92 lines
3.4 KiB
Diff
92 lines
3.4 KiB
Diff
From cbc38ebf8ff6d01cd11270d99762d4216ff4237d Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Mon, 26 Nov 2018 19:46:58 +0000
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Subject: [PATCH] net: lan78xx: Support auto-downshift to 100Mb/s
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Ethernet cables with faulty or missing pairs (specifically pairs C and
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D) allow auto-negotiation to 1000Mbs, but do not support the successful
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establishment of a link. Add a DT property, "microchip,downshift-after",
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to configure the number of auto-negotiation failures after which it
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falls back to 100Mbs. Valid values are 2, 3, 4, 5 and 0, where 0 means
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never downshift.
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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---
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.../bindings/net/microchip,lan78xx.txt | 3 +++
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drivers/net/phy/microchip.c | 27 +++++++++++++++++++
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include/linux/microchipphy.h | 8 ++++++
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3 files changed, 38 insertions(+)
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--- a/Documentation/devicetree/bindings/net/microchip,lan78xx.txt
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+++ b/Documentation/devicetree/bindings/net/microchip,lan78xx.txt
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@@ -14,6 +14,9 @@ Optional properties of the embedded PHY:
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- microchip,led-modes: a 0..4 element vector, with each element configuring
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the operating mode of an LED. Omitted LEDs are turned off. Allowed values
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are defined in "include/dt-bindings/net/microchip-lan78xx.h".
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+- microchip,downshift-after: sets the number of failed auto-negotiation
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+ attempts after which the link is downgraded from 1000BASE-T. Should be one of
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+ 2, 3, 4, 5 or 0, where 0 means never downshift.
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Example:
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--- a/drivers/net/phy/microchip.c
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+++ b/drivers/net/phy/microchip.c
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@@ -217,6 +217,7 @@ static int lan88xx_probe(struct phy_devi
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struct device *dev = &phydev->mdio.dev;
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struct lan88xx_priv *priv;
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u32 led_modes[4];
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+ u32 downshift_after = 0;
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int len;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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@@ -246,6 +247,32 @@ static int lan88xx_probe(struct phy_devi
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return -EINVAL;
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}
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+ if (!of_property_read_u32(dev->of_node,
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+ "microchip,downshift-after",
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+ &downshift_after)) {
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+ u32 mask = LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_MASK;
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+ u32 val= LAN78XX_PHY_CTRL3_AUTO_DOWNSHIFT;
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+
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+ switch (downshift_after) {
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+ case 2: val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_2;
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+ break;
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+ case 3: val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_3;
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+ break;
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+ case 4: val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_4;
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+ break;
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+ case 5: val |= LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_5;
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+ break;
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+ case 0: // Disable completely
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+ mask = LAN78XX_PHY_CTRL3_AUTO_DOWNSHIFT;
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+ val = 0;
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+ break;
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+ default:
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+ return -EINVAL;
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+ }
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+ (void)phy_modify_paged(phydev, 1, LAN78XX_PHY_CTRL3,
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+ mask, val);
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+ }
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+
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/* these values can be used to identify internal PHY */
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priv->chip_id = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_ID);
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priv->chip_rev = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_REV);
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--- a/include/linux/microchipphy.h
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+++ b/include/linux/microchipphy.h
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@@ -61,6 +61,14 @@
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/* Registers specific to the LAN7800/LAN7850 embedded phy */
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#define LAN78XX_PHY_LED_MODE_SELECT (0x1D)
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+#define LAN78XX_PHY_CTRL3 (0x14)
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+#define LAN78XX_PHY_CTRL3_AUTO_DOWNSHIFT (0x0010)
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+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_MASK (0x000c)
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+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_2 (0x0000)
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+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_3 (0x0004)
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+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_4 (0x0008)
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+#define LAN78XX_PHY_CTRL3_DOWNSHIFT_CTRL_5 (0x000c)
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+
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/* DSP registers */
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#define PHY_ARDENNES_MMD_DEV_3_PHY_CFG (0x806A)
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#define PHY_ARDENNES_MMD_DEV_3_PHY_CFG_ZD_DLY_EN_ (0x2000)
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