[PATCH net-next v3 3/8] net: dsa: mv88e6xxx: read switch ID in probe

[Vivien Didelot]

Read the switch ID only once, at probe time, to avoid multiple read
accesses and MII bus checking.

Signed-off-by: Vivien Didelot <vivien.dide...@savoirfairelinux.com>
---
 drivers/net/dsa/mv88e6xxx.c | 54 +++++++++++++++++++++++++--------------------
 1 file changed, 30 insertions(+), 24 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index b63e985..af5ae70 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -2667,8 +2667,6 @@ int mv88e6xxx_setup_common(struct dsa_switch *ds)
        ps->ds = ds;
        mutex_init(&ps->smi_mutex);
 
-       ps->id = REG_READ(REG_PORT(0), PORT_SWITCH_ID) & 0xfff0;
-
        INIT_WORK(&ps->bridge_work, mv88e6xxx_bridge_work);
 
        return 0;
@@ -3068,21 +3066,14 @@ int mv88e6xxx_get_temp_alarm(struct dsa_switch *ds, 
bool *alarm)
 }
 #endif /* CONFIG_NET_DSA_HWMON */
 
-static char *mv88e6xxx_lookup_name(struct mii_bus *bus, int sw_addr,
+static char *mv88e6xxx_lookup_name(unsigned int id,
                                   const struct mv88e6xxx_switch_id *table,
                                   unsigned int num)
 {
-       int i, ret;
-
-       if (!bus)
-               return NULL;
-
-       ret = __mv88e6xxx_reg_read(bus, sw_addr, REG_PORT(0), PORT_SWITCH_ID);
-       if (ret < 0)
-               return NULL;
+       int i;
 
        for (i = 0; i < num; ++i)
-               if (table[i].id == (ret & 0xfff0))
+               if (table[i].id == (id & 0xfff0))
                        return table[i].name;
 
        return NULL;
@@ -3094,23 +3085,38 @@ char *mv88e6xxx_drv_probe(struct device *dsa_dev, 
struct device *host_dev,
                          unsigned int num)
 {
        struct mv88e6xxx_priv_state *ps;
-       struct mii_bus *bus = dsa_host_dev_to_mii_bus(host_dev);
+       struct mii_bus *bus;
+       int id, prod_num, rev;
        char *name;
 
+       bus = dsa_host_dev_to_mii_bus(host_dev);
        if (!bus)
                return NULL;
 
-       name = mv88e6xxx_lookup_name(bus, sw_addr, table, num);
-       if (name) {
-               ps = devm_kzalloc(dsa_dev, sizeof(*ps), GFP_KERNEL);
-               if (!ps)
-                       return NULL;
-               *priv = ps;
-               ps->bus = dsa_host_dev_to_mii_bus(host_dev);
-               if (!ps->bus)
-                       return NULL;
-               ps->sw_addr = sw_addr;
-       }
+       id = __mv88e6xxx_reg_read(bus, sw_addr, REG_PORT(0), PORT_SWITCH_ID);
+       if (id < 0)
+               return NULL;
+
+       prod_num = (id & 0xfff0) >> 4;
+       rev = id & 0x000f;
+
+       name = mv88e6xxx_lookup_name(id, table, num);
+       if (!name)
+               return NULL;
+
+       ps = devm_kzalloc(dsa_dev, sizeof(*ps), GFP_KERNEL);
+       if (!ps)
+               return NULL;
+
+       ps->bus = bus;
+       ps->sw_addr = sw_addr;
+       ps->id = id & 0xfff0;
+
+       *priv = ps;
+
+       dev_info(&ps->bus->dev, "switch 0x%x probed: %s, revision %u\n",
+                prod_num, name, rev);
+
        return name;
 }
 
-- 
2.8.0