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