nslu2_iic.c revision 1.8
1/* $NetBSD: nslu2_iic.c,v 1.8 2012/10/14 14:20:58 msaitoh Exp $ */ 2 3/*- 4 * Copyright (c) 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Steve C. Woodford. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/kernel.h> 35#include <sys/device.h> 36#include <sys/mutex.h> 37#include <sys/bus.h> 38 39#include <dev/i2c/i2cvar.h> 40#include <dev/i2c/i2c_bitbang.h> 41 42#include <arm/xscale/ixp425reg.h> 43#include <arm/xscale/ixp425var.h> 44 45#include <evbarm/nslu2/nslu2reg.h> 46 47struct slugiic_softc { 48 struct i2c_controller sc_ic; 49 struct i2c_bitbang_ops sc_ibo; 50 kmutex_t sc_lock; 51 uint32_t sc_dirout; 52}; 53 54static int 55slugiic_acquire_bus(void *arg, int flags) 56{ 57 struct slugiic_softc *sc = arg; 58 59 if (flags & I2C_F_POLL) 60 return (0); 61 62 mutex_enter(&sc->sc_lock); 63 return (0); 64} 65 66static void 67slugiic_release_bus(void *arg, int flags) 68{ 69 struct slugiic_softc *sc = arg; 70 71 if (flags & I2C_F_POLL) 72 return; 73 74 mutex_exit(&sc->sc_lock); 75} 76 77static int 78slugiic_send_start(void *arg, int flags) 79{ 80 struct slugiic_softc *sc = arg; 81 82 return (i2c_bitbang_send_start(sc, flags, &sc->sc_ibo)); 83} 84 85static int 86slugiic_send_stop(void *arg, int flags) 87{ 88 struct slugiic_softc *sc = arg; 89 90 return (i2c_bitbang_send_stop(sc, flags, &sc->sc_ibo)); 91} 92 93static int 94slugiic_initiate_xfer(void *arg, i2c_addr_t addr, int flags) 95{ 96 struct slugiic_softc *sc = arg; 97 98 return (i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_ibo)); 99} 100 101static int 102slugiic_read_byte(void *arg, uint8_t *vp, int flags) 103{ 104 struct slugiic_softc *sc = arg; 105 106 return (i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_ibo)); 107} 108 109static int 110slugiic_write_byte(void *arg, uint8_t v, int flags) 111{ 112 struct slugiic_softc *sc = arg; 113 114 return (i2c_bitbang_write_byte(sc, v, flags, &sc->sc_ibo)); 115} 116 117static void 118slugiic_set_dir(void *arg, uint32_t bits) 119{ 120 struct slugiic_softc *sc = arg; 121 uint32_t reg; 122 int s; 123 124 if (sc->sc_dirout == bits) 125 return; 126 127 s = splhigh(); 128 129 sc->sc_dirout = bits; 130 131 if (sc->sc_dirout) { 132 /* SDA is output; enable SDA output if SDA OUTR is low */ 133 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 134 if ((reg & GPIO_I2C_SDA_BIT) == 0) { 135 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 136 reg &= ~GPIO_I2C_SDA_BIT; 137 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 138 } 139 } else { 140 /* SDA is input; disable SDA output */ 141 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 142 reg |= GPIO_I2C_SDA_BIT; 143 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 144 } 145 146 splx(s); 147} 148 149static void 150slugiic_set_bits(void *arg, uint32_t bits) 151{ 152 struct slugiic_softc *sc = arg; 153 uint32_t oer, outr; 154 int s; 155 156 s = splhigh(); 157 158 /* 159 * Enable SCL output if the SCL line is to be driven low. 160 * Enable SDA output if the SDA line is to be driven low and 161 * SDA direction is output. 162 * Otherwise switch them to input even if directions are output 163 * so that we can emulate open collector output with the pullup 164 * resistors. 165 * If lines are to be set to high, disable OER first then set OUTR. 166 * If lines are to be set to low, set OUTR first then enable OER. 167 */ 168 oer = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 169 if ((bits & GPIO_I2C_SCL_BIT) != 0) 170 oer |= GPIO_I2C_SCL_BIT; 171 if ((bits & GPIO_I2C_SDA_BIT) != 0) 172 oer |= GPIO_I2C_SDA_BIT; 173 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer); 174 175 outr = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 176 outr &= ~(GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT); 177 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, outr | bits); 178 179 if ((bits & GPIO_I2C_SCL_BIT) == 0) 180 oer &= ~GPIO_I2C_SCL_BIT; 181 if ((bits & GPIO_I2C_SDA_BIT) == 0 && sc->sc_dirout) 182 oer &= ~GPIO_I2C_SDA_BIT; 183 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer); 184 185 splx(s); 186} 187 188static uint32_t 189slugiic_read_bits(void *arg) 190{ 191 uint32_t reg; 192 193 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPINR); 194 return (reg & (GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT)); 195} 196 197static void 198slugiic_deferred_attach(device_t self) 199{ 200 struct slugiic_softc *sc = device_private(self); 201 struct i2cbus_attach_args iba; 202 uint32_t reg; 203 204 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 205 reg |= GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT; 206 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, reg); 207 208 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 209 reg &= ~GPIO_I2C_SCL_BIT; 210 reg |= GPIO_I2C_SDA_BIT; 211 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 212 213 iba.iba_tag = &sc->sc_ic; 214 (void) config_found_ia(self, "i2cbus", &iba, iicbus_print); 215} 216 217static int 218slugiic_match(device_t parent, cfdata_t cf, void *aux) 219{ 220 221 return (1); 222} 223 224static void 225slugiic_attach(device_t parent, device_t self, void *aux) 226{ 227 struct slugiic_softc *sc = device_private(self); 228 229 aprint_naive("\n"); 230 aprint_normal(": I2C bus\n"); 231 232 sc->sc_ic.ic_cookie = sc; 233 sc->sc_ic.ic_acquire_bus = slugiic_acquire_bus; 234 sc->sc_ic.ic_release_bus = slugiic_release_bus; 235 sc->sc_ic.ic_exec = NULL; 236 sc->sc_ic.ic_send_start = slugiic_send_start; 237 sc->sc_ic.ic_send_stop = slugiic_send_stop; 238 sc->sc_ic.ic_initiate_xfer = slugiic_initiate_xfer; 239 sc->sc_ic.ic_read_byte = slugiic_read_byte; 240 sc->sc_ic.ic_write_byte = slugiic_write_byte; 241 242 sc->sc_ibo.ibo_set_dir = slugiic_set_dir; 243 sc->sc_ibo.ibo_set_bits = slugiic_set_bits; 244 sc->sc_ibo.ibo_read_bits = slugiic_read_bits; 245 sc->sc_ibo.ibo_bits[I2C_BIT_SDA] = GPIO_I2C_SDA_BIT; 246 sc->sc_ibo.ibo_bits[I2C_BIT_SCL] = GPIO_I2C_SCL_BIT; 247 sc->sc_ibo.ibo_bits[I2C_BIT_OUTPUT] = 1; 248 sc->sc_ibo.ibo_bits[I2C_BIT_INPUT] = 0; 249 250 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 251 252 sc->sc_dirout = 0; 253 254 /* 255 * Defer until ixp425_softc has been initialised 256 */ 257 config_interrupts(self, slugiic_deferred_attach); 258} 259 260CFATTACH_DECL_NEW(slugiic, sizeof(struct slugiic_softc), 261 slugiic_match, slugiic_attach, NULL, NULL); 262