[RFC PATCH net-next 2/3] net: phy: broadcom: implement .disable_autonomous_eee for BCM54xx

[Nicolai Buchwitz <nb@tipi-net.de>]

Disable AutogrEEEn mode on BCM54210E when the MAC indicates EEE support
via phy_support_eee(). In AutogrEEEn mode the PHY manages LPI
autonomously without forwarding LPI signaling to the MAC over the RGMII
interface, which prevents the MAC from controlling TX LPI entry/exit.

Clearing the AutogrEEEn enable bit in MII_BUF_CNTL_0 switches the PHY
to Native EEE mode where the MAC controls TX LPI and the PHY forwards
received LPI on the RGMII interface.

Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>
---
 drivers/net/phy/broadcom.c | 7 +++++++
 include/linux/brcmphy.h    | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index cb306f9e80cc..bf0c6a04481e 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -1452,6 +1452,12 @@ static int bcm54811_read_status(struct phy_device *phydev)
 	return genphy_read_status(phydev);
 }
 
+static int bcm54xx_disable_autonomous_eee(struct phy_device *phydev)
+{
+	return bcm_phy_modify_exp(phydev, BCM54XX_TOP_MISC_MII_BUF_CNTL0,
+				  BCM54XX_MII_BUF_CNTL0_AUTOGREEEN_EN, 0);
+}
+
 static struct phy_driver broadcom_drivers[] = {
 {
 	PHY_ID_MATCH_MODEL(PHY_ID_BCM5411),
@@ -1495,6 +1501,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.get_wol	= bcm54xx_phy_get_wol,
 	.set_wol	= bcm54xx_phy_set_wol,
 	.led_brightness_set	= bcm_phy_led_brightness_set,
+	.disable_autonomous_eee	= bcm54xx_disable_autonomous_eee,
 }, {
 	PHY_ID_MATCH_MODEL(PHY_ID_BCM5461),
 	.name		= "Broadcom BCM5461",
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 115a964f3006..174687c4c80a 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -266,6 +266,9 @@
 #define BCM54XX_TOP_MISC_IDDQ_SD		(1 << 2)
 #define BCM54XX_TOP_MISC_IDDQ_SR		(1 << 3)
 
+#define BCM54XX_TOP_MISC_MII_BUF_CNTL0		(MII_BCM54XX_EXP_SEL_TOP + 0x00)
+#define  BCM54XX_MII_BUF_CNTL0_AUTOGREEEN_EN	BIT(0)
+
 #define BCM54XX_TOP_MISC_LED_CTL		(MII_BCM54XX_EXP_SEL_TOP + 0x0C)
 #define  BCM54XX_LED4_SEL_INTR			BIT(1)
 
-- 
2.51.0