Re: [PATCH 02/12] dt-bindings: interrupt-controller: stm32-exti: Add irq nexus child node

From: Rob Herring <robh@kernel.org>
To: Antonio Borneo <antonio.borneo@foss.st.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org,
	Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Subject: Re: [PATCH 02/12] dt-bindings: interrupt-controller: stm32-exti: Add irq nexus child node
Date: Thu, 22 Feb 2024 16:43:00 -0700	[thread overview]
Message-ID: <20240222234300.GA3809915-robh@kernel.org> (raw)
In-Reply-To: <20240216094758.916722-3-antonio.borneo@foss.st.com>

On Fri, Feb 16, 2024 at 10:47:47AM +0100, Antonio Borneo wrote:
> The mapping of EXTI interrupts to its parent interrupt controller
> is both SoC and instance dependent.
> The current implementation requires adding a new table to the
> driver's code and a new compatible for each new EXTI instance.
> 
> Add to the binding an interrupt nexus child node that will be
> used on the new EXTI instances and can be optionally used on the
> existing instances.
> The property 'interrupt-map' in the nexus node maps each EXTI
> interrupt to the parent interrupt.
> Align #address-cells and #interrupt-cells between the EXTI node
> and its nexus node.

Looks like an abuse of interrupt-map. You avoid adding yourself to the 
abuser list by putting it in a child node. Clever. (See list in 
drivers/of/irq.c if you don't know what I'm talking about)

I assume the EXTI has 0..N interrupts. Just define 'interrupts' with N 
entries with each entry mapping EXTI interrupt N to 'interrupts' entry 
N.

Rob

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