On Sun, Jun 17, 2018 at 08:49:47PM +0800, Dong Aisheng wrote:

The Messaging Unit module enables two processors within
the SoC to communicate and coordinate by passing messages
(e.g. data, status and control) through the MU interface.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Fabio Estevam <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree at vger.kernel.org
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
v1->v2:
 * typo fixes
 * remove status property
 * remove imx6&7 compatible string which may be added later for
   the generic mailbox binding

Note: Because MU used by SCU is not implemented as a mailbox driver,
Instead, they're provided in library calls to gain higher performance.

Using a binding doesn't mean you have to use an OS's subsystem.

What needs higher performance? What's the performance difference? Why 
can't the mailbox framework be improved?

Futhermore, SCU MU has only one channel. But the binding doc claims
(Change to allow 0?)
So we did not follow the mailbox binding.

For the generic mailbox driver binding way, it may be added later.

The h/w isn't changing later, so no.

---
 .../devicetree/bindings/arm/freescale/fsl,mu.txt   | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/freescale/fsl,mu.txt