Re: [PATCH v8 2/4] dt-bindings: mailbox: imx-mu: add generic MU channel support

From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	"A.s. Dong" <aisheng.dong@nxp.com>,
	Devicetree List <devicetree@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>, ",
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	srv_heupstream" <linux-arm-kernel@lists.infradead.org>, ",
	Sascha Hauer" <kernel@pengutronix.de>,
	Fabio Estevam <fabio.estevam@nxp.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>,
	dl-linux-imx <linux-imx@nxp.com>
Subject: Re: [PATCH v8 2/4] dt-bindings: mailbox: imx-mu: add generic MU channel support
Date: Wed, 1 Aug 2018 07:05:30 +0200	[thread overview]
Message-ID: <20180801050530.nzmomvvyo5pfwclz@pengutronix.de> (raw)
In-Reply-To: <CABb+yY1ZusgN4UVxmUgXZS9ObGdLwFAL4XkW7F1yVb6Gq=9XPA@mail.gmail.com>

[-- Attachment #1.1: Type: text/plain, Size: 3576 bytes --]

On Tue, Jul 31, 2018 at 09:28:09PM +0530, Jassi Brar wrote:
> On Tue, Jul 31, 2018 at 7:41 PM, Oleksij Rempel <o.rempel@pengutronix.de> wrote:
> > Each MU has four pairs of rx/tx data register with four rx/tx interrupts
> > which can also be used as a separate channel.
> >
> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > ---
> >  .../devicetree/bindings/mailbox/fsl,mu.txt    | 28 +++++++++++++++++--
> >  1 file changed, 25 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> > index 90e4905dfc69..9efd3a9ade44 100644
> > --- a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> > +++ b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> > @@ -18,11 +18,33 @@ Messaging Unit Device Node:
> >  Required properties:
> >  -------------------
> >  - compatible : should be "fsl,<chip>-mu", the supported chips include
> > -               imx8qxp, imx8qm.
> > +               imx6sx, imx7s, imx8qxp, imx8qm.
> > +               The "fsl,imx6sx-mu" compatible is seen as generic and should
> > +               be included together with SoC specific compatible.
> >  - reg :                Should contain the registers location and length
> >  - interrupts : Interrupt number. The interrupt specifier format depends
> >                 on the interrupt controller parent.
> > -- #mbox-cells:  Must be 0. Number of cells in a mailbox
> > +- #mbox-cells:  Must be 2.
> >
> This seems like modifying the bindings. But since nothing exists yet,
> maybe we should merge patch 1 and 2 ?

For some weeks I already asked to squash this patches.. it was not
ACKed. We can try again... @Rob, @Aisheng, should I merge this two
patches?

> 
> > +                         <&phandle type channel>
> > +                           phandle   : Label name of controller
> > +                           type      : Channel type
> > +                           channel   : Channel number
> > +
> > +               This MU support 4 type of unidirectional channels, each type
> > +               has 4 channels. A total of 16 channels. Following types are
> > +               supported:
> > +               0 - TX channel with 32bit transmit register and IRQ transmit
> > +               acknowledgment support.
> > +               1 - RX channel with 32bit receive register and IRQ support
> > +               2 - TX doorbell channel. Without own register and no ACK support.
> > +               3 - RX doorbell channel.
> >
> Thanks. This is great.
> 
> > +               The doorbell channels should be used with shared memory and protocol
> > +               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.

Ok.

> 
> > +Optional properties:
> > +-------------------
> > +- clocks :     phandle to the input clock.
> > +- fsl,mu-side-b : Should be set for side B MU.
> >
> Nit: can we call this 'fsl,no-init' ?

No. It is HW description and not functionality which is present in
current Linux driver.

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel