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From 68502f802a66b68a6b5fefb52e709807a702a94b Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Mon, 26 Nov 2018 19:46:58 +0000
Subject: [PATCH 443/454] net: lan78xx: Support auto-downshift to 100Mb/s
Ethernet cables with faulty or missing pairs (specifically pairs C and
D) allow auto-negotiation to 1000Mbs, but do not support the successful
establishment of a link. Add a DT property, "microchip,downshift-after",
to configure the number of auto-negotiation failures after which it
falls back to 100Mbs. Valid values are 2, 3, 4, 5 and 0, where 0 means
never downshift.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---
drivers/net/phy/microchip.c | 33 +++++++++++++++++++++++++++++++++
drivers/net/usb/lan78xx.c | 8 ++++++--
include/linux/microchipphy.h | 11 +++++++++++
3 files changed, 50 insertions(+), 2 deletions(-)
--- a/drivers/net/phy/microchip.c
+++ b/drivers/net/phy/microchip.c
@@ -21,6 +21,7 @@
#include <linux/phy.h>
#include <linux/microchipphy.h>
#include <linux/delay.h>
+#include <linux/of.h>
#define DRIVER_AUTHOR "WOOJUNG HUH <woojung.huh@microchip.com>"
#define DRIVER_DESC "Microchip LAN88XX PHY driver"
@@ -225,6 +226,7 @@ static int lan88xx_probe(struct phy_devi
{
struct device *dev = &phydev->mdio.dev;
struct lan88xx_priv *priv;
+ u32 downshift_after = 0;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -232,6 +234,37 @@ static int lan88xx_probe(struct phy_devi
priv->wolopts = 0;
+ if (!of_property_read_u32(dev->of_node,
+ "microchip,downshift-after",
+ &downshift_after)) {
+ u32 mask = LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_MASK;
+ u32 val = LAN78XX_PHY_CTRL3_AUTO_DOWNSHIFT;
+
+ switch (downshift_after) {
+ case 2:
+ val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_2;
+ break;
+ case 3:
+ val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_3;
+ break;
+ case 4:
+ val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_4;
+ break;
+ case 5:
+ val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_5;
+ break;
+ case 0:
+ /* Disable completely */
+ mask = LAN78XX_PHY_CTRL3_AUTO_DOWNSHIFT;
+ val = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+ (void)phy_modify_paged(phydev, 1, LAN78XX_PHY_CTRL3,
+ mask, val);
+ }
+
/* these values can be used to identify internal PHY */
priv->chip_id = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_ID);
priv->chip_rev = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_REV);
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -36,7 +36,8 @@
#include <linux/irq.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/microchipphy.h>
-#include <linux/phy.h>
+#include <linux/phy_fixed.h>
+#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include "lan78xx.h"
@@ -1763,6 +1764,7 @@ done:
static int lan78xx_mdio_init(struct lan78xx_net *dev)
{
+ struct device_node *node;
int ret;
dev->mdiobus = mdiobus_alloc();
@@ -1792,7 +1794,9 @@ static int lan78xx_mdio_init(struct lan7
break;
}
- ret = mdiobus_register(dev->mdiobus);
+ node = of_get_child_by_name(dev->udev->dev.of_node, "mdio");
+ ret = of_mdiobus_register(dev->mdiobus, node);
+ of_node_put(node);
if (ret) {
netdev_err(dev->net, "can't register MDIO bus\n");
goto exit1;
--- a/include/linux/microchipphy.h
+++ b/include/linux/microchipphy.h
@@ -70,6 +70,17 @@
#define LAN88XX_MMD3_CHIP_ID (32877)
#define LAN88XX_MMD3_CHIP_REV (32878)
+/* Registers specific to the LAN7800/LAN7850 embedded phy */
+#define LAN78XX_PHY_LED_MODE_SELECT (0x1D)
+
+#define LAN78XX_PHY_CTRL3 (0x14)
+#define LAN78XX_PHY_CTRL3_AUTO_DOWNSHIFT (0x0010)
+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_MASK (0x000c)
+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_2 (0x0000)
+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_3 (0x0004)
+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_4 (0x0008)
+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_5 (0x000c)
+
/* DSP registers */
#define PHY_ARDENNES_MMD_DEV_3_PHY_CFG (0x806A)
#define PHY_ARDENNES_MMD_DEV_3_PHY_CFG_ZD_DLY_EN_ (0x2000)
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