1 files changed, 915 insertions, 0 deletions

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
new file mode 100644
index 000000000000..fb2cf4342f48
--- /dev/null
+++ b/drivers/net/phy/sfp.c
@@ -0,0 +1,915 @@
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "mdio-i2c.h"
+#include "sfp.h"
+#include "swphy.h"
+
+enum {
+	GPIO_MODDEF0,
+	GPIO_LOS,
+	GPIO_TX_FAULT,
+	GPIO_TX_DISABLE,
+	GPIO_RATE_SELECT,
+	GPIO_MAX,
+
+	SFP_F_PRESENT = BIT(GPIO_MODDEF0),
+	SFP_F_LOS = BIT(GPIO_LOS),
+	SFP_F_TX_FAULT = BIT(GPIO_TX_FAULT),
+	SFP_F_TX_DISABLE = BIT(GPIO_TX_DISABLE),
+	SFP_F_RATE_SELECT = BIT(GPIO_RATE_SELECT),
+
+	SFP_E_INSERT = 0,
+	SFP_E_REMOVE,
+	SFP_E_DEV_DOWN,
+	SFP_E_DEV_UP,
+	SFP_E_TX_FAULT,
+	SFP_E_TX_CLEAR,
+	SFP_E_LOS_HIGH,
+	SFP_E_LOS_LOW,
+	SFP_E_TIMEOUT,
+
+	SFP_MOD_EMPTY = 0,
+	SFP_MOD_PROBE,
+	SFP_MOD_PRESENT,
+	SFP_MOD_ERROR,
+
+	SFP_DEV_DOWN = 0,
+	SFP_DEV_UP,
+
+	SFP_S_DOWN = 0,
+	SFP_S_INIT,
+	SFP_S_WAIT_LOS,
+	SFP_S_LINK_UP,
+	SFP_S_TX_FAULT,
+	SFP_S_REINIT,
+	SFP_S_TX_DISABLE,
+};
+
+static const char *gpio_of_names[] = {
+	"moddef0",
+	"los",
+	"tx-fault",
+	"tx-disable",
+	"rate-select",
+};
+
+static const enum gpiod_flags gpio_flags[] = {
+	GPIOD_IN,
+	GPIOD_IN,
+	GPIOD_IN,
+	GPIOD_ASIS,
+	GPIOD_ASIS,
+};
+
+#define T_INIT_JIFFIES	msecs_to_jiffies(300)
+#define T_RESET_US	10
+#define T_FAULT_RECOVER	msecs_to_jiffies(1000)
+
+/* SFP module presence detection is poor: the three MOD DEF signals are
+ * the same length on the PCB, which means it's possible for MOD DEF 0 to
+ * connect before the I2C bus on MOD DEF 1/2.
+ *
+ * The SFP MSA specifies 300ms as t_init (the time taken for TX_FAULT to
+ * be deasserted) but makes no mention of the earliest time before we can
+ * access the I2C EEPROM.  However, Avago modules require 300ms.
+ */
+#define T_PROBE_INIT	msecs_to_jiffies(300)
+#define T_PROBE_RETRY	msecs_to_jiffies(100)
+
+/*
+ * SFP modules appear to always have their PHY configured for bus address
+ * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
+ */
+#define SFP_PHY_ADDR	22
+
+/*
+ * Give this long for the PHY to reset.
