net: phy: broadcom: Enable 10BaseT DAC early wake

Enable the DAC early wake when then link operates at 10BaseT allows
power savings in the hundreds of milli Watts by shutting down the
transmitter. A number of errata have been issued for various Gigabit
PHYs and the recommendation is to enable both the early and forced DAC
wake to be on the safe side. This needs to be done dynamically based
upon the link state, which is why a link_change_notify callback is
utilized.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210916212742.1653088-1-f.fainelli@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/broadcom.c

@@ -702,6 +702,36 @@ static void bcm54xx_get_stats(struct phy_device *phydev,
 	bcm_phy_get_stats(phydev, priv->stats, stats, data);
 }
 
+static void bcm54xx_link_change_notify(struct phy_device *phydev)
+{
+	u16 mask = MII_BCM54XX_EXP_EXP08_EARLY_DAC_WAKE |
+		   MII_BCM54XX_EXP_EXP08_FORCE_DAC_WAKE;
+	int ret;
+
+	if (phydev->state != PHY_RUNNING)
+		return;
+
+	/* Don't change the DAC wake settings if auto power down
+	 * is not requested.
+	 */
+	if (!(phydev->dev_flags & PHY_BRCM_AUTO_PWRDWN_ENABLE))
+		return;
+
+	ret = bcm_phy_read_exp(phydev, MII_BCM54XX_EXP_EXP08);
+	if (ret < 0)
+		return;
+
+	/* Enable/disable 10BaseT auto and forced early DAC wake depending
+	 * on the negotiated speed, those settings should only be done
+	 * for 10Mbits/sec.
+	 */
+	if (phydev->speed == SPEED_10)
+		ret |= mask;
+	else
+		ret &= ~mask;
+	bcm_phy_write_exp(phydev, MII_BCM54XX_EXP_EXP08, ret);
+}
+
 static struct phy_driver broadcom_drivers[] = {
 {
 	.phy_id		= PHY_ID_BCM5411,
@@ -715,6 +745,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM5421,
 	.phy_id_mask	= 0xfffffff0,
@@ -727,6 +758,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM54210E,
 	.phy_id_mask	= 0xfffffff0,
@@ -739,6 +771,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM5461,
 	.phy_id_mask	= 0xfffffff0,
@@ -751,6 +784,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM54612E,
 	.phy_id_mask	= 0xfffffff0,
@@ -763,6 +797,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM54616S,
 	.phy_id_mask	= 0xfffffff0,
@@ -774,6 +809,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.handle_interrupt = bcm_phy_handle_interrupt,
 	.read_status	= bcm54616s_read_status,
 	.probe		= bcm54616s_probe,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM5464,
 	.phy_id_mask	= 0xfffffff0,
@@ -788,6 +824,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.handle_interrupt = bcm_phy_handle_interrupt,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM5481,
 	.phy_id_mask	= 0xfffffff0,
@@ -801,6 +838,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_aneg	= bcm5481_config_aneg,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id         = PHY_ID_BCM54810,
 	.phy_id_mask    = 0xfffffff0,
@@ -816,6 +854,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.handle_interrupt = bcm_phy_handle_interrupt,
 	.suspend	= genphy_suspend,
 	.resume		= bcm54xx_resume,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id         = PHY_ID_BCM54811,
 	.phy_id_mask    = 0xfffffff0,
@@ -831,6 +870,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.handle_interrupt = bcm_phy_handle_interrupt,
 	.suspend	= genphy_suspend,
 	.resume		= bcm54xx_resume,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM5482,
 	.phy_id_mask	= 0xfffffff0,
@@ -843,6 +883,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM50610,
 	.phy_id_mask	= 0xfffffff0,
@@ -855,6 +896,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM50610M,
 	.phy_id_mask	= 0xfffffff0,
@@ -867,6 +909,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM57780,
 	.phy_id_mask	= 0xfffffff0,
@@ -879,6 +922,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCMAC131,
 	.phy_id_mask	= 0xfffffff0,
@@ -905,6 +949,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.get_strings	= bcm_phy_get_strings,
 	.get_stats	= bcm54xx_get_stats,
 	.probe		= bcm54xx_phy_probe,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id		= PHY_ID_BCM53125,
 	.phy_id_mask	= 0xfffffff0,
@@ -918,6 +963,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init	= bcm54xx_config_init,
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 }, {
 	.phy_id         = PHY_ID_BCM89610,
 	.phy_id_mask    = 0xfffffff0,
@@ -930,6 +976,7 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_init    = bcm54xx_config_init,
 	.config_intr    = bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
+	.link_change_notify	= bcm54xx_link_change_notify,
 } };
 
 module_phy_driver(broadcom_drivers);

include/linux/brcmphy.h

@@ -233,6 +233,7 @@
 #define MII_BCM54XX_EXP_EXP08			0x0F08
 #define  MII_BCM54XX_EXP_EXP08_RJCT_2MHZ	0x0001
 #define  MII_BCM54XX_EXP_EXP08_EARLY_DAC_WAKE	0x0200
+#define  MII_BCM54XX_EXP_EXP08_FORCE_DAC_WAKE	0x0100
 #define MII_BCM54XX_EXP_EXP75			0x0f75
 #define  MII_BCM54XX_EXP_EXP75_VDACCTRL		0x003c
 #define  MII_BCM54XX_EXP_EXP75_CM_OSC		0x0001