target/linux/mvebu/patches-4.4/129-phy-add-I2C-mdio-bus.patch

   1 From 7f36ac946bfbd4090b8b94be3661b41ac73e21f4 Mon Sep 17 00:00:00 2001
   2 From: Russell King <rmk+kernel@arm.linux.org.uk>
   3 Date: Fri, 25 Sep 2015 17:43:52 +0100
   4 Subject: [PATCH 717/744] phy: add I2C mdio bus
   5
   6 Add an I2C MDIO bus bridge library, to allow phylib to access PHYs which
   7 are connected to an I2C bus instead of the more conventional MDIO bus.
   8 Such PHYs can be found in SFP adapters and SFF modules.
   9
  10 Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
  11 ---
  12  drivers/net/phy/Kconfig    | 10 ++++++
  13  drivers/net/phy/Makefile   |  1 +
  14  drivers/net/phy/mdio-i2c.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++
  15  drivers/net/phy/mdio-i2c.h | 19 ++++++++++
  16  4 files changed, 120 insertions(+)
  17  create mode 100644 drivers/net/phy/mdio-i2c.c
  18  create mode 100644 drivers/net/phy/mdio-i2c.h
  19
  20 --- a/drivers/net/phy/Kconfig
  21 +++ b/drivers/net/phy/Kconfig
  22 @@ -233,6 +233,16 @@ config MDIO_GPIO
  23           To compile this driver as a module, choose M here: the module
  24           will be called mdio-gpio.
  25
  26 +config MDIO_I2C
  27 +       tristate
  28 +       depends on I2C
  29 +       help
  30 +         Support I2C based PHYs.  This provides a MDIO bus bridged
  31 +         to I2C to allow PHYs connected in I2C mode to be accessed
  32 +         using the existing infrastructure.
  33 +
  34 +         This is library mode.
  35 +
  36  config MDIO_OCTEON
  37         tristate "Support for MDIO buses on Octeon and ThunderX SOCs"
  38         depends on 64BIT
  39 --- a/drivers/net/phy/Makefile
  40 +++ b/drivers/net/phy/Makefile
  41 @@ -41,6 +41,7 @@ obj-$(CONFIG_SWCONFIG_B53)    += b53/
  42  obj-$(CONFIG_FIXED_PHY)                += fixed_phy.o
  43  obj-$(CONFIG_MDIO_BITBANG)     += mdio-bitbang.o
  44  obj-$(CONFIG_MDIO_GPIO)                += mdio-gpio.o
  45 +obj-$(CONFIG_MDIO_I2C)         += mdio-i2c.o
  46  obj-$(CONFIG_NATIONAL_PHY)     += national.o
  47  obj-$(CONFIG_DP83640_PHY)      += dp83640.o
  48  obj-$(CONFIG_DP83848_PHY)      += dp83848.o
  49 --- /dev/null
  50 +++ b/drivers/net/phy/mdio-i2c.c
  51 @@ -0,0 +1,90 @@
  52 +/*
  53 + * MDIO I2C bridge
  54 + *
  55 + * Copyright (C) 2015 Russell King
  56 + *
  57 + * This program is free software; you can redistribute it and/or modify
  58 + * it under the terms of the GNU General Public License version 2 as
  59 + * published by the Free Software Foundation.
  60 + */
  61 +#include <linux/i2c.h>
  62 +#include <linux/phy.h>
  63 +
  64 +#include "mdio-i2c.h"
  65 +
  66 +static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
  67 +{
  68 +       struct i2c_adapter *i2c = bus->priv;
  69 +       struct i2c_msg msgs[2];
  70 +       u8 data[2], dev_addr = reg;
  71 +       int bus_addr, ret;
  72 +
  73 +       bus_addr = 0x40 + phy_id;
  74 +       if (bus_addr == 0x50 || bus_addr == 0x51)
  75 +               return 0xffff;
  76 +
  77 +       msgs[0].addr = bus_addr;
  78 +       msgs[0].flags = 0;
  79 +       msgs[0].len = 1;
  80 +       msgs[0].buf = &dev_addr;
  81 +       msgs[1].addr = bus_addr;
  82 +       msgs[1].flags = I2C_M_RD;
  83 +       msgs[1].len = sizeof(data);
  84 +       msgs[1].buf = data;
  85 +
  86 +       ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));
  87 +       if (ret != ARRAY_SIZE(msgs))
  88 +               return 0xffff;
  89 +
  90 +       return data[0] << 8 | data[1];
  91 +}
  92 +
  93 +static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
  94 +{
  95 +       struct i2c_adapter *i2c = bus->priv;
  96 +       struct i2c_msg msg;
  97 +       int bus_addr, ret;
  98 +       u8 data[3];
  99 +
 100 +       bus_addr = 0x40 + phy_id;
 101 +       if (bus_addr == 0x50 || bus_addr == 0x51)
 102 +               return 0;
 103 +
 104 +       data[0] = reg;
 105 +       data[1] = val >> 8;
 106 +       data[2] = val;
 107 +
 108 +       msg.addr = bus_addr;
 109 +       msg.flags = 0;
 110 +       msg.len = 3;
 111 +       msg.buf = data;
 112 +
 113 +       ret = i2c_transfer(i2c, &msg, 1);
 114 +
 115 +       return ret < 0 ? ret : 0;
 116 +}
 117 +
 118 +struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c)
 119 +{
 120 +       struct mii_bus *mii;
 121 +
 122 +       if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
 123 +               return ERR_PTR(-EINVAL);
 124 +
 125 +       mii = mdiobus_alloc();
 126 +       if (!mii)
 127 +               return ERR_PTR(-ENOMEM);
 128 +
 129 +       snprintf(mii->id, MII_BUS_ID_SIZE, "i2c:%s", dev_name(parent));
 130 +       mii->parent = parent;
 131 +       mii->read = i2c_mii_read;
 132 +       mii->write = i2c_mii_write;
 133 +       mii->priv = i2c;
 134 +
 135 +       return mii;
 136 +}
 137 +EXPORT_SYMBOL_GPL(mdio_i2c_alloc);
 138 +
 139 +MODULE_AUTHOR("Russell King");
 140 +MODULE_DESCRIPTION("MDIO I2C bridge library");
 141 +MODULE_LICENSE("GPL v2");
 142 --- /dev/null
 143 +++ b/drivers/net/phy/mdio-i2c.h
 144 @@ -0,0 +1,19 @@
 145 +/*
 146 + * MDIO I2C bridge
 147 + *
 148 + * Copyright (C) 2015 Russell King
 149 + *
 150 + * This program is free software; you can redistribute it and/or modify
 151 + * it under the terms of the GNU General Public License version 2 as
 152 + * published by the Free Software Foundation.
 153 + */
 154 +#ifndef MDIO_I2C_H
 155 +#define MDIO_I2C_H
 156 +
 157 +struct device;
 158 +struct i2c_adapter;
 159 +struct mii_bus;
 160 +
 161 +struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c);
 162 +
 163 +#endif