sc16is7xxi2c.c revision 1.1
1 /* $NetBSD: sc16is7xxi2c.c,v 1.1 2025/10/24 23:16:11 brad Exp $ */ 2 3 /* 4 * Copyright (c) 2025 Brad Spencer <brad (at) anduin.eldar.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/cdefs.h> 20 __KERNEL_RCSID(0, "$NetBSD: sc16is7xxi2c.c,v 1.1 2025/10/24 23:16:11 brad Exp $"); 21 22 /* 23 * I2C frontend driver for the SC16IS7xx UART bridge. 24 * The heavy lifting is done by the general sc16is7xx(4) 25 * driver and the com(4) backend. 26 */ 27 28 #include <sys/param.h> 29 #include <sys/systm.h> 30 #include <sys/kernel.h> 31 #include <sys/device.h> 32 #include <sys/module.h> 33 #include <sys/conf.h> 34 #include <sys/sysctl.h> 35 #include <sys/mutex.h> 36 #include <sys/condvar.h> 37 #include <sys/pool.h> 38 #include <sys/kmem.h> 39 40 #include <dev/i2c/i2cvar.h> 41 #include <dev/spi/spivar.h> 42 #include <dev/ic/sc16is7xxreg.h> 43 #include <dev/ic/sc16is7xxvar.h> 44 45 struct sc16is7xx_i2c_softc { 46 struct sc16is7xx_sc sc_sc16is7xx; 47 i2c_tag_t sc_tag; 48 i2c_addr_t sc_addr; 49 }; 50 51 #define SC16IS7XX_TO_I2C(sc) \ 52 container_of((sc), struct sc16is7xx_i2c_softc, sc_sc16is7xx) 53 54 static int sc16is7xxi2c_poke(i2c_tag_t, i2c_addr_t, bool); 55 static int sc16is7xxi2c_match(device_t, cfdata_t, void *); 56 static void sc16is7xxi2c_attach(device_t, device_t, void *); 57 static int sc16is7xxi2c_detach(device_t, int); 58 59 CFATTACH_DECL_NEW(sc16is7xxi2c, sizeof(struct sc16is7xx_sc), 60 sc16is7xxi2c_match, sc16is7xxi2c_attach, sc16is7xxi2c_detach, NULL); 61 62 static int 63 sc16is7xxi2c_read_register_direct(i2c_tag_t tag, i2c_addr_t addr, uint8_t reg, 64 int channel, uint8_t *buf, size_t blen) 65 { 66 int error; 67 uint8_t xreg; 68 69 xreg = (reg << 3) | (channel << 1); 70 71 error = iic_acquire_bus(tag, 0); 72 if (error == 0) { 73 error = iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, &xreg, 1, 74 buf, blen, 0); 75 } 76 iic_release_bus(tag, 0); 77 78 return error; 79 } 80 81 static int 82 sc16is7xxi2c_write_register_direct(i2c_tag_t tag, i2c_addr_t addr, uint8_t reg, 83 int channel, uint8_t *buf, size_t blen) 84 { 85 int error; 86 uint8_t xreg; 87 88 xreg = (reg << 3) | (channel << 1); 89 90 error = iic_acquire_bus(tag, 0); 91 if (error == 0) { 92 error = iic_exec(tag, I2C_OP_WRITE_WITH_STOP, addr, &xreg, 1, 93 buf, blen, 0); 94 } 95 iic_release_bus(tag, 0); 96 97 return error; 98 } 99 /* Use these after the hand off to the general driver happens */ 100 101 static int 102 sc16is7xxi2c_read_register(struct sc16is7xx_sc *sc, uint8_t reg, int channel, 103 uint8_t *buf, size_t blen) 104 { 105 struct sc16is7xx_i2c_softc *isc = SC16IS7XX_TO_I2C(sc); 106 int error; 107 108 KASSERT(blen > 0); 109 110 error = sc16is7xxi2c_read_register_direct(isc->sc_tag, isc->sc_addr, 111 reg, channel, buf, blen); 112 113 return error; 114 } 115 116 static int 117 sc16is7xxi2c_write_register(struct sc16is7xx_sc *sc, uint8_t reg, int channel, 118 uint8_t *buf, size_t blen) 119 { 120 struct sc16is7xx_i2c_softc *isc = SC16IS7XX_TO_I2C(sc); 121 int error; 122 123 KASSERT(blen > 0); 124 125 error = sc16is7xxi2c_write_register_direct(isc->sc_tag, isc->sc_addr, 126 reg, channel, buf, blen); 127 128 return error; 129 } 130 131 static void 132 sc16is7xxi2c_copy_handles(struct sc16is7xx_sc *sc, struct com_regs *regs) 133 { 134 struct sc16is7xx_i2c_softc *isc = SC16IS7XX_TO_I2C(sc); 135 136 regs->cr_tag = isc->sc_tag; 