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193 lines
5.6 KiB
Diff
193 lines
5.6 KiB
Diff
From 69226896ad636b94f6d2e55d75ff21a29c4de83b Mon Sep 17 00:00:00 2001
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From: Roger Quadros <rogerq@ti.com>
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Date: Fri, 21 Apr 2017 16:15:38 +0300
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Subject: [PATCH] mdio_bus: Issue GPIO RESET to PHYs.
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Some boards [1] leave the PHYs at an invalid state
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during system power-up or reset thus causing unreliability
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issues with the PHY which manifests as PHY not being detected
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or link not functional. To fix this, these PHYs need to be RESET
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via a GPIO connected to the PHY's RESET pin.
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Some boards have a single GPIO controlling the PHY RESET pin of all
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PHYs on the bus whereas some others have separate GPIOs controlling
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individual PHY RESETs.
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In both cases, the RESET de-assertion cannot be done in the PHY driver
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as the PHY will not probe till its reset is de-asserted.
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So do the RESET de-assertion in the MDIO bus driver.
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[1] - am572x-idk, am571x-idk, a437x-idk
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Signed-off-by: Roger Quadros <rogerq@ti.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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Documentation/devicetree/bindings/net/mdio.txt | 33 ++++++++++++++++++
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drivers/net/phy/mdio_bus.c | 47 ++++++++++++++++++++++++++
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drivers/of/of_mdio.c | 7 ++++
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include/linux/phy.h | 7 ++++
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4 files changed, 94 insertions(+)
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create mode 100644 Documentation/devicetree/bindings/net/mdio.txt
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--- /dev/null
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+++ b/Documentation/devicetree/bindings/net/mdio.txt
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@@ -0,0 +1,33 @@
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+Common MDIO bus properties.
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+
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+These are generic properties that can apply to any MDIO bus.
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+
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+Optional properties:
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+- reset-gpios: List of one or more GPIOs that control the RESET lines
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+ of the PHYs on that MDIO bus.
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+- reset-delay-us: RESET pulse width in microseconds as per PHY datasheet.
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+
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+A list of child nodes, one per device on the bus is expected. These
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+should follow the generic phy.txt, or a device specific binding document.
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+
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+Example :
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+This example shows these optional properties, plus other properties
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+required for the TI Davinci MDIO driver.
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+
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+ davinci_mdio: ethernet@0x5c030000 {
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+ compatible = "ti,davinci_mdio";
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+ reg = <0x5c030000 0x1000>;
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+ #address-cells = <1>;
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+ #size-cells = <0>;
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+
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+ reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>;
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+ reset-delay-us = <2>; /* PHY datasheet states 1us min */
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+
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+ ethphy0: ethernet-phy@1 {
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+ reg = <1>;
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+ };
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+
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+ ethphy1: ethernet-phy@3 {
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+ reg = <3>;
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+ };
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+ };
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--- a/drivers/net/phy/mdio_bus.c
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+++ b/drivers/net/phy/mdio_bus.c
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@@ -22,8 +22,11 @@
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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+#include <linux/gpio.h>
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+#include <linux/gpio/consumer.h>
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#include <linux/of_device.h>
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#include <linux/of_mdio.h>
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+#include <linux/of_gpio.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/skbuff.h>
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@@ -304,6 +307,7 @@ int __mdiobus_register(struct mii_bus *b
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{
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struct mdio_device *mdiodev;
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int i, err;
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+ struct gpio_desc *gpiod;
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if (NULL == bus || NULL == bus->name ||
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NULL == bus->read || NULL == bus->write)
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@@ -329,6 +333,35 @@ int __mdiobus_register(struct mii_bus *b
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if (bus->reset)
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bus->reset(bus);
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+ /* de-assert bus level PHY GPIO resets */
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+ if (bus->num_reset_gpios > 0) {
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+ bus->reset_gpiod = devm_kcalloc(&bus->dev,
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+ bus->num_reset_gpios,
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+ sizeof(struct gpio_desc *),
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+ GFP_KERNEL);
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+ if (!bus->reset_gpiod)
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+ return -ENOMEM;
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+ }
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+
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+ for (i = 0; i < bus->num_reset_gpios; i++) {
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+ gpiod = devm_gpiod_get_index(&bus->dev, "reset", i,
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+ GPIOD_OUT_LOW);
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+ if (IS_ERR(gpiod)) {
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+ err = PTR_ERR(gpiod);
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+ if (err != -ENOENT) {
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+ dev_err(&bus->dev,
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+ "mii_bus %s couldn't get reset GPIO\n",
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+ bus->id);
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+ return err;
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+ }
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+ } else {
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+ bus->reset_gpiod[i] = gpiod;
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+ gpiod_set_value_cansleep(gpiod, 1);
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+ udelay(bus->reset_delay_us);
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+ gpiod_set_value_cansleep(gpiod, 0);
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+ }
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+ }
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+
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for (i = 0; i < PHY_MAX_ADDR; i++) {
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if ((bus->phy_mask & (1 << i)) == 0) {
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struct phy_device *phydev;
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@@ -354,6 +387,13 @@ error:
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mdiodev->device_remove(mdiodev);
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mdiodev->device_free(mdiodev);
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}
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+
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+ /* Put PHYs in RESET to save power */
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+ for (i = 0; i < bus->num_reset_gpios; i++) {
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+ if (bus->reset_gpiod[i])
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+ gpiod_set_value_cansleep(bus->reset_gpiod[i], 1);
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+ }
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+
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device_del(&bus->dev);
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return err;
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}
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@@ -375,6 +415,13 @@ void mdiobus_unregister(struct mii_bus *
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mdiodev->device_remove(mdiodev);
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mdiodev->device_free(mdiodev);
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}
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+
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+ /* Put PHYs in RESET to save power */
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+ for (i = 0; i < bus->num_reset_gpios; i++) {
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+ if (bus->reset_gpiod[i])
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+ gpiod_set_value_cansleep(bus->reset_gpiod[i], 1);
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+ }
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+
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device_del(&bus->dev);
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}
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EXPORT_SYMBOL(mdiobus_unregister);
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--- a/drivers/of/of_mdio.c
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+++ b/drivers/of/of_mdio.c
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@@ -22,6 +22,8 @@
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#include <linux/of_net.h>
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#include <linux/module.h>
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+#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */
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+
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MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
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MODULE_LICENSE("GPL");
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@@ -220,6 +222,11 @@ int of_mdiobus_register(struct mii_bus *
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mdio->dev.of_node = np;
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+ /* Get bus level PHY reset GPIO details */
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+ mdio->reset_delay_us = DEFAULT_GPIO_RESET_DELAY;
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+ of_property_read_u32(np, "reset-delay-us", &mdio->reset_delay_us);
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+ mdio->num_reset_gpios = of_gpio_named_count(np, "reset-gpios");
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+
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/* Register the MDIO bus */
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rc = mdiobus_register(mdio);
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if (rc)
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--- a/include/linux/phy.h
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+++ b/include/linux/phy.h
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@@ -193,6 +193,13 @@ struct mii_bus {
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* matching its address
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*/
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int irq[PHY_MAX_ADDR];
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+
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+ /* GPIO reset pulse width in microseconds */
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+ int reset_delay_us;
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+ /* Number of reset GPIOs */
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+ int num_reset_gpios;
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+ /* Array of RESET GPIO descriptors */
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+ struct gpio_desc **reset_gpiod;
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};
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#define to_mii_bus(d) container_of(d, struct mii_bus, dev)
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