The XPCS in these NXP switches returns 0 when reading the ID registers,
and is integrated with a custom PMA.

The current way to support it is with hijacked PHYID register reads
in sja1105_pcs_mdio_read_c45(), to fake that it returns
NXP_SJA1105_XPCS_ID.

The new way to support it is with a specific compatible string. This
makes the platform XPCS driver use a specific struct dw_xpcs_info which
it assigns to mdiodev->dev.platform_data, and from there, xpcs_init_id()
picks it up and uses it. Later, xpcs_identify() doesn't overwrite the
xpcs->info.pcs and xpcs->info.pma unless they are set to
DW_XPCS_ID_NATIVE and DW_XPCS_PMA_ID_NATIVE, aka zeroes.

Since what is custom is the PMA and not the PCS, a later patch will
probably have to move the NXP constants around. But that should be done
only after this becomes strictly XPCS internal business.

Cc: Serge Semin <redacted>
Cc: Rob Herring <robh@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: none

 drivers/net/pcs/pcs-xpcs-plat.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
index 2bc0afe2bbb4..a256ae40c757 100644
--- a/drivers/net/pcs/pcs-xpcs-plat.c
+++ b/drivers/net/pcs/pcs-xpcs-plat.c

@@ -476,6 +476,8 @@ DW_XPCS_INFO_DECLARE(xpcs_pma_gen4_3g, DW_XPCS_ID_NATIVE, DW_XPCS_PMA_GEN4_3G_ID
 DW_XPCS_INFO_DECLARE(xpcs_pma_gen4_6g, DW_XPCS_ID_NATIVE, DW_XPCS_PMA_GEN4_6G_ID);
 DW_XPCS_INFO_DECLARE(xpcs_pma_gen5_10g, DW_XPCS_ID_NATIVE, DW_XPCS_PMA_GEN5_10G_ID);
 DW_XPCS_INFO_DECLARE(xpcs_pma_gen5_12g, DW_XPCS_ID_NATIVE, DW_XPCS_PMA_GEN5_12G_ID);
+DW_XPCS_INFO_DECLARE(xpcs_sja1105, NXP_SJA1105_XPCS_ID, DW_XPCS_PMA_ID_NATIVE);
+DW_XPCS_INFO_DECLARE(xpcs_sja1110, NXP_SJA1110_XPCS_ID, DW_XPCS_PMA_ID_NATIVE);
 
 static const struct of_device_id xpcs_of_ids[] = {
 	{ .compatible = "snps,dw-xpcs", .data = &xpcs_generic },

@@ -486,6 +488,8 @@ static const struct of_device_id xpcs_of_ids[] = {
 	{ .compatible = "snps,dw-xpcs-gen4-6g", .data = &xpcs_pma_gen4_6g },
 	{ .compatible = "snps,dw-xpcs-gen5-10g", .data = &xpcs_pma_gen5_10g },
 	{ .compatible = "snps,dw-xpcs-gen5-12g", .data = &xpcs_pma_gen5_12g },
+	{ .compatible = "nxp,sja1105-pcs", .data = &xpcs_sja1105 },
+	{ .compatible = "nxp,sja1110-pcs", .data = &xpcs_sja1110 },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, xpcs_of_ids);

-- 
2.34.1