1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2019 Ian Lepore <ian@freebsd.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 #include "opt_platform.h" 30 31 #include <sys/param.h> 32 #include <sys/bus.h> 33 #include <sys/kernel.h> 34 #include <sys/module.h> 35 #include <sys/systm.h> 36 37 #include <dev/iicbus/iicbus.h> 38 #include <dev/iicbus/iiconf.h> 39 #include "iicbus_if.h" 40 #include "iicmux_if.h" 41 42 static struct chip_info { 43 const char *partname; 44 const char *description; 45 int numchannels; 46 } chip_infos[] = { 47 {"ltc4305", "LTC4305 I2C Mux", 2}, 48 {"ltc4306", "LTC4306 I2C Mux", 4}, 49 }; 50 #define CHIP_NONE (-1) 51 #define CHIP_LTC4305 0 52 #define CHIP_LTC4306 1 53 54 #ifdef FDT 55 #include <dev/ofw/ofw_bus.h> 56 #include <dev/ofw/ofw_bus_subr.h> 57 #include <dev/ofw/openfirm.h> 58 59 static struct ofw_compat_data compat_data[] = { 60 {"lltc,ltc4305", CHIP_LTC4305}, 61 {"lltc,ltc4306", CHIP_LTC4306}, 62 {NULL, CHIP_NONE} 63 }; 64 IICBUS_FDT_PNP_INFO(compat_data); 65 #endif 66 67 #include <dev/iicbus/mux/iicmux.h> 68 69 struct ltc430x_softc { 70 struct iicmux_softc mux; 71 bool idle_disconnect; 72 }; 73 74 /* 75 * The datasheet doesn't name the registers, it calls them control register 0-3. 76 */ 77 #define LTC430X_CTLREG_0 0 78 #define LTC430X_CTLREG_1 1 79 #define LTC430X_CTLREG_2 2 80 #define LTC430X_CR2_ENABLE_MW (1u << 3) /* Enable mass write address. */ 81 #define LTC430X_CTLREG_3 3 82 83 static int 84 ltc430x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd) 85 { 86 struct ltc430x_softc *sc = device_get_softc(dev); 87 uint8_t busbits; 88 89 /* 90 * The iicmux caller ensures busidx is between 0 and the number of buses 91 * we passed to iicmux_init_softc(), no need for validation here. If 92 * the fdt data has the idle_disconnect property we idle the bus by 93 * selecting no downstream buses, otherwise we just leave the current 94 * bus active. The upper bits of control register 3 activate the 95 * downstream buses; bit 7 is the first bus, bit 6 the second, etc. 96 */ 97 if (busidx == IICMUX_SELECT_IDLE) { 98 if (sc->idle_disconnect) 99 busbits = 0; 100 else 101 return (0); 102 } else { 103 busbits = 1u << (7 - busidx); 104 } 105 106 /* 107 * We have to add the IIC_RECURSIVE flag because the iicmux core has 108 * already reserved the bus for us, and iicdev_writeto() is going to try 109 * to reserve it again, which is allowed with the recursive flag. 110 */ 111 return (iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits), 112 rd->flags | IIC_RECURSIVE)); 113 } 114 115 static int 116 ltc430x_find_chiptype(device_t dev) 117 { 118 #ifdef FDT 119 return (ofw_bus_search_compatible(dev, compat_data)->ocd_data); 120 #else 121 const char *type; 122 int i; 123 124 if (resource_string_value(device_get_name(dev), device_get_unit(dev), 125 "chip_type", &type) == 0) { 126 for (i = 0; i < nitems(chip_infos); ++i) { 127 if (strcasecmp(type, chip_infos[i].partname) == 0) { 128 return (i); 129 } 130 } 131 } 132 return (CHIP_NONE); 133 #endif 134 } 135 136 static int 137 ltc430x_probe(device_t