Re: [PATCH 0/1] Compact interface for Device-Tree

From: Rafael J. Wysocki
Date: Fri Oct 31 2014 - 18:33:09 EST


On Saturday, November 01, 2014 05:13:45 AM Rob Herring wrote:
> On Fri, Oct 31, 2014 at 6:59 AM, Gilad Avidov <gavidov@xxxxxxxxxxxxxx> wrote:
> >
> > Device-Tree compact API
> > ------------------------
> >
> > Common code seen in driverâs probe reads device tree values and handling
> > erroneous return codes from all those of_property_read_xxx() APIs. This
> > common code is factored out by the of_property_map module which allows
> > driverâs probe to replace that (often lengthy) code with a concise table:
> >
> > struct of_prop_map map[] = {
> > {"i2c", &dev->id, OF_REQ, OF_ID, -1},
> > {"qcom,clk-freq-out", &dev->clk_freq_out, OF_REQ, OF_U32, 0},
> > {"qcom,clk-freq-in", &dev->clk_freq_in, OF_REQ, OF_U32, 0},
> > {"qcom,disable-dma", &dev->disable_dma, OF_OPT, OF_BOOL, 0},
> > {"qcom,master-id", &dev->mstr_id, OF_SGST, OF_U32, 0},
> > {NULL, NULL, 0, 0, 0},
> > };
> >
> > Then call populate to read the values into the deviceâs variables:
> >
> > ret = of_prop_populate(dev, dev->of_node, map);
>
> Interesting idea. The main concern I have with this is there has been
> on-going discussions about how to generalize property handling across
> DT and ACPI to make drivers more agnostic, so I'm copying a few folks
> involved in that. That may be a bit orthogonal to what this is doing,
> but we may want some coordination here.

Agreed.

We actually have a patchset adding a unified device property API in linux-next (http://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/log/?h=device-properties)
and I'd prefer to see the "compactization" to happen at that level, if possible,
rather that for of_ only.

Rafael

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