net: dsa: realtek: realtek-mdio: reset before setup

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@public-files.de>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Tested-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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");
 
+	priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->reset)) {
+		dev_err(dev, "failed to get RESET GPIO\n");
+		return PTR_ERR(priv->reset);
+	}
+
+	if (priv->reset) {
+		gpiod_set_value(priv->reset, 1);
+		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);
 }
 

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)
 {
@@ -428,9 +426,9 @@ static int realtek_smi_probe(struct platform_device *pdev)
 	if (priv->reset) {
 		gpiod_set_value(priv->reset, 1);
 		dev_dbg(dev, "asserted RESET\n");
-		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_dbg(dev, "deasserted RESET\n");
 	}
 

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;