Re: [PATCH v2 2/2] powerpc/mpic: add global timer support

On 08/13/2012 09:15 PM, Wang Dongsheng-B40534 wrote:

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-----Original Message-----
From: Wood Scott-B07421
Sent: Tuesday, August 14, 2012 10:05 AM
To: Wang Dongsheng-B40534
Cc: Wood Scott-B07421; benh@kernel.crashing.org; paulus@samba.org;
linuxppc-dev@lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472
Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support

On 08/13/2012 09:00 PM, Wang Dongsheng-B40534 wrote:

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-----Original Message-----
From: Wood Scott-B07421
Sent: Tuesday, August 14, 2012 1:37 AM
To: Wang Dongsheng-B40534
Cc: Wood Scott-B07421; benh@kernel.crashing.org; paulus@samba.org;
linuxppc-dev@lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472
Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support

On 08/13/2012 01:18 AM, Wang Dongsheng-B40534 wrote:

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+	p = of_get_property(np, "available-ranges", &len);
+	if (p && len % (2 * sizeof(u32)) != 0) {
+		pr_err("%s: malformed fsl,available-ranges property.\n",
+				np->full_name);
+		return -EINVAL;
+	}

You need to support fsl,available-ranges since that's in an
accepted binding and people could have partitioned setups already

using it.

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[Wang Dongsheng] FSL chip or OPEN-PIC specification(Only a group) in
each group only four timer. This is unified. So i use a generic name.
I think there is not compatible with existing mpic timer nodes.

We need to be compatible with existing trees, so you'd need to check
for both -- but I think any further discussion of the details is
premature until we decide whether this is worthwhile to begin with
(both the support of non-FSL timers, and the creation of a new device
tree binding which will not be implemented by many of the machines
that have non-FSL openpic because they run real Open Firmware).

[Wang Dongsheng]
	p = of_get_property(np, "available-ranges", &len);
	if (!p)
		p = of_get_property(np, "fsl,available-ranges", &len);

	this code be compatible with existing trees.

Yes, that's what I meant by checking both.

I still think we need to discuss why we're doing this first.  What
specific machines are going to have these new openpic timer nodes?

[Wang Dongsheng] It's support to power management awakening. At present, 
the power management more and more important. This way is important to wake
up machine. At least need support power management of machine still needs
such a driver.

I mean specifically for the non-Freescale openpic nodes.

-Scott