drivers/sbus/char/bbc_i2c.c

   1 /* $Id: bbc_i2c.c,v 1.2 2001/04/02 09:59:08 davem Exp $
   2  * bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
   3  *            platforms.
   4  *
   5  * Copyright (C) 2001 David S. Miller (davem@redhat.com)
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kernel.h>
  10 #include <linux/types.h>
  11 #include <linux/slab.h>
  12 #include <linux/sched.h>
  13 #include <linux/wait.h>
  14 #include <linux/delay.h>
  15 #include <linux/init.h>
  16 #include <linux/interrupt.h>
  17 #include <asm/oplib.h>
  18 #include <asm/ebus.h>
  19 #include <asm/spitfire.h>
  20 #include <asm/bbc.h>
  21 #include <asm/io.h>
  22
  23 #include "bbc_i2c.h"
  24
  25 /* Convert this driver to use i2c bus layer someday... */
  26 #define I2C_PCF_PIN     0x80
  27 #define I2C_PCF_ESO     0x40
  28 #define I2C_PCF_ES1     0x20
  29 #define I2C_PCF_ES2     0x10
  30 #define I2C_PCF_ENI     0x08
  31 #define I2C_PCF_STA     0x04
  32 #define I2C_PCF_STO     0x02
  33 #define I2C_PCF_ACK     0x01
  34
  35 #define I2C_PCF_START    (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
  36 #define I2C_PCF_STOP     (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
  37 #define I2C_PCF_REPSTART (              I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
  38 #define I2C_PCF_IDLE     (I2C_PCF_PIN | I2C_PCF_ESO               | I2C_PCF_ACK)
  39
  40 #define I2C_PCF_INI 0x40   /* 1 if not initialized */
  41 #define I2C_PCF_STS 0x20
  42 #define I2C_PCF_BER 0x10
  43 #define I2C_PCF_AD0 0x08
  44 #define I2C_PCF_LRB 0x08
  45 #define I2C_PCF_AAS 0x04
  46 #define I2C_PCF_LAB 0x02
  47 #define I2C_PCF_BB  0x01
  48
  49 /* The BBC devices have two I2C controllers.  The first I2C controller
  50  * connects mainly to configuration proms (NVRAM, cpu configuration,
  51  * dimm types, etc.).  Whereas the second I2C controller connects to
  52  * environmental control devices such as fans and temperature sensors.
  53  * The second controller also connects to the smartcard reader, if present.
  54  */
  55
  56 #define NUM_CHILDREN    8
  57 struct bbc_i2c_bus {
  58         struct bbc_i2c_bus              *next;
  59         int                             index;
  60         spinlock_t                      lock;
  61         void                            __iomem *i2c_bussel_reg;
  62         void                            __iomem *i2c_control_regs;
  63         unsigned char                   own, clock;
  64
  65         wait_queue_head_t               wq;
  66         volatile int                    waiting;
  67
  68         struct linux_ebus_device        *bus_edev;
  69         struct {
  70                 struct linux_ebus_child *device;
  71                 int                     client_claimed;
  72         } devs[NUM_CHILDREN];
  73 };
  74
  75 static struct bbc_i2c_bus *all_bbc_i2c;
  76
  77 struct bbc_i2c_client {
  78         struct bbc_i2c_bus      *bp;
  79         struct linux_ebus_child *echild;
  80         int                     bus;
  81         int                     address;
  82 };
  83
  84 static int find_device(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild)
  85 {
  86         int i;
  87
  88         for (i = 0; i < NUM_CHILDREN; i++) {
  89                 if (bp->devs[i].device == echild) {
  90                         if (bp->devs[i].client_claimed)
  91                                 return 0;
  92                         return 1;
  93                 }
  94         }
  95         return 0;
  96 }
  97
  98 static void set_device_claimage(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild, int val)
  99 {
 100         int i;
 101
 102         for (i = 0; i < NUM_CHILDREN; i++) {
 103                 if (bp->devs[i].device == echild) {
 104                         bp->devs[i].client_claimed = val;
 105                         return;
 106                 }
 107         }
 108 }
 109
 110 #define claim_device(BP,ECHILD)         set_device_claimage(BP,ECHILD,1)
 111 #define release_device(BP,ECHILD)       set_device_claimage(BP,ECHILD,0)
 112
 113 static struct bbc_i2c_bus *find_bus_for_device(struct linux_ebus_child *echild)
 114 {
 115         struct bbc_i2c_bus *bp = all_bbc_i2c;
 116
 117         while (bp != NULL) {
 118                 if (find_device(bp, echild) != 0)
 119                         break;
 120                 bp = bp->next;
 121         }
 122
 123         return bp;
 124 }
 125
 126 struct linux_ebus_child *bbc_i2c_getdev(int index)
 127 {
 128         struct bbc_i2c_bus *bp = all_bbc_i2c;
 129         struct linux_ebus_child *echild = NULL;
 130         int curidx = 0;
