Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 1 | /* |
| 2 | * arch/ppc/platforms/pmac_low_i2c.c |
| 3 | * |
| 4 | * Copyright (C) 2003 Ben. Herrenschmidt (benh@kernel.crashing.org) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This file contains some low-level i2c access routines that |
| 12 | * need to be used by various bits of the PowerMac platform code |
| 13 | * at times where the real asynchronous & interrupt driven driver |
| 14 | * cannot be used. The API borrows some semantics from the darwin |
| 15 | * driver in order to ease the implementation of the platform |
| 16 | * properties parser |
| 17 | */ |
| 18 | |
| 19 | #undef DEBUG |
| 20 | |
| 21 | #include <linux/config.h> |
| 22 | #include <linux/types.h> |
| 23 | #include <linux/sched.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/module.h> |
| 26 | #include <linux/adb.h> |
| 27 | #include <linux/pmu.h> |
| 28 | #include <asm/keylargo.h> |
| 29 | #include <asm/uninorth.h> |
| 30 | #include <asm/io.h> |
| 31 | #include <asm/prom.h> |
| 32 | #include <asm/machdep.h> |
| 33 | #include <asm/pmac_low_i2c.h> |
| 34 | |
| 35 | #define MAX_LOW_I2C_HOST 4 |
| 36 | |
| 37 | #ifdef DEBUG |
| 38 | #define DBG(x...) do {\ |
| 39 | printk(KERN_DEBUG "KW:" x); \ |
| 40 | } while(0) |
| 41 | #else |
| 42 | #define DBG(x...) |
| 43 | #endif |
| 44 | |
| 45 | struct low_i2c_host; |
| 46 | |
| 47 | typedef int (*low_i2c_func_t)(struct low_i2c_host *host, u8 addr, u8 sub, u8 *data, int len); |
| 48 | |
| 49 | struct low_i2c_host |
| 50 | { |
| 51 | struct device_node *np; /* OF device node */ |
| 52 | struct semaphore mutex; /* Access mutex for use by i2c-keywest */ |
| 53 | low_i2c_func_t func; /* Access function */ |
| 54 | unsigned int is_open : 1; /* Poor man's access control */ |
| 55 | int mode; /* Current mode */ |
| 56 | int channel; /* Current channel */ |
| 57 | int num_channels; /* Number of channels */ |
| 58 | void __iomem *base; /* For keywest-i2c, base address */ |
| 59 | int bsteps; /* And register stepping */ |
| 60 | int speed; /* And speed */ |
| 61 | }; |
| 62 | |
| 63 | static struct low_i2c_host low_i2c_hosts[MAX_LOW_I2C_HOST]; |
| 64 | |
| 65 | /* No locking is necessary on allocation, we are running way before |
| 66 | * anything can race with us |
| 67 | */ |
| 68 | static struct low_i2c_host *find_low_i2c_host(struct device_node *np) |
| 69 | { |
| 70 | int i; |
| 71 | |
| 72 | for (i = 0; i < MAX_LOW_I2C_HOST; i++) |
| 73 | if (low_i2c_hosts[i].np == np) |
| 74 | return &low_i2c_hosts[i]; |
| 75 | return NULL; |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * |
| 80 | * i2c-keywest implementation (UniNorth, U2, U3, Keylargo's) |
| 81 | * |
| 82 | */ |
| 83 | |
| 84 | /* |
