nslu2_iic.c revision 1.6
1 /* $NetBSD: nslu2_iic.c,v 1.6 2008/06/09 15:42:25 tsutsui 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 47 struct slugiic_softc { 48 struct device sc_dev; 49 struct i2c_controller sc_ic; 50 struct i2c_bitbang_ops sc_ibo; 51 kmutex_t sc_lock; 52 uint32_t sc_dirout; 53 }; 54 55 static int 56 slugiic_acquire_bus(void *arg, int flags) 57 { 58 struct slugiic_softc *sc = arg; 59 60 if (flags & I2C_F_POLL) 61 return (0); 62 63 mutex_enter(&sc->sc_lock); 64 return (0); 65 } 66 67 static void 68 slugiic_release_bus(void *arg, int flags) 69 { 70 struct slugiic_softc *sc = arg; 71 72 if (flags & I2C_F_POLL) 73 return; 74 75 mutex_exit(&sc->sc_lock); 76 } 77 78 static int 79 slugiic_send_start(void *arg, int flags) 80 { 81 struct slugiic_softc *sc = arg; 82 83 return (i2c_bitbang_send_start(sc, flags, &sc->sc_ibo)); 84 } 85 86 static int 87 slugiic_send_stop(void *arg, int flags) 88 { 89 struct slugiic_softc *sc = arg; 90 91 return (i2c_bitbang_send_stop(sc, flags, &sc->sc_ibo)); 92 } 93 94 static int 95 slugiic_initiate_xfer(void *arg, i2c_addr_t addr, int flags) 96 { 97 struct slugiic_softc *sc = arg; 98 99 return (i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_ibo)); 100 } 101 102 static int 103 slugiic_read_byte(void *arg, uint8_t *vp, int flags) 104 { 105 struct slugiic_softc *sc = arg; 106 107 return (i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_ibo)); 108 } 109 110 static int 111 slugiic_write_byte(void *arg, uint8_t v, int flags) 112 { 113 struct slugiic_softc *sc = arg; 114 115 return (i2c_bitbang_write_byte(sc, v, flags, &sc->sc_ibo)); 116 } 117 118 static void 119 slugiic_set_dir(void *arg, uint32_t bits) 120 { 121 struct slugiic_softc *sc = arg; 122 uint32_t reg; 123 int s; 124 125 if (sc->sc_dirout == bits) 126 return; 127 128 s = splhigh(); 129 130 sc->sc_dirout = bits; 131 132 if (sc->sc_dirout) { 133 /* SDA is output; enable SDA output if SDA OUTR is low */ 134 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 135 if ((reg & GPIO_I2C_SDA_BIT) == 0) { 136 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 137 reg |= GPIO_I2C_SDA_BIT; 138 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 139 } 140 } else { 141 /* SDA is input; disable SDA output */ 142 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 143 reg &= ~GPIO_I2C_SDA_BIT; 144 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 145 } 146 147 splx(s); 148 } 149 150 static void 151 slugiic_set_bits(void *arg, uint32_t bits) 152 { 153 struct slugiic_softc *sc = arg; 154 uint32_t oer, outr; 155 int s; 156 157 s = splhigh(); 158 159 /* 160 * Enable SCL output if the SCL line is to be driven low. 161 * Enable SDA output if the SDA line is to be driven low and 162 * SDA direction is output. 163 * Otherwise switch them to input even if directions are output 164 * so that we can emulate open collector output with the pullup 165 * resistors. 166 * If lines are to be set to high, disable OER first then set OUTR. 167 * If lines are to be set to low, set OUTR first then enable OER. 168 */ 169 oer = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 170 if ((bits & GPIO_I2C_SCL_BIT) != 0) 171 oer &= ~GPIO_I2C_SCL_BIT; 172 if ((bits & GPIO_I2C_SDA_BIT) != 0) 173 oer &= ~GPIO_I2C_SDA_BIT; 174 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer); 175 176 outr = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 177 outr &= ~(GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT); 178 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, outr | bits); 179 180 if ((bits & GPIO_I2C_SCL_BIT) == 0) 181 oer |= GPIO_I2C_SCL_BIT; 182 if ((bits & GPIO_I2C_SDA_BIT) == 0 && sc->sc_dirout) 183 oer |= GPIO_I2C_SDA_BIT; 184 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer); 185 186 splx(s); 187 } 188 189 static uint32_t 190 slugiic_read_bits(void *arg) 191 { 192 uint32_t reg; 193 194 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPINR); 195 return (reg & (GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT)); 196 } 197 198 static void 199 slugiic_deferred_attach(struct device *device) 200 { 201 struct slugiic_softc *sc = (struct slugiic_softc *)device; 202 struct i2cbus_attach_args iba; 203 uint32_t reg; 204 205 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 206 reg |= GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT; 207 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, reg); 208 209 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 210 reg &= ~GPIO_I2C_SCL_BIT; 211 reg |= GPIO_I2C_SDA_BIT; 212 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 213 214 iba.iba_tag = &sc->sc_ic; 215 (void) config_found_ia(&sc->sc_dev, "i2cbus", &iba, iicbus_print); 216 } 217 218 static int 219 slugiic_match(struct device *parent, struct cfdata *cf, void *arg) 220 { 221 222 return (1); 223 } 224 225 static void 226 slugiic_attach(struct device *parent, struct device *self, void *arg) 227 { 228 struct slugiic_softc *sc = (struct slugiic_softc *)self; 229 230 aprint_naive("\n"); 231 aprint_normal(": I2C bus\n"); 232 233 sc->sc_ic.ic_cookie = sc; 234 sc->sc_ic.ic_acquire_bus = slugiic_acquire_bus; 235 sc->sc_ic.ic_release_bus = slugiic_release_bus; 236 sc->sc_ic.ic_exec = NULL; 237 sc->sc_ic.ic_send_start = slugiic_send_start; 238 sc->sc_ic.ic_send_stop = slugiic_send_stop; 239 sc->sc_ic.ic_initiate_xfer = slugiic_initiate_xfer; 240 sc->sc_ic.ic_read_byte = slugiic_read_byte; 241 sc->sc_ic.ic_write_byte = slugiic_write_byte; 242 243 sc->sc_ibo.ibo_set_dir = slugiic_set_dir; 244 sc->sc_ibo.ibo_set_bits = slugiic_set_bits; 245 sc->sc_ibo.ibo_read_bits = slugiic_read_bits; 246 sc->sc_ibo.ibo_bits[I2C_BIT_SDA] = GPIO_I2C_SDA_BIT; 247 sc->sc_ibo.ibo_bits[I2C_BIT_SCL] = GPIO_I2C_SCL_BIT; 248 sc->sc_ibo.ibo_bits[I2C_BIT_OUTPUT] = 1; 249 sc->sc_ibo.ibo_bits[I2C_BIT_INPUT] = 0; 250 251 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 252 253 sc->sc_dirout = 0; 254 255 /* 256 * Defer until ixp425_softc has been initialised 257 */ 258 config_interrupts(self, slugiic_deferred_attach); 259 } 260 261 CFATTACH_DECL(slugiic, sizeof(struct slugiic_softc), 262 slugiic_match, slugiic_attach, NULL, NULL); 263
Indexes created Fri Oct 17 23:09:53 GMT 2025