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
33 static int i2c_mii_read_default_c45(struct mii_bus *bus, int phy_id, int devad,  in i2c_mii_read_default_c45()  argument
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()
68 static int i2c_mii_write_default_c45(struct mii_bus *bus, int phy_id,  in i2c_mii_write_default_c45()  argument
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()
98 static int i2c_mii_read_default_c22(struct mii_bus *bus, int phy_id, int reg)  in i2c_mii_read_default_c22()  argument
100 	return i2c_mii_read_default_c45(bus, phy_id, -1, reg);  in i2c_mii_read_default_c22()
103 static int i2c_mii_write_default_c22(struct mii_bus *bus, int phy_id, int reg,  in i2c_mii_write_default_c22()  argument
106 	return i2c_mii_write_default_c45(bus, phy_id, -1, reg, val);  in i2c_mii_write_default_c22()
109 /* RollBall SFPs do not access internal PHY via I2C address 0x56, but
114  * -------  ----  --------  -----------
133 static int __i2c_transfer_err(struct i2c_adapter *i2c, struct i2c_msg *msgs,  in __i2c_transfer_err()  argument
138 	ret = __i2c_transfer(i2c, msgs, num);  in __i2c_transfer_err()
142 		return -EIO;  in __i2c_transfer_err()
147 static int __i2c_rollball_get_page(struct i2c_adapter *i2c, int bus_addr,  in __i2c_rollball_get_page()  argument
163 	return __i2c_transfer_err(i2c, msgs, 2);  in __i2c_rollball_get_page()
166 static int __i2c_rollball_set_page(struct i2c_adapter *i2c, int bus_addr,  in __i2c_rollball_set_page()  argument
180 	return __i2c_transfer_err(i2c, &msg, 1);  in __i2c_rollball_set_page()
185  *   1. lock the bus
190  *   6. unlock the bus
193  * unfortunately tests show that this does not work :-( Changed SFP_PAGE does
196 static int i2c_transfer_rollball(struct i2c_adapter *i2c,  in i2c_transfer_rollball()  argument
202 	i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);  in i2c_transfer_rollball()
205 	ret = __i2c_rollball_get_page(i2c, msgs->addr, &saved_page);  in i2c_transfer_rollball()
210 	ret = __i2c_rollball_set_page(i2c, msgs->addr, SFP_PAGE_ROLLBALL_MDIO);  in i2c_transfer_rollball()
215 	ret = __i2c_transfer_err(i2c, msgs, num);  in i2c_transfer_rollball()
220 	ret = __i2c_rollball_set_page(i2c, msgs->addr, saved_page);  in i2c_transfer_rollball()
223 	i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);  in i2c_transfer_rollball()
228 static int i2c_rollball_mii_poll(struct mii_bus *bus, int bus_addr, u8 *buf,  in i2c_rollball_mii_poll()  argument
231 	struct i2c_adapter *i2c = bus->priv;  in i2c_rollball_mii_poll()  local
258 		ret = i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));  in i2c_rollball_mii_poll()
264 	} while (i-- > 0);  in i2c_rollball_mii_poll()
266 	dev_dbg(&bus->dev, "poll timed out\n");  in i2c_rollball_mii_poll()
268 	return -ETIMEDOUT;  in i2c_rollball_mii_poll()
271 static int i2c_rollball_mii_cmd(struct mii_bus *bus, int bus_addr, u8 cmd,  in i2c_rollball_mii_cmd()  argument
274 	struct i2c_adapter *i2c = bus->priv;  in i2c_rollball_mii_cmd()  local
291 	return i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));  in i2c_rollball_mii_cmd()
294 static int i2c_mii_read_rollball(struct mii_bus *bus, int phy_id, int devad,  in i2c_mii_read_rollball()  argument
310 	ret = i2c_rollball_mii_cmd(bus, bus_addr, ROLLBALL_CMD_READ, buf,  in i2c_mii_read_rollball()
315 	ret = i2c_rollball_mii_poll(bus, bus_addr, res, sizeof(res));  in i2c_mii_read_rollball()
316 	if (ret == -ETIMEDOUT)  in i2c_mii_read_rollball()
326 static int i2c_mii_write_rollball(struct mii_bus *bus, int phy_id, int devad,  in i2c_mii_write_rollball()  argument
343 	ret = i2c_rollball_mii_cmd(bus, bus_addr, ROLLBALL_CMD_WRITE, buf,  in i2c_mii_write_rollball()
348 	ret = i2c_rollball_mii_poll(bus, bus_addr, NULL, 0);  in i2c_mii_write_rollball()
355 static int i2c_mii_init_rollball(struct i2c_adapter *i2c)  in i2c_mii_init_rollball()  argument
372 	ret = i2c_transfer(i2c, &msg, 1);  in i2c_mii_init_rollball()
376 		return -EIO;  in i2c_mii_init_rollball()
381 struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c,  in mdio_i2c_alloc()  argument
387 	if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))  in mdio_i2c_alloc()
388 		return ERR_PTR(-EINVAL);  in mdio_i2c_alloc()
392 		return ERR_PTR(-ENOMEM);  in mdio_i2c_alloc()
394 	snprintf(mii->id, MII_BUS_ID_SIZE, "i2c:%s", dev_name(parent));  in mdio_i2c_alloc()
395 	mii->parent = parent;  in mdio_i2c_alloc()
396 	mii->priv = i2c;  in mdio_i2c_alloc()
400 		ret = i2c_mii_init_rollball(i2c);  in mdio_i2c_alloc()
403 				"Cannot initialize RollBall MDIO I2C protocol: %d\n",  in mdio_i2c_alloc()
409 		mii->read_c45 = i2c_mii_read_rollball;  in mdio_i2c_alloc()
410 		mii->write_c45 = i2c_mii_write_rollball;  in mdio_i2c_alloc()
413 		mii->read = i2c_mii_read_default_c22;  in mdio_i2c_alloc()
414 		mii->write = i2c_mii_write_default_c22;  in mdio_i2c_alloc()
415 		mii->read_c45 = i2c_mii_read_default_c45;  in mdio_i2c_alloc()
416 		mii->write_c45 = i2c_mii_write_default_c45;  in mdio_i2c_alloc()
425 MODULE_DESCRIPTION("MDIO I2C bridge library");