tg3 / broadcom: Add code to disable rxc refclk

The 5785 does not use the RXC reference clock.  Turning it off is
desirable as it saves power.

By default, the 50610 enables the RXC reference clock and the 50610M
disables it.  Presumably this is one of the reasons why the hardware
architect chose one over the other.

Adding a "rx reference clock disable" flag is not the ideal way to
describe the option, as it would force the MAC using a 50610M to set
the flag.  Ideally we want the flags to represent opt-in behavior that
deviates from hardware defaults.  Furthermore, the lack of a
"disable" flag implies that the requester wants the rx reference clock
enabled, which doesn't necessarily follow.

By presenting the option as a passive statement (rx reference clock
unused) rather than a command, I hope to convey an opt-in option to
disable the rx reference clock that falls back to hardware defaults if
not set.  A secondary benefit of this is that it keeps the
intelligence about phy defaults in the broadcom module where it belongs
and allows the broadcom module more latitude should a bug arise.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index bddf4a42ae68..74914335f72c 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -25,6 +25,9 @@
 #define BRCM_PHY_MODEL(phydev) \
         ((phydev)->drv->phy_id & (phydev)->drv->phy_id_mask)
 
+#define BRCM_PHY_REV(phydev) \
+        ((phydev)->drv->phy_id & ~((phydev)->drv->phy_id_mask))
+
 
 #define MII_BCM54XX_ECR         0x10    /* BCM54xx extended control register */
 #define MII_BCM54XX_ECR_IM      0x1000  /* Interrupt mask */
@@ -95,11 +98,16 @@
 #define BCM_LED_SRC_OFF         0xe     /* Tied high */
 #define BCM_LED_SRC_ON          0xf     /* Tied low */
 
+
 /*
  * BCM5482: Shadow registers
  * Shadow values go into bits [14:10] of register 0x1c to select a shadow
  * register to access.
  */
+/* 00101: Spare Control Register 3 */
+#define BCM54XX_SHD_SCR3                0x05
+#define  BCM54XX_SHD_SCR3_DEF_CLK125    0x0001
+
 #define BCM5482_SHD_LEDS1       0x0d    /* 01101: LED Selector 1 */
                                         /* LED3 / ~LINKSPD[2] selector */
 #define BCM5482_SHD_LEDS1_LED3(src)     ((src & 0xf) << 4)
@@ -112,6 +120,7 @@
 #define BCM5482_SHD_MODE        0x1f    /* 11111: Mode Control Register */
 #define BCM5482_SHD_MODE_1000BX 0x0001  /* Enable 1000BASE-X registers */
 
+
 /*
  * EXPANSION SHADOW ACCESS REGISTERS.  (PHY REG 0x15, 0x16, and 0x17)
  */
@@ -309,6 +318,37 @@ error:
         return err ? err : err2;
 }
 
+static void bcm54xx_adjust_rxrefclk(struct phy_device *phydev)
+{
+        u32 val, orig;
+
+        /* Abort if we are using an untested phy. */
+        if (BRCM_PHY_MODEL(phydev) != PHY_ID_BCM50610 ||
+            BRCM_PHY_MODEL(phydev) != PHY_ID_BCM50610M)
+                return;
+
+        val = bcm54xx_shadow_read(phydev, BCM54XX_SHD_SCR3);
+        if (val < 0)
+                return;
+
+        orig = val;
+
+        if (phydev->dev_flags & PHY_BRCM_RX_REFCLK_UNUSED) {
+                if ((BRCM_PHY_MODEL(phydev) == PHY_ID_BCM50610 ||
+                     BRCM_PHY_MODEL(phydev) == PHY_ID_BCM50610M) &&
+                    BRCM_PHY_REV(phydev) >= 0x3) {
+                        /* Here, bit 0 _disables_ CLK125 when set */
+                        val |= BCM54XX_SHD_SCR3_DEF_CLK125;
+                } else {
+                        /* Here, bit 0 _enables_ CLK125 when set */
+                        val &= ~BCM54XX_SHD_SCR3_DEF_CLK125;
+                }
+        }
+
+        if (orig != val)
+                bcm54xx_shadow_write(phydev, BCM54XX_SHD_SCR3, val);
+}
+
 static int bcm54xx_config_init(struct phy_device *phydev)
 {
         int reg, err;
@@ -336,6 +376,9 @@ static int bcm54xx_config_init(struct phy_device *phydev)
             (phydev->dev_flags & PHY_BRCM_CLEAR_RGMII_MODE))
                 bcm54xx_shadow_write(phydev, BCM54XX_SHD_RGMII_MODE, 0);
 
+        if (phydev->dev_flags & PHY_BRCM_RX_REFCLK_UNUSED)
+                bcm54xx_adjust_rxrefclk(phydev);
+
         bcm54xx_phydsp_config(phydev);
 
         return 0;