137 regs->cr_addr = isc->sc_addr; 138 } 139 140 static const struct sc16is7xx_accessfuncs sc16is7xx_i2c_accessfuncs = { 141 .read_reg = sc16is7xxi2c_read_register, 142 .write_reg = sc16is7xxi2c_write_register, 143 .copy_handles = sc16is7xxi2c_copy_handles, 144 }; 145 /* These will be used by dev/ic/com.c, conform to what is expected */ 146 147 static uint8_t 148 sc16is7xx_i2c_com_read_1(struct com_regs *regs, u_int reg) 149 { 150 uint8_t buf; 151 int error; 152 153 error = sc16is7xxi2c_read_register_direct(regs->cr_tag, regs->cr_addr, 154 reg, regs->cr_channel, &buf, 1); 155 156 if (!error) 157 return buf; 158 159 return 0; 160 } 161 162 static void 163 sc16is7xx_i2c_com_write_1(struct com_regs *regs, u_int reg, uint8_t val) 164 { 165 sc16is7xxi2c_write_register_direct(regs->cr_tag, regs->cr_addr, 166 reg, regs->cr_channel, &val, 1); 167 } 168 169 static void 170 sc16is7xx_i2c_com_write_multi_1(struct com_regs *regs, u_int reg, const uint8_t *datap, 171 bus_size_t count) 172 { 173 sc16is7xxi2c_write_register_direct(regs->cr_tag, regs->cr_addr, 174 reg, regs->cr_channel, __UNCONST(datap), count); 175 } 176 177 static const struct sc16is7xx_accessfuncs sc16is7xx_i2c_com_accessfuncs = { 178 .com_read_1 = sc16is7xx_i2c_com_read_1, 179 .com_write_1 = sc16is7xx_i2c_com_write_1, 180 .com_write_multi_1 = sc16is7xx_i2c_com_write_multi_1, 181 }; 182 183 static int 184 sc16is7xxi2c_poke(i2c_tag_t tag, i2c_addr_t addr, bool matchdebug) 185 { 186 uint8_t reg = SC16IS7XX_REGISTER_SPR; 187 uint8_t buf[1]; 188 int error; 189 190 error = sc16is7xxi2c_read_register_direct(tag, addr, reg, 0, buf, 1); 191 if (matchdebug) { 192 printf("poke addr=%02x, error=%d\n", addr, error); 193 } 194 return error; 195 } 196 197 static int 198 sc16is7xxi2c_match(device_t parent, cfdata_t cf, void *aux) 199 { 200 struct i2c_attach_args *ia = aux; 201 int error, match_result; 202 const bool matchdebug = false; 203 bool indirect_found = false; 204 int i; 205 206 if (iic_use_direct_match(ia, cf, sc16is7xx_compat_data, &match_result)) { 207 return match_result; 208 } 209 for (i = SC16IS7XX_LOW_I2C_ADDR; i <= SC16IS7XX_HIGH_I2C_ADDR && indirect_found == false; i++) { 210 if (ia->ia_addr == i) { 211 if (matchdebug) { 212 printf("sc16is7xxi2c_match possible indirect: ia_addr=%02x, i=%02x\n", ia->ia_addr, i); 213 } 214 indirect_found = true; 215 } 216 } 217 218 if (!indirect_found) 219 return 0; 220 221 /* Check to see if something is really at this i2c address. This will 222 * keep phantom devices from appearing */ 223 224 error = sc16is7xxi2c_poke(ia->ia_tag, ia->ia_addr, matchdebug); 225 226 return error == 0 ? I2C_MATCH_ADDRESS_AND_PROBE : 0; 227 } 228 229 static void 230 sc16is7xxi2c_attach(device_t parent, device_t self, void *aux) 231 { 232 struct sc16is7xx_i2c_softc *isc = device_private(self); 233 struct sc16is7xx_sc *sc = &isc->sc_sc16is7xx; 234 struct i2c_attach_args *ia = aux; 235 236 sc->sc_dev = self; 237 sc->sc_funcs = &sc16is7xx_i2c_accessfuncs; 238 sc->sc_com_funcs = &sc16is7xx_i2c_com_accessfuncs; 239 240 isc->sc_tag = ia->ia_tag; 241 isc->sc_addr = ia->ia_addr; 242 243 sc16is7xx_attach(sc); 244 } 245 246 static int 247 sc16is7xxi2c_detach(device_t self, int flags) 248 { 249 struct sc16is7xx_i2c_softc *isc = device_private(self); 250 251 return sc16is7xx_detach(&isc->sc_sc16is7xx, flags); 252 } 253
Indexes created Sat Nov 08 00:09:40 GMT 2025