[PATCH net-next v3 2/2] net: sfp: add quirks for OEM XGSPONST2001 and FS XGS-SFP-ONT-MACI

[Martino Dell'Ambrogio <tillo@tillo.ch>]

Cheap XGS-PON ONT sticks identifying as vendor "OEM", PN "XGSPONST2001"
have broken TX_FAULT and LOS indicators (driven by the ONU serial
passthrough wires) and need a longer T_START_UP than the SFF-8472
default. The Fiberstore XGS-SFP-ONT-MACI MAC-mode ONT stick has the
same ONT-class TX_FAULT/LOS wiring and startup behaviour. Apply the
existing sfp_fixup_potron handler to both, which masks both signals
and bumps T_START_UP to T_START_UP_BAD_GPON.

The XGSPONST2001 returns the 12 legitimate PN characters followed by
non-printable garbage on cold power-up reads (the same module reads
back clean and space-padded after a warm reseat), which defeats
exact-length matching precisely on the boot where the quirk must
apply: the kernel honors the spurious TX_FAULT and the SFP state
machine eventually disables the module. Match its part as a prefix
using SFP_QUIRK_F_PREFIX.

The XGS-SFP-ONT-MACI PN is the product name (XGS-SFP-ONT-MAC-I)
truncated at the 16-byte field width, so the field is fully occupied
by legitimate characters and a plain exact-match SFP_QUIRK_F entry is
correct.

Signed-off-by: Martino Dell'Ambrogio <tillo@tillo.ch>
---
 drivers/net/phy/sfp.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 15033cbf7..2ec91466a 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -557,6 +557,13 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK("FS", "GPON-ONU-34-20BI", sfp_quirk_2500basex,
 		  sfp_fixup_ignore_tx_fault),
 
+	// Fiberstore XGS-SFP-ONT-MACI is a MAC-mode XGS-PON ONT stick with
+	// ONT-class serial-passthrough TX_FAULT/LOS wiring and slow startup;
+	// mask both signals and extend T_START_UP via the potron fixup. The
+	// PN is the product name (XGS-SFP-ONT-MAC-I) truncated at the 16-byte
+	// field width, so the field is fully occupied and matches exactly.
+	SFP_QUIRK_F("FS", "XGS-SFP-ONT-MACI", sfp_fixup_potron),
+
 	SFP_QUIRK_F("HALNy", "HL-GSFP", sfp_fixup_halny_gsfp),
 
 	SFP_QUIRK_F("H-COM", "SPP425H-GAB4", sfp_fixup_potron),
@@ -617,6 +624,14 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK_S("OEM", "SFP-2.5G-LH20-A", sfp_quirk_2500basex),
 	SFP_QUIRK_F("OEM", "RTSFP-10", sfp_fixup_rollball_cc),
 	SFP_QUIRK_F("OEM", "RTSFP-10G", sfp_fixup_rollball_cc),
+
+	// OEM XGSPONST2001 is an XGS-PON ONT stick with broken TX_FAULT and
+	// LOS indicators and slow startup, just like potron. On cold
+	// power-up the EEPROM vendor PN field reads back with non-printable
+	// garbage past the legitimate string instead of space padding, so
+	// match the part as a prefix.
+	SFP_QUIRK_F_PREFIX("OEM", "XGSPONST2001", sfp_fixup_potron),
+
 	SFP_QUIRK_F("Turris", "RTSFP-2.5G", sfp_fixup_rollball),
 	SFP_QUIRK_F("Turris", "RTSFP-10", sfp_fixup_rollball),
 	SFP_QUIRK_F("Turris", "RTSFP-10G", sfp_fixup_rollball),
-- 
2.47.3