+ */
+#define T_PHY_RESET_MS	50
+
+static DEFINE_MUTEX(sfp_mutex);
+
+struct sfp {
+	struct device *dev;
+	struct i2c_adapter *i2c;
+	struct mii_bus *i2c_mii;
+	struct sfp_bus *sfp_bus;
+	struct phy_device *mod_phy;
+
+	unsigned int (*get_state)(struct sfp *);
+	void (*set_state)(struct sfp *, unsigned int);
+	int (*read)(struct sfp *, bool, u8, void *, size_t);
+
+	struct gpio_desc *gpio[GPIO_MAX];
+
+	unsigned int state;
+	struct delayed_work poll;
+	struct delayed_work timeout;
+	struct mutex sm_mutex;
+	unsigned char sm_mod_state;
+	unsigned char sm_dev_state;
+	unsigned short sm_state;
+	unsigned int sm_retries;
+
+	struct sfp_eeprom_id id;
+};
+
+static unsigned long poll_jiffies;
+
+static unsigned int sfp_gpio_get_state(struct sfp *sfp)
+{
+	unsigned int i, state, v;
+
+	for (i = state = 0; i < GPIO_MAX; i++) {
+		if (gpio_flags[i] != GPIOD_IN || !sfp->gpio[i])
+			continue;
+
+		v = gpiod_get_value_cansleep(sfp->gpio[i]);
+		if (v)
+			state |= BIT(i);
+	}
+
+	return state;
+}
+
+static void sfp_gpio_set_state(struct sfp *sfp, unsigned int state)
+{
+	if (state & SFP_F_PRESENT) {
+		/* If the module is present, drive the signals */
+		if (sfp->gpio[GPIO_TX_DISABLE])
+			gpiod_direction_output(sfp->gpio[GPIO_TX_DISABLE],
+						state & SFP_F_TX_DISABLE);
+		if (state & SFP_F_RATE_SELECT)
+			gpiod_direction_output(sfp->gpio[GPIO_RATE_SELECT],
+						state & SFP_F_RATE_SELECT);
+	} else {
+		/* Otherwise, let them float to the pull-ups */
+		if (sfp->gpio[GPIO_TX_DISABLE])
+			gpiod_direction_input(sfp->gpio[GPIO_TX_DISABLE]);
+		if (state & SFP_F_RATE_SELECT)
+			gpiod_direction_input(sfp->gpio[GPIO_RATE_SELECT]);
+	}
+}
+
+static int sfp__i2c_read(struct i2c_adapter *i2c, u8 bus_addr, u8 dev_addr,
+	void *buf, size_t len)
+{
+	struct i2c_msg msgs[2];
+	int ret;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &dev_addr;
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = len;
+	msgs[1].buf = buf;
+
+	ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+
+	return ret == ARRAY_SIZE(msgs) ? len : 0;
+}
+
+static int sfp_i2c_read(struct sfp *sfp, bool a2, u8 addr, void *buf,
+	size_t len)
+{
+	return sfp__i2c_read(sfp->i2c, a2 ? 0x51 : 0x50, addr, buf, len);
+}
+
+static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
+{
+	struct mii_bus *i2c_mii;
+	int ret;
+
+	if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
+		return -EINVAL;
+
+	sfp->i2c = i2c;
+	sfp->read = sfp_i2c_read;
+
+	i2c_mii = mdio_i2c_alloc(sfp->dev, i2c);
+	if (IS_ERR(i2c_mii))
+		return PTR_ERR(i2c_mii);
+
+	i2c_mii->name = "SFP I2C Bus";
+	i2c_mii->phy_mask = ~0;
+
+	ret = mdiobus_register(i2c_mii);
+	if (ret < 0) {
+		mdiobus_free(i2c_mii);
+		return ret;
+	}
+
+	sfp->i2c_mii = i2c_mii;
+
+	return 0;
+}
+
+
+/* Interface */
+static unsigned int sfp_get_state(struct sfp *sfp)
+{
+	return sfp->get_state(sfp);
+}
+
