[PATCH RFC] ethernet: stmmac: clean up the code for release/suspend/resume function

[Joakim Zhang]

commit 1c35cc9cf6a0 ("net: stmmac: remove redundant null check before 
clk_disable_unprepare()"),
have not clean up check NULL clock parameter completely, this patch did it.

commit e8377e7a29efb ("net: stmmac: only call pmt() during suspend/resume if HW 
enables PMT"),
after this patch, we use
if (device_may_wakeup(priv->device) && priv->plat->pmt) check MAC wakeup
if (device_may_wakeup(priv->device)) check PHY wakeup
Add oneline comment for readability.

commit 77b2898394e3b ("net: stmmac: Speed down the PHY if WoL to save energy"),
slow down phy speed when release net device under any condition.

Slightly adjust the order of the codes so that suspend/resume look more
symmetrical, generally speaking they should appear symmetrically.

Signed-off-by: Joakim Zhang <qiangqing.zh...@nxp.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 22 +++++++++----------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c33db79cdd0a..a46e865c4acc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2908,8 +2908,7 @@ static int stmmac_release(struct net_device *dev)
        struct stmmac_priv *priv = netdev_priv(dev);
        u32 chan;
 
-       if (device_may_wakeup(priv->device))
-               phylink_speed_down(priv->phylink, false);
+       phylink_speed_down(priv->phylink, false);
        /* Stop and disconnect the PHY */
        phylink_stop(priv->phylink);
        phylink_disconnect_phy(priv->phylink);
@@ -5183,6 +5182,7 @@ int stmmac_suspend(struct device *dev)
        } else {
                mutex_unlock(&priv->lock);
                rtnl_lock();
+               /* For PHY wakeup case */
                if (device_may_wakeup(priv->device))
                        phylink_speed_down(priv->phylink, false);
                phylink_stop(priv->phylink);
@@ -5260,11 +5260,17 @@ int stmmac_resume(struct device *dev)
                /* enable the clk previously disabled */
                clk_prepare_enable(priv->plat->stmmac_clk);
                clk_prepare_enable(priv->plat->pclk);
-               if (priv->plat->clk_ptp_ref)
-                       clk_prepare_enable(priv->plat->clk_ptp_ref);
+               clk_prepare_enable(priv->plat->clk_ptp_ref);
                /* reset the phy so that it's ready */
                if (priv->mii)
                        stmmac_mdio_reset(priv->mii);
+
+               rtnl_lock();
+               phylink_start(priv->phylink);
+               /* We may have called phylink_speed_down before */
+               if (device_may_wakeup(priv->device))
+                       phylink_speed_up(priv->phylink);
+               rtnl_unlock();
        }
 
        if (priv->plat->serdes_powerup) {
@@ -5275,14 +5281,6 @@ int stmmac_resume(struct device *dev)
                        return ret;
        }
 
-       if (!device_may_wakeup(priv->device) || !priv->plat->pmt) {
-               rtnl_lock();
-               phylink_start(priv->phylink);
-               /* We may have called phylink_speed_down before */
-               phylink_speed_up(priv->phylink);
-               rtnl_unlock();
-       }
-
        rtnl_lock();
        mutex_lock(&priv->lock);
 
-- 
2.17.1