[PATCH 4/4] net: dsa: mv88e6xxx: Support serdes ports on MV88E6123/6131

[Chris Packham]

Implement serdes_power, serdes_get_lane and serdes_pcs_get_state ops for
the MV88E6123 so that the ports without a built-in PHY supported as
serdes ports and directly connected to other network interfaces or to
SFPs. Also implement serdes_get_regs_len and serdes_get_regs to aid
future debugging.

Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
---
This is untested (apart from compilation) it assumes the SERDES "phy"
address corresponds to the port number but I'm not confident that is a
valid assumption.

Changes in v4:
- Error handling in mv88e6123_serdes_get_regs
Changes in v3:
- None
Changes in v2:
- new

 drivers/net/dsa/mv88e6xxx/chip.c   | 10 +++++++
 drivers/net/dsa/mv88e6xxx/serdes.c | 46 ++++++++++++++++++++++++++++++
 drivers/net/dsa/mv88e6xxx/serdes.h |  4 +++
 3 files changed, 60 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index b582d98ca437..737416c666c1 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -3575,6 +3575,11 @@ static const struct mv88e6xxx_ops mv88e6123_ops = {
 	.set_egress_port = mv88e6095_g1_set_egress_port,
 	.watchdog_ops = &mv88e6097_watchdog_ops,
 	.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
+	.serdes_power = mv88e6123_serdes_power,
+	.serdes_get_lane = mv88e6185_serdes_get_lane,
+	.serdes_pcs_get_state = mv88e6185_serdes_pcs_get_state,
+	.serdes_get_regs_len = mv88e6123_serdes_get_regs_len,
+	.serdes_get_regs = mv88e6123_serdes_get_regs,
 	.pot_clear = mv88e6xxx_g2_pot_clear,
 	.reset = mv88e6352_g1_reset,
 	.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -3615,6 +3620,11 @@ static const struct mv88e6xxx_ops mv88e6131_ops = {
 	.set_egress_port = mv88e6095_g1_set_egress_port,
 	.watchdog_ops = &mv88e6097_watchdog_ops,
 	.mgmt_rsvd2cpu = mv88e6185_g2_mgmt_rsvd2cpu,
+	.serdes_power = mv88e6123_serdes_power,
+	.serdes_get_lane = mv88e6185_serdes_get_lane,
+	.serdes_pcs_get_state = mv88e6185_serdes_pcs_get_state,
+	.serdes_get_regs_len = mv88e6123_serdes_get_regs_len,
+	.serdes_get_regs = mv88e6123_serdes_get_regs,
 	.ppu_enable = mv88e6185_g1_ppu_enable,
 	.set_cascade_port = mv88e6185_g1_set_cascade_port,
 	.ppu_disable = mv88e6185_g1_ppu_disable,
diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c
index ec9ca7210bb0..0e84d5c7be61 100644
--- a/drivers/net/dsa/mv88e6xxx/serdes.c
+++ b/drivers/net/dsa/mv88e6xxx/serdes.c
@@ -430,6 +430,52 @@ u8 mv88e6341_serdes_get_lane(struct mv88e6xxx_chip *chip, int port)
 	return lane;
 }
 
+int mv88e6123_serdes_power(struct mv88e6xxx_chip *chip, int port, u8 lane,
+			   bool up)
+{
+	u16 val, new_val;
+	int err;
+
+	err = mv88e6xxx_phy_read(chip, port, MII_BMCR, &val);
+	if (err)
+		return err;
+
+	if (up)
+		new_val = val & ~BMCR_PDOWN;
+	else
+		new_val = val | BMCR_PDOWN;
+
+	if (val != new_val)
+		err = mv88e6xxx_phy_write(chip, port, MII_BMCR, val);
+
+	return err;
+}
+
+int mv88e6123_serdes_get_regs_len(struct mv88e6xxx_chip *chip, int port)
+{
+	if (mv88e6xxx_serdes_get_lane(chip, port) == 0)
+		return 0;
+
+	return 26 * sizeof(u16);
+}
+
+void mv88e6123_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
+{
+	u16 *p = _p;
+	u16 reg;
+	int err;
+	int i;
+
+	if (mv88e6xxx_serdes_get_lane(chip, port) == 0)
+		return;
+
+	for (i = 0; i < 26; i++) {
+		err = mv88e6xxx_phy_read(chip, port, i, &reg);
+		if (!err)
+			p[i] = reg;
+	}
+}
+
 int mv88e6185_serdes_power(struct mv88e6xxx_chip *chip, int port, u8 lane,
 			   bool up)
 {
diff --git a/drivers/net/dsa/mv88e6xxx/serdes.h b/drivers/net/dsa/mv88e6xxx/serdes.h
index c24ec4122c9e..b573139928c4 100644
--- a/drivers/net/dsa/mv88e6xxx/serdes.h
+++ b/drivers/net/dsa/mv88e6xxx/serdes.h
@@ -104,6 +104,8 @@ unsigned int mv88e6352_serdes_irq_mapping(struct mv88e6xxx_chip *chip,
 					  int port);
 unsigned int mv88e6390_serdes_irq_mapping(struct mv88e6xxx_chip *chip,
 					  int port);
+int mv88e6123_serdes_power(struct mv88e6xxx_chip *chip, int port, u8 lane,
+			   bool up);
 int mv88e6185_serdes_power(struct mv88e6xxx_chip *chip, int port, u8 lane,
 			   bool up);
 int mv88e6352_serdes_power(struct mv88e6xxx_chip *chip, int port, u8 lane,
@@ -129,6 +131,8 @@ int mv88e6390_serdes_get_strings(struct mv88e6xxx_chip *chip,
 int mv88e6390_serdes_get_stats(struct mv88e6xxx_chip *chip, int port,
 			       uint64_t *data);
 
+int mv88e6123_serdes_get_regs_len(struct mv88e6xxx_chip *chip, int port);
+void mv88e6123_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p);
 int mv88e6352_serdes_get_regs_len(struct mv88e6xxx_chip *chip, int port);
 void mv88e6352_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p);
 int mv88e6390_serdes_get_regs_len(struct mv88e6xxx_chip *chip, int port);
-- 
2.28.0