-----Original Message-----
From: Jassi Brar [mailto:jassisinghbrar at gmail.com]
Sent: Wednesday, August 1, 2018 5:58 PM
To: A.s. Dong <aisheng.dong@nxp.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>; Shawn Guo
[off-list ref]; Fabio Estevam [off-list ref]; Rob
Herring [off-list ref]; Mark Rutland [off-list ref];
Vladimir Zapolskiy [off-list ref]; , Sascha Hauer
[off-list ref]; , linux-arm-kernel at lists.infradead.org, linux-
mediatek at lists.infradead.org, srv_heupstream <linux-arm-
kernel at lists.infradead.org>; Devicetree List [off-list ref];
dl-linux-imx [off-list ref]
Subject: Re: [PATCH v8 2/4] dt-bindings: mailbox: imx-mu: add generic MU
channel support

On Wed, Aug 1, 2018 at 2:28 PM, A.s. Dong [off-list ref] wrote:

quoted

Hi Jassi,

quoted

quoted

+               The doorbell channels should be used with shared
+ memory and

protocol

quoted

+               level acknowledgment if needed.
+

I would avoid this. People might get notions that they have to use
shmem with doorbell -- a trivial protocol might mean doing some fixed
action (like
reset) whenever the doorbell rings.

That's right.
i.MX8 using the general purpose interrupt for peripherals. No shmem

needed.

quoted

e.g. RTC, Watchdog and ON/OFF interrupt.

BTW, this means the peripheral will use mailbox doorbell channels to
handle Interrupts. Is there such user case in kernel we can refer to?

I don't find any publicly in kernel.
It should be simple though. Acquire the RX channel, and populate the
rx_callback() with the "interrupt" handler.

Got it.
Thanks

Regards
Dong Aisheng