Thread (12 messages) flat view 12 messages, 5 authors, 2020-05-14

Re: [PATCH net-next v1] net: phy: tja11xx: add cable-test support

From: Andrew Lunn <andrew@lunn.ch>
Date: 2020-05-13 13:39:41
Also in: linux-devicetree, lkml

On Wed, May 13, 2020 at 02:34:40PM +0200, Oleksij Rempel wrote:
quoted hunk ↗ jump to hunk
Add initial cable testing support.
This PHY needs only 100usec for this test and it is recommended to run it
before the link is up. For now, provide at least ethtool support, so it
can be tested by more developers.

This patch was tested with TJA1102 PHY with following results:
- No cable, is detected as open
- 1m cable, with no connected other end and detected as open
- a 40m cable (out of spec, max lenght should be 15m) is detected as OK.

Current patch do not provide polarity test support. This test would
indicate not proper wire connection, where "+" wire of main phy is
connected to the "-" wire of the link partner.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/phy/nxp-tja11xx.c | 106 +++++++++++++++++++++++++++++++++-
 1 file changed, 105 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/nxp-tja11xx.c b/drivers/net/phy/nxp-tja11xx.c
index ca5f9d4dc57ed..8b743d25002b9 100644
--- a/drivers/net/phy/nxp-tja11xx.c
+++ b/drivers/net/phy/nxp-tja11xx.c
@@ -5,6 +5,7 @@
  */
 #include <linux/delay.h>
 #include <linux/ethtool.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/kernel.h>
 #include <linux/mdio.h>
 #include <linux/mii.h>
@@ -26,6 +27,7 @@
 #define MII_ECTRL_POWER_MODE_NO_CHANGE	(0x0 << 11)
 #define MII_ECTRL_POWER_MODE_NORMAL	(0x3 << 11)
 #define MII_ECTRL_POWER_MODE_STANDBY	(0xc << 11)
+#define MII_ECTRL_CABLE_TEST		BIT(5)
 #define MII_ECTRL_CONFIG_EN		BIT(2)
 #define MII_ECTRL_WAKE_REQUEST		BIT(0)
 
@@ -55,6 +57,11 @@
 #define MII_GENSTAT			24
 #define MII_GENSTAT_PLL_LOCKED		BIT(14)
 
+#define MII_EXTSTAT			25
+#define MII_EXTSTAT_SHORT_DETECT	BIT(8)
+#define MII_EXTSTAT_OPEN_DETECT		BIT(7)
+#define MII_EXTSTAT_POLARITY_DETECT	BIT(6)
+
Do these registers all conform to the standard? Can we pull this code
out into a library which all standards conformant PHY drivers can use?

The code itself looks O.K.

    Andrew
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