On Tue, Jul 28, 2015 at 8:19 AM, Tomeu Vizoso
<tomeu.vizoso@xxxxxxxxxxxxx> wrote:
> From an arbitrary node in the tree, find the enclosing node that
> corresponds to a platform device, as registered by
> of_platform_populate().
>
> This can be used to find out what device needs to be probed so the
> dependency described by a given node is made available.
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
> ---
>
> Changes in v2:
> - Move the logic for finding a platform device from its firmware node to
> of/platform.c as it's not needed for ACPI nodes.
>
> drivers/of/platform.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_platform.h | 1 +
> 2 files changed, 61 insertions(+)
>
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index ff27494cda8c..89c5cd513027 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -501,6 +501,66 @@ void of_platform_depopulate(struct device *parent)
> }
> EXPORT_SYMBOL_GPL(of_platform_depopulate);
>
> +static bool of_is_platform(struct device_node *np)
> +{
> + int count;
> +
> + count = of_property_count_strings(np, "compatible");
> +
> + /* The node has to have a compatible string */
> + if (!count)
> + return false;
> +
> + /* But it cannot be just a simple memory-mapped bus */
> + if (count == 1 && of_match_node(of_default_bus_match_table, np))
> + return false;
> +
> + /* But AMBA devices aren't platform devices */
> + if (of_device_is_compatible(np, "arm,primecell"))
> + return false;
> +
> + /* Node is immediately below root */
> + if (!np->parent || !np->parent->parent)
> + return true;
> +
> + /* If it's a node in a simple memory-mapped bus */
> + if (of_match_node(of_default_bus_match_table, np->parent))
> + return true;
This seems really fragile. What about platform devices which are
children of MFDs but are not "simple-mfd"?
Does of_find_device_by_node not work for you? That is probably not the
most efficient search, but we could fix that. We could add struct
device ptr to struct device_node and check without searching for
example.
Rob
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