[PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[Kendall Willis]

In TI AM62X, AM62A, and AM62P SoCs, the m_can pins can act as a wakeup
source in the deepest low power states. However, the m_can pins are a part
of the MCU domain which is OFF in deeper low power states. Since the m_can
pins continue to be ON even if the MCU domain is turned off, set
out-of-band wakeup for CAN device if `wakeup` pinctrl state exists and
device may wakeup.

Signed-off-by: Kendall Willis <k-willis@ti.com>
---
Tested on CAN IO wakeup from DeepSleep low power mode on AM62P EVM.
---
 drivers/net/can/m_can/m_can.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index eb856547ae7df27a844b236a0c1d4498cbb8b60f..8b277f5e208ffa634439b9ea8495ed56f12cfccb 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -2622,7 +2622,9 @@ int m_can_class_suspend(struct device *dev)
 		cdev->can.state = CAN_STATE_SLEEPING;
 	}
 
-	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
+	if (m_can_class_wakeup_pinctrl_enabled(cdev))
+		device_set_out_band_wakeup(dev);
+	else
 		pinctrl_pm_select_sleep_state(dev);
 
 	return ret;

---
base-commit: af98e93c5c39e6d0b87b42f0a32dd3066f795718
change-id: 20260213-mcan-out-of-band-bae2065f0bf5

Best regards,
-- 
Kendall Willis <k-willis@ti.com>

Re: [PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 862 bytes --]

On 13.02.2026 12:08:19, Kendall Willis wrote:
> In TI AM62X, AM62A, and AM62P SoCs, the m_can pins can act as a wakeup
> source in the deepest low power states. However, the m_can pins are a part
> of the MCU domain which is OFF in deeper low power states. Since the m_can
> pins continue to be ON even if the MCU domain is turned off, set
> out-of-band wakeup for CAN device if `wakeup` pinctrl state exists and
> device may wakeup.
>
> Signed-off-by: Kendall Willis <k-willis@ti.com>

@Markus, can you review the patch?

To both of you: Do we need a fixes tag?

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[Markus Schneider-Pargmann]

[-- Attachment #1: Type: text/plain, Size: 2052 bytes --]

Hi Kendall,

On Fri Feb 13, 2026 at 7:08 PM CET, Kendall Willis wrote:
> In TI AM62X, AM62A, and AM62P SoCs, the m_can pins can act as a wakeup
> source in the deepest low power states. However, the m_can pins are a part
> of the MCU domain which is OFF in deeper low power states. Since the m_can
> pins continue to be ON even if the MCU domain is turned off, set
> out-of-band wakeup for CAN device if `wakeup` pinctrl state exists and
> device may wakeup.

Thank you for your patch.

>
> Signed-off-by: Kendall Willis <k-willis@ti.com>
> ---
> Tested on CAN IO wakeup from DeepSleep low power mode on AM62P EVM.
> ---
>  drivers/net/can/m_can/m_can.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index eb856547ae7df27a844b236a0c1d4498cbb8b60f..8b277f5e208ffa634439b9ea8495ed56f12cfccb 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -2622,7 +2622,9 @@ int m_can_class_suspend(struct device *dev)
>  		cdev->can.state = CAN_STATE_SLEEPING;
>  	}
>  
> -	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
> +	if (m_can_class_wakeup_pinctrl_enabled(cdev))
> +		device_set_out_band_wakeup(dev);

This will set out of band wakeup for every m_can that has a
wakeup-pinctrl set. am62* is currently probably the only platform that
uses the wakeup pinctrl setting but that may change at some point in the
future. Can we narrow down setting the out of band wakeup to the
platforms that support it?

One idea could be to parse the supported system-idle-states from the
list of wakeup-sources and see if deep states are supported that would
require m_can to be off, e.g. mem-deep, off-wake. I think that would be
a clear indicator that out of band wakeups are supported.

For the list of state names you can have a look in the dtschema
repository:
  https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/system-idle-states.yaml

What do you think?

