net: phy: broadcom: Add IDDQ-SR mode

Add support for putting the PHY into IDDQ Soft Recovery mode by setting
the TOP_MISC register bits accordingly. This requires us to implement a
custom bcm54xx_suspend() routine which diverges from genphy_suspend() in
order to configure the PHY to enter IDDQ with software recovery as well
as avoid doing a read/modify/write on the BMCR register.

Doing a read/modify/write on the BMCR register means that the
auto-negotation bit may remain which interferes with the ability to put
the PHY into IDDQ-SR mode. We do software reset upon suspend in order to
put the PHY back into its state prior to suspend as recommended by the
datasheet.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 51 insertions, 0 deletions

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index add0c4e33425..f5868a0dee4b 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -392,10 +392,50 @@ static int bcm54xx_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+static int bcm54xx_iddq_set(struct phy_device *phydev, bool enable)
+{
+	int ret = 0;
+
+	if (!(phydev->dev_flags & PHY_BRCM_IDDQ_SUSPEND))
+		return ret;
+
+	ret = bcm_phy_read_exp(phydev, BCM54XX_TOP_MISC_IDDQ_CTRL);
+	if (ret < 0)
+		goto out;
+
+	if (enable)
+		ret |= BCM54XX_TOP_MISC_IDDQ_SR | BCM54XX_TOP_MISC_IDDQ_LP;
+	else
+		ret &= ~(BCM54XX_TOP_MISC_IDDQ_SR | BCM54XX_TOP_MISC_IDDQ_LP);
+
+	ret = bcm_phy_write_exp(phydev, BCM54XX_TOP_MISC_IDDQ_CTRL, ret);
+out:
+	return ret;
+}
+
+static int bcm54xx_suspend(struct phy_device *phydev)
+{
+	int ret;
+
+	/* We cannot use a read/modify/write here otherwise the PHY gets into
+	 * a bad state where its LEDs keep flashing, thus defeating the purpose
+	 * of low power mode.
+	 */
+	ret = phy_write(phydev, MII_BMCR, BMCR_PDOWN);
+	if (ret < 0)
+		return ret;
+
+	return bcm54xx_iddq_set(phydev, true);
+}
+
 static int bcm54xx_resume(struct phy_device *phydev)
 {
 	int ret;
 
+	ret = bcm54xx_iddq_set(phydev, false);
+	if (ret < 0)
+		return ret;
+
 	/* Writes to register other than BMCR would be ignored
 	 * unless we clear the PDOWN bit first
 	 */
@@ -408,6 +448,15 @@ static int bcm54xx_resume(struct phy_device *phydev)
 	 */
 	fsleep(40);
 
+	/* Issue a soft reset after clearing the power down bit
+	 * and before doing any other configuration.
+	 */
+	if (phydev->dev_flags & PHY_BRCM_IDDQ_SUSPEND) {
+		ret = genphy_soft_reset(phydev);
+		if (ret < 0)
+			return ret;
+	}
+
 	return bcm54xx_config_init(phydev);
 }
 
@@ -772,6 +821,8 @@ static struct phy_driver broadcom_drivers[] = {
 	.config_intr	= bcm_phy_config_intr,
 	.handle_interrupt = bcm_phy_handle_interrupt,
 	.link_change_notify	= bcm54xx_link_change_notify,
+	.suspend	= bcm54xx_suspend,
+	.resume		= bcm54xx_resume,
 }, {
 	.phy_id		= PHY_ID_BCM5461,
 	.phy_id_mask	= 0xfffffff0,