drivers/sbus/char/bbc_i2c.c

   1 /* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
   2  *            platforms.
   3  *
   4  * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/kernel.h>
   9 #include <linux/types.h>
  10 #include <linux/slab.h>
  11 #include <linux/sched.h>
  12 #include <linux/wait.h>
  13 #include <linux/delay.h>
  14 #include <linux/init.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <asm/bbc.h>
  19 #include <asm/io.h>
  20
  21 #include "bbc_i2c.h"
  22
  23 /* Convert this driver to use i2c bus layer someday... */
  24 #define I2C_PCF_PIN     0x80
  25 #define I2C_PCF_ESO     0x40
  26 #define I2C_PCF_ES1     0x20
  27 #define I2C_PCF_ES2     0x10
  28 #define I2C_PCF_ENI     0x08
  29 #define I2C_PCF_STA     0x04
  30 #define I2C_PCF_STO     0x02
  31 #define I2C_PCF_ACK     0x01
  32
  33 #define I2C_PCF_START    (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
  34 #define I2C_PCF_STOP     (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
  35 #define I2C_PCF_REPSTART (              I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
  36 #define I2C_PCF_IDLE     (I2C_PCF_PIN | I2C_PCF_ESO               | I2C_PCF_ACK)
  37
  38 #define I2C_PCF_INI 0x40   /* 1 if not initialized */
  39 #define I2C_PCF_STS 0x20
  40 #define I2C_PCF_BER 0x10
  41 #define I2C_PCF_AD0 0x08
  42 #define I2C_PCF_LRB 0x08
  43 #define I2C_PCF_AAS 0x04
  44 #define I2C_PCF_LAB 0x02
  45 #define I2C_PCF_BB  0x01
  46
  47 /* The BBC devices have two I2C controllers.  The first I2C controller
  48  * connects mainly to configuration proms (NVRAM, cpu configuration,
  49  * dimm types, etc.).  Whereas the second I2C controller connects to
  50  * environmental control devices such as fans and temperature sensors.
  51  * The second controller also connects to the smartcard reader, if present.
  52  */
  53
  54 static void set_device_claimage(struct bbc_i2c_bus *bp, struct of_device *op, int val)
  55 {
  56         int i;
  57
  58         for (i = 0; i < NUM_CHILDREN; i++) {
  59                 if (bp->devs[i].device == op) {
  60                         bp->devs[i].client_claimed = val;
  61                         return;
  62                 }
  63         }
  64 }
  65
  66 #define claim_device(BP,ECHILD)         set_device_claimage(BP,ECHILD,1)
  67 #define release_device(BP,ECHILD)       set_device_claimage(BP,ECHILD,0)
  68
  69 struct of_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index)
  70 {
  71         struct of_device *op = NULL;
  72         int curidx = 0, i;
  73
  74         for (i = 0; i < NUM_CHILDREN; i++) {
  75                 if (!(op = bp->devs[i].device))
  76                         break;
  77                 if (curidx == index)
  78                         goto out;
  79                 op = NULL;
  80                 curidx++;
  81         }
  82
  83 out:
  84         if (curidx == index)
  85                 return op;
  86         return NULL;
  87 }
  88
  89 struct bbc_i2c_client *bbc_i2c_attach(struct bbc_i2c_bus *bp, struct of_device *op)
  90 {
  91         struct bbc_i2c_client *client;
  92         const u32 *reg;
  93
  94         client = kzalloc(sizeof(*client), GFP_KERNEL);
  95         if (!client)
  96                 return NULL;
  97         client->bp = bp;
  98         client->op = op;
  99
 100         reg = of_get_property(op->node, "reg", NULL);
 101         if (!reg) {
 102                 kfree(client);
 103                 return NULL;
 104         }
 105
 106         client->bus = reg[0];
 107         client->address = reg[1];
 108
 109         claim_device(bp, op);
 110
 111         return client;
 112 }
 113
 114 void bbc_i2c_detach(struct bbc_i2c_client *client)
 115 {
 116         struct bbc_i2c_bus *bp = client->bp;
 117         struct of_device *op = client->op;
 118
 119         release_device(bp, op);
 120         kfree(client);
 121 }
 122
 123 static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
 124 {
 125         DECLARE_WAITQUEUE(wait, current);
 126         int limit = 32;
 127         int ret = 1;
 128
 129         bp->waiting = 1;
 130         add_wait_queue(&bp->wq, &wait);
 131         while (limit-- > 0) {
 132                 long val;
 133
 134                 val = wait_event_interruptible_timeout(
 135                                 bp->wq,
 136                                 (((*status = readb(bp->i2c_control_regs + 0))
 137                                   & I2C_PCF_PIN) == 0),