Best
Markus

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 289 bytes --]

Re: [PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[Markus Schneider-Pargmann]

[-- Attachment #1: Type: text/plain, Size: 923 bytes --]

Hi Marc,

On Tue Feb 17, 2026 at 10:08 PM CET, Marc Kleine-Budde wrote:
> On 13.02.2026 12:08:19, Kendall Willis wrote:
>> In TI AM62X, AM62A, and AM62P SoCs, the m_can pins can act as a wakeup
>> source in the deepest low power states. However, the m_can pins are a part
>> of the MCU domain which is OFF in deeper low power states. Since the m_can
>> pins continue to be ON even if the MCU domain is turned off, set
>> out-of-band wakeup for CAN device if `wakeup` pinctrl state exists and
>> device may wakeup.
>>
>> Signed-off-by: Kendall Willis <k-willis@ti.com>
>
> @Markus, can you review the patch?
>
> To both of you: Do we need a fixes tag?

I don't think so. device_out_band_wakeup() was introduced after the
wakeup pinctrl was added to this driver. So I don't think this qualifies
as a fix.

  4acbfb6c116b ("PM: wakeup: Add out-of-band system wakeup support for devices")

Best
Markus

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 289 bytes --]

Re: [PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[Kendall Willis]

Hi Markus,
On 2/18/26 04:51, Markus Schneider-Pargmann wrote:
> Hi Kendall,
> 
> On Fri Feb 13, 2026 at 7:08 PM CET, Kendall Willis wrote:
>> In TI AM62X, AM62A, and AM62P SoCs, the m_can pins can act as a wakeup
>> source in the deepest low power states. However, the m_can pins are a part
>> of the MCU domain which is OFF in deeper low power states. Since the m_can
>> pins continue to be ON even if the MCU domain is turned off, set
>> out-of-band wakeup for CAN device if `wakeup` pinctrl state exists and
>> device may wakeup.
> 
> Thank you for your patch.
> 
>>
>> Signed-off-by: Kendall Willis <k-willis@ti.com>
>> ---
>> Tested on CAN IO wakeup from DeepSleep low power mode on AM62P EVM.
>> ---
>>   drivers/net/can/m_can/m_can.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
>> index eb856547ae7df27a844b236a0c1d4498cbb8b60f..8b277f5e208ffa634439b9ea8495ed56f12cfccb 100644
>> --- a/drivers/net/can/m_can/m_can.c
>> +++ b/drivers/net/can/m_can/m_can.c
>> @@ -2622,7 +2622,9 @@ int m_can_class_suspend(struct device *dev)
>>   		cdev->can.state = CAN_STATE_SLEEPING;
>>   	}
>>   
>> -	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
>> +	if (m_can_class_wakeup_pinctrl_enabled(cdev))
>> +		device_set_out_band_wakeup(dev);
> 
> This will set out of band wakeup for every m_can that has a
> wakeup-pinctrl set. am62* is currently probably the only platform that
> uses the wakeup pinctrl setting but that may change at some point in the
> future. Can we narrow down setting the out of band wakeup to the
> platforms that support it?
> 
> One idea could be to parse the supported system-idle-states from the
> list of wakeup-sources and see if deep states are supported that would
> require m_can to be off, e.g. mem-deep, off-wake. I think that would be
> a clear indicator that out of band wakeups are supported.
> 
> For the list of state names you can have a look in the dtschema
> repository:
>    https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/system-idle-states.yaml
> 
> What do you think?

I agree that we should narrow down setting the out of band wakeup to the 
platform, but I am unsure of parsing the supported system-idle-states as 
the solution. Since we don't know how the power domains in other 
platforms are organized, it would be hard to say that if deeper idle 
states are supported mcan has out of band wakeup logic. It could be the 
whole power domain was designed for the deeper power states.

Additionally, without out of band wakeup for mcan on AM62 devices, mcan 
can only wakeup from mem-mcu-active idle state, and adding out of band 
wakeup allows for wakeup from mem idle state and deeper. Checking for 
mem idle state doesn't seem deep enough to warrant setting out of band 
wakeup for all platforms since some platforms could have mcan in a power 
domain that is ON during the mem idle state.

