1 // SPDX-License-Identifier: GPL-2.0
3  * MDIO I2C bridge
5  * Copyright (C) 2015-2016 Russell King
8  * Network PHYs can appear on I2C buses when they are part of SFP module.
13 #include <linux/i2c.h>
14 #include <linux/mdio/mdio-i2c.h>
19  * I2C bus addresses 0x50 and 0x51 are normally an EEPROM, which is
36 	struct i2c_adapter *i2c = bus->priv;  in i2c_mii_read_default_c45()  local
54 	msgs[0].len = p - addr;  in i2c_mii_read_default_c45()
61 	ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));  in i2c_mii_read_default_c45()
71 	struct i2c_adapter *i2c = bus->priv;  in i2c_mii_write_default_c45()  local
90 	msg.len = p - data;  in i2c_mii_write_default_c45()
93 	ret = i2c_transfer(i2c, &msg, 1);  in i2c_mii_write_default_c45()
100 	return i2c_mii_read_default_c45(bus, phy_id, -1, reg);  in i2c_mii_read_default_c22()
106 	return i2c_mii_write_default_c45(bus, phy_id, -1, reg, val);  in i2c_mii_write_default_c22()
112 	struct i2c_adapter *i2c = bus->priv;  in smbus_byte_mii_read_default_c22()  local
119 	i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);  in smbus_byte_mii_read_default_c22()
121 	ret = __i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,  in smbus_byte_mii_read_default_c22()
129 	ret = __i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,  in smbus_byte_mii_read_default_c22()
134 	i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);  in smbus_byte_mii_read_default_c22()
147 	struct i2c_adapter *i2c = bus->priv;  in smbus_byte_mii_write_default_c22()  local
156 	i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);  in smbus_byte_mii_write_default_c22()
158 	ret = __i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,  in smbus_byte_mii_write_default_c22()
166 	ret = __i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,  in smbus_byte_mii_write_default_c22()
171 	i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);  in smbus_byte_mii_write_default_c22()
176 /* RollBall SFPs do not access internal PHY via I2C address 0x56, but
181  * -------  ----  --------  -----------
200 static int __i2c_transfer_err(struct i2c_adapter *i2c, struct i2c_msg *msgs,  in __i2c_transfer_err()  argument
205 	ret = __i2c_transfer(i2c, msgs, num);  in __i2c_transfer_err()
209 		return -EIO;  in __i2c_transfer_err()
214 static int __i2c_rollball_get_page(struct i2c_adapter *i2c, int bus_addr,  in __i2c_rollball_get_page()  argument
230 	return __i2c_transfer_err(i2c, msgs, 2);  in __i2c_rollball_get_page()
233 static int __i2c_rollball_set_page(struct i2c_adapter *i2c, int bus_addr,  in __i2c_rollball_set_page()  argument
247 	return __i2c_transfer_err(i2c, &msg, 1);  in __i2c_rollball_set_page()
260  * unfortunately tests show that this does not work :-( Changed SFP_PAGE does
263 static int i2c_transfer_rollball(struct i2c_adapter *i2c,  in i2c_transfer_rollball()  argument
269 	i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);  in i2c_transfer_rollball()
272 	ret = __i2c_rollball_get_page(i2c, msgs->addr, &saved_page);  in i2c_transfer_rollball()
277 	ret = __i2c_rollball_set_page(i2c, msgs->addr, SFP_PAGE_ROLLBALL_MDIO);  in i2c_transfer_rollball()
282 	ret = __i2c_transfer_err(i2c, msgs, num);  in i2c_transfer_rollball()
287 	ret = __i2c_rollball_set_page(i2c, msgs->addr, saved_page);  in i2c_transfer_rollball()
290 	i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);  in i2c_transfer_rollball()
298 	struct i2c_adapter *i2c = bus->priv;  in i2c_rollball_mii_poll()  local
325 		ret = i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));  in i2c_rollball_mii_poll()
331 	} while (i-- > 0);  in i2c_rollball_mii_poll()
333 	dev_dbg(&bus->dev, "poll timed out\n");  in i2c_rollball_mii_poll()
335 	return -ETIMEDOUT;  in i2c_rollball_mii_poll()
341 	struct i2c_adapter *i2c = bus->priv;  in i2c_rollball_mii_cmd()  local
358 	return i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));  in i2c_rollball_mii_cmd()
383 	if (ret == -ETIMEDOUT)  in i2c_mii_read_rollball()
422 static int i2c_mii_init_rollball(struct i2c_adapter *i2c)  in i2c_mii_init_rollball()  argument
439 	ret = i2c_transfer(i2c, &msg, 1);  in i2c_mii_init_rollball()
443 		return -EIO;  in i2c_mii_init_rollball()
448 static bool mdio_i2c_check_functionality(struct i2c_adapter *i2c,  in mdio_i2c_check_functionality()  argument
449 					 enum mdio_i2c_proto protocol)  in mdio_i2c_check_functionality()  argument
451 	if (i2c_check_functionality(i2c, I2C_FUNC_I2C))  in mdio_i2c_check_functionality()
454 	if (i2c_check_functionality(i2c, I2C_FUNC_SMBUS_BYTE_DATA) &&  in mdio_i2c_check_functionality()
455 	    protocol == MDIO_I2C_MARVELL_C22)  in mdio_i2c_check_functionality()
461 struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c,  in mdio_i2c_alloc()  argument
462 			       enum mdio_i2c_proto protocol)  in mdio_i2c_alloc()  argument
467 	if (!mdio_i2c_check_functionality(i2c, protocol))  in mdio_i2c_alloc()
468 		return ERR_PTR(-EINVAL);  in mdio_i2c_alloc()
472 		return ERR_PTR(-ENOMEM);  in mdio_i2c_alloc()
474 	snprintf(mii->id, MII_BUS_ID_SIZE, "i2c:%s", dev_name(parent));  in mdio_i2c_alloc()
475 	mii->parent = parent;  in mdio_i2c_alloc()
476 	mii->priv = i2c;  in mdio_i2c_alloc()
479 	if (i2c_check_functionality(i2c, I2C_FUNC_SMBUS_BYTE_DATA) &&  in mdio_i2c_alloc()
480 	    !i2c_check_functionality(i2c, I2C_FUNC_I2C)) {  in mdio_i2c_alloc()
481 		mii->read = smbus_byte_mii_read_default_c22;  in mdio_i2c_alloc()
482 		mii->write = smbus_byte_mii_write_default_c22;  in mdio_i2c_alloc()
486 	switch (protocol) {  in mdio_i2c_alloc()
488 		ret = i2c_mii_init_rollball(i2c);  in mdio_i2c_alloc()
491 				"Cannot initialize RollBall MDIO I2C protocol: %d\n",  in mdio_i2c_alloc()
497 		mii->read_c45 = i2c_mii_read_rollball;  in mdio_i2c_alloc()
498 		mii->write_c45 = i2c_mii_write_rollball;  in mdio_i2c_alloc()
501 		mii->read = i2c_mii_read_default_c22;  in mdio_i2c_alloc()
502 		mii->write = i2c_mii_write_default_c22;  in mdio_i2c_alloc()
503 		mii->read_c45 = i2c_mii_read_default_c45;  in mdio_i2c_alloc()
504 		mii->write_c45 = i2c_mii_write_default_c45;  in mdio_i2c_alloc()
513 MODULE_DESCRIPTION("MDIO I2C bridge library");