From: Frank Wunderlich <frank-w@public-files.de>
Commit 8871389da151 introduces common pcs dts properties which writes
rx=normal,tx=normal polarity to register SGMSYS_QPHY_WRAP_CTRL of switch.
This is initialized with tx-bit set and so change inverts polarity
compared to before.
It looks like mt7531 has tx polarity inverted in hardware and set tx-bit
by default to restore the normal polarity.
The MT7531 datasheet quite clearly states:
Register 000050EC QPHY_WRAP_CTRL -- QPHY wrapper control
Reset value: 0x00000501
BIT 1 RX_BIT_POLARITY -- RX bit polarity control
1'b0: normal
1'b1: inverted
BIT 0 TX_BIT_POLARITY -- TX bit polarity control (TX default inversed
in MT7531)
1'b0: normal
1'b1: inverted
Till this patch the register write was only called when mediatek,pnswap
property was set which cannot be done for switch because the fw-node param
was always NULL from switch driver in the mtk_pcs_lynxi_create call.
Do not configure switch side like it's done before.
Fixes: 8871389da151 ("net: pcs: pcs-mtk-lynxi: deprecate "mediatek,pnswap"")
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v2:
- send as non-RFC
- add datasheet information from Daniel
---
drivers/net/pcs/pcs-mtk-lynxi.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/pcs/pcs-mtk-lynxi.c b/drivers/net/pcs/pcs-mtk-lynxi.c
index c12f8087af9b..a753bd88cbc2 100644
--- a/drivers/net/pcs/pcs-mtk-lynxi.c
+++ b/drivers/net/pcs/pcs-mtk-lynxi.c
@@ -129,6 +129,9 @@ static int mtk_pcs_config_polarity(struct mtk_pcs_lynxi *mpcs,
unsigned int val = 0;
int ret;
+ if (!fwnode)
+ return 0;
+
if (fwnode_property_read_bool(fwnode, "mediatek,pnswap"))
default_pol = PHY_POL_INVERT;
--
2.53.0