On 2/14/26 5:36 AM, Siddharth Vadapalli wrote:
Hello Marek,
On Fri, 2026-02-13 at 16:04 +0100, Marek Vasut wrote:
On 2/13/26 6:15 AM, Siddharth Vadapalli wrote:
[...]
+++ b/drivers/usb/cdns3/core.c
@@ -392,6 +392,63 @@ static const struct udevice_id cdns3_ids[] = {
{ },
};
+/*
+ * The VBUS Valid Bit in the OTG Status register can be used to determine
+ * the role. When VBUS Valid is set, it indicates that a USB Host is supplying
+ * power, so the Controller should assume the PERIPHERAL role. If it isn't set,
+ * it indicates the absence of a USB Host, so the Controller should assume the
+ * HOST role. If the OTG Status register is inaccessible, return an error.
+ */
+static int cdns3_get_otg_mode(ofnode node
Pass struct udevice *parent instead of node here ...
, enum usb_dr_mode *mode)
+{
+ struct cdns3 cdns, *cdnsp;
+ void __iomem *otg_regs;
+ fdt_addr_t otg_addr;
+ int otg_reg_index;
+ int vbus;
+
+ otg_reg_index = ofnode_stringlist_search(node, "reg-names", "otg");
+ if (otg_reg_index < 0) {
+ printf("%s: dr_mode is otg but otg register name is missing\n",
__func__);
+ return -ENOENT;
+ }
+
+ otg_addr = ofnode_get_addr_index(node, otg_reg_index);
+ if (otg_addr == FDT_ADDR_T_NONE) {
+ printf("%s: address of otg registers is unspecified\n",
__func__);
+ return -ENOENT;
+ }
+
+ otg_regs = map_physmem(otg_addr, 0, MAP_NOCACHE);
+ if (!otg_regs) {
+ printf("%s: failed to map otg registers\n", __func__);
+ return -EINVAL;
+ }
... and replace all that ^ with devfdt_remap_addr_name(parent, "otg") .
That should work.
It doesn't work because the 'parent' node doesn't have the 'otg' registers.
It is the child node which has it. The device-tree nodes for parent and
child are:
usbss0: usb@4104000 {
=> PARENT
bootph-all;
compatible = "ti,j721e-usb";
reg = <0x00 0x4104000 0x00 0x100>;
dma-coherent;
[TRIMMED]
usb0: usb@6000000
{ => CHILD
bootph-all;
compatible = "cdns,usb3";
reg = <0x00 0x6000000 0x00 0x10000>,
<0x00 0x6010000 0x00 0x10000>,
<0x00 0x6020000 0x00 0x10000>;
reg-names = "otg", "xhci",
"dev"; => OTG Register is defined here
[TRIMMED]
};
The 'udevice' for the child node is created in the cdns3_bind() function
__after__ the function in this patch is invoked. Therefore, we don't yet
have the child device which is created by:
device_bind_driver_to_node(parent, driver, name, node,
&dev);
I did consider the possibility of using the standard APIs
(devfdt_remap_addr_name), but since the child device doesn't exist yet,
they cannot be used. Hence, I had to implement custom logic.
Maybe it would be possible to create a temporary udevice on stack and
pass it to devfdt_remap_addr_name() ? I think this should be complete
enough, although I might have missed something:
"
struct udevice cdev = { .parent = parent; };
dev_set_ofnode(cdev, node);
"
devfdt_remap_addr_name() internally calls dev_of_offset(dev) on the
cdev, tests is device_get_uclass_id(dev->parent) == UCLASS_SIMPLE_BUS
(it is not) and that is it.