| 85 | * Keywest i2c definitions borrowed from drivers/i2c/i2c-keywest.h, |
| 86 | * should be moved somewhere in include/asm-ppc/ |
| 87 | */ |
| 88 | /* Register indices */ |
| 89 | typedef enum { |
| 90 | reg_mode = 0, |
| 91 | reg_control, |
| 92 | reg_status, |
| 93 | reg_isr, |
| 94 | reg_ier, |
| 95 | reg_addr, |
| 96 | reg_subaddr, |
| 97 | reg_data |
| 98 | } reg_t; |
| 99 | |
| 100 | |
| 101 | /* Mode register */ |
| 102 | #define KW_I2C_MODE_100KHZ 0x00 |
| 103 | #define KW_I2C_MODE_50KHZ 0x01 |
| 104 | #define KW_I2C_MODE_25KHZ 0x02 |
| 105 | #define KW_I2C_MODE_DUMB 0x00 |
| 106 | #define KW_I2C_MODE_STANDARD 0x04 |
| 107 | #define KW_I2C_MODE_STANDARDSUB 0x08 |
| 108 | #define KW_I2C_MODE_COMBINED 0x0C |
| 109 | #define KW_I2C_MODE_MODE_MASK 0x0C |
| 110 | #define KW_I2C_MODE_CHAN_MASK 0xF0 |
| 111 | |
| 112 | /* Control register */ |
| 113 | #define KW_I2C_CTL_AAK 0x01 |
| 114 | #define KW_I2C_CTL_XADDR 0x02 |
| 115 | #define KW_I2C_CTL_STOP 0x04 |
| 116 | #define KW_I2C_CTL_START 0x08 |
| 117 | |
| 118 | /* Status register */ |
| 119 | #define KW_I2C_STAT_BUSY 0x01 |
| 120 | #define KW_I2C_STAT_LAST_AAK 0x02 |
| 121 | #define KW_I2C_STAT_LAST_RW 0x04 |
| 122 | #define KW_I2C_STAT_SDA 0x08 |
| 123 | #define KW_I2C_STAT_SCL 0x10 |
| 124 | |
| 125 | /* IER & ISR registers */ |
| 126 | #define KW_I2C_IRQ_DATA 0x01 |
| 127 | #define KW_I2C_IRQ_ADDR 0x02 |
| 128 | #define KW_I2C_IRQ_STOP 0x04 |
| 129 | #define KW_I2C_IRQ_START 0x08 |
| 130 | #define KW_I2C_IRQ_MASK 0x0F |
| 131 | |
| 132 | /* State machine states */ |
| 133 | enum { |
| 134 | state_idle, |
| 135 | state_addr, |
| 136 | state_read, |
| 137 | state_write, |
| 138 | state_stop, |
| 139 | state_dead |
| 140 | }; |
| 141 | |
| 142 | #define WRONG_STATE(name) do {\ |
| 143 | printk(KERN_DEBUG "KW: wrong state. Got %s, state: %s (isr: %02x)\n", \ |
| 144 | name, __kw_state_names[state], isr); \ |
| 145 | } while(0) |
| 146 | |
| 147 | static const char *__kw_state_names[] = { |
| 148 | "state_idle", |
| 149 | "state_addr", |
| 150 | "state_read", |
| 151 | "state_write", |
| 152 | "state_stop", |
| 153 | "state_dead" |
| 154 | }; |
| 155 | |
| 156 | static inline u8 __kw_read_reg(struct low_i2c_host *host, reg_t reg) |
| 157 | { |
| 158 | return readb(host->base + (((unsigned int)reg) << host->bsteps)); |
| 159 | } |
| 160 | |
| 161 | static inline void __kw_write_reg(struct low_i2c_host *host, reg_t reg, u8 val) |
| 162 | { |
| 163 | writeb(val, host->base + (((unsigned)reg) << host->bsteps)); |
| 164 | (void)__kw_read_reg(host, reg_subaddr); |
| 165 | } |
| 166 | |
| 167 | #define kw_write_reg(reg, val) __kw_write_reg(host, reg, val) |
| 168 | #define kw_read_reg(reg) __kw_read_reg(host, reg) |
