netdev - RE: [EXT] [PATCH net v3] net: fec: fix clock count mis-match

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Date:   Tue, 19 Nov 2019 01:49:29 +0000
From:   Andy Duan <fugang.duan@....com>
To:     Chuhong Yuan <hslester96@...il.com>
CC:     "David S . Miller" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [EXT] [PATCH net v3] net: fec: fix clock count mis-match

From: Chuhong Yuan <hslester96@...il.com> Sent: Monday, November 18, 2019 8:18 PM
> pm_runtime_put_autosuspend in probe will call suspend to disable clks
> automatically if CONFIG_PM is defined. (If CONFIG_PM is not defined, its
> implementation will be empty, then suspend will not be called.)

suspend -> runtime suspend
> 
> Therefore, we can call pm_runtime_get_sync to resume it first to enable clks,
resume -> runtime resume
> which matches the suspend. (Only when CONFIG_PM is defined, otherwise
suspend -> runtime suspend
> pm_runtime_get_sync will also be empty, then 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>
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index a9c386b63581..4bb30761abfc 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -3636,6 +3636,11 @@ fec_drv_remove(struct platform_device *pdev)
>         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);
> @@ -3643,15 +3648,17 @@ fec_drv_remove(struct platform_device *pdev)
>         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;
>  }
> 
> --
> 2.24.0