+static void sfp_set_state(struct sfp *sfp, unsigned int state)
+{
+	sfp->set_state(sfp, state);
+}
+
+static int sfp_read(struct sfp *sfp, bool a2, u8 addr, void *buf, size_t len)
+{
+	return sfp->read(sfp, a2, addr, buf, len);
+}
+
+static unsigned int sfp_check(void *buf, size_t len)
+{
+	u8 *p, check;
+
+	for (p = buf, check = 0; len; p++, len--)
+		check += *p;
+
+	return check;
+}
+
+/* Helpers */
+static void sfp_module_tx_disable(struct sfp *sfp)
+{
+	dev_dbg(sfp->dev, "tx disable %u -> %u\n",
+		sfp->state & SFP_F_TX_DISABLE ? 1 : 0, 1);
+	sfp->state |= SFP_F_TX_DISABLE;
+	sfp_set_state(sfp, sfp->state);
+}
+
+static void sfp_module_tx_enable(struct sfp *sfp)
+{
+	dev_dbg(sfp->dev, "tx disable %u -> %u\n",
+		sfp->state & SFP_F_TX_DISABLE ? 1 : 0, 0);
+	sfp->state &= ~SFP_F_TX_DISABLE;
+	sfp_set_state(sfp, sfp->state);
+}
+
+static void sfp_module_tx_fault_reset(struct sfp *sfp)
+{
+	unsigned int state = sfp->state;
+
+	if (state & SFP_F_TX_DISABLE)
+		return;
+
+	sfp_set_state(sfp, state | SFP_F_TX_DISABLE);
+
+	udelay(T_RESET_US);
+
+	sfp_set_state(sfp, state);
+}
+
+/* SFP state machine */
+static void sfp_sm_set_timer(struct sfp *sfp, unsigned int timeout)
+{
+	if (timeout)
+		mod_delayed_work(system_power_efficient_wq, &sfp->timeout,
+				 timeout);
+	else
+		cancel_delayed_work(&sfp->timeout);
+}
+
+static void sfp_sm_next(struct sfp *sfp, unsigned int state,
+			unsigned int timeout)
+{
+	sfp->sm_state = state;
+	sfp_sm_set_timer(sfp, timeout);
+}
+
+static void sfp_sm_ins_next(struct sfp *sfp, unsigned int state, unsigned int timeout)
+{
+	sfp->sm_mod_state = state;
+	sfp_sm_set_timer(sfp, timeout);
+}
+
+static void sfp_sm_phy_detach(struct sfp *sfp)
+{
+	phy_stop(sfp->mod_phy);
+	sfp_remove_phy(sfp->sfp_bus);
+	phy_device_remove(sfp->mod_phy);
+	phy_device_free(sfp->mod_phy);
+	sfp->mod_phy = NULL;
+}
+
+static void sfp_sm_probe_phy(struct sfp *sfp)
+{
+	struct phy_device *phy;
+	int err;
+
+	msleep(T_PHY_RESET_MS);
+
+	phy = mdiobus_scan(sfp->i2c_mii, SFP_PHY_ADDR);
+	if (IS_ERR(phy)) {
+		dev_err(sfp->dev, "mdiobus scan returned %ld\n", PTR_ERR(phy));
+		return;
+	}
+	if (!phy) {
+		dev_info(sfp->dev, "no PHY detected\n");
+		return;
+	}
+
+	err = sfp_add_phy(sfp->sfp_bus, phy);
+	if (err) {
+		phy_device_remove(phy);
+		phy_device_free(phy);
+		dev_err(sfp->dev, "sfp_add_phy failed: %d\n", err);
+		return;
+	}
+
+	sfp->mod_phy = phy;
+	phy_start(phy);
+}
+
+static void sfp_sm_link_up(struct sfp *sfp)
+{
+	sfp_link_up(sfp->sfp_bus);
+	sfp_sm_next(sfp, SFP_S_LINK_UP, 0);
+}
+
+static void sfp_sm_link_down(struct sfp *sfp)
+{
+	sfp_link_down(sfp->sfp_bus);
+}
+
+static void sfp_sm_link_check_los(struct sfp *sfp)
+{
+	unsigned int los = sfp->state & SFP_F_LOS;
+
+	/* FIXME: what if neither SFP_OPTIONS_LOS_INVERTED nor
+	 * SFP_OPTIONS_LOS_NORMAL are set?  For now, we assume
+	 * the same as SFP_OPTIONS_LOS_NORMAL set.
