[alsa-devel] Use of of_parse_phandle()/of_node_put()

[Peter Ujfalusi]

On 02/13/2013 05:40 PM, Anil Kumar wrote:
> It looks issue is different here.
> I have done some testing here with patch[1]. In this patch i tried to
> get same "of_device" node pointer
> again and found refcount for this dt node is 1 [Result].
> 
> As of_parse_phandle() says it "returns the device_node pointer with
> refcount incremented".
> But why refcount  value is 1 [Result] again ?

Documentation/kref.txt

> 
> -----------------------------8---------------------
> Patch[1]:-
> diff --git a/sound/soc/omap/omap-twl4030.c b/sound/soc/omap/omap-twl4030.c
> index fd98509..0828a5c 100644
> --- a/sound/soc/omap/omap-twl4030.c
> +++ b/sound/soc/omap/omap-twl4030.c
> @@ -297,6 +297,16 @@ static int omap_twl4030_probe(struct platform_device *pdev)
>                         dev_err(&pdev->dev, "McBSP node is not provided\n");
>                         return -EINVAL;
>                 }
> +               printk(KERN_ERR"refcount 0x%x",
> atomic_read(&dai_node->kref.refcount));
> +
> +               dai_node = of_parse_phandle(node, "ti,mcbsp", 0);
> +                if (!dai_node) {
> +                        dev_err(&pdev->dev, "McBSP node is not provided\n");
> +                        return -EINVAL;
> +                }
> +               printk(KERN_ERR"refcount 0x%x",
> atomic_read(&dai_node->kref.refcount));
> +
> +
>                 omap_twl4030_dai_links[0].cpu_dai_name  = NULL;
>                 omap_twl4030_dai_links[0].cpu_of_node = dai_node;
> 
> [Result]:-
> root at DevKit8000:/# insmod snd-soc-omap-twl4030.ko
> [   95.718109] refcount 0x1
> [   95.720611] refcount 0x1 [   95.818054] omap-twl4030 sound.20:
> twl4030-hifi <-> 49022000.mcbsp mapping ok
> 
> 
> Thanks,
> Anil
> [...]
> 


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