netdev - Re: [PATCH net-next v2] net: dsa: realtek: realtek-mdio: reset before setup

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Message-Id: <B3AA2DEA-D04C-49C8-9D22-BA6D64F7A6B2@arinc9.com>
Date:   Sat, 12 Feb 2022 05:47:49 +0300
From:   Arınç ÜNAL <arinc.unal@...nc9.com>
To:     Luiz Angelo Daros de Luca <luizluca@...il.com>
Cc:     netdev@...r.kernel.org, linus.walleij@...aro.org, andrew@...n.ch,
        vivien.didelot@...il.com, f.fainelli@...il.com, olteanv@...il.com,
        davem@...emloft.net, kuba@...nel.org, alsi@...g-olufsen.dk,
        Frank Wunderlich <frank-w@...lic-files.de>
Subject: Re:  [PATCH net-next v2] net: dsa: realtek: realtek-mdio: reset before setup


> 
> On 12 Feb 2022, at 05:27, Luiz Angelo Daros de Luca <luizluca@...il.com> 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.
> 
> In realtek-smi, only assert the reset when the gpio is defined.

If realtek-smi also resets before setup with this patch (I don’t understand code very well) can you mention it next to mdio in the summary too?

In any case:
Acked-by: Arınç ÜNAL <arinc.unal@...nc9.com>

> 
> Reported-by: Frank Wunderlich <frank-w@...lic-files.de>
> Signed-off-by: Luiz Angelo Daros de Luca <luizluca@...il.com>
> Tested-by: Frank Wunderlich <frank-w@...lic-files.de>
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
> Reviewed-by: Alvin Šipraga <alsi@...g-olufsen.dk>
> ---
> drivers/net/dsa/realtek/realtek-mdio.c | 19 +++++++++++++++++++
> drivers/net/dsa/realtek/realtek-smi.c  | 17 ++++++++++-------
> drivers/net/dsa/realtek/realtek.h      |  3 +++
> 3 files changed, 32 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/dsa/realtek/realtek-mdio.c b/drivers/net/dsa/realtek/realtek-mdio.c
> index 0c5f2bdced9d..fa2339763c71 100644
> --- a/drivers/net/dsa/realtek/realtek-mdio.c
> +++ b/drivers/net/dsa/realtek/realtek-mdio.c
> @@ -152,6 +152,21 @@ static int realtek_mdio_probe(struct mdio_device *mdiodev)
>   /* TODO: if power is software controlled, set up any regulators here */
>   priv->leds_disabled = of_property_read_bool(np, "realtek,disable-leds");
> 
> +    /* Assert then deassert RESET */
> +    priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +    if (IS_ERR(priv->reset)) {
> +        dev_err(dev, "failed to get RESET GPIO\n");
> +        return PTR_ERR(priv->reset);
> +    }
> +
> +    if (priv->reset) {
> +        dev_dbg(dev, "asserted RESET\n");
> +        msleep(REALTEK_HW_STOP_DELAY);
> +        gpiod_set_value(priv->reset, 0);
> +        msleep(REALTEK_HW_START_DELAY);
> +        dev_dbg(dev, "deasserted RESET\n");
> +    }
> +
>   ret = priv->ops->detect(priv);
>   if (ret) {
>       dev_err(dev, "unable to detect switch\n");
> @@ -185,6 +200,10 @@ static void realtek_mdio_remove(struct mdio_device *mdiodev)
> 
>   dsa_unregister_switch(priv->ds);
> 
> +    /* leave the device reset asserted */
> +    if (priv->reset)
> +        gpiod_set_value(priv->reset, 1);
> +
>   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 946fbbd70153..a13ef07080a2 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)
> {
> @@ -426,10 +424,13 @@ 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);
> -    gpiod_set_value(priv->reset, 0);
> -    msleep(REALTEK_SMI_HW_START_DELAY);
> -    dev_info(dev, "deasserted RESET\n");
> +    if (priv->reset) {
> +        dev_dbg(dev, "asserted RESET\n");
> +        msleep(REALTEK_HW_STOP_DELAY);
> +        gpiod_set_value(priv->reset, 0);
> +        msleep(REALTEK_HW_START_DELAY);
> +        dev_dbg(dev, "deasserted RESET\n");
> +    }
> 
>   /* Fetch MDIO pins */
>   priv->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);
> @@ -474,7 +475,9 @@ static int realtek_smi_remove(struct platform_device *pdev)
>   dsa_unregister_switch(priv->ds);
>   if (priv->slave_mii_bus)
>       of_node_put(priv->slave_mii_bus->dev.of_node);
> -    gpiod_set_value(priv->reset, 1);
> +
> +    if (priv->reset)
> +        gpiod_set_value(priv->reset, 1);
> 
>   platform_set_drvdata(pdev, NULL);
> 
> diff --git a/drivers/net/dsa/realtek/realtek.h b/drivers/net/dsa/realtek/realtek.h
> index 3512b832b148..e7d3e1bcf8b8 100644
> --- a/drivers/net/dsa/realtek/realtek.h
> +++ b/drivers/net/dsa/realtek/realtek.h
> @@ -13,6 +13,9 @@
> #include <linux/gpio/consumer.h>
> #include <net/dsa.h>
> 
> +#define REALTEK_HW_STOP_DELAY        25    /* msecs */
> +#define REALTEK_HW_START_DELAY        100    /* msecs */
> +
> struct realtek_ops;
> struct dentry;
> struct inode;
> -- 
> 2.35.1