Add Davicom phy + reset-gpios

Changes in v3:
- Consider the v3 a new implmentation - almost nothing was left from v2. Thus also invalidate any former review - sorry.
- Dropped the need for the mdio {} node, as this node is only used when there is dedicated HW support for the mdio.
- Added so PHY child nodes to ethernet nodes are registered, and as part of registration the PHY nodes are reset if the reset-gpios property is present.
- Further dropped that the parsed info is stored in the bus, as we only do reset once, thus there is no need to save the info from the DT
- Futher dropped helper function to reset. They was not needed
- Named the gpio with the name of the PHY node
in the DT. This makes it unique and easier to recognize.

Changes in v2:
- Added patch to enable Davicom PHY on at91sam9263ek - evaluation kit
- Fix so we do reset before comunicating with the PHY
- Rename to mdio_reset()
- Reference correct binding file in commit log (mdio.txt)
- Tested on at91sam9263ek
The at91sam9263ek kit do not require the reset like my proprietary board, so no DT changes required

Intro:
The following patches was necessary to get networking operational on my proprietary target.
The target is at91sam9263 based with a Davicom PHY.

The Davicom PHY is a straight copy form the Linux kernel with the interrupt routine removed and minor adjustments to the rest.

The davicom PHY would not work until it had seen a reset cycle - which I think may be an artifact of the board design.

To fix the reset issue I have implemented support for the reset-gpios binding (see net/phy.txt bindings). A minimal implmentation was done, just enough to get my target running.

I could have implemented something in macb - but I preferred the more generic solution.

Also included are a patch that for the at91sam9263ek evaluation board. The patch adds several extra tools that are usefull for testing, and enable the Davicom PHY.

Sam

Sam Ravnborg (3):
phylib: add Davicom PHY support
phylib: add support for reset-gpios
at91sam9263ek: add PHY, miitool etc. to config

 arch/arm/configs/at91sam9263ek_defconfig |   12 ++
 drivers/net/phy/Kconfig                  |    5 +
 drivers/net/phy/Makefile                 |    1 
 drivers/net/phy/davicom.c                |  140 +++++++++++++++++++++++++++++++
 drivers/net/phy/mdio_bus.c               |   82 ++++++++++++++++++
 5 files changed, 239 insertions(+), 1 deletion(-)

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Based on driver from Linux kernel 4.18.0-rc4

---
 drivers/net/phy/Kconfig   |   5 ++
 drivers/net/phy/Makefile  |   1 +
 drivers/net/phy/davicom.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 146 insertions(+)
 create mode 100644 drivers/net/phy/davicom.c

index cda752b65..79fb917ee 100644
@@ -18,6 +18,11 @@ config AT803X_PHY
 	---help---
 	  Currently supports the AT8030, AT8031 and AT8035 PHYs.
 
+config DAVICOM_PHY
+	bool "Driver for Davicom PHYs"
+	---help---
+	  Currently supports dm9161e and dm9131
+
 config LXT_PHY
 	bool "Driver for the Intel LXT PHYs"
 	---help---

index 30b20f8ee..4424054d9 100644
@@ -1,6 +1,7 @@
 obj-y += phy.o mdio_bus.o
 obj-$(CONFIG_AR8327N_PHY)	+= ar8327.o
 obj-$(CONFIG_AT803X_PHY)	+= at803x.o
+obj-$(CONFIG_DAVICOM_PHY)	+= davicom.o
 obj-$(CONFIG_LXT_PHY)		+= lxt.o
 obj-$(CONFIG_MARVELL_PHY)	+= marvell.o
 obj-$(CONFIG_MICREL_PHY)	+= micrel.o

2.12.0


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Add minimal support for reset-gpios in the PHY node.

Example DT that uses this:

	macb0: ethernet@fffbc000 {
		phy-mode = "rmii";
		#address-cells = <1>;
		#size-cells = <0>;

		ethphy0: ethernet-phy@1 {
			reg = <3>;
			reset-gpios = <&pioE 17 GPIO_ACTIVE_LOW>;
			reset-assert-us = <1000>;
			reset-deassert-us = <2000>;
		};
	};

The reset is required to get the Davicom PHY operational on my proprietary board, and is assumed relavant for other boards too.

The PHY is reset when we read the info from DT,
before the phy_id is retreived.

The bindings are documented in dts/Bindings/net/phy.txt.

A side-effect of this patch is that we may see phy devices created from the DT due to the extra call to:

of_mdiobus_register()

with the ethernet node as argument.

The logic to determine if a child node is a PHY node is a simpler version compared to the one used in the kernel. The kernel have a whitelist of compatible strings and will also reconize compatible = ethernet-phy-idAAAA.BBBB. If these are required then they can be added later.