+	 */
+	if (sfp->id.ext.options & SFP_OPTIONS_LOS_INVERTED)
+		los ^= SFP_F_LOS;
+
+	if (los)
+		sfp_sm_next(sfp, SFP_S_WAIT_LOS, 0);
+	else
+		sfp_sm_link_up(sfp);
+}
+
+static void sfp_sm_fault(struct sfp *sfp, bool warn)
+{
+	if (sfp->sm_retries && !--sfp->sm_retries) {
+		dev_err(sfp->dev, "module persistently indicates fault, disabling\n");
+		sfp_sm_next(sfp, SFP_S_TX_DISABLE, 0);
+	} else {
+		if (warn)
+			dev_err(sfp->dev, "module transmit fault indicated\n");
+
+		sfp_sm_next(sfp, SFP_S_TX_FAULT, T_FAULT_RECOVER);
+	}
+}
+
+static void sfp_sm_mod_init(struct sfp *sfp)
+{
+	sfp_module_tx_enable(sfp);
+
+	/* Wait t_init before indicating that the link is up, provided the
+	 * current state indicates no TX_FAULT.  If TX_FAULT clears before
+	 * this time, that's fine too.
+	 */
+	sfp_sm_next(sfp, SFP_S_INIT, T_INIT_JIFFIES);
+	sfp->sm_retries = 5;
+
+	/* Setting the serdes link mode is guesswork: there's no
+	 * field in the EEPROM which indicates what mode should
+	 * be used.
+	 *
+	 * If it's a gigabit-only fiber module, it probably does
+	 * not have a PHY, so switch to 802.3z negotiation mode.
+	 * Otherwise, switch to SGMII mode (which is required to
+	 * support non-gigabit speeds) and probe for a PHY.
+	 */
+	if (sfp->id.base.e1000_base_t ||
+	    sfp->id.base.e100_base_lx ||
+	    sfp->id.base.e100_base_fx)
+		sfp_sm_probe_phy(sfp);
+}
+
+static int sfp_sm_mod_probe(struct sfp *sfp)
+{
+	/* SFP module inserted - read I2C data */
+	struct sfp_eeprom_id id;
+	char vendor[17];
+	char part[17];
+	char sn[17];
+	char date[9];
+	char rev[5];
+	u8 check;
+	int err;
+
+	err = sfp_read(sfp, false, 0, &id, sizeof(id));
+	if (err < 0) {
+		dev_err(sfp->dev, "failed to read EEPROM: %d\n", err);
+		return -EAGAIN;
+	}
+
+	if (err != sizeof(id)) {
+		dev_err(sfp->dev, "EEPROM short read: %d\n", err);
+		return -EAGAIN;
+	}
+
+	/* Validate the checksum over the base structure */
+	check = sfp_check(&id.base, sizeof(id.base) - 1);
+	if (check != id.base.cc_base) {
+		dev_err(sfp->dev,
+			"EEPROM base structure checksum failure: 0x%02x\n",
+			check);
+		print_hex_dump(KERN_ERR, "sfp EE: ", DUMP_PREFIX_OFFSET,
+			       16, 1, &id, sizeof(id.base) - 1, true);
+		return -EINVAL;
+	}
+
+	check = sfp_check(&id.ext, sizeof(id.ext) - 1);
+	if (check != id.ext.cc_ext) {
+		dev_err(sfp->dev,
+			"EEPROM extended structure checksum failure: 0x%02x\n",
+			check);
+		memset(&id.ext, 0, sizeof(id.ext));
+	}
+
+	sfp->id = id;
+
+	memcpy(vendor, sfp->id.base.vendor_name, 16);
+	vendor[16] = '\0';
+	memcpy(part, sfp->id.base.vendor_pn, 16);
+	part[16] = '\0';
+	memcpy(rev, sfp->id.base.vendor_rev, 4);
+	rev[4] = '\0';
+	memcpy(sn, sfp->id.ext.vendor_sn, 16);
+	sn[16] = '\0';
+	memcpy(date, sfp->id.ext.datecode, 8);
+	date[8] = '\0';
+
+	dev_info(sfp->dev, "module %s %s rev %s sn %s dc %s\n", vendor, part, rev, sn, date);
+
+	/* We only support SFP modules, not the legacy GBIC modules. */
+	if (sfp->id.base.phys_id != SFP_PHYS_ID_SFP ||
+	    sfp->id.base.phys_ext_id != SFP_PHYS_EXT_ID_SFP) {
