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

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Date:   Fri, 11 Feb 2022 07:09:25 +0100
From:   Frank Wunderlich <frank-w@...lic-files.de>
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,
        f.fainelli@...il.com, olteanv@...il.com, davem@...emloft.net,
        kuba@...nel.org, alsi@...g-olufsen.dk, arinc.unal@...nc9.com
Subject: Re: [PATCH net-next] net: dsa: realtek: realtek-mdio: reset before setup

Am 11. Februar 2022 06:14:04 MEZ schrieb Luiz Angelo Daros de Luca <luizluca@...il.com>:
>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>
>---
> drivers/net/dsa/realtek/realtek-mdio.c | 19 +++++++++++++++++++
> drivers/net/dsa/realtek/realtek-smi.c  |  6 ++----
> drivers/net/dsa/realtek/realtek.h      |  9 ++++++---
> 3 files changed, 27 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/net/dsa/realtek/realtek-mdio.c
>b/drivers/net/dsa/realtek/realtek-mdio.c
>index e6e3c1769166..78b419a6cb01 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_info(dev, "asserted RESET\n");
>+		msleep(REALTEK_HW_STOP_DELAY);
>+		gpiod_set_value(priv->reset, 0);
>+		msleep(REALTEK_HW_START_DELAY);
>+		dev_info(dev, "deasserted RESET\n");
>+	}
>+
> 	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");
> 
> 	/* Fetch MDIO pins */
>diff --git a/drivers/net/dsa/realtek/realtek.h
>b/drivers/net/dsa/realtek/realtek.h
>index ed5abf6cb3d6..e7d3e1bcf8b8 100644
>--- a/drivers/net/dsa/realtek/realtek.h
>+++ b/drivers/net/dsa/realtek/realtek.h
>@@ -5,14 +5,17 @@
>  * Copyright (C) 2009-2010 Gabor Juhos <juhosg@...nwrt.org>
>  */
> 
>-#ifndef _REALTEK_SMI_H
>-#define _REALTEK_SMI_H
>+#ifndef _REALTEK_H
>+#define _REALTEK_H
> 
> #include <linux/phy.h>
> #include <linux/platform_device.h>
> #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;
>@@ -142,4 +145,4 @@ void rtl8366_get_ethtool_stats(struct dsa_switch
>*ds, int port, uint64_t *data);
> extern const struct realtek_variant rtl8366rb_variant;
> extern const struct realtek_variant rtl8365mb_variant;
> 
>-#endif /*  _REALTEK_SMI_H */
>+#endif /*  _REALTEK_H */

Tested on Bpi-r64 v0.1. After this reset switch gets recognized. Before mdio-read is always 0.

Tested-by: Frank Wunderlich <frank-w@...lic-files.de>
regards Frank