---
 drivers/net/phy/mdio_bus.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

index d209716a1..c479c25bd 100644
@@ -17,14 +17,19 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <common.h>
+#include <of_gpio.h>
 #include <driver.h>
 #include <init.h>
+#include <gpio.h>
 #include <clock.h>
 #include <net.h>
 #include <errno.h>
 #include <linux/phy.h>
 #include <linux/err.h>
 
+#define DEFAULT_GPIO_RESET_ASSERT       1000      /* us */
+#define DEFAULT_GPIO_RESET_DEASSERT     1000      /* us */
+
 LIST_HEAD(mii_bus_list);
 
 int mdiobus_detect(struct device_d *dev)

@@ -82,6 +87,76 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio, struct device_node *chi
 	return 0;
 }
 
+/*
+ * Node is considered a PHY node if:
+ * o Compatible string of "ethernet-phy-ieee802.3-c45"
+ * o Compatible string of "ethernet-phy-ieee802.3-c22"
+ * o No compatibility string
+ *
+ * A device which is not a phy is expected to have a compatible string
+ * indicating what sort of device it is.
+ */
+static bool of_mdiobus_child_is_phy(struct device_node *np)
+{
+	if (of_device_is_compatible(np, "ethernet-phy-ieee802.3-c45"))
+		return true;
+
+	if (of_device_is_compatible(np, "ethernet-phy-ieee802.3-c22"))
+		return true;
+
+	if (!of_find_property(np, "compatible", NULL))
+		return true;
+
+	return false;
+}
+
+/*
+ * Reset the PHY, based on DT info
+ *
+ * If np is a phy node, and the phy node contains a reset-gpios property
+ * then reset the phy.
+ */
+static void of_reset_phy(struct mii_bus *bus, struct device_node *np)
+{
+	enum of_gpio_flags of_flags;
+	u32 reset_deassert_delay;
+	u32 reset_assert_delay;
+	unsigned long flags;
+	int gpio;
+	int ret;
+
+	if (!of_mdiobus_child_is_phy(np))
+		return;
+
+	gpio = of_get_named_gpio_flags(np, "reset-gpios", 0, &of_flags);
+	if (!gpio_is_valid(gpio))
+		return;
+
+	flags = GPIOF_OUT_INIT_INACTIVE;
+	if (of_flags & OF_GPIO_ACTIVE_LOW)
+		flags |= GPIOF_ACTIVE_LOW;
+
+	ret = gpio_request_one(gpio, flags, np->name);
+	if (ret) {
+		dev_err(&bus->dev, "failed to request reset gpio for: %s\n",
+			np->name);
+		return;
+	}
+
+	reset_assert_delay = DEFAULT_GPIO_RESET_ASSERT;
+	of_property_read_u32(np, "reset-assert-us", &reset_assert_delay);
+
+	reset_deassert_delay = DEFAULT_GPIO_RESET_DEASSERT;
+	of_property_read_u32(np, "reset-deassert-us", &reset_deassert_delay);
+
+	/* reset the PHY */
+	dev_dbg(&bus->dev, "reset PHY with GPIO: %d\n", gpio);
+	gpio_set_active(gpio, 1);
+	udelay(reset_assert_delay);
+	gpio_set_active(gpio, 0);
+	udelay(reset_deassert_delay);
+}
+
 /**
  * of_mdiobus_register - Register mii_bus and create PHYs from the device tree
  * @mdio: pointer to mii_bus structure

@@ -111,6 +186,8 @@ static int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
 			continue;
 		}
 
+		of_reset_phy(mdio, child);
+
 		of_mdiobus_register_phy(mdio, child, addr);
 	}
 

@@ -154,6 +231,11 @@ int mdiobus_register(struct mii_bus *bus)
 
 	pr_info("%s: probed\n", dev_name(&bus->dev));
 
+	/* register PHY's as child node to the ethernet node */
+	if (bus->parent->device_node)
+		of_mdiobus_register(bus, bus->parent->device_node);
+
+	/* register PHY's as child node to mdio node */
 	if (bus->dev.device_node)
 		of_mdiobus_register(bus, bus->dev.device_node);
 

2.12.0


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Hi Sam,

Looks good generally, but there's one point

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Hi Sasha.

To Andrey - please read comment on mdio support in macb driver.

I have analyzed on the current situation.

