drivers/i2c/busses/i2c-mpc.c

   1 /*
   2  * (C) Copyright 2003-2004
   3  * Humboldt Solutions Ltd, adrian@humboldt.co.uk.
   4
   5  * This is a combined i2c adapter and algorithm driver for the
   6  * MPC107/Tsi107 PowerPC northbridge and processors that include
   7  * the same I2C unit (8240, 8245, 85xx).
   8  *
   9  * Release 0.8
  10  *
  11  * This file is licensed under the terms of the GNU General Public
  12  * License version 2. This program is licensed "as is" without any
  13  * warranty of any kind, whether express or implied.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/init.h>
  20 #include <linux/of_platform.h>
  21 #include <linux/of_i2c.h>
  22
  23 #include <asm/io.h>
  24 #include <linux/fsl_devices.h>
  25 #include <linux/i2c.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/delay.h>
  28
  29 #define DRV_NAME "mpc-i2c"
  30
  31 #define MPC_I2C_FDR     0x04
  32 #define MPC_I2C_CR      0x08
  33 #define MPC_I2C_SR      0x0c
  34 #define MPC_I2C_DR      0x10
  35 #define MPC_I2C_DFSRR 0x14
  36
  37 #define CCR_MEN  0x80
  38 #define CCR_MIEN 0x40
  39 #define CCR_MSTA 0x20
  40 #define CCR_MTX  0x10
  41 #define CCR_TXAK 0x08
  42 #define CCR_RSTA 0x04
  43
  44 #define CSR_MCF  0x80
  45 #define CSR_MAAS 0x40
  46 #define CSR_MBB  0x20
  47 #define CSR_MAL  0x10
  48 #define CSR_SRW  0x04
  49 #define CSR_MIF  0x02
  50 #define CSR_RXAK 0x01
  51
  52 struct mpc_i2c {
  53         void __iomem *base;
  54         u32 interrupt;
  55         wait_queue_head_t queue;
  56         struct i2c_adapter adap;
  57         int irq;
  58         u32 flags;
  59 };
  60
  61 static __inline__ void writeccr(struct mpc_i2c *i2c, u32 x)
  62 {
  63         writeb(x, i2c->base + MPC_I2C_CR);
  64 }
  65
  66 static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
  67 {
  68         struct mpc_i2c *i2c = dev_id;
  69         if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
  70                 /* Read again to allow register to stabilise */
  71                 i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
  72                 writeb(0, i2c->base + MPC_I2C_SR);
  73                 wake_up_interruptible(&i2c->queue);
  74         }
  75         return IRQ_HANDLED;
  76 }
  77
  78 /* Sometimes 9th clock pulse isn't generated, and slave doesn't release
  79  * the bus, because it wants to send ACK.
  80  * Following sequence of enabling/disabling and sending start/stop generates
  81  * the pulse, so it's all OK.
  82  */
  83 static void mpc_i2c_fixup(struct mpc_i2c *i2c)
  84 {
  85         writeccr(i2c, 0);
  86         udelay(30);
  87         writeccr(i2c, CCR_MEN);
  88         udelay(30);
  89         writeccr(i2c, CCR_MSTA | CCR_MTX);
  90         udelay(30);
  91         writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
  92         udelay(30);
  93         writeccr(i2c, CCR_MEN);
  94         udelay(30);
  95 }
  96
  97 static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
  98 {
  99         unsigned long orig_jiffies = jiffies;
 100         u32 x;
 101         int result = 0;
 102
 103         if (i2c->irq == NO_IRQ)
 104         {
 105                 while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
 106                         schedule();
 107                         if (time_after(jiffies, orig_jiffies + timeout)) {
 108                                 pr_debug("I2C: timeout\n");
 109                                 writeccr(i2c, 0);
 110                                 result = -EIO;
 111                                 break;
 112                         }
 113                 }
 114                 x = readb(i2c->base + MPC_I2C_SR);
 115                 writeb(0, i2c->base + MPC_I2C_SR);
 116         } else {
 117                 /* Interrupt mode */
 118                 result = wait_event_interruptible_timeout(i2c->queue,
 119                         (i2c->interrupt & CSR_MIF), timeout * HZ);
 120
 121                 if (unlikely(result < 0)) {
 122                         pr_debug("I2C: wait interrupted\n");
 123                         writeccr(i2c, 0);
 124                 } else if (unlikely(!(i2c->interrupt & CSR_MIF))) {
 125                         pr_debug("I2C: wait timeout\n");
 126                         writeccr(i2c, 0);
 127                         result = -ETIMEDOUT;
 128                 }
 129
 130                 x = i2c->interrupt;
 131                 i2c->interrupt = 0;
 132         }
 133
 134         if (result < 0)
 135                 return result;
 136
 137         if (!(x & CSR_MCF)) {
 138                 pr_debug("I2C: unfinished\n");
 139                 return -EIO;
 140         }
 141
 142         if (x & CSR_MAL) {
 143                 pr_debug("I2C: MAL\n");