| 169 | |
| 170 | |
| 171 | /* Don't schedule, the g5 fan controller is too |
| 172 | * timing sensitive |
| 173 | */ |
| 174 | static u8 kw_wait_interrupt(struct low_i2c_host* host) |
| 175 | { |
| 176 | int i, j; |
| 177 | u8 isr; |
| 178 | |
| 179 | for (i = 0; i < 100000; i++) { |
| 180 | isr = kw_read_reg(reg_isr) & KW_I2C_IRQ_MASK; |
| 181 | if (isr != 0) |
| 182 | return isr; |
| 183 | |
| 184 | /* This code is used with the timebase frozen, we cannot rely |
| 185 | * on udelay ! For now, just use a bogus loop |
| 186 | */ |
| 187 | for (j = 1; j < 10000; j++) |
| 188 | mb(); |
| 189 | } |
| 190 | return isr; |
| 191 | } |
| 192 | |
| 193 | static int kw_handle_interrupt(struct low_i2c_host *host, int state, int rw, int *rc, u8 **data, int *len, u8 isr) |
| 194 | { |
| 195 | u8 ack; |
| 196 | |
| 197 | DBG("kw_handle_interrupt(%s, isr: %x)\n", __kw_state_names[state], isr); |
| 198 | |
| 199 | if (isr == 0) { |
| 200 | if (state != state_stop) { |
| 201 | DBG("KW: Timeout !\n"); |
| 202 | *rc = -EIO; |
| 203 | goto stop; |
| 204 | } |
| 205 | if (state == state_stop) { |
| 206 | ack = kw_read_reg(reg_status); |
| 207 | if (!(ack & KW_I2C_STAT_BUSY)) { |
| 208 | state = state_idle; |
| 209 | kw_write_reg(reg_ier, 0x00); |
| 210 | } |
| 211 | } |
| 212 | return state; |
| 213 | } |
| 214 | |
| 215 | if (isr & KW_I2C_IRQ_ADDR) { |
| 216 | ack = kw_read_reg(reg_status); |
| 217 | if (state != state_addr) { |
| 218 | kw_write_reg(reg_isr, KW_I2C_IRQ_ADDR); |
| 219 | WRONG_STATE("KW_I2C_IRQ_ADDR"); |
| 220 | *rc = -EIO; |
| 221 | goto stop; |
| 222 | } |
| 223 | if ((ack & KW_I2C_STAT_LAST_AAK) == 0) { |
| 224 | *rc = -ENODEV; |
| 225 | DBG("KW: NAK on address\n"); |
| 226 | return state_stop; |
| 227 | } else { |
| 228 | if (rw) { |
| 229 | state = state_read; |
| 230 | if (*len > 1) |
| 231 | kw_write_reg(reg_control, KW_I2C_CTL_AAK); |
| 232 | } else { |
| 233 | state = state_write; |
| 234 | kw_write_reg(reg_data, **data); |
| 235 | (*data)++; (*len)--; |
| 236 | } |
| 237 | } |
| 238 | kw_write_reg(reg_isr, KW_I2C_IRQ_ADDR); |
| 239 | } |
| 240 | |
| 241 | if (isr & KW_I2C_IRQ_DATA) { |
| 242 | if (state == state_read) { |
| 243 | **data = kw_read_reg(reg_data); |
| 244 | (*data)++; (*len)--; |
| 245 | kw_write_reg(reg_isr, KW_I2C_IRQ_DATA); |
| 246 | if ((*len) == 0) |
| 247 | state = state_stop; |
| 248 | else if ((*len) == 1) |
| 249 | kw_write_reg(reg_control, 0); |
| 250 | } else if (state == state_write) { |
| 251 | ack = kw_read_reg(reg_status); |
| 252 | if ((ack & KW_I2C_STAT_LAST_AAK) == 0) { |
| 253 | DBG("KW: nack on data write\n"); |
| 254 | *rc = -EIO; |
| 255 | goto stop; |
| 256 | } else if (*len) { |
| 257 | kw_write_reg(reg_data, **data); |