+		dev_err(sfp->dev, "module is not SFP - phys id 0x%02x 0x%02x\n",
+			sfp->id.base.phys_id, sfp->id.base.phys_ext_id);
+		return -EINVAL;
+	}
+
+	return sfp_module_insert(sfp->sfp_bus, &sfp->id);
+}
+
+static void sfp_sm_mod_remove(struct sfp *sfp)
+{
+	sfp_module_remove(sfp->sfp_bus);
+
+	if (sfp->mod_phy)
+		sfp_sm_phy_detach(sfp);
+
+	sfp_module_tx_disable(sfp);
+
+	memset(&sfp->id, 0, sizeof(sfp->id));
+
+	dev_info(sfp->dev, "module removed\n");
+}
+
+static void sfp_sm_event(struct sfp *sfp, unsigned int event)
+{
+	mutex_lock(&sfp->sm_mutex);
+
+	dev_dbg(sfp->dev, "SM: enter %u:%u:%u event %u\n",
+		sfp->sm_mod_state, sfp->sm_dev_state, sfp->sm_state, event);
+
+	/* This state machine tracks the insert/remove state of
+	 * the module, and handles probing the on-board EEPROM.
+	 */
+	switch (sfp->sm_mod_state) {
+	default:
+		if (event == SFP_E_INSERT) {
+			sfp_module_tx_disable(sfp);
+			sfp_sm_ins_next(sfp, SFP_MOD_PROBE, T_PROBE_INIT);
+		}
+		break;
+
+	case SFP_MOD_PROBE:
+		if (event == SFP_E_REMOVE) {
+			sfp_sm_ins_next(sfp, SFP_MOD_EMPTY, 0);
+		} else if (event == SFP_E_TIMEOUT) {
+			int err = sfp_sm_mod_probe(sfp);
+
+			if (err == 0)
+				sfp_sm_ins_next(sfp, SFP_MOD_PRESENT, 0);
+			else if (err == -EAGAIN)
+				sfp_sm_set_timer(sfp, T_PROBE_RETRY);
+			else
+				sfp_sm_ins_next(sfp, SFP_MOD_ERROR, 0);
+		}
+		break;
+
+	case SFP_MOD_PRESENT:
+	case SFP_MOD_ERROR:
+		if (event == SFP_E_REMOVE) {
+			sfp_sm_mod_remove(sfp);
+			sfp_sm_ins_next(sfp, SFP_MOD_EMPTY, 0);
+		}
+		break;
+	}
+
+	/* This state machine tracks the netdev up/down state */
+	switch (sfp->sm_dev_state) {
+	default:
+		if (event == SFP_E_DEV_UP)
+			sfp->sm_dev_state = SFP_DEV_UP;
+		break;
+
+	case SFP_DEV_UP:
+		if (event == SFP_E_DEV_DOWN) {
+			/* If the module has a PHY, avoid raising TX disable
+			 * as this resets the PHY. Otherwise, raise it to
+			 * turn the laser off.
+			 */
+			if (!sfp->mod_phy)
+				sfp_module_tx_disable(sfp);
+			sfp->sm_dev_state = SFP_DEV_DOWN;
+		}
+		break;
+	}
+
+	/* Some events are global */
+	if (sfp->sm_state != SFP_S_DOWN &&
+	    (sfp->sm_mod_state != SFP_MOD_PRESENT ||
+	     sfp->sm_dev_state != SFP_DEV_UP)) {
+		if (sfp->sm_state == SFP_S_LINK_UP &&
+		    sfp->sm_dev_state == SFP_DEV_UP)
+			sfp_sm_link_down(sfp);
+		if (sfp->mod_phy)
+			sfp_sm_phy_detach(sfp);
+		sfp_sm_next(sfp, SFP_S_DOWN, 0);
+		mutex_unlock(&sfp->sm_mutex);
+		return;
+	}
+
+	/* The main state machine */
+	switch (sfp->sm_state) {
+	case SFP_S_DOWN:
+		if (sfp->sm_mod_state == SFP_MOD_PRESENT &&
+		    sfp->sm_dev_state == SFP_DEV_UP)
+			sfp_sm_mod_init(sfp);
+		break;
+
+	case SFP_S_INIT:
+		if (event == SFP_E_TIMEOUT && sfp->state & SFP_F_TX_FAULT)
+			sfp_sm_fault(sfp, true);
+		else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR)
+			sfp_sm_link_check_los(sfp);
+		break;
+
+	case SFP_S_WAIT_LOS:
+		if (event == SFP_E_TX_FAULT)
+			sfp_sm_fault(sfp, true);
+		else if (event ==
+			 (sfp->id.ext.options & SFP_OPTIONS_LOS_INVERTED ?
