of: Add dummy driver

With deep probe support we decide that a device for a new device node is
available when the device has a driver. It sometimes happens that a
consumer of a device node doesn't point to the node to which the driver
is attached to, but instead a subnode, like this:

	usb2phy0: usb2-phy@fe8a0000 {
		compatible = "rockchip,rk3568-usb2phy";

		u2phy0_host: host-port {
			status = "disabled";
		};
	};

	usbhost_dwc3: dwc3@fd000000 {
		compatible = "snps,dwc3";
		phys = <&u2phy0_host>;
		phy-names = "usb2-phy";
	};

of_device_ensure_probed() would now expect a driver for the &u2phy0_host
node, but the driver is attached to the &usb2phy0 node. This patch adds
of_platform_device_dummy_drv() which can be used in such situations. When
called on the &u2phy0_host it will attach a dummy driver to it so that
deep probe is happy.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.barebox.org/20210625072540.32717-20-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/of.h b/include/of.h
index 98de9d8480..6f1ec94e7e 100644
--- a/include/of.h
+++ b/include/of.h
@@ -268,6 +268,7 @@ extern int barebox_register_fdt(const void *dtb);
 
 extern struct device_d *of_platform_device_create(struct device_node *np,
 						struct device_d *parent);
+extern void of_platform_device_dummy_drv(struct device_d *dev);
 extern int of_platform_populate(struct device_node *root,
 				const struct of_device_id *matches,
 				struct device_d *parent);
@@ -365,6 +366,10 @@ static inline struct device_d *of_platform_device_create(struct device_node *np,
 	return NULL;
 }
 
+static inline void of_platform_device_dummy_drv(struct device_d *dev)
+{
+}
+
 static inline int of_device_ensure_probed(struct device_node *np)
 {
 	return 0;