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

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

quoted

-----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:

quoted

quoted

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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.

[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?

-Scott