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 = kzalloc(sizeof(*client), GFP_KERNEL);
 160         if (!client)
 161                 return NULL;
 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                 unsigned long val;
 191
 192                 val = wait_event_interruptible_timeout(
 193                                 bp->wq,
 194                                 (((*status = readb(bp->i2c_control_regs + 0))
 195                                   & I2C_PCF_PIN) == 0),
 196                                 msecs_to_jiffies(250));
 197                 if (val > 0) {
 198                         ret = 0;
 199                         break;
 200                 }
 201         }
 202         remove_wait_queue(&bp->wq, &wait);
 203         bp->waiting = 0;
 204
 205         return ret;
 206 }
 207
 208 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
 209 {
 210         struct bbc_i2c_bus *bp = client->bp;
 211         int address = client->address;
 212         u8 status;
 213         int ret = -1;
 214
 215         if (bp->i2c_bussel_reg != NULL)
 216                 writeb(client->bus, bp->i2c_bussel_reg);
 217
 218         writeb(address, bp->i2c_control_regs + 0x1);
 219         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 220         if (wait_for_pin(bp, &status))
 221                 goto out;
 222
 223         writeb(off, bp->i2c_control_regs + 0x1);
 224         if (wait_for_pin(bp, &status) ||
 225             (status & I2C_PCF_LRB) != 0)
 226                 goto out;
 227
 228         writeb(val, bp->i2c_control_regs + 0x1);
 229         if (wait_for_pin(bp, &status))
 230                 goto out;
 231
 232         ret = 0;
 233
 234 out:
 235         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 236         return ret;
 237 }
 238
 239 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
 240 {
 241         struct bbc_i2c_bus *bp = client->bp;
 242         unsigned char address = client->address, status;
 243         int ret = -1;
 244
 245         if (bp->i2c_bussel_reg != NULL)
 246                 writeb(client->bus, bp->i2c_bussel_reg);
 247
 248         writeb(address, bp->i2c_control_regs + 0x1);
 249         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 250         if (wait_for_pin(bp, &status))
 251                 goto out;
 252
 253         writeb(off, bp->i2c_control_regs + 0x1);
 254         if (wait_for_pin(bp, &status) ||
 255             (status & I2C_PCF_LRB) != 0)
 256                 goto out;
 257
 258         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 259
 260         address |= 0x1; /* READ */
 261
 262         writeb(address, bp->i2c_control_regs + 0x1);
 263         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 264         if (wait_for_pin(bp, &status))
 265                 goto out;
 266
 267         /* Set PIN back to one so the device sends the first
 268          * byte.
 269          */
 270         (void) readb(bp->i2c_control_regs + 0x1);
 271         if (wait_for_pin(bp, &status))
 272                 goto out;
 273
 274         writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
 275         *byte = readb(bp->i2c_control_regs + 0x1);
 276         if (wait_for_pin(bp, &status))
 277                 goto out;
 278
 279         ret = 0;
 280
 281 out:
 282         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 283         (void) readb(bp->i2c_control_regs + 0x1);
 284
 285         return ret;
 286 }
 287
 288 int bbc_i2c_write_buf(struct bbc_i2c_client *client,
 289                       char *buf, int len, int off)
 290 {
 291         int ret = 0;
 292
 293         while (len > 0) {
 294                 int err = bbc_i2c_writeb(client, *buf, off);
 295
 296                 if (err < 0) {
 297                         ret = err;
 298                         break;
 299                 }
 300
 301                 len--;
 302                 buf++;
 303                 off++;
 304         }
 305         return ret;
 306 }
 307
 308 int bbc_i2c_read_buf(struct bbc_i2c_client *client,
 309                      char *buf, int len, int off)
 310 {
 311         int ret = 0;
 312
 313         while (len > 0) {
 314                 int err = bbc_i2c_readb(client, buf, off);
 315                 if (err < 0) {
 316                         ret = err;
 317                         break;
 318                 }
 319                 len--;
 320                 buf++;
 321                 off++;
 322         }
 323
 324         return ret;
 325 }
 326
 327 EXPORT_SYMBOL(bbc_i2c_getdev);
 328 EXPORT_SYMBOL(bbc_i2c_attach);
 329 EXPORT_SYMBOL(bbc_i2c_detach);
 330 EXPORT_SYMBOL(bbc_i2c_writeb);
 331 EXPORT_SYMBOL(bbc_i2c_readb);
 332 EXPORT_SYMBOL(bbc_i2c_write_buf);
 333 EXPORT_SYMBOL(bbc_i2c_read_buf);
 334
 335 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
 336 {
 337         struct bbc_i2c_bus *bp = dev_id;
 338
 339         /* PIN going from set to clear is the only event which
 340          * makes the i2c assert an interrupt.
