When the device tree indicates support for role switching through
the "usb-role-switch" property, take the "role-switch-default-mode"
property into account when deciding which role to put the
controller into.
This makes USB devices work on Apple M1 systems where the device
tree may include a "dr_mode" property that is set to "otg", but
where we need to put the controller into "host" mode to see
devices connected to the type-C ports.
Signed-off-by: Mark Kettenis <kette...@openbsd.org>
---
I'm far from sure this is the right approach. But it does appear that
U-Boot doesn't really support role switching. So making sure U-Boot
uses the default role defined in the device tree makes sense to me.
drivers/usb/common/common.c | 16 ++++++++++++++++
drivers/usb/host/xhci-dwc3.c | 6 ++++++
include/linux/usb/otg.h | 10 ++++++++++
3 files changed, 32 insertions(+)
diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c
index ee0c064f1f..cff86a51ae 100644
--- a/drivers/usb/common/common.c
+++ b/drivers/usb/common/common.c
@@ -40,6 +40,22 @@ enum usb_dr_mode usb_get_dr_mode(ofnode node)
return USB_DR_MODE_UNKNOWN;
}
+enum usb_dr_mode usb_get_role_switch_default_mode(ofnode node)
+{
+ const char *dr_mode;
+ int i;
+
+ dr_mode = ofnode_read_string(node, "role-switch-default-mode");
+ if (!dr_mode)
+ return USB_DR_MODE_UNKNOWN;
+
+ for (i = 0; i < ARRAY_SIZE(usb_dr_modes); i++)
+ if (!strcmp(dr_mode, usb_dr_modes[i]))
+ return i;
+
+ return USB_DR_MODE_UNKNOWN;
+}
+
static const char *const speed_names[] = {
[USB_SPEED_UNKNOWN] = "UNKNOWN",
[USB_SPEED_LOW] = "low-speed",
diff --git a/drivers/usb/host/xhci-dwc3.c b/drivers/usb/host/xhci-dwc3.c
index bec0d98081..1dbd65dfaa 100644
--- a/drivers/usb/host/xhci-dwc3.c
+++ b/drivers/usb/host/xhci-dwc3.c
@@ -209,6 +209,12 @@ static int xhci_dwc3_probe(struct udevice *dev)
writel(reg, &dwc3_reg->g_usb2phycfg[0]);
dr_mode = usb_get_dr_mode(dev_ofnode(dev));
+ if (dr_mode == USB_DR_MODE_OTG &&
+ dev_read_bool(dev, "usb-role-switch")) {
+ dr_mode = usb_get_role_switch_default_mode(dev_ofnode(dev));
+ if (dr_mode == USB_DR_MODE_UNKNOWN)
+ dr_mode = USB_DR_MODE_OTG;
+ }
if (dr_mode == USB_DR_MODE_UNKNOWN)
/* by default set dual role mode to HOST */
dr_mode = USB_DR_MODE_HOST;
diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index c19b916be9..5d0dac950e 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -27,6 +27,16 @@ enum usb_dr_mode {
*/
enum usb_dr_mode usb_get_dr_mode(ofnode node);
+/**
+ * usb_get_dr_mode() - Get dual role mode for given device
+ * @node: ofnode of the given device
+ *
+ * The function gets phy interface string from property
+ * 'role-switch-defaulr-mode', and returns the correspondig enum
+ * usb_dr_mode
+ */
+enum usb_dr_mode usb_get_role_switch_default_mode(ofnode node);
+
/**
* usb_get_maximum_speed() - Get maximum speed for given device
* @node: ofnode of the given device
--
2.34.1