 138                                 msecs_to_jiffies(250));
 139                 if (val > 0) {
 140                         ret = 0;
 141                         break;
 142                 }
 143         }
 144         remove_wait_queue(&bp->wq, &wait);
 145         bp->waiting = 0;
 146
 147         return ret;
 148 }
 149
 150 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
 151 {
 152         struct bbc_i2c_bus *bp = client->bp;
 153         int address = client->address;
 154         u8 status;
 155         int ret = -1;
 156
 157         if (bp->i2c_bussel_reg != NULL)
 158                 writeb(client->bus, bp->i2c_bussel_reg);
 159
 160         writeb(address, bp->i2c_control_regs + 0x1);
 161         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 162         if (wait_for_pin(bp, &status))
 163                 goto out;
 164
 165         writeb(off, bp->i2c_control_regs + 0x1);
 166         if (wait_for_pin(bp, &status) ||
 167             (status & I2C_PCF_LRB) != 0)
 168                 goto out;
 169
 170         writeb(val, bp->i2c_control_regs + 0x1);
 171         if (wait_for_pin(bp, &status))
 172                 goto out;
 173
 174         ret = 0;
 175
 176 out:
 177         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 178         return ret;
 179 }
 180
 181 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
 182 {
 183         struct bbc_i2c_bus *bp = client->bp;
 184         unsigned char address = client->address, status;
 185         int ret = -1;
 186
 187         if (bp->i2c_bussel_reg != NULL)
 188                 writeb(client->bus, bp->i2c_bussel_reg);
 189
 190         writeb(address, bp->i2c_control_regs + 0x1);
 191         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 192         if (wait_for_pin(bp, &status))
 193                 goto out;
 194
 195         writeb(off, bp->i2c_control_regs + 0x1);
 196         if (wait_for_pin(bp, &status) ||
 197             (status & I2C_PCF_LRB) != 0)
 198                 goto out;
 199
 200         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 201
 202         address |= 0x1; /* READ */
 203
 204         writeb(address, bp->i2c_control_regs + 0x1);
 205         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 206         if (wait_for_pin(bp, &status))
 207                 goto out;
 208
 209         /* Set PIN back to one so the device sends the first
 210          * byte.
 211          */
 212         (void) readb(bp->i2c_control_regs + 0x1);
 213         if (wait_for_pin(bp, &status))
 214                 goto out;
 215
 216         writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
 217         *byte = readb(bp->i2c_control_regs + 0x1);
 218         if (wait_for_pin(bp, &status))
 219                 goto out;
 220
 221         ret = 0;
 222
 223 out:
 224         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 225         (void) readb(bp->i2c_control_regs + 0x1);
 226
 227         return ret;
 228 }
 229
 230 int bbc_i2c_write_buf(struct bbc_i2c_client *client,
 231                       char *buf, int len, int off)
 232 {
 233         int ret = 0;
 234
 235         while (len > 0) {
 236                 int err = bbc_i2c_writeb(client, *buf, off);
 237
 238                 if (err < 0) {
 239                         ret = err;
 240                         break;
 241                 }
 242
 243                 len--;
 244                 buf++;
 245                 off++;
 246         }
 247         return ret;
 248 }
 249
 250 int bbc_i2c_read_buf(struct bbc_i2c_client *client,
 251                      char *buf, int len, int off)
 252 {
 253         int ret = 0;
 254
 255         while (len > 0) {
 256                 int err = bbc_i2c_readb(client, buf, off);
 257                 if (err < 0) {
 258                         ret = err;
 259                         break;
 260                 }
 261                 len--;
 262                 buf++;
 263                 off++;
 264         }
 265
 266         return ret;
 267 }
 268
 269 EXPORT_SYMBOL(bbc_i2c_getdev);
 270 EXPORT_SYMBOL(bbc_i2c_attach);
 271 EXPORT_SYMBOL(bbc_i2c_detach);
 272 EXPORT_SYMBOL(bbc_i2c_writeb);
 273 EXPORT_SYMBOL(bbc_i2c_readb);
 274 EXPORT_SYMBOL(bbc_i2c_write_buf);
 275 EXPORT_SYMBOL(bbc_i2c_read_buf);
 276
 277 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
 278 {
 279         struct bbc_i2c_bus *bp = dev_id;
 280
 281         /* PIN going from set to clear is the only event which
 282          * makes the i2c assert an interrupt.
