[PATCH] net: phy: add suspend_halted module param

[Sebastian Hesselbarth]

commit 1211ce53077164e0d34641d0ca5fb4d4a7574498
  ("net: phy: resume/suspend PHYs on attach/detach")
introduced a feature to suspend PHYs when entering halted state.

Unfortunately, not all bootloaders properly power-up PHYs on reset
and fail to access ethernet because the PHY is still powered down.

Therefore, we add a boolean module parameter suspend_halted with
default value of true. Disabling that parameter prevents PHYs from
being suspended when entering halted state.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth at gmail.com>
Reported-by: Andrew Lunn <andrew at lunn.ch>
---
Andrew, can you please re-test if disabling the feature does work on
your board? I tried a bunch of mine, but none failed to power-up the
PHY in u-boot.

Cc: David Miller <davem at davemloft.net>
Cc: Florian Fainelli <f.fainelli at gmail.com>
Cc: Andrew Lunn <andrew at lunn.ch>
Cc: netdev at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
 drivers/net/phy/phy_device.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 4b03e63639b7..671eea0eb5db 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -40,6 +40,10 @@ MODULE_DESCRIPTION("PHY library");
 MODULE_AUTHOR("Andy Fleming");
 MODULE_LICENSE("GPL");
 
+static bool suspend_halted = true;
+module_param(suspend_halted, bool, 0644);
+MODULE_PARM_DESC(suspend_halted, "Suspend PHYs when entering halted state.");
+
 void phy_device_free(struct phy_device *phydev)
 {
 	put_device(&phydev->dev);
@@ -685,6 +689,12 @@ int phy_suspend(struct phy_device *phydev)
 	struct phy_driver *phydrv = to_phy_driver(phydev->dev.driver);
 	struct ethtool_wolinfo wol;
 
+	/* Some bootloaders do not power-up PHYs properly after reset,
+	 * allow to disable the suspend halted PHYs feature.
+	 */
+	if (!suspend_halted)
+		return -ENOSYS;
+
 	/* If the device has WOL enabled, we cannot suspend the PHY */
 	wol.cmd = ETHTOOL_GWOL;
 	phy_ethtool_get_wol(phydev, &wol);
-- 
1.8.5.3