Re: [PATCH 1/4] dt-binding: irq: imx-irqsteer: use irq number per channel instead of group number

From: Marc Zyngier <marc.zyngier@arm.com>
To: Aisheng Dong <aisheng.dong@nxp.com>,
	Lucas Stach <l.stach@pengutronix.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	dl-linux-imx <linux-imx@nxp.com>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>
Subject: Re: [PATCH 1/4] dt-binding: irq: imx-irqsteer: use irq number per channel instead of group number
Date: Fri, 18 Jan 2019 10:12:22 +0000	[thread overview]
Message-ID: <ef6eb38d-8e74-a55d-6d78-516d81fa957f@arm.com> (raw)
In-Reply-To: <AM0PR04MB42114D5B25B23C0D7FFF95BA809C0@AM0PR04MB4211.eurprd04.prod.outlook.com>

On 18/01/2019 09:46, Aisheng Dong wrote:
>> From: Marc Zyngier [mailto:marc.zyngier@arm.com]
>> Sent: Friday, January 18, 2019 5:39 PM
>> On 18/01/2019 08:48, Lucas Stach wrote:
>>> Am Freitag, den 18.01.2019, 07:53 +0000 schrieb Aisheng Dong:
>>>> Not all 64 interrupts may be used in one group. e.g. most irqsteer in
>>>> imx8qxp and imx8qm subsystems supports only 32 interrupts.
>>>>
>>>> As the IP integration parameters are Channel number and interrupts
>>>> number, let's use fsl,irqs-per-chan to represents how many interrupts
>>>> supported by this irqsteer channel.
>>>
>>> Sorry, but total NACK. I've got to great lengths with dumping the
>>> actually implemented register layout on i.MX8M and AFAICS the IRQs are
>>> always managed in groups of 64 IRQs, even if less than that are
>>> connected as input IRQs. This is what the actually present register
>>> set on i.MX8M tells us.
>>
>> Also, I'd really like the DT bindings not to change at every release. So whatever
>> change (if any) has to be done for this driver to support existing HW, please
>> make sure that the DT bindings are kept as stable as possible.
>>
> 
> Sorry I should clarify it a bit.
> There's still no users in Devicetree.
> So I guess we can update it, right? Or not?

What do you mean by no users? This driver is in 5.0, and I assume people
are using it one way or another. Not having a platform in the kernel
tree is pretty much irrelevant, as the kernel tree is not a canonical
repository of existing platforms.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...