v4l2_fwnode_reference_parse_int_prop() will find an fwnode such that under
the device's own fwnode, it will follow child fwnodes with the given
property-value pair and return the resulting fwnode.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-fwnode.c | 201 ++++++++++++++++++++++++++++++++++
1 file changed, 201 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index f739dfd16cf7..f93049c361e4 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -578,6 +578,207 @@ static int v4l2_fwnode_reference_parse(
return ret;
}
+/*
+ * v4l2_fwnode_reference_get_int_prop - parse a reference with integer
+ * arguments
+ * @dev: struct device pointer
+ * @notifier: notifier for @dev
+ * @prop: the name of the property
+ * @index: the index of the reference to get
+ * @props: the array of integer property names
+ * @nprops: the number of integer property names in @nprops
+ *
+ * Find fwnodes referred to by a property @prop, then under that
+ * iteratively, @nprops times, follow each child node which has a
+ * property in @props array at a given child index the value of which
+ * matches the integer argument at an index.
+ *
+ * For example, if this function was called with arguments and values
+ * @dev corresponding to device "SEN", @prop == "flash-leds", @index
+ * == 1, @props == { "led" }, @nprops == 1, with the ASL snippet below
+ * it would return the node marked with THISONE. The @dev argument in
+ * the ASL below.
+ *
+ * Device (LED)
+ * {
+ * Name (_DSD, Package () {
+ * ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+ * Package () {
+ * Package () { "led0", "LED0" },
+ * Package () { "led1", "LED1" },
+ * }
+ * })
+ * Name (LED0, Package () {
+ * ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ * Package () {
+ * Package () { "led", 0 },
+ * }
+ * })
+ * Name (LED1, Package () {
+ * // THISONE
+ * ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ * Package () {
+ * Package () { "led", 1 },
+ * }
+ * })
+ * }
+ *
+ * Device (SEN)
+ * {
+ * Name (_DSD, Package () {
+ * ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ * Package () {
+ * Package () {
+ * "flash-leds",
+ * Package () { ^LED, 0, ^LED, 1 },
+ * }
+ * }
+ * })
+ * }
+ *
+ * where
+ *
+ * LED LED driver device
+ * LED0 First LED
+ * LED1 Second LED
+ * SEN Camera sensor device (or another device the LED is
+ * related to)
+ *
+ * Return: 0 on success
+ * -ENOENT if no entries (or the property itself) were found
+ * -EINVAL if property parsing otherwise failed
+ * -ENOMEM if memory allocation failed
+ */
+static struct fwnode_handle *v4l2_fwnode_reference_get_int_prop(
+ struct fwnode_handle *fwnode, const char *prop, unsigned int index,
+ const char **props, unsigned int nprops)
+{
+ struct fwnode_reference_args fwnode_args;
+ unsigned int *args = fwnode_args.args;
+ struct fwnode_handle *child;
+ int ret;
+
+ /*
+ * Obtain remote fwnode as well as the integer arguments.
+ *
+ * Note that right now both -ENODATA and -ENOENT may signal
+ * out-of-bounds access. Return -ENOENT in that case.
+ */
+ ret = fwnode_property_get_reference_args(fwnode, prop, NULL, nprops,
+ index, &fwnode_args);
+ if (ret)
+ return ERR_PTR(ret == -ENODATA ? -ENOENT : ret);
+
+ /*
+ * Find a node in the tree under the referred fwnode corresponding the
+ * integer arguments.
+ */
+ fwnode = fwnode_args.fwnode;
+ while (nprops--) {
+ u32 val;
+
+ /* Loop over all child nodes under fwnode. */
+ fwnode_for_each_child_node(fwnode, child) {
+ if (fwnode_property_read_u32(child, *props, &val))
+ continue;
+
+ /* Found property, see if its value matches. */
+ if (val == *args)
+ break;
+ }
+
+ fwnode_handle_put(fwnode);
+
+ /* No property found; return an error here. */
+ if (!child) {
+ fwnode = ERR_PTR(-ENOENT);
+ break;
+ }
+
+ props++;
+ args++;
+ fwnode = child;
+ }
+
+ return fwnode;
+}
+
+/*
+ * v4l2_fwnode_reference_parse_int_props - parse references for async sub-devices
+ * @dev: struct device pointer
+ * @notifier: notifier for @dev
+ * @prop: the name of the property
+ * @props: the array of integer property names
+ * @nprops: the number of integer properties
+ *
+ * Use v4l2_fwnode_reference_get_int_prop to find fwnodes through reference in
+ * property @prop with integer arguments with child nodes matching in properties
+ * @props. Then, set up V4L2 async sub-devices for those fwnodes in the notifier
+ * accordingly.
+ *
+ * While it is technically possible to use this function on DT, it is only
+ * meaningful on ACPI. On Device tree you can refer to any node in the tree but
+ * on ACPI the references are limited to devices.
+ *
+ * Return: 0 on success
+ * -ENOENT if no entries (or the property itself) were found
+ * -EINVAL if property parsing otherwisefailed
+ * -ENOMEM if memory allocation failed
+ */
+static int v4l2_fwnode_reference_parse_int_props(
+ struct device *dev, struct v4l2_async_notifier *notifier,
+ const char *prop, const char **props, unsigned int nprops)
+{
+ struct fwnode_handle *fwnode;
+ unsigned int index;
+ int ret;
+
+ for (index = 0; !IS_ERR((fwnode = v4l2_fwnode_reference_get_int_prop(
+ dev_fwnode(dev), prop, index, props,
+ nprops))); index++)
+ fwnode_handle_put(fwnode);
+
+ /*
+ * Note that right now both -ENODATA and -ENOENT may signal
+ * out-of-bounds access. Return the error in cases other than that.
+ */
+ if (PTR_ERR(fwnode) != -ENOENT && PTR_ERR(fwnode) != -ENODATA)
+ return PTR_ERR(fwnode);
+
+ ret = v4l2_async_notifier_realloc(notifier,
+ notifier->num_subdevs + index);
+ if (ret)
+ return -ENOMEM;
+
+ for (index = 0; !IS_ERR((fwnode = v4l2_fwnode_reference_get_int_prop(
+ dev_fwnode(dev), prop, index, props,
+ nprops))); index++) {
+ struct v4l2_async_subdev *asd;
+
+ if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs)) {
+ ret = -EINVAL;
+ goto error;
+ }
+
+ asd = kzalloc(sizeof(struct v4l2_async_subdev), GFP_KERNEL);
+ if (!asd) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ notifier->subdevs[notifier->num_subdevs] = asd;
+ asd->match.fwnode.fwnode = fwnode;
+ asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+ notifier->num_subdevs++;
+ }
+
+ return PTR_ERR(fwnode) == -ENOENT ? 0 : PTR_ERR(fwnode);
+
+error:
+ fwnode_handle_put(fwnode);
+ return ret;
+}
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>");
MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>");
--
2.11.0
--
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