sys/arch/evbarm/nslu2/nslu2_iic.c

   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);