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