cc63c7 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -280,6 +280,7 @@ static const struct acpi_device_id
> dw_i2c_acpi_match[] = {
>         { .id = "INT3433" },
>         { .id = "INTC10EF" },
>         { .id = "LECA0003" },
> +       { .id = "MSFT0006" },
>         { }
>  };
>  MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
> --
> 2.45.4

Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Jarred White]

> [You don't often get email from sidchintamaneni@gmail.com. Learn why 
> this is important at https://aka.ms/LearnAboutSenderIdentification 
> <https://aka.ms/LearnAboutSenderIdentification> ]
> 
> Add the MSFT0006 ACPI ID for the DesignWare I2C controller integrated
> on Microsoft Cobalt SoCs, along with its 300 MHz input clock description
> in acpi_apd.c.
> 
> Without an explicit MSFT0006 entry, ACPI device matching falls back to
> its _CID (APMC0D0F), which configures a 100 MHz input clock instead of
> the controller's actual 300 MHz clock.
> 
> Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>

Acked-by: Jarred White <jarredwhite@linux.microsoft.com>

> ---
 > Cc: Jarred White <jarredwhite@linux.microsoft.com>
 > Cc: Jeff Kirsher <jeff.kirsher@microsoft.com>
 >
>   drivers/acpi/acpi_apd.c                     | 6 ++++++
>   drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
>   2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
> index 9fc667d6776c8..a1baa056931c4 100644
> --- a/drivers/acpi/acpi_apd.c
> +++ b/drivers/acpi/acpi_apd.c
> @@ -198,6 +198,11 @@ static const struct apd_device_desc hjmc_i2c_desc = {
>          .fixed_clk_rate = 200 * HZ_PER_MHZ,
>   };
> 
> +static const struct apd_device_desc msft_i2c_desc = {
> +       .setup = acpi_apd_setup,
> +       .fixed_clk_rate = 300 * HZ_PER_MHZ,
> +};
> +
>   #endif /* CONFIG_ARM64 */
> 
>   #endif
> @@ -272,6 +277,7 @@ static const struct acpi_device_id 
> acpi_apd_device_ids[] = {
>          { "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
>          { "LECA0002", APD_ADDR(leca_spi_desc) },
>          { "LECA0003", APD_ADDR(leca_i2c_desc) },
> +       { "MSFT0006", APD_ADDR(msft_i2c_desc) },
>          { "NXP0001", APD_ADDR(nxp_i2c_desc) },
>   #endif
>          { }
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/ 
> busses/i2c-designware-platdrv.c
> index 1da6b0314b6a0..f359d38cc63c7 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -280,6 +280,7 @@ static const struct acpi_device_id 
> dw_i2c_acpi_match[] = {
>          { .id = "INT3433" },
>          { .id = "INTC10EF" },
>          { .id = "LECA0003" },
> +       { .id = "MSFT0006" },
>          { }
>   };
>   MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
> --
> 2.45.4
> 

Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Siddharth Chintamaneni]

On Thu, 5 Nov 2026 at 13:27, Jarred White
<jarredwhite@linux.microsoft.com> wrote:
>
> > [You don't often get email from sidchintamaneni@gmail.com. Learn why
> > this is important at https://aka.ms/LearnAboutSenderIdentification
> > <https://aka.ms/LearnAboutSenderIdentification> ]
> >
> > Add the MSFT0006 ACPI ID for the DesignWare I2C controller integrated
> > on Microsoft Cobalt SoCs, along with its 300 MHz input clock description
> > in acpi_apd.c.
> >
> > Without an explicit MSFT0006 entry, ACPI device matching falls back to
> > its _CID (APMC0D0F), which configures a 100 MHz input clock instead of
> > the controller's actual 300 MHz clock.
> >
> > Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
>
> Acked-by: Jarred White <jarredwhite@linux.microsoft.com>
>

Thanks!
Do I have to respin the patch?

> > ---
>  > Cc: Jarred White <jarredwhite@linux.microsoft.com>
>  > Cc: Jeff Kirsher <jeff.kirsher@microsoft.com>
>  >
> >   drivers/acpi/acpi_apd.c                     | 6 ++++++
> >   drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
> >   2 files changed, 7 insertions(+)
> >
> > diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
> > index 9fc667d6776c8..a1baa056931c4 100644
> > --- a/drivers/acpi/acpi_apd.c
> > +++ b/drivers/acpi/acpi_apd.c
> > @@ -198,6 +198,11 @@ static const struct apd_device_desc hjmc_i2c_desc = {
> >          .fixed_clk_rate = 200 * HZ_PER_MHZ,
> >   };
> >
> > +static const struct apd_device_desc msft_i2c_desc = {
> > +       .setup = acpi_apd_setup,
> > +       .fixed_clk_rate = 300 * HZ_PER_MHZ,
> > +};
> > +
> >   #endif /* CONFIG_ARM64 */
> >
> >   #endif
> > @@ -272,6 +277,7 @@ static const struct acpi_device_id
> > acpi_apd_device_ids[] = {
> >          { "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
> >          { "LECA0002", APD_ADDR(leca_spi_desc) },
> >          { "LECA0003", APD_ADDR(leca_i2c_desc) },
> > +       { "MSFT0006", APD_ADDR(msft_i2c_desc) },
> >          { "NXP0001", APD_ADDR(nxp_i2c_desc) },
> >   #endif
> >          { }
> > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/
> > busses/i2c-designware-platdrv.c
> > index 1da6b0314b6a0..f359d38cc63c7 100644
> > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > @@ -280,6 +280,7 @@ static const struct acpi_device_id
> > dw_i2c_acpi_match[] = {
> >          { .id = "INT3433" },
> >          { .id = "INTC10EF" },
> >          { .id = "LECA0003" },
> > +       { .id = "MSFT0006" },
> >          { }
> >   };
> >   MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
> > --
> > 2.45.4
> >
>

Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Siddharth Chintamaneni]

On Fri, 6 Nov 2026 at 08:30, Siddharth Chintamaneni
<sidchintamaneni@gmail.com> wrote:
>
> On Thu, 5 Nov 2026 at 13:27, Jarred White
> <jarredwhite@linux.microsoft.com> wrote:
> >
> > > [You don't often get email from sidchintamaneni@gmail.com. Learn why
> > > this is important at https://aka.ms/LearnAboutSenderIdentification
> > > <https://aka.ms/LearnAboutSenderIdentification> ]
> > >
> > > Add the MSFT0006 ACPI ID for the DesignWare I2C controller integrated
> > > on Microsoft Cobalt SoCs, along with its 300 MHz input clock description
> > > in acpi_apd.c.
> > >
> > > Without an explicit MSFT0006 entry, ACPI device matching falls back to
> > > its _CID (APMC0D0F), which configures a 100 MHz input clock instead of
> > > the controller's actual 300 MHz clock.
> > >
> > > Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
> >
> > Acked-by: Jarred White <jarredwhite@linux.microsoft.com>
> >
>
> Thanks!
> Do I have to respin the patch?
>
> > > ---
> >  > Cc: Jarred White <jarredwhite@linux.microsoft.com>
> >  > Cc: Jeff Kirsher <jeff.kirsher@microsoft.com>
> >  >
> > >   drivers/acpi/acpi_apd.c                     | 6 ++++++
> > >   drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
> > >   2 files changed, 7 insertions(+)
> > >
> > > diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
> > > index 9fc667d6776c8..a1baa056931c4 100644
> > > --- a/drivers/acpi/acpi_apd.c
> > > +++ b/drivers/acpi/acpi_apd.c
> > > @@ -198,6 +198,11 @@ static const struct apd_device_desc hjmc_i2c_desc = {
> > >          .fixed_clk_rate = 200 * HZ_PER_MHZ,
> > >   };
> > >
> > > +static const struct apd_device_desc msft_i2c_desc = {
> > > +       .setup = acpi_apd_setup,
> > > +       .fixed_clk_rate = 300 * HZ_PER_MHZ,
> > > +};
> > > +
> > >   #endif /* CONFIG_ARM64 */
> > >
> > >   #endif
> > > @@ -272,6 +277,7 @@ static const struct acpi_device_id
> > > acpi_apd_device_ids[] = {
> > >          { "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
> > >          { "LECA0002", APD_ADDR(leca_spi_desc) },
> > >          { "LECA0003", APD_ADDR(leca_i2c_desc) },
> > > +       { "MSFT0006", APD_ADDR(msft_i2c_desc) },
> > >          { "NXP0001", APD_ADDR(nxp_i2c_desc) },
> > >   #endif
> > >          { }
> > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/
> > > busses/i2c-designware-platdrv.c
> > > index 1da6b0314b6a0..f359d38cc63c7 100644
> > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > @@ -280,6 +280,7 @@ static const struct acpi_device_id
> > > dw_i2c_acpi_match[] = {
> > >          { .id = "INT3433" },
> > >          { .id = "INTC10EF" },
> > >          { .id = "LECA0003" },
> > > +       { .id = "MSFT0006" },
> > >          { }
> > >   };
> > >   MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
> > > --
> > > 2.45.4
> > >
> >

Andy,

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?
Although the frequency is currently constant, it could change in
future hardware revisions that use the same ACPI HID. Would it make
sense to retrieve the frequency from firmware instead of relying on a
fixed value?

Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Wolfram Sang]

> Do I have to respin the patch?

Yes, please.

Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Wolfram Sang]

Hi Siddharth,

> 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.

> Although the frequency is currently constant, it could change in
> future hardware revisions that use the same ACPI HID. Would it make
> sense to retrieve the frequency from firmware instead of relying on a
> fixed value?

Yes, as long at it can be overridden by the driver. I heard of buggy
firmware out there...

Happy hacking,

   Wolfram