ralink_i2c.c revision 1.2
1 /* $NetBSD: ralink_i2c.c,v 1.2 2011/07/28 15:38:49 matt Exp $ */ 2 /*- 3 * Copyright (c) 2011 CradlePoint Technology, Inc. 4 * All rights reserved. 5 * 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY CRADLEPOINT TECHNOLOGY, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* ra_i2c.c - Ralink i2c 3052 driver */ 30 31 #include <sys/cdefs.h> 32 __KERNEL_RCSID(0, "$NetBSD: ralink_i2c.c,v 1.2 2011/07/28 15:38:49 matt Exp $"); 33 34 #include <sys/param.h> 35 #include <sys/bus.h> 36 #include <sys/device.h> 37 #include <sys/errno.h> 38 #include <sys/kernel.h> 39 #include <sys/malloc.h> 40 #include <sys/proc.h> 41 #include <sys/systm.h> 42 43 #include <dev/i2c/i2cvar.h> 44 45 #include <mips/ralink/ralink_var.h> 46 #include <mips/ralink/ralink_reg.h> 47 48 #if 0 49 /* 50 * Defined for the Ralink 3050, w/320MHz CPU: milage may vary. 51 * Set the I2C clock to 100K bps (low speed) transfer rate. 52 * Value is based upon the forms defined in the Ralink reference document 53 * for RT3050, page 53. JCL. 54 */ 55 #define CLKDIV_VALUE 533 56 #endif 57 58 /* 59 * Slow the I2C bus clock to 12.5 KHz to work around the misbehavior 60 * of the TI part. 61 */ 62 #define CLKDIV_VALUE 4264 63 64 #define i2c_busy_loop (clkdiv*30) 65 #define max_ee_busy_loop (clkdiv*25) 66 67 68 typedef struct ra_i2c_softc { 69 device_t sc_dev; 70 struct i2c_controller sc_i2c; 71 bus_space_tag_t sc_memt; 72 bus_space_handle_t sc_i2c_memh; 73 bus_space_handle_t sc_sy_memh; 74 } ra_i2c_softc_t; 75 76 77 static int ra_i2c_match(struct device *, cfdata_t, void *); 78 static void ra_i2c_attach(struct device *, struct device *, void *); 79 80 /* RT3052 I2C functions */ 81 static int i2c_write(ra_i2c_softc_t *, u_long, const u_char *, u_long); 82 static int i2c_read(ra_i2c_softc_t *, u_long, u_char *, u_long); 83 #ifdef NOTYET 84 static void i2c_write_stop(ra_i2c_softc_t *, u_long, u_char *); 85 static void i2c_read_stop(ra_i2c_softc_t *, u_long, u_char *); 86 #endif 87 88 /* i2c driver functions */ 89 int ra_i2c_acquire_bus(void *, int); 90 void ra_i2c_release_bus(void *, int); 91 int ra_i2c_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t, 92 void *, size_t, int); 93 void ra_i2c_reset(ra_i2c_softc_t *); 94 95 CFATTACH_DECL_NEW(ri2c, sizeof(struct ra_i2c_softc), 96 ra_i2c_match, ra_i2c_attach, NULL, NULL); 97 98 unsigned int clkdiv = CLKDIV_VALUE; 99 100 static inline void 101 ra_i2c_busy_wait(ra_i2c_softc_t *sc) 102 { 103 for (int i=0; i < i2c_busy_loop; i++) { 104 uint32_t r; 105 r = bus_space_read_4(sc->sc_memt, sc->sc_i2c_memh, 106 RA_I2C_STATUS); 107 if ((r & I2C_STATUS_BUSY) == 0) 108 break; 109 } 110 } 111 112 int 113 ra_i2c_match(device_t parent, cfdata_t cf, void *aux) 114 { 115 return 1; 116 } 117 118 119 void 120 ra_i2c_attach(device_t parent, device_t self, void *aux) 121 { 122 ra_i2c_softc_t * const sc = device_private(self); 123 const struct mainbus_attach_args *ma = aux; 124 struct i2cbus_attach_args iba; 125 uint32_t r; 126 int error; 127 128 aprint_naive(": Ralink I2C