net: sfp: add mode quirk for GPON module Ubiquiti U-Fiber Instant

The Ubiquiti U-Fiber Instant SFP GPON module has nonsensical information
stored in its EEPROM. It claims to support all transceiver types including
10G Ethernet. Clear all claimed modes and set only 1000baseX_Full, which is
the only one supported.

This module has also phys_id set to SFF, and the SFP subsystem currently
does not allow to use SFP modules detected as SFFs. Add exception for this
module so it can be detected as supported.

This change finally allows to detect and use SFP GPON module Ubiquiti
U-Fiber Instant on Linux system.

EEPROM content of this SFP module is (where XX is serial number):

00: 02 04 0b ff ff ff ff ff ff ff ff 03 0c 00 14 c8    ???........??.??
10: 00 00 00 00 55 42 4e 54 20 20 20 20 20 20 20 20    ....UBNT
20: 20 20 20 20 00 18 e8 29 55 46 2d 49 4e 53 54 41        .??)UF-INSTA
30: 4e 54 20 20 20 20 20 20 34 20 20 20 05 1e 00 36    NT      4   ??.6
40: 00 06 00 00 55 42 4e 54 XX XX XX XX XX XX XX XX    .?..UBNTXXXXXXXX
50: 20 20 20 20 31 34 30 31 32 33 20 20 60 80 02 41        140123  `??A

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
index 3c67ad9..3cfd773 100644
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -44,6 +44,17 @@ static void sfp_quirk_2500basex(const struct sfp_eeprom_id *id,
 	phylink_set(modes, 2500baseX_Full);
 }
 
+static void sfp_quirk_ubnt_uf_instant(const struct sfp_eeprom_id *id,
+				      unsigned long *modes)
+{
+	/* Ubiquiti U-Fiber Instant module claims that support all transceiver
+	 * types including 10G Ethernet which is not truth. So clear all claimed
+	 * modes and set only one mode which module supports: 1000baseX_Full.
+	 */
+	phylink_zero(modes);
+	phylink_set(modes, 1000baseX_Full);
+}
+
 static const struct sfp_quirk sfp_quirks[] = {
 	{
 		// Alcatel Lucent G-010S-P can operate at 2500base-X, but
@@ -63,6 +74,10 @@ static const struct sfp_quirk sfp_quirks[] = {
 		.vendor = "HUAWEI",
 		.part = "MA5671A",
 		.modes = sfp_quirk_2500basex,
+	}, {
+		.vendor = "UBNT",
+		.part = "UF-INSTANT",
+		.modes = sfp_quirk_ubnt_uf_instant,
 	},
 };