net: phy: broadcom: Fix bcm_write_exp()

On newer PHYs, we need to select the expansion register to write with
setting bits [11:8] to 0xf. This was done correctly by bcm7xxx.c prior
to being migrated to generic code under bcm-phy-lib.c which
unfortunately used the older implementation from the BCM54xx days.

Fix this by creating an inline stub: bcm_write_exp_sel() which adds the
correct value (MII_BCM54XX_EXP_SEL_ER) and update both the Cygnus PHY
and BCM7xxx PHY drivers which require setting these bits.

broadcom.c is unchanged because some PHYs even use a different selector
method, so let them specify it directly (e.g: SerDes secondary selector).

Fixes: a1cba5613edf ("net: phy: Add Broadcom phy library for common interfaces")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/bcm-cygnus.c

@@ -61,17 +61,17 @@ static int bcm_cygnus_afe_config(struct phy_device *phydev)
 		return rc;
 
 	/* make rcal=100, since rdb default is 000 */
-	rc = bcm_phy_write_exp(phydev, MII_BRCM_CORE_EXPB1, 0x10);
+	rc = bcm_phy_write_exp_sel(phydev, MII_BRCM_CORE_EXPB1, 0x10);
 	if (rc < 0)
 		return rc;
 
 	/* CORE_EXPB0, Reset R_CAL/RC_CAL Engine */
-	rc = bcm_phy_write_exp(phydev, MII_BRCM_CORE_EXPB0, 0x10);
+	rc = bcm_phy_write_exp_sel(phydev, MII_BRCM_CORE_EXPB0, 0x10);
 	if (rc < 0)
 		return rc;
 
 	/* CORE_EXPB0, Disable Reset R_CAL/RC_CAL Engine */
-	rc = bcm_phy_write_exp(phydev, MII_BRCM_CORE_EXPB0, 0x00);
+	rc = bcm_phy_write_exp_sel(phydev, MII_BRCM_CORE_EXPB0, 0x00);
 
 	return 0;
 }

drivers/net/phy/bcm-phy-lib.h

@@ -14,11 +14,18 @@
 #ifndef _LINUX_BCM_PHY_LIB_H
 #define _LINUX_BCM_PHY_LIB_H
 
+#include <linux/brcmphy.h>
 #include <linux/phy.h>
 
 int bcm_phy_write_exp(struct phy_device *phydev, u16 reg, u16 val);
 int bcm_phy_read_exp(struct phy_device *phydev, u16 reg);
 
+static inline int bcm_phy_write_exp_sel(struct phy_device *phydev,
+					u16 reg, u16 val)
+{
+	return bcm_phy_write_exp(phydev, reg | MII_BCM54XX_EXP_SEL_ER, val);
+}
+
 int bcm54xx_auxctl_write(struct phy_device *phydev, u16 regnum, u16 val);
 int bcm54xx_auxctl_read(struct phy_device *phydev, u16 regnum);
 

drivers/net/phy/bcm7xxx.c

@@ -65,10 +65,10 @@ struct bcm7xxx_phy_priv {
 static void r_rc_cal_reset(struct phy_device *phydev)
 {
 	/* Reset R_CAL/RC_CAL Engine */
-	bcm_phy_write_exp(phydev, 0x00b0, 0x0010);
+	bcm_phy_write_exp_sel(phydev, 0x00b0, 0x0010);
 
 	/* Disable Reset R_AL/RC_CAL Engine */
-	bcm_phy_write_exp(phydev, 0x00b0, 0x0000);
+	bcm_phy_write_exp_sel(phydev, 0x00b0, 0x0000);
 }
 
 static int bcm7xxx_28nm_b0_afe_config_init(struct phy_device *phydev)