1 /* $NetBSD: nslu2_iic.c,v 1.13 2025/09/15 13:23:01 thorpej 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 i2c_controller sc_ic; 49 struct i2c_bitbang_ops sc_ibo; 50 uint32_t sc_dirout; 51 }; 52 53 static int 54 slugiic_send_start(void *arg, int flags) 55 { 56 struct slugiic_softc *sc = arg; 57 58 return (i2c_bitbang_send_start(sc, flags, &sc->sc_ibo)); 59 } 60 61 static int 62 slugiic_send_stop(void *arg, int flags) 63 { 64 struct slugiic_softc *sc = arg; 65 66 return (i2c_bitbang_send_stop(sc, flags, &sc->sc_ibo)); 67 } 68 69 static int 70 slugiic_initiate_xfer(void *arg, i2c_addr_t addr, int flags) 71 { 72 struct slugiic_softc *sc = arg; 73 74 return (i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_ibo)); 75 } 76 77 static int 78 slugiic_read_byte(void *arg, uint8_t *vp, int flags) 79 { 80 struct slugiic_softc *sc = arg; 81 82 return (i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_ibo)); 83 } 84 85 static int 86 slugiic_write_byte(void *arg, uint8_t v, int flags) 87 { 88 struct slugiic_softc *sc = arg; 89 90 return (i2c_bitbang_write_byte(sc, v, flags, &sc->sc_ibo)); 91 } 92 93 static void 94 slugiic_set_dir(void *arg, uint32_t bits) 95 { 96 struct slugiic_softc *sc = arg; 97 uint32_t reg; 98 int s; 99 100 if (sc->sc_dirout == bits) 101 return; 102 103 s = splhigh(); 104 105 sc->sc_dirout = bits; 106 107 if (sc->sc_dirout) { 108 /* SDA is output; enable SDA output if SDA OUTR is low */ 109 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 110 if ((reg & GPIO_I2C_SDA_BIT) == 0) { 111 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 112 reg &= ~GPIO_I2C_SDA_BIT; 113 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 114 } 115 } else { 116 /* SDA is input; disable SDA output */ 117 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 118 reg |= GPIO_I2C_SDA_BIT; 119 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 120 } 121 122 splx(s); 123 } 124 125 static void 126 slugiic_set_bits(void *arg, uint32_t bits) 127 { 128 struct slugiic_softc *sc = arg; 129 uint32_t oer, outr; 130 int s; 131 132 s = splhigh(); 133 134 /* 135 * Enable SCL output if the SCL line is to be driven low. 136 * Enable SDA output if the SDA line is to be driven low and 137 * SDA direction is output. 138 * Otherwise switch them to input even if directions are output 139 * so that we can emulate open collector output with the pullup 140 * resistors. 141 * If lines are to be set to high, disable OER first then set OUTR. 142 * If lines are to be set to low, set OUTR first then enable OER. 143 */ 144 oer = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 145 if ((bits & GPIO_I2C_SCL_BIT) != 0) 146 oer |= GPIO_I2C_SCL_BIT; 147 if ((bits & GPIO_I2C_SDA_BIT) != 0) 148 oer |= GPIO_I2C_SDA_BIT; 149 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer); 150 151 outr = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 152 outr &= ~(GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT); 153 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, outr | bits); 154 155 if ((bits & GPIO_I2C_SCL_BIT) == 0) 156 oer &= ~GPIO_I2C_SCL_BIT; 157 if ((bits & GPIO_I2C_SDA_BIT) == 0 && sc->sc_dirout) 158 oer &= ~GPIO_I2C_SDA_BIT; 159 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer); 160 161 splx(s); 162 } 163 164 static uint32_t 165 slugiic_read_bits(void *arg) 166 { 167 uint32_t reg; 168 169 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPINR); 170 return (reg & (GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT)); 171 } 172 173 static void 174 slugiic_deferred_attach(device_t self) 175 { 176 struct slugiic_softc *sc = device_private(self); 177 uint32_t reg; 178 179 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR); 180 reg |= GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT; 181 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, reg); 182 183 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER); 184 reg &= ~GPIO_I2C_SCL_BIT; 185 reg |= GPIO_I2C_SDA_BIT; 186 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg); 187 188 iicbus_attach(self, &sc->sc_ic); 189 } 190 191 static int 192 slugiic_match(device_t parent, cfdata_t cf, void *aux) 193 { 194 195 return (1); 196 } 197 198 static void 199 slugiic_attach(device_t parent, device_t self, void *aux) 200 { 201 struct slugiic_softc *sc = device_private(self); 202 203 aprint_naive("\n"); 204 aprint_normal(": I2C bus\n"); 205 206 iic_tag_init(&sc->sc_ic); 207 sc->sc_ic.ic_cookie = sc; 208 sc->sc_ic.ic_send_start = slugiic_send_start; 209 sc->sc_ic.ic_send_stop = slugiic_send_stop; 210 sc->sc_ic.ic_initiate_xfer = slugiic_initiate_xfer; 211 sc->sc_ic.ic_read_byte = slugiic_read_byte; 212 sc->sc_ic.ic_write_byte = slugiic_write_byte; 213 214 sc->sc_ibo.ibo_set_dir = slugiic_set_dir; 215 sc->sc_ibo.ibo_set_bits = slugiic_set_bits; 216 sc->sc_ibo.ibo_read_bits = slugiic_read_bits; 217 sc->sc_ibo.ibo_bits[I2C_BIT_SDA] = GPIO_I2C_SDA_BIT; 218 sc->sc_ibo.ibo_bits[I2C_BIT_SCL] = GPIO_I2C_SCL_BIT; 219 sc->sc_ibo.ibo_bits[I2C_BIT_OUTPUT] = 1; 220 sc->sc_ibo.ibo_bits[I2C_BIT_INPUT] = 0; 221 222 sc->sc_dirout = 0; 223 224 /* 225 * Defer until ixp425_softc has been initialised 226 */ 227 config_interrupts(self, slugiic_deferred_attach); 228 } 229 230 CFATTACH_DECL_NEW(slugiic, sizeof(struct slugiic_softc), 231 slugiic_match, slugiic_attach, NULL, NULL); 232
Indexes created Fri Oct 17 23:09:53 GMT 2025