netdev - Re: [PATCH net-next] net: dsa: realtek: realtek-mdio: reset before setup

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Message-ID: <ccf3f079-4567-7de6-46f2-7b8896b06d77@gmail.com>
Date:   Fri, 11 Feb 2022 13:01:53 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Luiz Angelo Daros de Luca <luizluca@...il.com>,
        netdev@...r.kernel.org
Cc:     linus.walleij@...aro.org, andrew@...n.ch, vivien.didelot@...il.com,
        olteanv@...il.com, davem@...emloft.net, kuba@...nel.org,
        alsi@...g-olufsen.dk, arinc.unal@...nc9.com,
        Frank Wunderlich <frank-w@...lic-files.de>
Subject: Re: [PATCH net-next] net: dsa: realtek: realtek-mdio: reset before
 setup

On 2/10/22 9:14 PM, Luiz Angelo Daros de Luca wrote:
> Some devices, like the switch in Banana Pi BPI R64 only starts to answer
> after a HW reset. It is the same reset code from realtek-smi.
> 
> Reported-by: Frank Wunderlich <frank-w@...lic-files.de>
> Signed-off-by: Luiz Angelo Daros de Luca <luizluca@...il.com>
> ---

[snip]

>  	ret = priv->ops->detect(priv);
>  	if (ret) {
>  		dev_err(dev, "unable to detect switch\n");
> @@ -183,6 +198,10 @@ static void realtek_mdio_remove(struct mdio_device *mdiodev)
>  	if (!priv)
>  		return;
>  
> +	/* leave the device reset asserted */
> +	if (priv->reset)
> +		gpiod_set_value(priv->reset, 1);
> +
>  	dsa_unregister_switch(priv->ds);
>  
>  	dev_set_drvdata(&mdiodev->dev, NULL);
> diff --git a/drivers/net/dsa/realtek/realtek-smi.c b/drivers/net/dsa/realtek/realtek-smi.c
> index a849b5cbb4e4..cada5386f6a2 100644
> --- a/drivers/net/dsa/realtek/realtek-smi.c
> +++ b/drivers/net/dsa/realtek/realtek-smi.c
> @@ -43,8 +43,6 @@
>  #include "realtek.h"
>  
>  #define REALTEK_SMI_ACK_RETRY_COUNT		5
> -#define REALTEK_SMI_HW_STOP_DELAY		25	/* msecs */
> -#define REALTEK_SMI_HW_START_DELAY		100	/* msecs */
>  
>  static inline void realtek_smi_clk_delay(struct realtek_priv *priv)
>  {
> @@ -426,9 +424,9 @@ static int realtek_smi_probe(struct platform_device *pdev)
>  		dev_err(dev, "failed to get RESET GPIO\n");
>  		return PTR_ERR(priv->reset);
>  	}
> -	msleep(REALTEK_SMI_HW_STOP_DELAY);
> +	msleep(REALTEK_HW_STOP_DELAY);
>  	gpiod_set_value(priv->reset, 0);
> -	msleep(REALTEK_SMI_HW_START_DELAY);
> +	msleep(REALTEK_HW_START_DELAY);
>  	dev_info(dev, "deasserted RESET\n");

Maybe demote these to debug prints since they would show up every time
you load/unload the driver.
-- 
Florian