 131
 132         while (bp != NULL) {
 133                 struct bbc_i2c_bus *next = bp->next;
 134                 int i;
 135
 136                 for (i = 0; i < NUM_CHILDREN; i++) {
 137                         if (!(echild = bp->devs[i].device))
 138                                 break;
 139                         if (curidx == index)
 140                                 goto out;
 141                         echild = NULL;
 142                         curidx++;
 143                 }
 144                 bp = next;
 145         }
 146 out:
 147         if (curidx == index)
 148                 return echild;
 149         return NULL;
 150 }
 151
 152 struct bbc_i2c_client *bbc_i2c_attach(struct linux_ebus_child *echild)
 153 {
 154         struct bbc_i2c_bus *bp = find_bus_for_device(echild);
 155         struct bbc_i2c_client *client;
 156
 157         if (!bp)
 158                 return NULL;
 159         client = kmalloc(sizeof(*client), GFP_KERNEL);
 160         if (!client)
 161                 return NULL;
 162         memset(client, 0, sizeof(*client));
 163         client->bp = bp;
 164         client->echild = echild;
 165         client->bus = echild->resource[0].start;
 166         client->address = echild->resource[1].start;
 167
 168         claim_device(bp, echild);
 169
 170         return client;
 171 }
 172
 173 void bbc_i2c_detach(struct bbc_i2c_client *client)
 174 {
 175         struct bbc_i2c_bus *bp = client->bp;
 176         struct linux_ebus_child *echild = client->echild;
 177
 178         release_device(bp, echild);
 179         kfree(client);
 180 }
 181
 182 static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
 183 {
 184         DECLARE_WAITQUEUE(wait, current);
 185         int limit = 32;
 186         int ret = 1;
 187
 188         bp->waiting = 1;
 189         add_wait_queue(&bp->wq, &wait);
 190         while (limit-- > 0) {
 191                 unsigned long val;
 192
 193                 val = wait_event_interruptible_timeout(
 194                                 bp->wq,
 195                                 (((*status = readb(bp->i2c_control_regs + 0))
 196                                   & I2C_PCF_PIN) == 0),
 197                                 msecs_to_jiffies(250));
 198                 if (val > 0) {
 199                         ret = 0;
 200                         break;
 201                 }
 202         }
 203         remove_wait_queue(&bp->wq, &wait);
 204         bp->waiting = 0;
 205
 206         return ret;
 207 }
 208
 209 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
 210 {
 211         struct bbc_i2c_bus *bp = client->bp;
 212         int address = client->address;
 213         u8 status;
 214         int ret = -1;
 215
 216         if (bp->i2c_bussel_reg != NULL)
 217                 writeb(client->bus, bp->i2c_bussel_reg);
 218
 219         writeb(address, bp->i2c_control_regs + 0x1);
 220         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 221         if (wait_for_pin(bp, &status))
 222                 goto out;
 223
 224         writeb(off, bp->i2c_control_regs + 0x1);
 225         if (wait_for_pin(bp, &status) ||
 226             (status & I2C_PCF_LRB) != 0)
 227                 goto out;
 228
 229         writeb(val, bp->i2c_control_regs + 0x1);
 230         if (wait_for_pin(bp, &status))
 231                 goto out;
 232
 233         ret = 0;
 234
 235 out:
 236         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 237         return ret;
 238 }
 239
 240 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
 241 {
 242         struct bbc_i2c_bus *bp = client->bp;
 243         unsigned char address = client->address, status;
 244         int ret = -1;
 245
 246         if (bp->i2c_bussel_reg != NULL)
 247                 writeb(client->bus, bp->i2c_bussel_reg);
 248
 249         writeb(address, bp->i2c_control_regs + 0x1);
 250         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 251         if (wait_for_pin(bp, &status))
 252                 goto out;
 253
 254         writeb(off, bp->i2c_control_regs + 0x1);
 255         if (wait_for_pin(bp, &status) ||
 256             (status & I2C_PCF_LRB) != 0)
 257                 goto out;
 258
 259         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 260
 261         address |= 0x1; /* READ */
 262
 263         writeb(address, bp->i2c_control_regs + 0x1);
 264         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 265         if (wait_for_pin(bp, &status))
 266                 goto out;
 267
 268         /* Set PIN back to one so the device sends the first
 269          * byte.