 283          */
 284         if (bp->waiting &&
 285             !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
 286                 wake_up_interruptible(&bp->wq);
 287
 288         return IRQ_HANDLED;
 289 }
 290
 291 static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
 292 {
 293         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 294         writeb(bp->own, bp->i2c_control_regs + 0x1);
 295         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 296         writeb(bp->clock, bp->i2c_control_regs + 0x1);
 297         writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
 298 }
 299
 300 static struct bbc_i2c_bus * __init attach_one_i2c(struct of_device *op, int index)
 301 {
 302         struct bbc_i2c_bus *bp;
 303         struct device_node *dp;
 304         int entry;
 305
 306         bp = kzalloc(sizeof(*bp), GFP_KERNEL);
 307         if (!bp)
 308                 return NULL;
 309
 310         bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
 311         if (!bp->i2c_control_regs)
 312                 goto fail;
 313
 314         bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
 315         if (!bp->i2c_bussel_reg)
 316                 goto fail;
 317
 318         bp->waiting = 0;
 319         init_waitqueue_head(&bp->wq);
 320         if (request_irq(op->irqs[0], bbc_i2c_interrupt,
 321                         IRQF_SHARED, "bbc_i2c", bp))
 322                 goto fail;
 323
 324         bp->index = index;
 325         bp->op = op;
 326
 327         spin_lock_init(&bp->lock);
 328
 329         entry = 0;
 330         for (dp = op->node->child;
 331              dp && entry < 8;
 332              dp = dp->sibling, entry++) {
 333                 struct of_device *child_op;
 334
 335                 child_op = of_find_device_by_node(dp);
 336                 bp->devs[entry].device = child_op;
 337                 bp->devs[entry].client_claimed = 0;
 338         }
 339
 340         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 341         bp->own = readb(bp->i2c_control_regs + 0x01);
 342         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 343         bp->clock = readb(bp->i2c_control_regs + 0x01);
 344
 345         printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
 346                bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
 347
 348         reset_one_i2c(bp);
 349
 350         return bp;
 351
 352 fail:
 353         if (bp->i2c_bussel_reg)
 354                 of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1);
 355         if (bp->i2c_control_regs)
 356                 of_iounmap(&op->resource[0], bp->i2c_control_regs, 2);
 357         kfree(bp);
 358         return NULL;
 359 }
 360
 361 extern int bbc_envctrl_init(struct bbc_i2c_bus *bp);
 362 extern void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp);
 363
 364 static int __devinit bbc_i2c_probe(struct of_device *op,
 365                                    const struct of_device_id *match)
 366 {
 367         struct bbc_i2c_bus *bp;
 368         int err, index = 0;
 369
 370         bp = attach_one_i2c(op, index);
 371         if (!bp)
 372                 return -EINVAL;
 373
 374         err = bbc_envctrl_init(bp);
 375         if (err) {
 376                 free_irq(op->irqs[0], bp);
 377                 if (bp->i2c_bussel_reg)
 378                         of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
 379                 if (bp->i2c_control_regs)
 380                         of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
 381                 kfree(bp);
 382         } else {
 383                 dev_set_drvdata(&op->dev, bp);
 384         }
 385
 386         return err;
 387 }
 388
 389 static int __devexit bbc_i2c_remove(struct of_device *op)
 390 {
 391         struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);
 392
 393         bbc_envctrl_cleanup(bp);
 394
 395         free_irq(op->irqs[0], bp);
 396
 397         if (bp->i2c_bussel_reg)
 398                 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
 399         if (bp->i2c_control_regs)
 400                 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
 401
 402         kfree(bp);
 403
 404         return 0;
 405 }
 406
 407 static const struct of_device_id bbc_i2c_match[] = {
 408         {
 409                 .name = "i2c",
 410                 .compatible = "SUNW,bbc-i2c",
 411         },
 412         {},
 413 };
 414 MODULE_DEVICE_TABLE(of, bbc_i2c_match);
 415
 416 static struct of_platform_driver bbc_i2c_driver = {
 417         .name           = "bbc_i2c",
 418         .match_table    = bbc_i2c_match,
 419         .probe          = bbc_i2c_probe,
 420         .remove         = __devexit_p(bbc_i2c_remove),
 421 };
 422
 423 static int __init bbc_i2c_init(void)
 424 {
 425         return of_register_driver(&bbc_i2c_driver, &of_bus_type);
 426 }
 427
 428 static void __exit bbc_i2c_exit(void)
 429 {
 430         of_unregister_driver(&bbc_i2c_driver);
 431 }
 432
 433 module_init(bbc_i2c_init);
 434 module_exit(bbc_i2c_exit);
 435
 436 MODULE_LICENSE("GPL");