[PATCH net-next v3 3/4] net: phy: aquantia: wait for the GLOBAL_CFG to start returning real values

[Bartosz Golaszewski <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

When the PHY is first coming up (or resuming from suspend), it's
possible that although the FW status shows as running, we still see
zeroes in the GLOBAL_CFG set of registers and cannot determine available
modes. Since all models support 10M, add a poll and wait the config to
become available.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/net/phy/aquantia/aquantia_main.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/aquantia/aquantia_main.c b/drivers/net/phy/aquantia/aquantia_main.c
index 974795bd0860..2c8ba2725a91 100644
--- a/drivers/net/phy/aquantia/aquantia_main.c
+++ b/drivers/net/phy/aquantia/aquantia_main.c
@@ -652,7 +652,13 @@ static int aqr107_fill_interface_modes(struct phy_device *phydev)
 	unsigned long *possible = phydev->possible_interfaces;
 	unsigned int serdes_mode, rate_adapt;
 	phy_interface_t interface;
-	int i, val;
+	int i, val, ret;
+
+	ret = phy_read_mmd_poll_timeout(phydev, MDIO_MMD_VEND1,
+					VEND1_GLOBAL_CFG_10M, val, val != 0,
+					1000, 100000, false);
+	if (ret)
+		return ret;
 
 	/* Walk the media-speed configuration registers to determine which
 	 * host-side serdes modes may be used by the PHY depending on the
-- 
2.43.0