 270          */
 271         (void) readb(bp->i2c_control_regs + 0x1);
 272         if (wait_for_pin(bp, &status))
 273                 goto out;
 274
 275         writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
 276         *byte = readb(bp->i2c_control_regs + 0x1);
 277         if (wait_for_pin(bp, &status))
 278                 goto out;
 279
 280         ret = 0;
 281
 282 out:
 283         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 284         (void) readb(bp->i2c_control_regs + 0x1);
 285
 286         return ret;
 287 }
 288
 289 int bbc_i2c_write_buf(struct bbc_i2c_client *client,
 290                       char *buf, int len, int off)
 291 {
 292         int ret = 0;
 293
 294         while (len > 0) {
 295                 int err = bbc_i2c_writeb(client, *buf, off);
 296
 297                 if (err < 0) {
 298                         ret = err;
 299                         break;
 300                 }
 301
 302                 len--;
 303                 buf++;
 304                 off++;
 305         }
 306         return ret;
 307 }
 308
 309 int bbc_i2c_read_buf(struct bbc_i2c_client *client,
 310                      char *buf, int len, int off)
 311 {
 312         int ret = 0;
 313
 314         while (len > 0) {
 315                 int err = bbc_i2c_readb(client, buf, off);
 316                 if (err < 0) {
 317                         ret = err;
 318                         break;
 319                 }
 320                 len--;
 321                 buf++;
 322                 off++;
 323         }
 324
 325         return ret;
 326 }
 327
 328 EXPORT_SYMBOL(bbc_i2c_getdev);
 329 EXPORT_SYMBOL(bbc_i2c_attach);
 330 EXPORT_SYMBOL(bbc_i2c_detach);
 331 EXPORT_SYMBOL(bbc_i2c_writeb);
 332 EXPORT_SYMBOL(bbc_i2c_readb);
 333 EXPORT_SYMBOL(bbc_i2c_write_buf);
 334 EXPORT_SYMBOL(bbc_i2c_read_buf);
 335
 336 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
 337 {
 338         struct bbc_i2c_bus *bp = dev_id;
 339
 340         /* PIN going from set to clear is the only event which
 341          * makes the i2c assert an interrupt.
