On Thu, Feb 13, 2014 at 11:22 PM, Kevin Hao <haokexin@xxxxxxxxx> wrote:
> Currently, of_match_node compares each given match against all node's
> compatible strings with of_device_is_compatible.
>
> To achieve multiple compatible strings per node with ordering from
> specific to generic, this requires given matches to be ordered from
> specific to generic. For most of the drivers this is not true and also
> an alphabetical ordering is more sane there.
>
> Therefore, this patch introduces a function to match each of the node's
> compatible strings against all given compatible matches without type and
> name first, before checking the next compatible string. This implies
> that node's compatibles are ordered from specific to generic while
> given matches can be in any order. If we fail to find such a match
> entry, then fall-back to the old method in order to keep compatibility.
>
> Cc: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
> Signed-off-by: Kevin Hao <haokexin@xxxxxxxxx>
Looks good to me. I'll put this in next for a few days. I'd really
like to see some acks and tested-by's before sending to Linus.
We could be a bit more strict here and fallback to the old matching if
the match table has any entries with name or type. I don't think that
should be necessary though.
Rob
> ---
> drivers/of/base.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index ba195fbce4c6..10b51106c854 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -730,13 +730,49 @@ out:
> }
> EXPORT_SYMBOL(of_find_node_with_property);
>
> +static const struct of_device_id *
> +of_match_compatible(const struct of_device_id *matches,
> + const struct device_node *node)
> +{
> + const char *cp;
> + int cplen, l;
> + const struct of_device_id *m;
> +
> + cp = __of_get_property(node, "compatible", &cplen);
> + while (cp && (cplen > 0)) {
> + m = matches;
> + while (m->name[0] || m->type[0] || m->compatible[0]) {
> + /* Only match for the entries without type and name */
> + if (m->name[0] || m->type[0] ||
> + of_compat_cmp(m->compatible, cp,
> + strlen(m->compatible)))
> + m++;
> + else
> + return m;
> + }
> +
> + /* Get node's next compatible string */
> + l = strlen(cp) + 1;
> + cp += l;
> + cplen -= l;
> + }
> +
> + return NULL;
> +}
> +
> static
> const struct of_device_id *__of_match_node(const struct of_device_id *matches,
> const struct device_node *node)
> {
> + const struct of_device_id *m;
> +
> if (!matches)
> return NULL;
>
> + m = of_match_compatible(matches, node);
> + if (m)
> + return m;
> +
> while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
> int match = 1;
> if (matches->name[0])
> @@ -760,7 +796,12 @@ const struct of_device_id *__of_match_node(const struct of_device_id *matches,
> * @matches: array of of device match structures to search in
> * @node: the of device structure to match against
> *
> - * Low level utility function used by device matching.
> + * Low level utility function used by device matching. We have two ways
> + * of matching:
> + * - Try to find the best compatible match by comparing each compatible
> + * string of device node with all the given matches respectively.
> + * - If the above method failed, then try to match the compatible by using
> + * __of_device_is_compatible() besides the match in type and name.
> */
> const struct of_device_id *of_match_node(const struct of_device_id *matches,
> const struct device_node *node)
> --
> 1.8.5.3
>
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