Re: [PATCH 01/10] dt/bindings: Add binding for BCM2835 mailbox driver

Stephen Warren [off-list ref] writes:

On 03/03/2015 12:28 PM, Eric Anholt wrote:

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Lee Jones [off-list ref] writes:

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On Mon, 02 Mar 2015, Eric Anholt wrote:

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From: Lubomir Rintel <redacted>

v2: Split into a separate patch for submitting to the 
devicetree list.

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---

Generally, the changelog should go below the --- since most people
don't want to see the changelog committed into the source.

Huh.  I'm coming from drivers/gpu/drm/ (and non-kernel communities)
where people are expected to keep changelog in the commit message.  I'll
strip it out of this series.

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.../devicetree/bindings/mailbox/brcm,bcm2835-mbox.txt | 19 
+++++++++++++++++++ 1 file changed, 19 insertions(+) create 
mode 100644 
Documentation/devicetree/bindings/mailbox/brcm,bcm2835-mbox.txt

diff --git
a/Documentation/devicetree/bindings/mailbox/brcm,bcm2835-mbox.txt
b/Documentation/devicetree/bindings/mailbox/brcm,bcm2835-mbox.txt

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new file mode 100644 index 0000000..f5741a0 --- /dev/null +++ 
b/Documentation/devicetree/bindings/mailbox/brcm,bcm2835-mbox.txt

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Rename these files to conform to the current naming convention.  In

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-next we currently have 'altera-mailbox.txt' and 
'omap-mailbox.txt', so 'bcm2835-mbox.txt' seems appropriate.

Will do.

I believe all the current bcm2835 bindings use the compatible value as
the filename. I personally prefer this to picking a different "random"
name for the filenames. It means you only have to name the thing once,
and then use the same value for the compatible property and binding
document.

"git grep brcm | grep 2835" thinks that we're quite confused on whether
you put the "brcm," in the filename or not.  And then there's some that
don't follow either convention:

watchdog/brcm,bcm2835-pm-wdog.txt:	compatible = "brcm,bcm2835-pm-wdt";
pwm/pwm-bcm2835.txt:	compatible = "brcm,bcm2835-pwm";
rng/brcm,bcm2835.txt:        compatible = "brcm,bcm2835-rng";

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+Example: + +mailbox: mailbox@7e00b800 { +	compatible = 
"brcm,bcm2835-mbox"; +	reg = <0x7e00b880 0x40>; +	interrupts = 
<0 1>; +	#mbox-cells = <1>; +};

It would be good to see the client examples here as well.
Please consider pulling in brcm,bcm2835-mbox-power.txt and 
brcm,bcm2835-mbox-property.txt.

Oh, so have those two just smashed into this file as one set of 
documentation for everything to do with mailbox on bcm2835?  That 
seems good to me.  When I was adding the client drivers, the fact 
that the other brcm file was named after the compatible string
made me generate new files under then new compatible strings, but
the other drivers already in the tree obviously aren't formatted
that way.

The HW mailbox seems like a different process to the upper-layer
protocols/message formats running over the top of it. Sure right now
the Pi has a single firmware, but do all bcm2835-based devices share
the same firmware? Is so, we'd be warranted in lumping the HW and
firmware protocol together, but I rather wonder whether e.g. the
bcm2835-based Roku uses the same firmware protocol?

I don't know the answer to that one, and I've only got RPi firmware
myself.

Ultimately, my hope is to get enough merged that we can basically get
off the firmware, other than the bits of clock management that are only
doable from the VPU.