Another idea would be to add some sort of property to the device tree to 
denote the wakeup source is an out of band wakeup source.

I am good with implementing the idea you suggested, but those were some 
considerations that I was unsure about for the implementation.

Let me know what you think, and thanks for reviewing!

Best,
Kendall

> 
> Best
> Markus

Re: [PATCH] can: m_can: set out-of-band wakeup if wakeup pinctrl exists

[Markus Schneider-Pargmann]

[-- Attachment #1: Type: text/plain, Size: 3421 bytes --]

Hi Kendall,

On Thu Feb 19, 2026 at 9:31 PM CET, Kendall Willis wrote:
> Hi Markus,
> On 2/18/26 04:51, Markus Schneider-Pargmann wrote:
>> Hi Kendall,
>> 
>> On Fri Feb 13, 2026 at 7:08 PM CET, Kendall Willis wrote:
>>> In TI AM62X, AM62A, and AM62P SoCs, the m_can pins can act as a wakeup
>>> source in the deepest low power states. However, the m_can pins are a part
>>> of the MCU domain which is OFF in deeper low power states. Since the m_can
>>> pins continue to be ON even if the MCU domain is turned off, set
>>> out-of-band wakeup for CAN device if `wakeup` pinctrl state exists and
>>> device may wakeup.
>> 
>> Thank you for your patch.
>> 
>>>
>>> Signed-off-by: Kendall Willis <k-willis@ti.com>
>>> ---
>>> Tested on CAN IO wakeup from DeepSleep low power mode on AM62P EVM.
>>> ---
>>>   drivers/net/can/m_can/m_can.c | 4 +++-
>>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
>>> index eb856547ae7df27a844b236a0c1d4498cbb8b60f..8b277f5e208ffa634439b9ea8495ed56f12cfccb 100644
>>> --- a/drivers/net/can/m_can/m_can.c
>>> +++ b/drivers/net/can/m_can/m_can.c
>>> @@ -2622,7 +2622,9 @@ int m_can_class_suspend(struct device *dev)
>>>   		cdev->can.state = CAN_STATE_SLEEPING;
>>>   	}
>>>   
>>> -	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
>>> +	if (m_can_class_wakeup_pinctrl_enabled(cdev))
>>> +		device_set_out_band_wakeup(dev);
>> 
>> This will set out of band wakeup for every m_can that has a
>> wakeup-pinctrl set. am62* is currently probably the only platform that
>> uses the wakeup pinctrl setting but that may change at some point in the
>> future. Can we narrow down setting the out of band wakeup to the
>> platforms that support it?
>> 
>> One idea could be to parse the supported system-idle-states from the
>> list of wakeup-sources and see if deep states are supported that would
>> require m_can to be off, e.g. mem-deep, off-wake. I think that would be
>> a clear indicator that out of band wakeups are supported.
>> 
>> For the list of state names you can have a look in the dtschema
>> repository:
>>    https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/system-idle-states.yaml
>> 
>> What do you think?
>
> I agree that we should narrow down setting the out of band wakeup to the 
> platform, but I am unsure of parsing the supported system-idle-states as 
> the solution. Since we don't know how the power domains in other 
> platforms are organized, it would be hard to say that if deeper idle 
> states are supported mcan has out of band wakeup logic. It could be the 
> whole power domain was designed for the deeper power states.
>
> Additionally, without out of band wakeup for mcan on AM62 devices, mcan 
> can only wakeup from mem-mcu-active idle state, and adding out of band 
> wakeup allows for wakeup from mem idle state and deeper. Checking for 
> mem idle state doesn't seem deep enough to warrant setting out of band 
> wakeup for all platforms since some platforms could have mcan in a power 
> domain that is ON during the mem idle state.
>
> Another idea would be to add some sort of property to the device tree to 
> denote the wakeup source is an out of band wakeup source.

Sure, a generic DT property would be good as well. Do you already have
something in mind?

Best
Markus

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 289 bytes --]