In certain projects, the main system regulator, composed of simple
components including an under-voltage detector and capacitors, can be
aptly described as a fixed regulator in the device tree. To cater to
such use cases, this patch extends the fixed regulator binding to
support the 'system-critical-regulator' property. This property
signifies that the fixed-regulator is vital for system stability.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 .../devicetree/bindings/regulator/fixed-regulator.yaml          | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
index ce7751b9129c..9ff9abf2691a 100644
--- a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
+++ b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
@@ -105,6 +105,8 @@ properties:
     description:
       Interrupt signaling a critical under-voltage event.
 
+  system-critical-regulator: true
+
 required:
   - compatible
   - regulator-name
-- 
2.39.2

On Thu, 26 Oct 2023 16:48:22 +0200, Oleksij Rempel wrote:
> In certain projects, the main system regulator, composed of simple
> components including an under-voltage detector and capacitors, can be
> aptly described as a fixed regulator in the device tree. To cater to
> such use cases, this patch extends the fixed regulator binding to
> support the 'system-critical-regulator' property. This property
> signifies that the fixed-regulator is vital for system stability.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  .../devicetree/bindings/regulator/fixed-regulator.yaml          | 2 ++
>  1 file changed, 2 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>

On Thu, Oct 26, 2023 at 04:48:22PM +0200, Oleksij Rempel wrote:
> In certain projects, the main system regulator, composed of simple
> components including an under-voltage detector and capacitors, can be
> aptly described as a fixed regulator in the device tree. To cater to
> such use cases, this patch extends the fixed regulator binding to
> support the 'system-critical-regulator' property. This property
> signifies that the fixed-regulator is vital for system stability.

There is no programming interface for fixed-regulators, so how do you 
know an under/over voltage condition?

> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  .../devicetree/bindings/regulator/fixed-regulator.yaml          | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
> index ce7751b9129c..9ff9abf2691a 100644
> --- a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
> +++ b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
> @@ -105,6 +105,8 @@ properties:
>      description:
>        Interrupt signaling a critical under-voltage event.
>  
> +  system-critical-regulator: true
> +
>  required:
>    - compatible
>    - regulator-name
> -- 
> 2.39.2
>

On Fri, Oct 27, 2023 at 04:24:40PM -0500, Rob Herring wrote:
> On Thu, Oct 26, 2023 at 04:48:22PM +0200, Oleksij Rempel wrote:

> > In certain projects, the main system regulator, composed of simple
> > components including an under-voltage detector and capacitors, can be
> > aptly described as a fixed regulator in the device tree. To cater to
> > such use cases, this patch extends the fixed regulator binding to
> > support the 'system-critical-regulator' property. This property
> > signifies that the fixed-regulator is vital for system stability.

> There is no programming interface for fixed-regulators, so how do you 
> know an under/over voltage condition?

There's support for interrupts now - it's a just a simple signal so if
the interrupt is asserted you know there's an error but that's all you
know.