[PATCH 2/2] drm/rockchip: Convert the probe function to the generic drm_of_component_probe()
Russell King - ARM Linux
linux at arm.linux.org.uk
Mon Nov 16 08:30:16 PST 2015
I've tweaked your patch to make the above (buggy) change a little clearer.
On Mon, Nov 16, 2015 at 02:44:53PM +0000, Liviu Dudau wrote:
> - for (i = 0;; i++) {
> - port = of_parse_phandle(np, "ports", i);
> - if (!port)
> - break;
> -
> - if (!of_device_is_available(port->parent)) {
> - of_node_put(port);
> - continue;
> - }
>
> - component_match_add(dev, &match, compare_of, port->parent);
> - of_node_put(port);
> - }
> -static int compare_of(struct device *dev, void *data)
> -{
> - struct device_node *np = data;
> -
> - return dev->of_node == np;
> -}
The original above passes port->parent to component_match_add(). This
means 'np' in the above compare_of() function is 'port->parent'.
This means the above comparison is effectively:
dev->of_node == port->parent
The generic code instead does this:
component_match_add(dev, &match, compare_of, port);
So what we get in the comparison function is 'port' rather than
'port->parent':
> +static int compare_port(struct device *dev, void *data)
> {
> + struct device_node *np = data;
> + return dev->parent->of_node == np;
> +}
which means the comparison is:
dev->parent->of_node == port
which is a different comparison from the above.
You instead want this to be:
return dev->of_node == np->parent;
Heiko, please test the above change to compare_port() - I think you'll
find that will fix your issue.
Thanks.
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