linux-kernel - [PATCH 4.9 125/125] net: fec: fix clock count mis-match

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Date:   Wed,  4 Dec 2019 18:57:10 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chuhong Yuan <hslester96@...il.com>,
        Fugang Duan <fugang.duan@....com>,
        "David S. Miller" <davem@...emloft.net>,
        Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
Subject: [PATCH 4.9 125/125] net: fec: fix clock count mis-match

From: Chuhong Yuan <hslester96@...il.com>

commit a31eda65ba210741b598044d045480494d0ed52a upstream.

pm_runtime_put_autosuspend in probe will call runtime suspend to
disable clks automatically if CONFIG_PM is defined. (If CONFIG_PM
is not defined, its implementation will be empty, then runtime
suspend will not be called.)

Therefore, we can call pm_runtime_get_sync to runtime resume it
first to enable clks, which matches the runtime suspend. (Only when
CONFIG_PM is defined, otherwise pm_runtime_get_sync will also be
empty, then runtime resume will not be called.)

Then it is fine to disable clks without causing clock count mis-match.

Fixes: c43eab3eddb4 ("net: fec: add missed clk_disable_unprepare in remove")
Signed-off-by: Chuhong Yuan <hslester96@...il.com>
Acked-by: Fugang Duan <fugang.duan@....com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Cc: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/ethernet/freescale/fec_main.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3530,6 +3530,11 @@ fec_drv_remove(struct platform_device *p
 	struct net_device *ndev = platform_get_drvdata(pdev);
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0)
+		return ret;

 	cancel_work_sync(&fep->tx_timeout_work);
 	fec_ptp_stop(pdev);
@@ -3537,15 +3542,17 @@ fec_drv_remove(struct platform_device *p
 	fec_enet_mii_remove(fep);
 	if (fep->reg_phy)
 		regulator_disable(fep->reg_phy);
-	pm_runtime_put(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-	clk_disable_unprepare(fep->clk_ahb);
-	clk_disable_unprepare(fep->clk_ipg);
+
 	if (of_phy_is_fixed_link(np))
 		of_phy_deregister_fixed_link(np);
 	of_node_put(fep->phy_node);
 	free_netdev(ndev);

+	clk_disable_unprepare(fep->clk_ahb);
+	clk_disable_unprepare(fep->clk_ipg);
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
 	return 0;
 }