+			  SFP_E_LOS_HIGH : SFP_E_LOS_LOW))
+			sfp_sm_link_up(sfp);
+		break;
+
+	case SFP_S_LINK_UP:
+		if (event == SFP_E_TX_FAULT) {
+			sfp_sm_link_down(sfp);
+			sfp_sm_fault(sfp, true);
+		} else if (event ==
+			   (sfp->id.ext.options & SFP_OPTIONS_LOS_INVERTED ?
+			    SFP_E_LOS_LOW : SFP_E_LOS_HIGH)) {
+			sfp_sm_link_down(sfp);
+			sfp_sm_next(sfp, SFP_S_WAIT_LOS, 0);
+		}
+		break;
+
+	case SFP_S_TX_FAULT:
+		if (event == SFP_E_TIMEOUT) {
+			sfp_module_tx_fault_reset(sfp);
+			sfp_sm_next(sfp, SFP_S_REINIT, T_INIT_JIFFIES);
+		}
+		break;
+
+	case SFP_S_REINIT:
+		if (event == SFP_E_TIMEOUT && sfp->state & SFP_F_TX_FAULT) {
+			sfp_sm_fault(sfp, false);
+		} else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR) {
+			dev_info(sfp->dev, "module transmit fault recovered\n");
+			sfp_sm_link_check_los(sfp);
+		}
+		break;
+
+	case SFP_S_TX_DISABLE:
+		break;
+	}
+
+	dev_dbg(sfp->dev, "SM: exit %u:%u:%u\n",
+		sfp->sm_mod_state, sfp->sm_dev_state, sfp->sm_state);
+
+	mutex_unlock(&sfp->sm_mutex);
+}
+
+static void sfp_start(struct sfp *sfp)
+{
+	sfp_sm_event(sfp, SFP_E_DEV_UP);
+}
+
+static void sfp_stop(struct sfp *sfp)
+{
+	sfp_sm_event(sfp, SFP_E_DEV_DOWN);
+}
+
+static int sfp_module_info(struct sfp *sfp, struct ethtool_modinfo *modinfo)
+{
+	/* locking... and check module is present */
+
+	if (sfp->id.ext.sff8472_compliance) {
+		modinfo->type = ETH_MODULE_SFF_8472;
+		modinfo->eeprom_len = ETH_MODULE_SFF_8472_LEN;
+	} else {
+		modinfo->type = ETH_MODULE_SFF_8079;
+		modinfo->eeprom_len = ETH_MODULE_SFF_8079_LEN;
+	}
+	return 0;
+}
+
+static int sfp_module_eeprom(struct sfp *sfp, struct ethtool_eeprom *ee,
+	u8 *data)
+{
+	unsigned int first, last, len;
+	int ret;
+
+	if (ee->len == 0)
+		return -EINVAL;
+
+	first = ee->offset;
+	last = ee->offset + ee->len;
+	if (first < ETH_MODULE_SFF_8079_LEN) {
+		len = min_t(unsigned int, last, ETH_MODULE_SFF_8079_LEN);
+		len -= first;
+
+		ret = sfp->read(sfp, false, first, data, len);
+		if (ret < 0)
+			return ret;
+
+		first += len;
+		data += len;
+	}
+	if (first >= ETH_MODULE_SFF_8079_LEN &&
+	    first < ETH_MODULE_SFF_8472_LEN) {
+		len = min_t(unsigned int, last, ETH_MODULE_SFF_8472_LEN);
+		len -= first;
+		first -= ETH_MODULE_SFF_8079_LEN;
+
+		ret = sfp->read(sfp, true, first, data, len);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static const struct sfp_socket_ops sfp_module_ops = {
+	.start = sfp_start,
+	.stop = sfp_stop,
+	.module_info = sfp_module_info,
