Re: [PATCH v2 3/4] dt-bindings: i2c-stm32: add SMBus Alert bindings

From: Wolfram Sang
Date: Tue Jun 30 2020 - 15:41:20 EST


On Thu, Jun 25, 2020 at 09:39:28AM +0200, Alain Volmat wrote:
> Add a new binding of the i2c-stm32f7 driver to enable the handling
> of the SMBUS-Alert.
>
> The I2C/SMBUS framework already provides a mechanism to enable SMBus-Alert
> by naming an IRQ line "smbus_alert". However, on stm32, the SMBus-Alert is
> part of the i2c IRQ. Using the smbus_alert naming here would lead to having
> 2 handlers (the handler of the driver and the smbus_alert handler
> from I2C/SMBUS framework) on the unique i2c IRQ of the stm32. Meaning that
> the smbus_alert handler would get called for all IRQ generated by the stm32
> I2C controller.
>
> For that reason, the smbus_alert IRQ naming cannot be used and a dedicated
> binding is introduced.

What if we update the core to not register another irq handler if the
"smbus_alert" and main irq are the same?

I think it could work. However, while trying to make a proof-of-concept,
I found that irq descriptions in the generic i2c binding document are
probably mixed up. And before fixing that, I'd like to get HostNotify
done first.

Makes sense?

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