[PATCH v2 09/11] of: property: Simplify of_link_to_phandle()

Saravana Kannan
2023-01-27T00:13:10Z

The driver core now:
- Has the parent device of a supplier pick up the consumers if the
supplier never has a device created for it.
- Ignores a supplier if the supplier has no parent device and will never
be probed by a driver

And already prevents creating a device link with the consumer as a
supplier of a parent.

So, we no longer need to find the "compatible" node of the supplier or
do any other checks in of_link_to_phandle(). We simply need to make sure
that the supplier is available in DT.

Signed-off-by: Saravana Kannan <saravanak@google.com>
---
drivers/of/property.c | 84 +++++++------------------------------------
1 file changed, 13 insertions(+), 71 deletions(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 134cfc980b70..c651aad6f34b 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1062,20 +1062,6 @@ of_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
return of_device_get_match_data(dev);
}

-static bool of_is_ancestor_of(struct device_node *test_ancestor,
- struct device_node *child)
-{
- of_node_get(child);
- while (child) {
- if (child == test_ancestor) {
- of_node_put(child);
- return true;
- }
- child = of_get_next_parent(child);
- }
- return false;
-}
-
static struct device_node *of_get_compat_node(struct device_node *np)
{
of_node_get(np);
@@ -1106,71 +1092,27 @@ static struct device_node *of_get_compat_node_parent(struct device_node *np)
return node;
}

-/**
- * of_link_to_phandle - Add fwnode link to supplier from supplier phandle
- * @con_np: consumer device tree node
- * @sup_np: supplier device tree node
- *
- * Given a phandle to a supplier device tree node (@sup_np), this function
- * finds the device that owns the supplier device tree node and creates a
- * device link from @dev consumer device to the supplier device. This function
- * doesn't create device links for invalid scenarios such as trying to create a
- * link with a parent device as the consumer of its child device. In such
- * cases, it returns an error.
- *
- * Returns:
- * - 0 if fwnode link successfully created to supplier
- * - -EINVAL if the supplier link is invalid and should not be created
- * - -ENODEV if struct device will never be create for supplier
- */
-static int of_link_to_phandle(struct device_node *con_np,
+static void of_link_to_phandle(struct device_node *con_np,
struct device_node *sup_np)
{
- struct device *sup_dev;
- struct device_node *tmp_np = sup_np;
+ struct device_node *tmp_np = of_node_get(sup_np);

- /*
- * Find the device node that contains the supplier phandle. It may be
- * @sup_np or it may be an ancestor of @sup_np.
- */
- sup_np = of_get_compat_node(sup_np);
- if (!sup_np) {
- pr_debug("Not linking %pOFP to %pOFP - No device\n",
- con_np, tmp_np);
- return -ENODEV;
- }
+ /* Check that sup_np and its ancestors are available. */
+ while (tmp_np) {
+ if (of_fwnode_handle(tmp_np)->dev) {
+ of_node_put(tmp_np);
+ break;
+ }

- /*
- * Don't allow linking a device node as a consumer of one of its
- * descendant nodes. By definition, a child node can't be a functional
- * dependency for the parent node.
- */
- if (of_is_ancestor_of(con_np, sup_np)) {
- pr_debug("Not linking %pOFP to %pOFP - is descendant\n",
- con_np, sup_np);
- of_node_put(sup_np);
- return -EINVAL;
- }
+ if (!of_device_is_available(tmp_np)) {
+ of_node_put(tmp_np);
+ return;
+ }

- /*
- * Don't create links to "early devices" that won't have struct devices
- * created for them.
- */
- sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
- if (!sup_dev &&
- (of_node_check_flag(sup_np, OF_POPULATED) ||
- sup_np->fwnode.flags & FWNODE_FLAG_NOT_DEVICE)) {
- pr_debug("Not linking %pOFP to %pOFP - No struct device\n",
- con_np, sup_np);
- of_node_put(sup_np);
- return -ENODEV;
+ tmp_np = of_get_next_parent(tmp_np);
}
- put_device(sup_dev);

fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));
- of_node_put(sup_np);
-
- return 0;
}

/**
--
2.39.1.456.gfc5497dd1b-goog