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Message-ID: <ZEK8Hvl0Zl/0NntI@debian>
Date: Fri, 21 Apr 2023 18:38:54 +0200
From: Ramón Nordin Rodriguez
<ramon.nordin.rodriguez@...roamp.se>
To: Andrew Lunn <andrew@...n.ch>,
Heiner Kallweit <hkallweit1@...il.com>,
Russell King <linux@...linux.org.uk>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org
Subject: [PATCH v5] drivers/net/phy: add driver for Microchip LAN867x
10BASE-T1S PHY
This patch adds support for the Microchip LAN867x 10BASE-T1S family
(LAN8670/1/2). The driver supports P2MP with PLCA.
Reviewed-by: Andrew Lunn <andrew@...n.ch>
Signed-off-by: Ramón Nordin Rodriguez <ramon.nordin.rodriguez@...roamp.se>
---
Changes:
v2:
- Removed mentioning of not supporting auto-negotiation from commit
message
- Renamed file drivers/net/phy/lan867x.c ->
drivers/net/phy/microchip_t1s.c
- Renamed Kconfig option to reflect implementation filename (from
LAN867X_PHY to MICROCHIP_T1S_PHY)
- Moved entry in drivers/net/phy/KConfig to correct sort order
- Moved entry in drivers/net/phy/Makefile to correct sort order
- Moved variable declarations to conform to reverse christmas tree order
(in func lan867x_config_init)
- Moved register write to disable chip interrupts to func lan867x_config_init, when omitting the irq disable all togheter I got null pointer dereference, see the call trace below:
Call Trace:
<TASK>
phy_interrupt+0xa8/0xf0 [libphy]
irq_thread_fn+0x1c/0x60
irq_thread+0xf7/0x1c0
? __pfx_irq_thread_dtor+0x10/0x10
? __pfx_irq_thread+0x10/0x10
kthread+0xe6/0x110
? __pfx_kthread+0x10/0x10
ret_from_fork+0x29/0x50
</TASK>
- Removed func lan867x_config_interrupt and removed the member
.config_intr from the phy_driver struct
v3:
- Indentation level in drivers/net/phy/Kconfig
- Moved const arrays into global scope and made them static in order to have
them placed in the .rodata section
- Renamed array variables, since they are no longer as closely scoped as
earlier
- Added comment about why phy_write_mmd is used over phy_modify_mmd
(this should have been addressed in the V2 change since it was brought
up in the V1 review)
- Return result of last call instead of saving it in a var and then
returning the var (in lan867x_config_init)
v4:
- Moved history out of commit message
v5:
- Added Reviewed-by: Andrew Lunn <andrew@...n.ch>
- Moved history to (what I truly hope is) the expected location
- Fixed typo in comment (exacly -> exactly)
Testing:
This has been tested with ethtool --set/get-plca-cfg and verified on an
oscilloscope where it was observed that:
- The PLCA beacon was enabled/disabled when setting the node-id to 0/not
0
- The PLCA beacon is transmitted with the expected frequency when
changing max nodes
- Two devices using the evaluation board EVB-LAN8670-USB could ping each
other
---
drivers/net/phy/Kconfig | 5 ++
drivers/net/phy/Makefile | 1 +
drivers/net/phy/microchip_t1s.c | 138 ++++++++++++++++++++++++++++++++
3 files changed, 144 insertions(+)
create mode 100644 drivers/net/phy/microchip_t1s.c
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 54874555c921..15a0bd95f12c 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -235,6 +235,11 @@ config MICREL_PHY
help
Supports the KSZ9021, VSC8201, KS8001 PHYs.
+config MICROCHIP_T1S_PHY
+ tristate "Microchip 10BASE-T1S Ethernet PHY"
+ help
+ Currently supports the LAN8670, LAN8671, LAN8672
+
config MICROCHIP_PHY
tristate "Microchip PHYs"
help
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index b5138066ba04..64f649f2f62f 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_MICREL_KS8995MA) += spi_ks8995.o
obj-$(CONFIG_MICREL_PHY) += micrel.o
obj-$(CONFIG_MICROCHIP_PHY) += microchip.o
obj-$(CONFIG_MICROCHIP_T1_PHY) += microchip_t1.o
+obj-$(CONFIG_MICROCHIP_T1S_PHY) += microchip_t1s.o
obj-$(CONFIG_MICROSEMI_PHY) += mscc/
obj-$(CONFIG_MOTORCOMM_PHY) += motorcomm.o
obj-$(CONFIG_NATIONAL_PHY) += national.o
diff --git a/drivers/net/phy/microchip_t1s.c b/drivers/net/phy/microchip_t1s.c
new file mode 100644
index 000000000000..094967b3c111
--- /dev/null
+++ b/drivers/net/phy/microchip_t1s.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Microchip 10BASE-T1S LAN867X PHY
+ *
+ * Support: Microchip Phys:
+ * lan8670, lan8671, lan8672
