linux-kernel - RE: [EXT] [PATCH] net: fec: add missed clk_disable

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Message-ID: <VI1PR0402MB36006B7BEAA7F4BCB9278598FF7E0@VI1PR0402MB3600.eurprd04.prod.outlook.com>
Date:   Tue, 5 Nov 2019 01:26:29 +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: fec: add missed clk_disable_unprepare in
 remove

From: Chuhong Yuan <hslester96@...il.com> Sent: Monday, November 4, 2019 11:50 PM
> This driver forgets to disable and unprepare clks when remove.
> Add calls to clk_disable_unprepare to fix it.
> 
> Signed-off-by: Chuhong Yuan <hslester96@...il.com>

If runtime is enabled, the patch will introduce clock count mis-match.
Probe->
    Enable clk_ipg, clk_ahb clocks
    ...
    In the end, runtime auto suspend callback disable clk_ipg, clk_ahb clocks.

You should check CONFIG_PM is enabled or not in your platform, if not,
it can disable these two clocks by checking CONFIG_PM.

Regards,
Andy
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index 22c01b224baa..a9c386b63581 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -3645,6 +3645,8 @@ fec_drv_remove(struct platform_device *pdev)
>                 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);
> --
> 2.23.0