controller\n"); 129 aprint_normal(": Ralink I2C controller\n"); 130 131 /* save out bus space tag */ 132 sc->sc_memt = ma->ma_memt; 133 134 /* Map Sysctl registers */ 135 if ((error = bus_space_map(ma->ma_memt, RA_SYSCTL_BASE, 0x10000, 136 0, &sc->sc_sy_memh)) != 0) { 137 aprint_error_dev(self, "unable to map Sysctl registers, " 138 "error=%d\n", error); 139 return; 140 } 141 142 /* map the I2C registers */ 143 if ((error = bus_space_map(sc->sc_memt, RA_I2C_BASE, 0x100, 144 0, &sc->sc_i2c_memh)) != 0) { 145 aprint_error_dev(self, "unable to map registers, " 146 "error=%d\n", error); 147 bus_space_unmap(ma->ma_memt, sc->sc_sy_memh, 0x10000); 148 return; 149 } 150 151 /* Enable I2C block */ 152 r = bus_space_read_4(sc->sc_memt, sc->sc_sy_memh, 153 RA_SYSCTL_GPIOMODE); 154 r &= ~GPIOMODE_I2C; 155 bus_space_write_4(sc->sc_memt, sc->sc_sy_memh, 156 RA_SYSCTL_GPIOMODE, r); 157 158 sc->sc_i2c.ic_cookie = sc; 159 sc->sc_i2c.ic_acquire_bus = ra_i2c_acquire_bus; 160 sc->sc_i2c.ic_release_bus = ra_i2c_release_bus; 161 sc->sc_i2c.ic_exec = ra_i2c_exec; 162 163 memset(&iba, 0, sizeof(iba)); 164 iba.iba_type = I2C_TYPE_SMBUS; 165 iba.iba_tag = &sc->sc_i2c; 166 config_found(self, &iba, iicbus_print); 167 } 168 169 170 171 /* 172 * I2C API 173 */ 174 175 /* Might not be needed. JCL. */ 176 int 177 ra_i2c_acquire_bus(void *cookie, int flags) 178 { 179 /* nothing */ 180 return 0; 181 } 182 183 184 185 /* Might not be needed. JCL. */ 186 void 187 ra_i2c_release_bus(void *cookie, int flags) 188 { 189 /* nothing */ 190 } 191 192 int 193 ra_i2c_exec(void *cookie, i2c_op_t op, i2c_addr_t addr, const void *cmdbuf, 194 size_t cmdlen, void *buf, size_t len, int flags) 195 { 196 ra_i2c_softc_t * const sc = cookie; 197 198 /* 199 * Make sure we only pass a seven-bit device address, 200 * as per I2C standard. 201 */ 202 KASSERT(addr <= 127); 203 if (addr > 127) 204 return -1; 205 206 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_DEVADDR, 207 addr); 208 209 ra_i2c_reset(sc); 210 211 /* 212 * Process the requested operation. 213 * There are four I2C operations of interest: 214 * - Write 215 * - Write with stop 216 * - Read 217 * - Read with stop 218 * Because the I2C block on the Ralink part generates stop markers 219 * at approprite places, based upon the byte count, the read and write 220 * with stop operations will rarely be needed. They are included here 221 * as placeholders, but haven't been implemented or tested. 222 */ 223 switch(op) { 224 case I2C_OP_WRITE: 225 return i2c_write(sc, addr, cmdbuf, cmdlen); 226 break; 227 case I2C_OP_READ: 228 return i2c_read(sc, addr, buf, len); 229 break; 230 #ifdef NOTYET 231 case I2C_OP_WRITE_WITH_STOP: 232 i2c_write_stop(sc, addr, buf); 233 break; 234 case I2C_OP_READ_WITH_STOP: 235 i2c_read_stop(sc, addr, buf); 236 break; 237 #endif 238 default: 239 return -1; /* Illegal operation, error return. */ 240 } 241 242 return 0; 243 } 244 245 static int 246 i2c_write(ra_i2c_softc_t *sc, u_long addr, const u_char *data, 247 u_long nbytes) 248 { 249 uint32_t r; 250 int