Gentle Reminder, as I wrote in my previous responce, smbus_alert interrupt
refers to an host and not a client. And since we do not have a dedicated
irq for smbus_alert, I propose to add this st, binding to enable the
smbus_alert mechanism.

On Wed, May 13, 2020 at 07:42:31AM +0200, Alain Volmat wrote:

Hello Rob,

On Wed, May 13, 2020 at 02:19:32AM +0000, Rob Herring wrote:

quoted

On Tue, May 05, 2020 at 07:51:10AM +0200, Alain Volmat wrote:

quoted

Add a new binding of the i2c-stm32f7 driver to enable the handling
of the SMBUS-Alert

Signed-off-by: Alain Volmat <redacted>
---
 Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
index b50a2f420b36..04c0882c3661 100644
--- a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml

@@ -36,6 +36,10 @@ allOf:
                 minItems: 3
                 maxItems: 3
 
+        st,smbus-alert:
+          description: Enable the SMBus Alert feature
+          $ref: /schemas/types.yaml#/definitions/flag
+

We already have smbus_alert interrupt. Can't you just check for this in 
the slave nodes and enable if found?

My understanding reading the code (smbalert_probe within i2c-smbus.c, of_i2c_setup_smbus_alert called when
registering an adapter within i2c-core-smbus.c) is that smbus_alert refers to an interrupt on the
adapter side. That is an interrupt that would be triggered when the adapter is receiving an smbus_alert
message.
In our case (stm32f7), we do not have specific interrupt for that purpose. The interrupt triggered when
an SMBUS Alert is received (by the adapter) is the same interrupt as for other reasons and we check
within the irq handler within stm32f7 the reason before calling i2c_handle_smbus_alert if the status
register indicated an SMBUS Alert.
So my understanding is that we cannot rely on the mechanism of naming an interrupt smbus_alert.
Did I misunderstood something ?

quoted

quoted

   - if:
       properties:
         compatible:
-- 
2.17.1

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