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define PHY_ID_LAN867X 0x0007C160
+
+#define LAN867X_REG_IRQ_1_CTL 0x001C
+#define LAN867X_REG_IRQ_2_CTL 0x001D
+
+/* The arrays below are pulled from the following table from AN1699
+ * Access MMD Address Value Mask
+ * RMW 0x1F 0x00D0 0x0002 0x0E03
+ * RMW 0x1F 0x00D1 0x0000 0x0300
+ * RMW 0x1F 0x0084 0x3380 0xFFC0
+ * RMW 0x1F 0x0085 0x0006 0x000F
+ * RMW 0x1F 0x008A 0xC000 0xF800
+ * RMW 0x1F 0x0087 0x801C 0x801C
+ * RMW 0x1F 0x0088 0x033F 0x1FFF
+ * W 0x1F 0x008B 0x0404 ------
+ * RMW 0x1F 0x0080 0x0600 0x0600
+ * RMW 0x1F 0x00F1 0x2400 0x7F00
+ * RMW 0x1F 0x0096 0x2000 0x2000
+ * W 0x1F 0x0099 0x7F80 ------
+ */
+
+static const int lan867x_fixup_registers[12] = {
+ 0x00D0, 0x00D1, 0x0084, 0x0085,
+ 0x008A, 0x0087, 0x0088, 0x008B,
+ 0x0080, 0x00F1, 0x0096, 0x0099,
+};
+
+static const int lan867x_fixup_values[12] = {
+ 0x0002, 0x0000, 0x3380, 0x0006,
+ 0xC000, 0x801C, 0x033F, 0x0404,
+ 0x0600, 0x2400, 0x2000, 0x7F80,
+};
+
+static const int lan867x_fixup_masks[12] = {
+ 0x0E03, 0x0300, 0xFFC0, 0x000F,
+ 0xF800, 0x801C, 0x1FFF, 0xFFFF,
+ 0x0600, 0x7F00, 0x2000, 0xFFFF,
+};
+
+static int lan867x_config_init(struct phy_device *phydev)
+{
+ /* HW quirk: Microchip states in the application note (AN1699) for the phy
+ * that a set of read-modify-write (rmw) operations has to be performed
+ * on a set of seemingly magic registers.
+ * The result of these operations is just described as 'optimal performance'
+ * Microchip gives no explanation as to what these mmd regs do,
+ * in fact they are marked as reserved in the datasheet.
+ * It is unclear if phy_modify_mmd would be safe to use or if a write
+ * really has to happen to each register.
+ * In order to exactly conform to what is stated in the AN phy_write_mmd is
+ * used, which might then write the same value back as read + modified.
+ */
+
+ int reg_value;
+ int err;
+ int reg;
+
+ /* Read-Modified Write Pseudocode (from AN1699)
+ * current_val = read_register(mmd, addr) // Read current register value
+ * new_val = current_val AND (NOT mask) // Clear bit fields to be written
+ * new_val = new_val OR value // Set bits
+ * write_register(mmd, addr, new_val) // Write back updated register value
+ */
+ for (int i = 0; i < ARRAY_SIZE(lan867x_fixup_registers); i++) {
+ reg = lan867x_fixup_registers[i];
+ reg_value = phy_read_mmd(phydev, MDIO_MMD_VEND2, reg);
+ reg_value &= ~lan867x_fixup_masks[i];
+ reg_value |= lan867x_fixup_values[i];
+ err = phy_write_mmd(phydev, MDIO_MMD_VEND2, reg, reg_value);
+ if (err != 0)
+ return err;
+ }
+
+ /* None of the interrupts in the lan867x phy seem relevant.
+ * Other phys inspect the link status and call phy_trigger_machine
+ * in the interrupt handler.
+ * This phy does not support link status, and thus has no interrupt
+ * for it either.
+ * So we'll just disable all interrupts on the chip.
+ */
+ err = phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN867X_REG_IRQ_1_CTL, 0xFFFF);
+ if (err != 0)
+ return err;
+ return phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN867X_REG_IRQ_2_CTL, 0xFFFF);
+}
+
+static int lan867x_read_status(struct phy_device *phydev)
+{
+ /* The phy has some limitations, namely:
+ * - always reports link up
+ * - only supports 10MBit half duplex
+ * - does not support auto negotiate
+ */
+ phydev->link = 1;
+ phydev->duplex = DUPLEX_HALF;
+ phydev->speed = SPEED_10;
+ phydev->autoneg = AUTONEG_DISABLE;
+
+ return 0;
+}
+
+static struct phy_driver lan867x_driver[] = {
+ {
+ PHY_ID_MATCH_MODEL(PHY_ID_LAN867X),
+ .name = "LAN867X",
+ .features = PHY_BASIC_T1S_P2MP_FEATURES,
+ .config_init = lan867x_config_init,
+ .read_status = lan867x_read_status,
+ .get_plca_cfg = genphy_c45_plca_get_cfg,
+ .set_plca_cfg = genphy_c45_plca_set_cfg,
+ .get_plca_status = genphy_c45_plca_get_status,
+ }
+};
+
+module_phy_driver(lan867x_driver);
+
+static struct mdio_device_id __maybe_unused tbl[] = {
+ { PHY_ID_MATCH_MODEL(PHY_ID_LAN867X) },
+ { }
+};
+
+MODULE_DEVICE_TABLE(mdio, tbl);
+
+MODULE_DESCRIPTION("Microchip 10BASE-T1S lan867x Phy driver");
+MODULE_AUTHOR("Ramón Nordin Rodriguez");
+MODULE_LICENSE("GPL");
--
2.39.2
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