i, j; 251 252 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_DEVADDR, 253 addr); 254 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_BYTECNT, 255 nbytes - 1); 256 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_STARTXFR, 257 I2C_OP_WRITE); 258 259 for (i=0; i < nbytes; i++) { 260 for (j=0; j < max_ee_busy_loop; j++) { 261 r = bus_space_read_4(sc->sc_memt, sc->sc_i2c_memh, 262 RA_I2C_STATUS); 263 if ((r & I2C_STATUS_SDOEMPTY) != 0) { 264 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, 265 RA_I2C_DATAOUT, data[i]); 266 break; 267 } 268 } 269 #if 0 270 if ((r & I2C_STATUS_ACKERR) != 0) { 271 aprint_error_dev(sc->sc_dev, "ACK error in %s\n", 272 __func__); 273 return EAGAIN; 274 } 275 #endif 276 if (j == max_ee_busy_loop) { 277 aprint_error_dev(sc->sc_dev, "timeout error in %s\n", 278 __func__); 279 return EAGAIN; 280 } 281 } 282 283 ra_i2c_busy_wait(sc); 284 285 return 0; 286 } 287 288 289 static int 290 i2c_read(ra_i2c_softc_t *sc, u_long addr, u_char *data, u_long nbytes) 291 { 292 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_DEVADDR, 293 addr); 294 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_BYTECNT, 295 nbytes - 1); 296 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_STARTXFR, 297 I2C_OP_READ); 298 299 for (u_int i = 0; i < nbytes; i++) { 300 u_long j; 301 uint32_t r; 302 303 for (j=0; j < max_ee_busy_loop; j++) { 304 r = bus_space_read_4(sc->sc_memt, sc->sc_i2c_memh, 305 RA_I2C_STATUS); 306 if ((r & I2C_STATUS_DATARDY) != 0) { 307 data[i] = bus_space_read_4( 308 sc->sc_memt, sc->sc_i2c_memh, 309 RA_I2C_DATAIN); 310 break; 311 } 312 } 313 #if 0 314 if ((r & I2C_STATUS_ACKERR) != 0) { 315 aprint_error_dev(sc->sc_dev, "ACK error in %s\n", 316 __func__); 317 return EAGAIN; 318 } 319 #endif 320 if (j == max_ee_busy_loop) { 321 aprint_error_dev(sc->sc_dev, "timeout error in %s\n", 322 __func__); 323 return EAGAIN; 324 } 325 } 326 327 ra_i2c_busy_wait(sc); 328 329 return 0; 330 331 } 332 333 334 #ifdef NOTYET 335 static void 336 i2c_write_stop(ra_i2c_softc_t *sc, u_long address, u_char *data) 337 { 338 /* unimplemented */ 339 } 340 341 static void 342 i2c_read_stop(ra_i2c_softc_t *sc, u_long address, u_char *data) 343 { 344 /* unimplemented */ 345 } 346 #endif 347 348 void 349 ra_i2c_reset(ra_i2c_softc_t *sc) 350 { 351 uint32_t r; 352 353 /* reset i2c block */ 354 r = bus_space_read_4(sc->sc_memt, sc->sc_sy_memh, RA_SYSCTL_RST); 355 bus_space_write_4(sc->sc_memt, sc->sc_sy_memh, RA_SYSCTL_RST, 356 r | RST_I2C); 357 bus_space_write_4(sc->sc_memt, sc->sc_sy_memh, RA_SYSCTL_RST, r); 358 359 r = I2C_CONFIG_ADDRLEN(I2C_CONFIG_ADDRLEN_8) | 360 I2C_CONFIG_DEVADLEN(I2C_CONFIG_DEVADLEN_7) | 361 I2C_CONFIG_ADDRDIS; 362 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_CONFIG, r); 363 364 /* 365 * Set the I2C clock divider. Appears to be set to 200,000, 366 * which is strange, as I2C is 100K/400K/3.?M bps. 367 */ 368 bus_space_write_4(sc->sc_memt, sc->sc_i2c_memh, RA_I2C_CLKDIV, 369 clkdiv); 370 } 371
Indexes created Fri Sep 26 08:10:20 GMT 2025