// SPDX-License-Identifier: GPL-2.0 /* * MDIO I2C bridge * * Copyright (C) 2015-2016 Russell King * Copyright (C) 2021 Marek Behun * * Network PHYs can appear on I2C buses when they are part of SFP module. * This driver exposes these PHYs to the networking PHY code, allowing * our PHY drivers access to these PHYs, and so allowing configuration * of their settings. */ #include <linux/i2c.h> #include <linux/mdio/mdio-i2c.h> #include <linux/phy.h> #include <linux/sfp.h> /* * I2C bus addresses 0x50 and 0x51 are normally an EEPROM, which is * specified to be present in SFP modules. These correspond with PHY * addresses 16 and 17. Disallow access to these "phy" addresses. */ static bool i2c_mii_valid_phy_id(int phy_id) { … } static unsigned int i2c_mii_phy_addr(int phy_id) { … } static int i2c_mii_read_default_c45(struct mii_bus *bus, int phy_id, int devad, int reg) { … } static int i2c_mii_write_default_c45(struct mii_bus *bus, int phy_id, int devad, int reg, u16 val) { … } static int i2c_mii_read_default_c22(struct mii_bus *bus, int phy_id, int reg) { … } static int i2c_mii_write_default_c22(struct mii_bus *bus, int phy_id, int reg, u16 val) { … } /* RollBall SFPs do not access internal PHY via I2C address 0x56, but * instead via address 0x51, when SFP page is set to 0x03 and password to * 0xffffffff. * * address size contents description * ------- ---- -------- ----------- * 0x80 1 CMD 0x01/0x02/0x04 for write/read/done * 0x81 1 DEV Clause 45 device * 0x82 2 REG Clause 45 register * 0x84 2 VAL Register value */ #define ROLLBALL_PHY_I2C_ADDR … #define ROLLBALL_PASSWORD … #define ROLLBALL_CMD_ADDR … #define ROLLBALL_DATA_ADDR … #define ROLLBALL_CMD_WRITE … #define ROLLBALL_CMD_READ … #define ROLLBALL_CMD_DONE … #define SFP_PAGE_ROLLBALL_MDIO … static int __i2c_transfer_err(struct i2c_adapter *i2c, struct i2c_msg *msgs, int num) { … } static int __i2c_rollball_get_page(struct i2c_adapter *i2c, int bus_addr, u8 *page) { … } static int __i2c_rollball_set_page(struct i2c_adapter *i2c, int bus_addr, u8 page) { … } /* In order to not interfere with other SFP code (which possibly may manipulate * SFP_PAGE), for every transfer we do this: * 1. lock the bus * 2. save content of SFP_PAGE * 3. set SFP_PAGE to 3 * 4. do the transfer * 5. restore original SFP_PAGE * 6. unlock the bus * Note that one might think that steps 2 to 5 could be theoretically done all * in one call to i2c_transfer (by constructing msgs array in such a way), but * unfortunately tests show that this does not work :-( Changed SFP_PAGE does * not take into account until i2c_transfer() is done. */ static int i2c_transfer_rollball(struct i2c_adapter *i2c, struct i2c_msg *msgs, int num) { … } static int i2c_rollball_mii_poll(struct mii_bus *bus, int bus_addr, u8 *buf, size_t len) { … } static int i2c_rollball_mii_cmd(struct mii_bus *bus, int bus_addr, u8 cmd, u8 *data, size_t len) { … } static int i2c_mii_read_rollball(struct mii_bus *bus, int phy_id, int devad, int reg) { … } static int i2c_mii_write_rollball(struct mii_bus *bus, int phy_id, int devad, int reg, u16 val) { … } static int i2c_mii_init_rollball(struct i2c_adapter *i2c) { … } struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c, enum mdio_i2c_proto protocol) { … } EXPORT_SYMBOL_GPL(…); MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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