[PATCH net-next v2] net: phy: broadcom: Implement suspend/resume for AC131 and BCM5241

From: Florian Fainelli
Date: Mon Aug 15 2022 - 16:45:16 EST


Implement the suspend/resume procedure for the Broadcom AC131 and BCM5241 type
of PHYs (10/100 only) by entering the standard power down followed by the
proprietary standby mode in the auxiliary mode 4 shadow register. On resume,
the PHY software reset is enough to make it come out of standby mode so we can
utilize brcm_fet_config_init() as the resume hook.

Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
Changes in v2:

- utilize phy_modify() to write to MII_BRCM_FET_SHDW_AUXMODE4 (Russell)

drivers/net/phy/broadcom.c | 39 ++++++++++++++++++++++++++++++++++++++
include/linux/brcmphy.h | 1 +
2 files changed, 40 insertions(+)

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 31fbcdddc9ad..ad71c88c87e7 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -766,6 +766,41 @@ static irqreturn_t brcm_fet_handle_interrupt(struct phy_device *phydev)
return IRQ_HANDLED;
}

+static int brcm_fet_suspend(struct phy_device *phydev)
+{
+ int reg, err, err2, brcmtest;
+
+ /* We cannot use a read/modify/write here otherwise the PHY continues
+ * to drive LEDs which defeats the purpose of low power mode.
+ */
+ err = phy_write(phydev, MII_BMCR, BMCR_PDOWN);
+ if (err < 0)
+ return err;
+
+ /* Enable shadow register access */
+ brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
+ if (brcmtest < 0)
+ return brcmtest;
+
+ reg = brcmtest | MII_BRCM_FET_BT_SRE;
+
+ err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
+ if (err < 0)
+ return err;
+
+ /* Set standby mode */
+ err = phy_modify(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
+ MII_BRCM_FET_SHDW_AM4_STANDBY,
+ MII_BRCM_FET_SHDW_AM4_STANDBY);
+
+ /* Disable shadow register access */
+ err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
+ if (!err)
+ err = err2;
+
+ return err;
+}
+
static int bcm54xx_phy_probe(struct phy_device *phydev)
{
struct bcm54xx_phy_priv *priv;
@@ -1033,6 +1068,8 @@ static struct phy_driver broadcom_drivers[] = {
.config_init = brcm_fet_config_init,
.config_intr = brcm_fet_config_intr,
.handle_interrupt = brcm_fet_handle_interrupt,
+ .suspend = brcm_fet_suspend,
+ .resume = brcm_fet_config_init,
}, {
.phy_id = PHY_ID_BCM5241,
.phy_id_mask = 0xfffffff0,
@@ -1041,6 +1078,8 @@ static struct phy_driver broadcom_drivers[] = {
.config_init = brcm_fet_config_init,
.config_intr = brcm_fet_config_intr,
.handle_interrupt = brcm_fet_handle_interrupt,
+ .suspend = brcm_fet_suspend,
+ .resume = brcm_fet_config_init,
}, {
.phy_id = PHY_ID_BCM5395,
.phy_id_mask = 0xfffffff0,
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 6ff567ece34a..9e77165f3ef6 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -293,6 +293,7 @@
#define MII_BRCM_FET_SHDW_MC_FAME 0x4000 /* Force Auto MDIX enable */

#define MII_BRCM_FET_SHDW_AUXMODE4 0x1a /* Auxiliary mode 4 */
+#define MII_BRCM_FET_SHDW_AM4_STANDBY 0x0008 /* Standby enable */
#define MII_BRCM_FET_SHDW_AM4_LED_MASK 0x0003
#define MII_BRCM_FET_SHDW_AM4_LED_MODE1 0x0001

--
2.25.1