+	.module_eeprom = sfp_module_eeprom,
+};
+
+static void sfp_timeout(struct work_struct *work)
+{
+	struct sfp *sfp = container_of(work, struct sfp, timeout.work);
+
+	rtnl_lock();
+	sfp_sm_event(sfp, SFP_E_TIMEOUT);
+	rtnl_unlock();
+}
+
+static void sfp_check_state(struct sfp *sfp)
+{
+	unsigned int state, i, changed;
+
+	state = sfp_get_state(sfp);
+	changed = state ^ sfp->state;
+	changed &= SFP_F_PRESENT | SFP_F_LOS | SFP_F_TX_FAULT;
+
+	for (i = 0; i < GPIO_MAX; i++)
+		if (changed & BIT(i))
+			dev_dbg(sfp->dev, "%s %u -> %u\n", gpio_of_names[i],
+				!!(sfp->state & BIT(i)), !!(state & BIT(i)));
+
+	state |= sfp->state & (SFP_F_TX_DISABLE | SFP_F_RATE_SELECT);
+	sfp->state = state;
+
+	rtnl_lock();
+	if (changed & SFP_F_PRESENT)
+		sfp_sm_event(sfp, state & SFP_F_PRESENT ?
+				SFP_E_INSERT : SFP_E_REMOVE);
+
+	if (changed & SFP_F_TX_FAULT)
+		sfp_sm_event(sfp, state & SFP_F_TX_FAULT ?
+				SFP_E_TX_FAULT : SFP_E_TX_CLEAR);
+
+	if (changed & SFP_F_LOS)
+		sfp_sm_event(sfp, state & SFP_F_LOS ?
+				SFP_E_LOS_HIGH : SFP_E_LOS_LOW);
+	rtnl_unlock();
+}
+
+static irqreturn_t sfp_irq(int irq, void *data)
+{
+	struct sfp *sfp = data;
+
+	sfp_check_state(sfp);
+
+	return IRQ_HANDLED;
+}
+
+static void sfp_poll(struct work_struct *work)
+{
+	struct sfp *sfp = container_of(work, struct sfp, poll.work);
+
+	sfp_check_state(sfp);
+	mod_delayed_work(system_wq, &sfp->poll, poll_jiffies);
+}
+
+static struct sfp *sfp_alloc(struct device *dev)
+{
+	struct sfp *sfp;
+
+	sfp = kzalloc(sizeof(*sfp), GFP_KERNEL);
+	if (!sfp)
+		return ERR_PTR(-ENOMEM);
+
+	sfp->dev = dev;
+
+	mutex_init(&sfp->sm_mutex);
+	INIT_DELAYED_WORK(&sfp->poll, sfp_poll);
+	INIT_DELAYED_WORK(&sfp->timeout, sfp_timeout);
+
+	return sfp;
+}
+
+static void sfp_cleanup(void *data)
+{
+	struct sfp *sfp = data;
+
+	cancel_delayed_work_sync(&sfp->poll);
+	cancel_delayed_work_sync(&sfp->timeout);
+	if (sfp->i2c_mii) {
+		mdiobus_unregister(sfp->i2c_mii);
+		mdiobus_free(sfp->i2c_mii);
+	}
+	if (sfp->i2c)
+		i2c_put_adapter(sfp->i2c);
+	kfree(sfp);
+}
+
+static int sfp_probe(struct platform_device *pdev)
+{
+	struct sfp *sfp;
+	bool poll = false;
+	int irq, err, i;
+
+	sfp = sfp_alloc(&pdev->dev);
+	if (IS_ERR(sfp))
+		return PTR_ERR(sfp);
+
+	platform_set_drvdata(pdev, sfp);
+
+	err = devm_add_action(sfp->dev, sfp_cleanup, sfp);
+	if (err < 0)
+		return err;
+
+	if (pdev->dev.of_node) {
+		struct device_node *node = pdev->dev.of_node;
+		struct device_node *np;
+
