path: root/drivers/net/phy/sfp.c

#include <linux/delay.h>
#include <linux/gpio/consumer.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_HPOWER,
	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[] = {
	"mod-def0",
	"los",
	"tx-fault",
	"tx-disable",
	"rate-select0",
};

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_HPOWER_LEVEL	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 sff_data {
	unsigned int gpios;
	bool (*module_supported)(const struct sfp_eeprom_id *id);
};

struct sfp {
	struct device *dev;
	struct i2c_adapter *i2c;
	struct mii_bus *i2c_mii;
	struct sfp_bus *sfp_bus;
	struct phy_device *mod_phy;
	const struct sff_data *type;
	u32 max_power_mW;

	unsigned int (*get_state)(struct sfp *);
	void (*set_state)(struct sfp *, unsigned int);
	int (*read)(struct sfp *, bool, u8, void *, size_t);
	int (*write)(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 bool sff_module_supported(const struct sfp_eeprom_id *id)
{
	return id->base.phys_id == SFP_PHYS_ID_SFF &&
	       id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP;
}

static const struct sff_data sff_data = {
	.gpios = SFP_F_LOS | SFP_F_TX_FAULT | SFP_F_TX_DISABLE,
	.module_supported = sff_module_supported,
};

static bool sfp_module_supported(const struct sfp_eeprom_id *id)
{
	return id->base.phys_id == SFP_PHYS_ID_SFP &&
	       id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP;
}

static const struct sff_data sfp_data = {
	.gpios = SFP_F_PRESENT | SFP_F_LOS | SFP_F_TX_FAULT |
		 SFP_F_TX_DISABLE | SFP_F_RATE_SELECT,
	.module_supported = sfp_module_supported,
};

static const struct of_device_id sfp_of_match[] = {
	{ .compatible = "sff,sff", .data = &sff_data, },
	{ .compatible = "sff,sfp", .data = &sfp_data, },
	{ },
};
MODULE_DEVICE_TABLE(of, sfp_of_match);

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);