The HW can swap the USB differential-pair (D+/D-) for each port
separately. So the USB signals can be re-aligned with a misplaced
USB connector on the PCB.
Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
Reviewed-by: Richard Leitner <richard.leitner@xxxxxxxxxxx>
---
Changes:
v3:
- fix comment
v2:
- rename property s/sw-dx-lanes-ports/swap-dx-lanes
- add comment for future users
drivers/usb/misc/usb251xb.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/misc/usb251xb.c b/drivers/usb/misc/usb251xb.c
index a6efb9a72939..4d72b7d1d383 100644
--- a/drivers/usb/misc/usb251xb.c
+++ b/drivers/usb/misc/usb251xb.c
@@ -337,10 +337,12 @@ static int usb251xb_get_ofdata(struct usb251xb *hub,
struct device *dev = hub->dev;
struct device_node *np = dev->of_node;
int len, err, i;
- u32 property_u32 = 0;
+ u32 port, property_u32 = 0;
const u32 *cproperty_u32;
const char *cproperty_char;
char str[USB251XB_STRING_BUFSIZE / 2];
+ struct property *prop;
+ const __be32 *p;
if (!np) {
dev_err(dev, "failed to get ofdata\n");
@@ -539,6 +541,16 @@ static int usb251xb_get_ofdata(struct usb251xb *hub,
(wchar_t *)hub->serial,
USB251XB_STRING_BUFSIZE);
+ /*
+ * The datasheet documents the register as 'Port Swap' but in real the
+ * register controls the USB DP/DM signal swapping for each port.
+ */
+ hub->port_swap = USB251XB_DEF_PORT_SWAP;
+ of_property_for_each_u32(np, "swap-dx-lanes", prop, p, port) {
+ if ((port >= 0) && (port <= data->port_cnt))
+ hub->port_swap |= BIT(port);
+ }
+
/* The following parameters are currently not exposed to devicetree, but
* may be as soon as needed.
*/
@@ -546,7 +558,6 @@ static int usb251xb_get_ofdata(struct usb251xb *hub,
hub->boost_up = USB251XB_DEF_BOOST_UP;
hub->boost_57 = USB251XB_DEF_BOOST_57;
hub->boost_14 = USB251XB_DEF_BOOST_14;
- hub->port_swap = USB251XB_DEF_PORT_SWAP;
hub->port_map12 = USB251XB_DEF_PORT_MAP_12;
hub->port_map34 = USB251XB_DEF_PORT_MAP_34;
hub->port_map56 = USB251XB_DEF_PORT_MAP_56;
--
2.20.1