| 258 | (*data)++; (*len)--; |
| 259 | } else { |
| 260 | kw_write_reg(reg_control, KW_I2C_CTL_STOP); |
| 261 | state = state_stop; |
| 262 | *rc = 0; |
| 263 | } |
| 264 | kw_write_reg(reg_isr, KW_I2C_IRQ_DATA); |
| 265 | } else { |
| 266 | kw_write_reg(reg_isr, KW_I2C_IRQ_DATA); |
| 267 | WRONG_STATE("KW_I2C_IRQ_DATA"); |
| 268 | if (state != state_stop) { |
| 269 | *rc = -EIO; |
| 270 | goto stop; |
| 271 | } |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | if (isr & KW_I2C_IRQ_STOP) { |
| 276 | kw_write_reg(reg_isr, KW_I2C_IRQ_STOP); |
| 277 | if (state != state_stop) { |
| 278 | WRONG_STATE("KW_I2C_IRQ_STOP"); |
| 279 | *rc = -EIO; |
| 280 | } |
| 281 | return state_idle; |
| 282 | } |
| 283 | |
| 284 | if (isr & KW_I2C_IRQ_START) |
| 285 | kw_write_reg(reg_isr, KW_I2C_IRQ_START); |
| 286 | |
| 287 | return state; |
| 288 | |
| 289 | stop: |
| 290 | kw_write_reg(reg_control, KW_I2C_CTL_STOP); |
| 291 | return state_stop; |
| 292 | } |
| 293 | |
| 294 | static int keywest_low_i2c_func(struct low_i2c_host *host, u8 addr, u8 subaddr, u8 *data, int len) |
| 295 | { |
| 296 | u8 mode_reg = host->speed; |
| 297 | int state = state_addr; |
| 298 | int rc = 0; |
| 299 | |
| 300 | /* Setup mode & subaddress if any */ |
| 301 | switch(host->mode) { |
| 302 | case pmac_low_i2c_mode_dumb: |
| 303 | printk(KERN_ERR "low_i2c: Dumb mode not supported !\n"); |
| 304 | return -EINVAL; |
| 305 | case pmac_low_i2c_mode_std: |
| 306 | mode_reg |= KW_I2C_MODE_STANDARD; |
| 307 | break; |
| 308 | case pmac_low_i2c_mode_stdsub: |
| 309 | mode_reg |= KW_I2C_MODE_STANDARDSUB; |
| 310 | break; |
| 311 | case pmac_low_i2c_mode_combined: |
| 312 | mode_reg |= KW_I2C_MODE_COMBINED; |
| 313 | break; |
| 314 | } |
| 315 | |
| 316 | /* Setup channel & clear pending irqs */ |
| 317 | kw_write_reg(reg_isr, kw_read_reg(reg_isr)); |
| 318 | kw_write_reg(reg_mode, mode_reg | (host->channel << 4)); |
| 319 | kw_write_reg(reg_status, 0); |
| 320 | |
| 321 | /* Set up address and r/w bit */ |
| 322 | kw_write_reg(reg_addr, addr); |
| 323 | |
| 324 | /* Set up the sub address */ |
| 325 | if ((mode_reg & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB |
| 326 | || (mode_reg & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_COMBINED) |
| 327 | kw_write_reg(reg_subaddr, subaddr); |
| 328 | |
| 329 | /* Start sending address & disable interrupt*/ |
| 330 | kw_write_reg(reg_ier, 0 /*KW_I2C_IRQ_MASK*/); |
| 331 | kw_write_reg(reg_control, KW_I2C_CTL_XADDR); |
| 332 | |
| 333 | /* State machine, to turn into an interrupt handler */ |
| 334 | while(state != state_idle) { |
| 335 | u8 isr = kw_wait_interrupt(host); |
| 336 | state = kw_handle_interrupt(host, state, addr & 1, &rc, &data, &len, isr); |