 342          */
 343         if (bp->waiting &&
 344             !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
 345                 wake_up_interruptible(&bp->wq);
 346
 347         return IRQ_HANDLED;
 348 }
 349
 350 static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
 351 {
 352         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 353         writeb(bp->own, bp->i2c_control_regs + 0x1);
 354         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 355         writeb(bp->clock, bp->i2c_control_regs + 0x1);
 356         writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
 357 }
 358
 359 static int __init attach_one_i2c(struct linux_ebus_device *edev, int index)
 360 {
 361         struct bbc_i2c_bus *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
 362         struct linux_ebus_child *echild;
 363         int entry;
 364
 365         if (!bp)
 366                 return -ENOMEM;
 367         memset(bp, 0, sizeof(*bp));
 368
 369         bp->i2c_control_regs = ioremap(edev->resource[0].start, 0x2);
 370         if (!bp->i2c_control_regs)
 371                 goto fail;
 372
 373         if (edev->num_addrs == 2) {
 374                 bp->i2c_bussel_reg = ioremap(edev->resource[1].start, 0x1);
 375                 if (!bp->i2c_bussel_reg)
 376                         goto fail;
 377         }
 378
 379         bp->waiting = 0;
 380         init_waitqueue_head(&bp->wq);
 381         if (request_irq(edev->irqs[0], bbc_i2c_interrupt,
 382                         IRQF_SHARED, "bbc_i2c", bp))
 383                 goto fail;
 384
 385         bp->index = index;
 386         bp->bus_edev = edev;
 387
 388         spin_lock_init(&bp->lock);
 389         bp->next = all_bbc_i2c;
 390         all_bbc_i2c = bp;
 391
 392         entry = 0;
 393         for (echild = edev->children;
 394              echild && entry < 8;
 395              echild = echild->next, entry++) {
 396                 bp->devs[entry].device = echild;
 397                 bp->devs[entry].client_claimed = 0;
 398         }
 399
 400         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 401         bp->own = readb(bp->i2c_control_regs + 0x01);
 402         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 403         bp->clock = readb(bp->i2c_control_regs + 0x01);
 404
 405         printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
 406                bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
 407
 408         reset_one_i2c(bp);
 409
 410         return 0;
 411
 412 fail:
 413         if (bp->i2c_bussel_reg)
 414                 iounmap(bp->i2c_bussel_reg);
 415         if (bp->i2c_control_regs)
 416                 iounmap(bp->i2c_control_regs);
 417         kfree(bp);
 418         return -EINVAL;
 419 }
 420
 421 static int __init bbc_present(void)
 422 {
 423         struct linux_ebus *ebus = NULL;
 424         struct linux_ebus_device *edev = NULL;
 425
 426         for_each_ebus(ebus) {
 427                 for_each_ebusdev(edev, ebus) {
 428                         if (!strcmp(edev->prom_node->name, "bbc"))
 429                                 return 1;
 430                 }
 431         }
 432         return 0;
 433 }
 434
 435 extern int bbc_envctrl_init(void);
 436 extern void bbc_envctrl_cleanup(void);
 437 static void bbc_i2c_cleanup(void);
 438
 439 static int __init bbc_i2c_init(void)
 440 {
 441         struct linux_ebus *ebus = NULL;
 442         struct linux_ebus_device *edev = NULL;
 443         int err, index = 0;
 444
 445         if ((tlb_type != cheetah && tlb_type != cheetah_plus) ||
 446             !bbc_present())
 447                 return -ENODEV;
 448
 449         for_each_ebus(ebus) {
 450                 for_each_ebusdev(edev, ebus) {
 451                         if (!strcmp(edev->prom_node->name, "i2c")) {
 452                                 if (!attach_one_i2c(edev, index))
 453                                         index++;
 454                         }
 455                 }
 456         }
 457
 458         if (!index)
 459                 return -ENODEV;
 460
 461         err = bbc_envctrl_init();
 462         if (err)
 463                 bbc_i2c_cleanup();
 464         return err;
 465 }
 466
 467 static void bbc_i2c_cleanup(void)
 468 {
 469         struct bbc_i2c_bus *bp = all_bbc_i2c;
 470
 471         bbc_envctrl_cleanup();
 472
 473         while (bp != NULL) {
 474                 struct bbc_i2c_bus *next = bp->next;
 475
 476                 free_irq(bp->bus_edev->irqs[0], bp);
 477
 478                 if (bp->i2c_bussel_reg)
 479                         iounmap(bp->i2c_bussel_reg);
 480                 if (bp->i2c_control_regs)
 481                         iounmap(bp->i2c_control_regs);
 482
 483                 kfree(bp);
 484
 485                 bp = next;
 486         }
 487         all_bbc_i2c = NULL;
 488 }
 489
 490 module_init(bbc_i2c_init);
 491 module_exit(bbc_i2c_cleanup);
 492 MODULE_LICENSE("GPL");