dev) 138 { 139 int type; 140 141 #ifdef FDT 142 if (!ofw_bus_status_okay(dev)) 143 return (ENXIO); 144 #endif 145 146 type = ltc430x_find_chiptype(dev); 147 if (type == CHIP_NONE) 148 return (ENXIO); 149 150 device_set_desc(dev, chip_infos[type].description); 151 152 return (BUS_PROBE_DEFAULT); 153 } 154 155 static int 156 ltc430x_attach(device_t dev) 157 { 158 struct ltc430x_softc *sc __unused; 159 int chip, err, numchan, val; 160 uint8_t busbits, ctlreg2; 161 162 sc = device_get_softc(dev); 163 164 busbits = 0; 165 ctlreg2 = LTC430X_CR2_ENABLE_MW; 166 167 /* 168 * Check for the idle-disconnect and ctlreg2 options, first in FDT data, 169 * then allow them to be overridden by hints data. 170 */ 171 #ifdef FDT 172 phandle_t node; 173 174 node = ofw_bus_get_node(dev); 175 sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect"); 176 177 if (OF_getprop(node, "freebsd,ctlreg2", &val, sizeof(val)) > 0) { 178 ctlreg2 = val; 179 } 180 #endif 181 182 if (resource_int_value(device_get_name(dev), device_get_unit(dev), 183 "idle_disconnect", &val) == 0) { 184 sc->idle_disconnect = val; 185 } 186 187 if (resource_int_value(device_get_name(dev), device_get_unit(dev), 188 "ctlreg2", &val) == 0) { 189 ctlreg2 = val; 190 } 191 192 /* We found the chip type when probing, so now it "can't fail". */ 193 if ((chip = ltc430x_find_chiptype(dev)) == CHIP_NONE) { 194 device_printf(dev, "impossible: can't identify chip type\n"); 195 return (ENXIO); 196 } 197 numchan = chip_infos[chip].numchannels; 198 199 /* Set control reg 2 with configured (or default) values. */ 200 iicdev_writeto(dev, LTC430X_CTLREG_2, &ctlreg2, sizeof(ctlreg2), 201 IIC_WAIT); 202 203 /* If configured for idle-disconnect, ensure we start disconnected. */ 204 if (sc->idle_disconnect) { 205 iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits), 206 IIC_WAIT); 207 } 208 209 /* 210 * Invoke the iicmux framework's attach code, and if it succeeds, invoke 211 * the probe and attach code of any child iicbus instances it added. 212 */ 213 if ((err = iicmux_attach(dev, device_get_parent(dev), numchan)) == 0) 214 bus_generic_attach(dev); 215 216 return (err); 217 } 218 219 static int 220 ltc430x_detach(device_t dev) 221 { 222 int err; 223 224 if ((err = iicmux_detach(dev)) != 0) 225 return (err); 226 227 return (0); 228 } 229 230 static device_method_t ltc430x_methods[] = { 231 /* device methods */ 232 DEVMETHOD(device_probe, ltc430x_probe), 233 DEVMETHOD(device_attach, ltc430x_attach), 234 DEVMETHOD(device_detach, ltc430x_detach), 235 236 /* iicmux methods */ 237 DEVMETHOD(iicmux_bus_select, ltc430x_bus_select), 238 239 DEVMETHOD_END 240 }; 241 242 DEFINE_CLASS_1(ltc430x, ltc430x_driver, ltc430x_methods, 243 sizeof(struct ltc430x_softc), iicmux_driver); 244 DRIVER_MODULE(ltc430x, iicbus, ltc430x_driver, 0, 0); 245 246 #ifdef FDT 247 DRIVER_MODULE(ofw_iicbus, ltc430x, ofw_iicbus_driver, 0, 0); 248 #else 249 DRIVER_MODULE(iicbus, ltc430x, iicbus_driver, 0, 0); 250 #endif 251 252 MODULE_DEPEND(ltc430x, iicmux, 1, 1, 1); 253 MODULE_DEPEND(ltc430x, iicbus, 1, 1, 1); 254 255