| 337 | } |
| 338 | |
| 339 | return rc; |
| 340 | } |
| 341 | |
| 342 | static void keywest_low_i2c_add(struct device_node *np) |
| 343 | { |
| 344 | struct low_i2c_host *host = find_low_i2c_host(NULL); |
| 345 | u32 *psteps, *prate, steps, aoffset = 0; |
| 346 | struct device_node *parent; |
| 347 | |
| 348 | if (host == NULL) { |
| 349 | printk(KERN_ERR "low_i2c: Can't allocate host for %s\n", |
| 350 | np->full_name); |
| 351 | return; |
| 352 | } |
| 353 | memset(host, 0, sizeof(*host)); |
| 354 | |
| 355 | init_MUTEX(&host->mutex); |
| 356 | host->np = of_node_get(np); |
| 357 | psteps = (u32 *)get_property(np, "AAPL,address-step", NULL); |
| 358 | steps = psteps ? (*psteps) : 0x10; |
| 359 | for (host->bsteps = 0; (steps & 0x01) == 0; host->bsteps++) |
| 360 | steps >>= 1; |
| 361 | parent = of_get_parent(np); |
| 362 | host->num_channels = 1; |
| 363 | if (parent && parent->name[0] == 'u') { |
| 364 | host->num_channels = 2; |
| 365 | aoffset = 3; |
| 366 | } |
| 367 | /* Select interface rate */ |
| 368 | host->speed = KW_I2C_MODE_100KHZ; |
| 369 | prate = (u32 *)get_property(np, "AAPL,i2c-rate", NULL); |
| 370 | if (prate) switch(*prate) { |
| 371 | case 100: |
| 372 | host->speed = KW_I2C_MODE_100KHZ; |
| 373 | break; |
| 374 | case 50: |
| 375 | host->speed = KW_I2C_MODE_50KHZ; |
| 376 | break; |
| 377 | case 25: |
| 378 | host->speed = KW_I2C_MODE_25KHZ; |
| 379 | break; |
| 380 | } |
| 381 | |
| 382 | host->mode = pmac_low_i2c_mode_std; |
| 383 | host->base = ioremap(np->addrs[0].address + aoffset, |
| 384 | np->addrs[0].size); |
| 385 | host->func = keywest_low_i2c_func; |
| 386 | } |
| 387 | |
| 388 | /* |
| 389 | * |
| 390 | * PMU implementation |
| 391 | * |
| 392 | */ |
| 393 | |
| 394 | |
| 395 | #ifdef CONFIG_ADB_PMU |
| 396 | |
| 397 | static int pmu_low_i2c_func(struct low_i2c_host *host, u8 addr, u8 sub, u8 *data, int len) |
| 398 | { |
| 399 | // TODO |
| 400 | return -ENODEV; |
| 401 | } |
| 402 | |
| 403 | static void pmu_low_i2c_add(struct device_node *np) |
| 404 | { |
| 405 | struct low_i2c_host *host = find_low_i2c_host(NULL); |
| 406 | |
| 407 | if (host == NULL) { |
| 408 | printk(KERN_ERR "low_i2c: Can't allocate host for %s\n", |
| 409 | np->full_name); |
| 410 | return; |
| 411 | } |
| 412 | memset(host, 0, sizeof(*host)); |
| 413 | |
| 414 | init_MUTEX(&host->mutex); |
| 415 | host->np = of_node_get(np); |
| 416 | host->num_channels = 3; |
| 417 | host->mode = pmac_low_i2c_mode_std; |
| 418 | host->func = pmu_low_i2c_func; |
| 419 | } |
| 420 | |
| 421 | #endif /* CONFIG_ADB_PMU */ |
| 422 | |
| 423 | void __init pmac_init_low_i2c(void) |
| 424 | { |
| 425 | struct device_node *np; |
| 426 | |
| 427 | /* Probe keywest-i2c busses */ |