 341          */
 342         if (bp->waiting &&
 343             !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
 344                 wake_up_interruptible(&bp->wq);
 345
 346         return IRQ_HANDLED;
 347 }
 348
 349 static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
 350 {
 351         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 352         writeb(bp->own, bp->i2c_control_regs + 0x1);
 353         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 354         writeb(bp->clock, bp->i2c_control_regs + 0x1);
 355         writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
 356 }
 357
 358 static int __init attach_one_i2c(struct linux_ebus_device *edev, int index)
 359 {
 360         struct bbc_i2c_bus *bp;
 361         struct linux_ebus_child *echild;
 362         int entry;
 363
 364         bp = kzalloc(sizeof(*bp), GFP_KERNEL);
 365         if (!bp)
 366                 return -ENOMEM;
 367
 368         bp->i2c_control_regs = ioremap(edev->resource[0].start, 0x2);
 369         if (!bp->i2c_control_regs)
 370                 goto fail;
 371
 372         if (edev->num_addrs == 2) {
 373                 bp->i2c_bussel_reg = ioremap(edev->resource[1].start, 0x1);
 374                 if (!bp->i2c_bussel_reg)
 375                         goto fail;
 376         }
 377
 378         bp->waiting = 0;
 379         init_waitqueue_head(&bp->wq);
 380         if (request_irq(edev->irqs[0], bbc_i2c_interrupt,
 381                         IRQF_SHARED, "bbc_i2c", bp))
 382                 goto fail;
 383
 384         bp->index = index;
 385         bp->bus_edev = edev;
 386
 387         spin_lock_init(&bp->lock);
 388         bp->next = all_bbc_i2c;
 389         all_bbc_i2c = bp;
 390
 391         entry = 0;
 392         for (echild = edev->children;
 393              echild && entry < 8;
 394              echild = echild->next, entry++) {
 395                 bp->devs[entry].device = echild;
 396                 bp->devs[entry].client_claimed = 0;
 397         }
 398
 399         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 400         bp->own = readb(bp->i2c_control_regs + 0x01);
 401         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 402         bp->clock = readb(bp->i2c_control_regs + 0x01);
 403
 404         printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
 405                bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
 406
 407         reset_one_i2c(bp);
 408
 409         return 0;
 410
 411 fail:
 412         if (bp->i2c_bussel_reg)
 413                 iounmap(bp->i2c_bussel_reg);
 414         if (bp->i2c_control_regs)
 415                 iounmap(bp->i2c_control_regs);
 416         kfree(bp);
 417         return -EINVAL;
 418 }
 419
 420 static int __init bbc_present(void)
 421 {
 422         struct linux_ebus *ebus = NULL;
 423         struct linux_ebus_device *edev = NULL;
 424
 425         for_each_ebus(ebus) {
 426                 for_each_ebusdev(edev, ebus) {
 427                         if (!strcmp(edev->prom_node->name, "bbc"))
 428                                 return 1;
 429                 }
 430         }
 431         return 0;
 432 }
 433
 434 extern int bbc_envctrl_init(void);
 435 extern void bbc_envctrl_cleanup(void);
 436 static void bbc_i2c_cleanup(void);
 437
 438 static int __init bbc_i2c_init(void)
 439 {
 440         struct linux_ebus *ebus = NULL;
 441         struct linux_ebus_device *edev = NULL;
 442         int err, index = 0;
 443
 444         if ((tlb_type != cheetah && tlb_type != cheetah_plus) ||
 445             !bbc_present())
 446                 return -ENODEV;
 447
 448         for_each_ebus(ebus) {
 449                 for_each_ebusdev(edev, ebus) {
 450                         if (!strcmp(edev->prom_node->name, "i2c")) {
 451                                 if (!attach_one_i2c(edev, index))
 452                                         index++;
 453                         }
 454                 }
 455         }
 456
 457         if (!index)
 458                 return -ENODEV;
 459
 460         err = bbc_envctrl_init();
 461         if (err)
 462                 bbc_i2c_cleanup();
 463         return err;
 464 }
 465
 466 static void bbc_i2c_cleanup(void)
 467 {
 468         struct bbc_i2c_bus *bp = all_bbc_i2c;
 469
 470         bbc_envctrl_cleanup();
 471
 472         while (bp != NULL) {
 473                 struct bbc_i2c_bus *next = bp->next;
 474
 475                 free_irq(bp->bus_edev->irqs[0], bp);
 476
 477                 if (bp->i2c_bussel_reg)
 478                         iounmap(bp->i2c_bussel_reg);
 479                 if (bp->i2c_control_regs)
 480                         iounmap(bp->i2c_control_regs);
 481
 482                 kfree(bp);
 483
 484                 bp = next;
 485         }
 486         all_bbc_i2c = NULL;
 487 }
 488
 489 module_init(bbc_i2c_init);
 490 module_exit(bbc_i2c_cleanup);
 491 MODULE_LICENSE("GPL");