linux-kernel - Re: [PATCH net-next RESEND 3/5] net: stmmac: dwmac-sun8i: Use reset_control

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Message-ID: <CAKgT0Ue3GAWbjZcX7aFxuM-iY-Ga2E0JOTftUqPBQC_dEGz_Eg@mail.gmail.com>
Date:   Mon, 8 Feb 2021 08:29:45 -0800
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Samuel Holland <samuel@...lland.org>
Cc:     Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Corentin Labbe <clabbe@...libre.com>,
        Ondrej Jirman <megous@...ous.com>,
        Netdev <netdev@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org,
        LKML <linux-kernel@...r.kernel.org>, linux-sunxi@...glegroups.com
Subject: Re: [PATCH net-next RESEND 3/5] net: stmmac: dwmac-sun8i: Use reset_control_reset

On Sun, Feb 7, 2021 at 10:32 PM Samuel Holland <samuel@...lland.org> wrote:
>
> Use the appropriate function instead of reimplementing it,
> and update the error message to match the code.
>
> Reviewed-by: Chen-Yu Tsai <wens@...e.org>
> Signed-off-by: Samuel Holland <samuel@...lland.org>
> ---
>  drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> index 3c3d0b99d3e8..0e8d88417251 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> @@ -806,11 +806,9 @@ static int sun8i_dwmac_power_internal_phy(struct stmmac_priv *priv)
>         /* Make sure the EPHY is properly reseted, as U-Boot may leave
>          * it at deasserted state, and thus it may fail to reset EMAC.
>          */
> -       reset_control_assert(gmac->rst_ephy);
> -
> -       ret = reset_control_deassert(gmac->rst_ephy);
> +       ret = reset_control_reset(gmac->rst_ephy);
>         if (ret) {
> -               dev_err(priv->device, "Cannot deassert internal phy\n");
> +               dev_err(priv->device, "Cannot reset internal PHY\n");
>                 clk_disable_unprepare(gmac->ephy_clk);
>                 return ret;
>         }

I'm assuming you have exclusive access to the phy and this isn't a
shared line? Just wanting to confirm since the function call has the
following comment in the header for the documentation.

 * Consumers must not use reset_control_(de)assert on shared reset lines when
 * reset_control_reset has been used.
 *

If that is the case it might not hurt to add some documentation to
your call to reset_control_reset here explaining that it is safe to do
so since you have exclusive access.