net: dsa/mv88e6123_61_65: Report chip temperature

MV88E6123 and compatible chips support reading the chip temperature
from PHY register 6:26.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6123_61_65.c

@@ -291,6 +291,54 @@ static int mv88e6123_61_65_setup_port(struct dsa_switch *ds, int p)
 	return 0;
 }
 
+#ifdef CONFIG_NET_DSA_HWMON
+
+static int  mv88e6123_61_65_get_temp(struct dsa_switch *ds, int *temp)
+{
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+	int ret;
+	int val;
+
+	*temp = 0;
+
+	mutex_lock(&ps->phy_mutex);
+
+	ret = mv88e6xxx_phy_write(ds, 0x0, 0x16, 0x6);
+	if (ret < 0)
+		goto error;
+
+	/* Enable temperature sensor */
+	ret = mv88e6xxx_phy_read(ds, 0x0, 0x1a);
+	if (ret < 0)
+		goto error;
+
+	ret = mv88e6xxx_phy_write(ds, 0x0, 0x1a, ret | (1 << 5));
+	if (ret < 0)
+		goto error;
+
+	/* Wait for temperature to stabilize */
+	usleep_range(10000, 12000);
+
+	val = mv88e6xxx_phy_read(ds, 0x0, 0x1a);
+	if (val < 0) {
+		ret = val;
+		goto error;
+	}
+
+	/* Disable temperature sensor */
+	ret = mv88e6xxx_phy_write(ds, 0x0, 0x1a, ret & ~(1 << 5));
+	if (ret < 0)
+		goto error;
+
+	*temp = ((val & 0x1f) - 5) * 5;
+
+error:
+	mv88e6xxx_phy_write(ds, 0x0, 0x16, 0x0);
+	mutex_unlock(&ps->phy_mutex);
+	return ret;
+}
+#endif /* CONFIG_NET_DSA_HWMON */
+
 static int mv88e6123_61_65_setup(struct dsa_switch *ds)
 {
 	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
@@ -299,6 +347,7 @@ static int mv88e6123_61_65_setup(struct dsa_switch *ds)
 
 	mutex_init(&ps->smi_mutex);
 	mutex_init(&ps->stats_mutex);
+	mutex_init(&ps->phy_mutex);
 
 	ret = mv88e6123_61_65_switch_reset(ds);
 	if (ret < 0)
@@ -329,16 +378,28 @@ static int mv88e6123_61_65_port_to_phy_addr(int port)
 static int
 mv88e6123_61_65_phy_read(struct dsa_switch *ds, int port, int regnum)
 {
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
 	int addr = mv88e6123_61_65_port_to_phy_addr(port);
-	return mv88e6xxx_phy_read(ds, addr, regnum);
+	int ret;
+
+	mutex_lock(&ps->phy_mutex);
+	ret = mv88e6xxx_phy_read(ds, addr, regnum);
+	mutex_unlock(&ps->phy_mutex);
+	return ret;
 }
 
 static int
 mv88e6123_61_65_phy_write(struct dsa_switch *ds,
 			      int port, int regnum, u16 val)
 {
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
 	int addr = mv88e6123_61_65_port_to_phy_addr(port);
-	return mv88e6xxx_phy_write(ds, addr, regnum, val);
+	int ret;
+
+	mutex_lock(&ps->phy_mutex);
+	ret = mv88e6xxx_phy_write(ds, addr, regnum, val);
+	mutex_unlock(&ps->phy_mutex);
+	return ret;
 }
 
 static struct mv88e6xxx_hw_stat mv88e6123_61_65_hw_stats[] = {
@@ -406,6 +467,9 @@ struct dsa_switch_driver mv88e6123_61_65_switch_driver = {
 	.get_strings		= mv88e6123_61_65_get_strings,
 	.get_ethtool_stats	= mv88e6123_61_65_get_ethtool_stats,
 	.get_sset_count		= mv88e6123_61_65_get_sset_count,
+#ifdef CONFIG_NET_DSA_HWMON
+	.get_temp		= mv88e6123_61_65_get_temp,
+#endif
 };
 
 MODULE_ALIAS("platform:mv88e6123");