In barebox we have two drivers that set miibus.dev.device_node, both in the case where they have found a child named "mdio". -> fec-imx.c and macb.c
When reading dts/Bindings/net/fsl-fec.txt then this binding specify an optional mdio child, so fec-imx.c is fine.
But macb.txt or the general bindigns do not mention
a mdio child.
And the Linux macb_main.c do not support a "mdio" node either. So my best guess is that the "mdio" support in macb was accidently ported over from fec-imx when adding DT support.

If we only consider the DT cases we will call mdio_register() in the following cases:

1) Typical from an ethernet driver:
bus->dev.device_node is NULL
bus->parent->device_node is the ethernet node

2) fec-imx case:
bus->dev.device_node is the "mdio" node, that agin hold the PHY nodes bus->parent->device_node is the ethernet node

3) mdio drivers:
bus->dev.device_node is the "mdio" node bus->parent->device_node is equal to bus->dev.device_node

Considering the above I will do the following:
a) Remove "mdio" support from macb.c
b) Modify my patch to something like this:

	if (bus->dev.device_node)
		of_mdiobus_register(bus, bus->dev.device_node);
	else if (bus->parent->device_node)
		of_mdiobus_register(bus, bus->parent->device_node);

With the above I have covered point 1 to 3 above in a simple way. And this looks a simple and straghtforward way to do it.

I also looked at how the kernel does thing.
In of_mdiobus_register it has:

	for_each_child() {
		if (of_node_is_phy(child))
			of_mdiobus_register_phy()
		else
			of_mdiobus_register_device()
	}

I so far failed to follow where the code will iterate over the PHY nodes inside the mdio node (that trigger the of_mdiobus_register_device() call).
So therefore I am reluctant to try to implment this, and the suggested solution is also more in the line with a simpler and straightforward approach preferred in barebox.

I no-one else objects and I do not get any better ideas I will implement and test this tomorrow.

Sam

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Hello Sam,

[snip]

While submitting a macb patch to linux-netdev, I was asked [1] to add support for a "mdio" subtree in the macb binding. I intend to submit it when net-next opens for inclusion into Linux v4.20. That way, macb would look at phys in the list of its children as well as the children of its "mdio" child.

Just a heads up to avoid removing functionality that would've to be reinstated later on...

[1]: https://www.spinics.net/lists/netdev/msg519196.html

Cheers
Ahmad

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Hi Ahmad.

Thanks for bringing this to my attention.
I will leave the code as-is.

Sam

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Added Davicom phy to the config now it is supported. Add miitool to show the phy info.
Also add a bunch of extra commands that can be useful when handling the evaluation board.

---
 arch/arm/configs/at91sam9263ek_defconfig | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

index e8ad841fa..45c6f79de 100644
@@ -18,7 +18,7 @@ CONFIG_BOOTM_OFTREE=y
 CONFIG_BOOTM_OFTREE_UIMAGE=y
 CONFIG_CONSOLE_ACTIVATE_ALL=y
 CONFIG_DEFAULT_ENVIRONMENT_GENERIC=y
-# CONFIG_CMD_ARM_CPUINFO is not set
+CONFIG_CMD_DMESG=y
 CONFIG_LONGHELP=y
 CONFIG_CMD_IOMEM=y
 CONFIG_CMD_MEMINFO=y

@@ -33,22 +33,32 @@ CONFIG_CMD_PRINTENV=y
 CONFIG_CMD_SAVEENV=y
 CONFIG_CMD_SLEEP=y
 CONFIG_CMD_DHCP=y
+CONFIG_CMD_HOST=y
+CONFIG_NET_CMD_IFUP=y
+CONFIG_CMD_MIITOOL=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_TFTP=y
 CONFIG_CMD_EDIT=y
 CONFIG_CMD_SPLASH=y
+CONFIG_CMD_FBTEST=y
 CONFIG_CMD_READLINE=y
 CONFIG_CMD_TIMEOUT=y
 CONFIG_CMD_CLK=y
+CONFIG_CMD_DETECT=y
 CONFIG_CMD_FLASH=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_LED=y
 CONFIG_CMD_LED_TRIGGER=y
+CONFIG_CMD_OF_NODE=y
+CONFIG_CMD_OF_PROPERTY=y
+CONFIG_CMD_OF_DISPLAY_TIMINGS=y
+CONFIG_CMD_OF_FIXUP_STATUS=y
 CONFIG_CMD_OFTREE=y
 CONFIG_NET=y
 CONFIG_NET_NFS=y
 CONFIG_OF_BAREBOX_DRIVERS=y
 CONFIG_DRIVER_NET_MACB=y
+CONFIG_DAVICOM_PHY=y
 # CONFIG_SPI is not set
 CONFIG_MTD=y
 # CONFIG_MTD_OOB_DEVICE is not set

2.12.0


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