dsa: mv88e6xxx: make serdes SGMII/Fiber tx amplitude configurable

The mv88e6352, mv88e6240 and mv88e6176  have a serdes interface. This patch
allows to configure the output swing to a desired value in the
phy-handle of the port. The value which is peak to peak has to be
specified in microvolts. As the chips only supports eight dedicated
values we return EINVAL if the value in the DTS does not match one of
these values.

Signed-off-by: Holger Brunck <holger.brunck@hitachienergy.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Marek Behún <kabel@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 5344d0c0647e2d965046ced3d0735ce26270170b..85527fe4fcc87a021d83380149fe8af1b649f37e 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2987,7 +2987,10 @@ static int mv88e6xxx_setup_upstream_port(struct mv88e6xxx_chip *chip, int port)
 
 static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
 {
+       struct device_node *phy_handle = NULL;
        struct dsa_switch *ds = chip->ds;
+       struct dsa_port *dp;
+       int tx_amp;
        int err;
        u16 reg;
 
@@ -3178,6 +3181,23 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
                        return err;
        }
 
+       if (chip->info->ops->serdes_set_tx_amplitude) {
+               dp = dsa_to_port(ds, port);
+               if (dp)
+                       phy_handle = of_parse_phandle(dp->dn, "phy-handle", 0);
+
+               if (phy_handle && !of_property_read_u32(phy_handle,
+                                                       "tx-p2p-microvolt",
+                                                       &tx_amp))
+                       err = chip->info->ops->serdes_set_tx_amplitude(chip,
+                                                               port, tx_amp);
+               if (phy_handle) {
+                       of_node_put(phy_handle);
+                       if (err)
+                               return err;
+               }
+       }
+
        /* Port based VLAN map: give each port the same default address
         * database, and allow bidirectional communication between the
         * CPU and DSA port(s), and the other ports.
@@ -4246,6 +4266,7 @@ static const struct mv88e6xxx_ops mv88e6176_ops = {
        .serdes_irq_status = mv88e6352_serdes_irq_status,
        .serdes_get_regs_len = mv88e6352_serdes_get_regs_len,
        .serdes_get_regs = mv88e6352_serdes_get_regs,
+       .serdes_set_tx_amplitude = mv88e6352_serdes_set_tx_amplitude,
        .gpio_ops = &mv88e6352_gpio_ops,
        .phylink_get_caps = mv88e6352_phylink_get_caps,
 };
@@ -4526,6 +4547,7 @@ static const struct mv88e6xxx_ops mv88e6240_ops = {
        .serdes_irq_status = mv88e6352_serdes_irq_status,
        .serdes_get_regs_len = mv88e6352_serdes_get_regs_len,
        .serdes_get_regs = mv88e6352_serdes_get_regs,
+       .serdes_set_tx_amplitude = mv88e6352_serdes_set_tx_amplitude,
        .gpio_ops = &mv88e6352_gpio_ops,
        .avb_ops = &mv88e6352_avb_ops,
        .ptp_ops = &mv88e6352_ptp_ops,
@@ -4932,6 +4954,7 @@ static const struct mv88e6xxx_ops mv88e6352_ops = {
        .serdes_get_stats = mv88e6352_serdes_get_stats,
        .serdes_get_regs_len = mv88e6352_serdes_get_regs_len,
        .serdes_get_regs = mv88e6352_serdes_get_regs,
+       .serdes_set_tx_amplitude = mv88e6352_serdes_set_tx_amplitude,
        .phylink_get_caps = mv88e6352_phylink_get_caps,
 };
 

diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 12aa637779f51a7bb1eb9f4676d3dbd7a169e8a4..30b92a265613195b6c4b7df2526dab5b8b67fddf 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -588,6 +588,10 @@ struct mv88e6xxx_ops {
        void (*serdes_get_regs)(struct mv88e6xxx_chip *chip, int port,
                                void *_p);
 
+       /* SERDES SGMII/Fiber Output Amplitude */
+       int (*serdes_set_tx_amplitude)(struct mv88e6xxx_chip *chip, int port,
+                                      int val);
+
        /* Address Translation Unit operations */
        int (*atu_get_hash)(struct mv88e6xxx_chip *chip, u8 *hash);
        int (*atu_set_hash)(struct mv88e6xxx_chip *chip, u8 hash);

diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c
index 6a177bf654ee504fe440613b97a3cdcd3cb43bae..7b37d45bc9fb52c1f580b9efa7ce5b67fe149163 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/serdes.c
+++ b/drivers/net/dsa/mv88e6xxx/serdes.c
@@ -1313,6 +1313,44 @@ void mv88e6390_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
        }
 }
 
+static const int mv88e6352_serdes_p2p_to_reg[] = {
+       /* Index of value in microvolts corresponds to the register value */
+       14000, 112000, 210000, 308000, 406000, 504000, 602000, 700000,
+};
+
+int mv88e6352_serdes_set_tx_amplitude(struct mv88e6xxx_chip *chip, int port,
+                                     int val)
+{
+       bool found = false;
+       u16 ctrl, reg;
+       int err;
+       int i;
+
+       err = mv88e6352_g2_scratch_port_has_serdes(chip, port);
+       if (err <= 0)
+               return err;
+
+       for (i = 0; i < ARRAY_SIZE(mv88e6352_serdes_p2p_to_reg); ++i) {
+               if (mv88e6352_serdes_p2p_to_reg[i] == val) {
+                       reg = i;
+                       found = true;
+                       break;
+               }
+       }
+
+       if (!found)
+               return -EINVAL;
+
+       err = mv88e6352_serdes_read(chip, MV88E6352_SERDES_SPEC_CTRL2, &ctrl);
+       if (err)
+               return err;
+
+       ctrl &= ~MV88E6352_SERDES_OUT_AMP_MASK;
+       ctrl |= reg;
+
+       return mv88e6352_serdes_write(chip, MV88E6352_SERDES_SPEC_CTRL2, ctrl);
+}
+
 static int mv88e6393x_serdes_power_lane(struct mv88e6xxx_chip *chip, int lane,
                                        bool on)
 {

diff --git a/drivers/net/dsa/mv88e6xxx/serdes.h b/drivers/net/dsa/mv88e6xxx/serdes.h
index 8dd8ed225b4594f5421d91fb3755dfe242cb0bfb..29bb4e91e2f6be1715e0a2f47b15c099a7cc329a 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/serdes.h
+++ b/drivers/net/dsa/mv88e6xxx/serdes.h
@@ -27,6 +27,8 @@
 #define MV88E6352_SERDES_INT_FIBRE_ENERGY      BIT(4)
 #define MV88E6352_SERDES_INT_STATUS    0x13
 
+#define MV88E6352_SERDES_SPEC_CTRL2    0x1a
+#define MV88E6352_SERDES_OUT_AMP_MASK          0x0007
 
 #define MV88E6341_PORT5_LANE           0x15
 
@@ -176,6 +178,9 @@ 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);
 void mv88e6390_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p);
 
+int mv88e6352_serdes_set_tx_amplitude(struct mv88e6xxx_chip *chip, int port,
+                                     int val);
+
 /* Return the (first) SERDES lane address a port is using, -errno otherwise. */
 static inline int mv88e6xxx_serdes_get_lane(struct mv88e6xxx_chip *chip,
                                            int port)