+		np = of_parse_phandle(node, "i2c-bus", 0);
+		if (np) {
+			struct i2c_adapter *i2c;
+
+			i2c = of_find_i2c_adapter_by_node(np);
+			of_node_put(np);
+			if (!i2c)
+				return -EPROBE_DEFER;
+
+			err = sfp_i2c_configure(sfp, i2c);
+			if (err < 0) {
+				i2c_put_adapter(i2c);
+				return err;
+			}
+		}
+
+		for (i = 0; i < GPIO_MAX; i++) {
+			sfp->gpio[i] = devm_gpiod_get_optional(sfp->dev,
+					   gpio_of_names[i], gpio_flags[i]);
+			if (IS_ERR(sfp->gpio[i]))
+				return PTR_ERR(sfp->gpio[i]);
+		}
+
+		sfp->get_state = sfp_gpio_get_state;
+		sfp->set_state = sfp_gpio_set_state;
+	}
+
+	sfp->sfp_bus = sfp_register_socket(sfp->dev, sfp, &sfp_module_ops);
+	if (!sfp->sfp_bus)
+		return -ENOMEM;
+
+	/* Get the initial state, and always signal TX disable,
+	 * since the network interface will not be up.
+	 */
+	sfp->state = sfp_get_state(sfp) | SFP_F_TX_DISABLE;
+
+	if (sfp->gpio[GPIO_RATE_SELECT] &&
+	    gpiod_get_value_cansleep(sfp->gpio[GPIO_RATE_SELECT]))
+		sfp->state |= SFP_F_RATE_SELECT;
+	sfp_set_state(sfp, sfp->state);
+	sfp_module_tx_disable(sfp);
+	rtnl_lock();
+	if (sfp->state & SFP_F_PRESENT)
+		sfp_sm_event(sfp, SFP_E_INSERT);
+	rtnl_unlock();
+
+	for (i = 0; i < GPIO_MAX; i++) {
+		if (gpio_flags[i] != GPIOD_IN || !sfp->gpio[i])
+			continue;
+
+		irq = gpiod_to_irq(sfp->gpio[i]);
+		if (!irq) {
+			poll = true;
+			continue;
+		}
+
+		err = devm_request_threaded_irq(sfp->dev, irq, NULL, sfp_irq,
+						IRQF_ONESHOT |
+						IRQF_TRIGGER_RISING |
+						IRQF_TRIGGER_FALLING,
+						dev_name(sfp->dev), sfp);
+		if (err)
+			poll = true;
+	}
+
+	if (poll)
+		mod_delayed_work(system_wq, &sfp->poll, poll_jiffies);
+
+	return 0;
+}
+
+static int sfp_remove(struct platform_device *pdev)
+{
+	struct sfp *sfp = platform_get_drvdata(pdev);
+
+	sfp_unregister_socket(sfp->sfp_bus);
+
+	return 0;
+}
+
+static const struct of_device_id sfp_of_match[] = {
+	{ .compatible = "sff,sfp", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sfp_of_match);
+
+static struct platform_driver sfp_driver = {
+	.probe = sfp_probe,
+	.remove = sfp_remove,
+	.driver = {
+		.name = "sfp",
+		.of_match_table = sfp_of_match,
+	},
+};
+
+static int sfp_init(void)
+{
+	poll_jiffies = msecs_to_jiffies(100);
+
+	return platform_driver_register(&sfp_driver);
+}
+module_init(sfp_init);
+
+static void sfp_exit(void)
+{
+	platform_driver_unregister(&sfp_driver);
+}
+module_exit(sfp_exit);
+
+MODULE_ALIAS("platform:sfp");
+MODULE_AUTHOR("Russell King");
+MODULE_LICENSE("GPL v2");