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 __FBSDID("$FreeBSD$"); 30 31 #include "opt_platform.h" 32 33 #include <sys/param.h> 34 #include <sys/bus.h> 35 #include <sys/kernel.h> 36 #include <sys/module.h> 37 #include <sys/systm.h> 38 39 #include <dev/iicbus/iicbus.h> 40 #include <dev/iicbus/iiconf.h> 41 #include "iicbus_if.h" 42 #include "iicmux_if.h" 43 44 static struct chip_info { 45 const char *partname; 46 const char *description; 47 int numchannels; 48 } chip_infos[] = { 49 {"ltc4305", "LTC4305 I2C Mux", 2}, 50 {"ltc4306", "LTC4306 I2C Mux", 4}, 51 }; 52 #define CHIP_NONE (-1) 53 #define CHIP_LTC4305 0 54 #define CHIP_LTC4306 1 55 56 #ifdef FDT 57 #include <dev/ofw/ofw_bus.h> 58 #include <dev/ofw/ofw_bus_subr.h> 59 #include <dev/ofw/openfirm.h> 60 61 static struct ofw_compat_data compat_data[] = { 62 {"lltc,ltc4305", CHIP_LTC4305}, 63 {"lltc,ltc4306", CHIP_LTC4306}, 64 {NULL, CHIP_NONE} 65 }; 66 IICBUS_FDT_PNP_INFO(compat_data); 67 #endif 68 69 #include <dev/iicbus/mux/iicmux.h> 70 71 struct ltc430x_softc { 72 struct iicmux_softc mux; 73 bool idle_disconnect; 74 }; 75 76 /* 77 * The datasheet doesn't name the registers, it calls them control register 0-3. 78 */ 79 #define LTC430X_CTLREG_0 0 80 #define LTC430X_CTLREG_1 1 81 #define LTC430X_CTLREG_2 2 82 #define LTC430X_CTLREG_3 3 83 84 static int 85 ltc430x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd) 86 { 87 struct ltc430x_softc *sc = device_get_softc(dev); 88 uint8_t busbits; 89 90 /* 91 * The iicmux caller ensures busidx is between 0 and the number of buses 92 * we passed to iicmux_init_softc(), no need for validation here. If 93 * the fdt data has the idle_disconnect property we idle the bus by 94 * selecting no downstream buses, otherwise we just leave the current 95 * bus active. The upper bits of control register 3 activate the 96 * downstream buses; bit 7 is the first bus, bit 6 the second, etc. 97 */ 98 if (busidx == IICMUX_SELECT_IDLE) { 99 if (sc->idle_disconnect) 100 busbits = 0; 101 else 102 return (0); 103 } else { 104 busbits = 1u << (7 - busidx); 105 } 106 107 /* 108 * We have to add the IIC_RECURSIVE flag because the iicmux core has 109 * already reserved the bus for us, and iicdev_writeto() is going to try 110 * to reserve it again, which is allowed with the recursive flag. 111 */ 112 return (iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits), 113 rd->flags | IIC_RECURSIVE)); 114 } 115 116 static int 117 ltc430x_find_chiptype(device_t dev) 118 { 119 #ifdef FDT 120 return (ofw_bus_search_compatible(dev, compat_data)->ocd_data); 121 #else 122 const char *type; 123 int i; 124 125 if (resource_string_value(device_get_name(dev), device_get_unit(dev), 126 "chip_type", &type) == 0) { 127 for (i = 0; i < nitems(chip_infos); ++i) { 128 if (strcasecmp(type, chip_infos[i].partname) == 0) { 129 return (i); 130 } 131 } 132 } 133 return (CHIP_NONE); 134 #endif 135 } 136 137 static int 138 ltc430x_probe(device_t dev) 139 { 140 int type; 141 142 #ifdef FDT 143 if (!ofw_bus_status_okay(dev)) 144 return (ENXIO); 145 #endif 146 147 type = ltc430x_find_chiptype(dev); 148 if (type == CHIP_NONE) 149 return (ENXIO); 150 151 device_set_desc(dev, chip_infos[type].description); 152 153 return (BUS_PROBE_DEFAULT); 154 } 155 156 static int 157 ltc430x_attach(device_t dev) 158 { 159 struct ltc430x_softc *sc __unused; 160 int chip, err, numchan; 161 162 sc = device_get_softc(dev); 163 164 #ifdef FDT 165 phandle_t node; 166 167 node = ofw_bus_get_node(dev); 168 sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect"); 169 #endif 170 171 /* We found the chip type when probing, so now it "can't fail". */ 172 if ((chip = ltc430x_find_chiptype(dev)) == CHIP_NONE) { 173 device_printf(dev, "impossible: can't identify chip type\n"); 174 return (ENXIO); 175 } 176 numchan = chip_infos[chip].numchannels; 177 178 if ((err = iicmux_attach(dev, device_get_parent(dev), numchan)) == 0) 179 bus_generic_attach(dev); 180 181 return (err); 182 } 183 184 static int 185 ltc430x_detach(device_t dev) 186 { 187 int err; 188 189 if ((err = iicmux_detach(dev)) != 0) 190 return (err); 191 192 return (0); 193 } 194 195 static device_method_t ltc430x_methods[] = { 196 /* device methods */ 197 DEVMETHOD(device_probe, ltc430x_probe), 198 DEVMETHOD(device_attach, ltc430x_attach), 199 DEVMETHOD(device_detach, ltc430x_detach), 200 201 /* iicmux methods */ 202 DEVMETHOD(iicmux_bus_select, ltc430x_bus_select), 203 204 DEVMETHOD_END 205 }; 206 207 static devclass_t ltc430x_devclass; 208 209 DEFINE_CLASS_1(ltc430x, ltc430x_driver, ltc430x_methods, 210 sizeof(struct ltc430x_softc), iicmux_driver); 211 DRIVER_MODULE(ltc430x, iicbus, ltc430x_driver, ltc430x_devclass, 0, 0); 212 213 #ifdef FDT 214 DRIVER_MODULE(ofw_iicbus, ltc430x, ofw_iicbus_driver, ofw_iicbus_devclass, 0, 0); 215 #else 216 DRIVER_MODULE(iicbus, ltc430x, iicbus_driver, iicbus_devclass, 0, 0); 217 #endif 218 219 MODULE_DEPEND(ltc430x, iicmux, 1, 1, 1); 220 MODULE_DEPEND(ltc430x, iicbus, 1, 1, 1); 221 222