netdev - Re: [PATCH 3/3] net: ftgmac100: Ungate RCLK for RMII on ASPEED MACs

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Message-ID: <CACPK8XfmtW9AY7QyBVkWJPvTQncV5o1DVkDwaPUa+ARVYZ4wJQ@mail.gmail.com>
Date:   Tue, 8 Oct 2019 12:44:25 +0000
From:   Joel Stanley <joel@....id.au>
To:     Andrew Jeffery <andrew@...id.au>
Cc:     netdev@...r.kernel.org, "David S . Miller" <davem@...emloft.net>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: Re: [PATCH 3/3] net: ftgmac100: Ungate RCLK for RMII on ASPEED MACs

On Tue, 8 Oct 2019 at 11:50, Andrew Jeffery <andrew@...id.au> wrote:
>
> The 50MHz RCLK has to be enabled before the RMII interface will function.
>
> Signed-off-by: Andrew Jeffery <andrew@...id.au>
> ---
>  drivers/net/ethernet/faraday/ftgmac100.c | 35 +++++++++++++++++++-----
>  1 file changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
> index 9b7af94a40bb..9ff791fb0449 100644
> --- a/drivers/net/ethernet/faraday/ftgmac100.c
> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> @@ -90,6 +90,9 @@ struct ftgmac100 {
>         struct mii_bus *mii_bus;
>         struct clk *clk;
>
> +       /* 2600 RMII clock gate */
> +       struct clk *rclk;
> +
>         /* Link management */
>         int cur_speed;
>         int cur_duplex;
> @@ -1718,12 +1721,14 @@ static void ftgmac100_ncsi_handler(struct ncsi_dev *nd)
>                    nd->link_up ? "up" : "down");
>  }
>
> -static void ftgmac100_setup_clk(struct ftgmac100 *priv)
> +static int ftgmac100_setup_clk(struct ftgmac100 *priv)
>  {
> -       priv->clk = devm_clk_get(priv->dev, NULL);
> -       if (IS_ERR(priv->clk))
> -               return;
> +       struct clk *clk;
>
> +       clk = devm_clk_get(priv->dev, NULL /* MACCLK */);
> +       if (IS_ERR(clk))
> +               return PTR_ERR(clk);
> +       priv->clk = clk;
>         clk_prepare_enable(priv->clk);
>
>         /* Aspeed specifies a 100MHz clock is required for up to
> @@ -1732,6 +1737,14 @@ static void ftgmac100_setup_clk(struct ftgmac100 *priv)
>          */
>         clk_set_rate(priv->clk, priv->use_ncsi ? FTGMAC_25MHZ :
>                         FTGMAC_100MHZ);
> +
> +       /* RCLK is for RMII, typically used for NCSI. Optional because its not
> +        * necessary if it's the 2400 MAC or the MAC is configured for RGMII
> +        */

Or for non-ASPEED users of this driver, assuming they exist.

Reviewed-by: Joel Stanley <joel@....id.au>


> +       priv->rclk = devm_clk_get_optional(priv->dev, "RCLK");
> +       clk_prepare_enable(priv->rclk);
> +
> +       return 0;
>  }
>
>  static int ftgmac100_probe(struct platform_device *pdev)
> @@ -1853,8 +1866,11 @@ static int ftgmac100_probe(struct platform_device *pdev)
>                         goto err_setup_mdio;
>         }
>
> -       if (priv->is_aspeed)
> -               ftgmac100_setup_clk(priv);
> +       if (priv->is_aspeed) {
> +               err = ftgmac100_setup_clk(priv);
> +               if (err)
> +                       goto err_ncsi_dev;
> +       }
>
>         /* Default ring sizes */
>         priv->rx_q_entries = priv->new_rx_q_entries = DEF_RX_QUEUE_ENTRIES;
> @@ -1886,8 +1902,11 @@ static int ftgmac100_probe(struct platform_device *pdev)
>
>         return 0;
>
> -err_ncsi_dev:
>  err_register_netdev:
> +       if (priv->rclk)
> +               clk_disable_unprepare(priv->rclk);
> +       clk_disable_unprepare(priv->clk);
> +err_ncsi_dev:
>         ftgmac100_destroy_mdio(netdev);
>  err_setup_mdio:
>         iounmap(priv->base);
> @@ -1909,6 +1928,8 @@ static int ftgmac100_remove(struct platform_device *pdev)
>
>         unregister_netdev(netdev);
>
> +       if (priv->rclk)
> +               clk_disable_unprepare(priv->rclk);
>         clk_disable_unprepare(priv->clk);
>
>         /* There's a small chance the reset task will have been re-queued,
> --
> 2.20.1
>