Re: [PATCH v2 1/5] dt-bindings: interrupt-controller: Update STM32 EXTI interrupt controller

On Fri, 17 Dec 2021 13:39:11 +0000,
Alexandre TORGUE [off-list ref] wrote:

On 12/16/21 9:15 PM, Rob Herring wrote:

quoted

On Wed, Dec 15, 2021 at 11:58:43AM +0100, Alexandre Torgue wrote:

quoted

Document new entry "st,exti-mapping" which links EXTI lines with GIC
interrupt lines and add an include file to define EXTI interrupt type.

Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

diff --git a/Documentation/devicetree/bindings/interrupt-controller/st,stm32-exti.yaml b/Documentation/devicetree/bindings/interrupt-controller/st,stm32-exti.yaml
index d19c881b4abc..e08bb51e97a8 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/st,stm32-exti.yaml
+++ b/Documentation/devicetree/bindings/interrupt-controller/st,stm32-exti.yaml

@@ -41,6 +41,17 @@ properties:
      description:
        Interrupts references to primary interrupt controller
  +  st,exti-mapping:
+    $ref: "/schemas/types.yaml#/definitions/uint32-matrix"
+    description: |
+            Define mapping between EXTI lines and GIC irq lines. Should be:
+            st,exti-mapping = <EXTI_LINE GIC_IRQ EXTI_TYPE>, ...;
+            With:
+            - EXTI_LINE: EXTI line number.
+            - GIC_IRQ: GIC IRQ associated to the EXTI line.
+            - EXTI_TYPE: STM32_EXTI_TYPE_CONFIGURABLE or STM32_EXTI_TYPE_DIRECT.
+              Defined in include/dt-bindings/interrupt-controller/stm32-exti.h

No custom properties for this. See[1][2][3].

Thanks for inputs. In my case the mapping consists to map an EXTI line
with a GIC irq line which could be done using interrupt-map (avoiding
to parse it in my driver).

The problem is that 'interrupt-map' defines an interrupt mapping
between an input and an output, and that mentioning the GIC in such a
table will only result in your EXTI to be bypassed.

'interrupt-map' really is a dispatch table for targeting an interrupt
controller (or multiple controllers, even), but really isn't the
correct tool to carry configuration informations to an interrupt
controller driver.

But for each EXTI/GIC association I would
like also to describe the EXTI_TYPE (which actually describe the well
irqchip to use inside my exti driver) . This property is not generic
and so I assume I can't use a generic binding such "interrupt-map".

If the solution consists to use a common binding (i.e. interrupt-map)
plus a conversion table in exti driver to affect the well irq_chip to
the well EXTI line then we could envisage to keep the whole mapping
inside the driver (even if it's not the best solution).

A possible solution would be to have:

- A set of standard 'interrupts' properties describing the output
signals

- A set of properties describing the input to output mapping (if
relevant) and additional configuration information that for the
interrupt controller driver.

	M.

-- 
Without deviation from the norm, progress is not possible.

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