[PATCH net-next v4 13/12] net: lan865x: optional hardware reset

[Ramón Nordin Rodriguez <ramon.nordin.rodriguez@xxxxxxxxxxx>]

>From c65e42982684d5fd8b2294eb6acf755aa0fcab83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ram=C3=B3n=20Nordin=20Rodriguez?=
 <ramon.nordin.rodriguez@xxxxxxxxxxx>
Date: Sun, 28 Apr 2024 22:25:12 +0200
Subject: [PATCH net-next v4 13/12] net: lan865x: optional hardware reset
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This commit optionally enables a hardware reset of the lan8650/1
mac-phy. These chips have a software reset that is discourage from use
in the manual since it only resets the internal phy.

Signed-off-by: Ramón Nordin Rodriguez <ramon.nordin.rodriguez@xxxxxxxxxxx>
---
 .../bindings/net/microchip,lan865x.yaml       |  4 +++
 .../net/ethernet/microchip/lan865x/lan865x.c  | 28 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/microchip,lan865x.yaml b/Documentation/devicetree/bindings/net/microchip,lan865x.yaml
index 4fdec0ba3532..0f11f431df06 100644
--- a/Documentation/devicetree/bindings/net/microchip,lan865x.yaml
+++ b/Documentation/devicetree/bindings/net/microchip,lan865x.yaml
@@ -44,6 +44,9 @@ properties:
     minimum: 15000000
     maximum: 25000000
 
+  reset-gpios:
+    maxItems: 1
+
   "#address-cells":
     const: 1
 
@@ -76,5 +79,6 @@ examples:
         interrupts = <6 IRQ_TYPE_EDGE_FALLING>;
         local-mac-address = [04 05 06 01 02 03];
         spi-max-frequency = <15000000>;
+        reset-gpios = <&gpio2 8 GPIO_ACTIVE_HIGH>;
       };
     };
diff --git a/drivers/net/ethernet/microchip/lan865x/lan865x.c b/drivers/net/ethernet/microchip/lan865x/lan865x.c
index 9abefa8b9d9f..bed9033574b2 100644
--- a/drivers/net/ethernet/microchip/lan865x/lan865x.c
+++ b/drivers/net/ethernet/microchip/lan865x/lan865x.c
@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/phy.h>
 #include <linux/oa_tc6.h>
+#include <linux/gpio/driver.h>
 
 #define DRV_NAME			"lan865x"
 
@@ -33,6 +34,7 @@
 
 struct lan865x_priv {
 	struct work_struct multicast_work;
+	struct gpio_desc *reset_gpio;
 	struct net_device *netdev;
 	struct spi_device *spi;
 	struct oa_tc6 *tc6;
@@ -283,6 +285,24 @@ static int lan865x_set_zarfe(struct lan865x_priv *priv)
 	return oa_tc6_write_register(priv->tc6, OA_TC6_REG_CONFIG0, regval);
 }
 
+static int lan865x_probe_reset_gpio(struct lan865x_priv *priv)
+{
+	priv->reset_gpio = devm_gpiod_get_optional(&priv->spi->dev, "reset",
+						   GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->reset_gpio))
+		return PTR_ERR(priv->reset_gpio);
+
+	return 0;
+}
+
+static void lan865x_hw_reset(struct lan865x_priv *priv)
+{
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	// section 9.6.3 RESET_N Timing specifies a minimum hold of 5us
+	usleep_range(5, 10);
+	gpiod_set_value_cansleep(priv->reset_gpio, 0);
+}
+
 static int lan865x_probe(struct spi_device *spi)
 {
 	struct net_device *netdev;
@@ -297,6 +317,14 @@ static int lan865x_probe(struct spi_device *spi)
 	priv->netdev = netdev;
 	priv->spi = spi;
 	spi_set_drvdata(spi, priv);
+	if (lan865x_probe_reset_gpio(priv)) {
+		dev_err(&spi->dev, "failed to probe reset pin");
+		ret = -ENODEV;
+		goto free_netdev;
+	}
+
+	if (priv->reset_gpio)
+		lan865x_hw_reset(priv);
 	INIT_WORK(&priv->multicast_work, lan865x_multicast_work_handler);
 
 	priv->tc6 = oa_tc6_init(spi, netdev);
-- 
2.43.0