| 428 | np = of_find_compatible_node(NULL, "i2c", "keywest-i2c"); |
| 429 | while(np) { |
| 430 | keywest_low_i2c_add(np); |
| 431 | np = of_find_compatible_node(np, "i2c", "keywest-i2c"); |
| 432 | } |
| 433 | |
| 434 | #ifdef CONFIG_ADB_PMU |
| 435 | /* Probe PMU busses */ |
| 436 | np = of_find_node_by_name(NULL, "via-pmu"); |
| 437 | if (np) |
| 438 | pmu_low_i2c_add(np); |
| 439 | #endif /* CONFIG_ADB_PMU */ |
| 440 | |
| 441 | /* TODO: Add CUDA support as well */ |
| 442 | } |
| 443 | |
| 444 | int pmac_low_i2c_lock(struct device_node *np) |
| 445 | { |
| 446 | struct low_i2c_host *host = find_low_i2c_host(np); |
| 447 | |
| 448 | if (!host) |
| 449 | return -ENODEV; |
| 450 | down(&host->mutex); |
| 451 | return 0; |
| 452 | } |
| 453 | EXPORT_SYMBOL(pmac_low_i2c_lock); |
| 454 | |
| 455 | int pmac_low_i2c_unlock(struct device_node *np) |
| 456 | { |
| 457 | struct low_i2c_host *host = find_low_i2c_host(np); |
| 458 | |
| 459 | if (!host) |
| 460 | return -ENODEV; |
| 461 | up(&host->mutex); |
| 462 | return 0; |
| 463 | } |
| 464 | EXPORT_SYMBOL(pmac_low_i2c_unlock); |
| 465 | |
| 466 | |
| 467 | int pmac_low_i2c_open(struct device_node *np, int channel) |
| 468 | { |
| 469 | struct low_i2c_host *host = find_low_i2c_host(np); |
| 470 | |
| 471 | if (!host) |
| 472 | return -ENODEV; |
| 473 | |
| 474 | if (channel >= host->num_channels) |
| 475 | return -EINVAL; |
| 476 | |
| 477 | down(&host->mutex); |
| 478 | host->is_open = 1; |
| 479 | host->channel = channel; |
| 480 | |
| 481 | return 0; |
| 482 | } |
| 483 | EXPORT_SYMBOL(pmac_low_i2c_open); |
| 484 | |
| 485 | int pmac_low_i2c_close(struct device_node *np) |
| 486 | { |
| 487 | struct low_i2c_host *host = find_low_i2c_host(np); |
| 488 | |
| 489 | if (!host) |
| 490 | return -ENODEV; |
| 491 | |
| 492 | host->is_open = 0; |
| 493 | up(&host->mutex); |
| 494 | |
| 495 | return 0; |
| 496 | } |
| 497 | EXPORT_SYMBOL(pmac_low_i2c_close); |
| 498 | |
| 499 | int pmac_low_i2c_setmode(struct device_node *np, int mode) |
| 500 | { |
| 501 | struct low_i2c_host *host = find_low_i2c_host(np); |
| 502 | |
| 503 | if (!host) |
| 504 | return -ENODEV; |
| 505 | WARN_ON(!host->is_open); |
| 506 | host->mode = mode; |
| 507 | |
| 508 | return 0; |
| 509 | } |
| 510 | EXPORT_SYMBOL(pmac_low_i2c_setmode); |
| 511 | |
| 512 | int pmac_low_i2c_xfer(struct device_node *np, u8 addrdir, u8 subaddr, u8 *data, int len) |
| 513 | { |
| 514 | struct low_i2c_host *host = find_low_i2c_host(np); |
| 515 | |
| 516 | if (!host) |
| 517 | return -ENODEV; |
| 518 | WARN_ON(!host->is_open); |
| 519 | |
| 520 | return host->func(host, addrdir, subaddr, data, len); |
| 521 | } |
| 522 | EXPORT_SYMBOL(pmac_low_i2c_xfer); |
| 523 | |