 144                 return -EIO;
 145         }
 146
 147         if (writing && (x & CSR_RXAK)) {
 148                 pr_debug("I2C: No RXAK\n");
 149                 /* generate stop */
 150                 writeccr(i2c, CCR_MEN);
 151                 return -EIO;
 152         }
 153         return 0;
 154 }
 155
 156 static void mpc_i2c_setclock(struct mpc_i2c *i2c)
 157 {
 158         /* Set clock and filters */
 159         if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
 160                 writeb(0x31, i2c->base + MPC_I2C_FDR);
 161                 writeb(0x10, i2c->base + MPC_I2C_DFSRR);
 162         } else if (i2c->flags & FSL_I2C_DEV_CLOCK_5200)
 163                 writeb(0x3f, i2c->base + MPC_I2C_FDR);
 164         else
 165                 writel(0x1031, i2c->base + MPC_I2C_FDR);
 166 }
 167
 168 static void mpc_i2c_start(struct mpc_i2c *i2c)
 169 {
 170         /* Clear arbitration */
 171         writeb(0, i2c->base + MPC_I2C_SR);
 172         /* Start with MEN */
 173         writeccr(i2c, CCR_MEN);
 174 }
 175
 176 static void mpc_i2c_stop(struct mpc_i2c *i2c)
 177 {
 178         writeccr(i2c, CCR_MEN);
 179 }
 180
 181 static int mpc_write(struct mpc_i2c *i2c, int target,
 182                      const u8 * data, int length, int restart)
 183 {
 184         int i, result;
 185         unsigned timeout = i2c->adap.timeout;
 186         u32 flags = restart ? CCR_RSTA : 0;
 187
 188         /* Start with MEN */
 189         if (!restart)
 190                 writeccr(i2c, CCR_MEN);
 191         /* Start as master */
 192         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 193         /* Write target byte */
 194         writeb((target << 1), i2c->base + MPC_I2C_DR);
 195
 196         result = i2c_wait(i2c, timeout, 1);
 197         if (result < 0)
 198                 return result;
 199
 200         for (i = 0; i < length; i++) {
 201                 /* Write data byte */
 202                 writeb(data[i], i2c->base + MPC_I2C_DR);
 203
 204                 result = i2c_wait(i2c, timeout, 1);
 205                 if (result < 0)
 206                         return result;
 207         }
 208
 209         return 0;
 210 }
 211
 212 static int mpc_read(struct mpc_i2c *i2c, int target,
 213                     u8 * data, int length, int restart)
 214 {
 215         unsigned timeout = i2c->adap.timeout;
 216         int i, result;
 217         u32 flags = restart ? CCR_RSTA : 0;
 218
 219         /* Start with MEN */
 220         if (!restart)
 221                 writeccr(i2c, CCR_MEN);
 222         /* Switch to read - restart */
 223         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 224         /* Write target address byte - this time with the read flag set */
 225         writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
 226
 227         result = i2c_wait(i2c, timeout, 1);
 228         if (result < 0)
 229                 return result;
 230
 231         if (length) {
 232                 if (length == 1)
 233                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 234                 else
 235                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
 236                 /* Dummy read */
 237                 readb(i2c->base + MPC_I2C_DR);
 238         }
 239
 240         for (i = 0; i < length; i++) {
 241                 result = i2c_wait(i2c, timeout, 0);
 242                 if (result < 0)
 243                         return result;
 244
 245                 /* Generate txack on next to last byte */
 246                 if (i == length - 2)
 247                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 248                 /* Generate stop on last byte */
 249                 if (i == length - 1)
 250                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
 251                 data[i] = readb(i2c->base + MPC_I2C_DR);
 252         }
 253
 254         return length;
 255 }
 256
 257 static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 258 {
 259         struct i2c_msg *pmsg;
 260         int i;
 261         int ret = 0;
 262         unsigned long orig_jiffies = jiffies;
 263         struct mpc_i2c *i2c = i2c_get_adapdata(adap);
 264
 265         mpc_i2c_start(i2c);
 266
 267         /* Allow bus up to 1s to become not busy */
 268         while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
 269                 if (signal_pending(current)) {
 270                         pr_debug("I2C: Interrupted\n");
 271                         writeccr(i2c, 0);
 272                         return -EINTR;
 273                 }
 274                 if (time_after(jiffies, orig_jiffies + HZ)) {
 275                         pr_debug("I2C: timeout\n");
 276                         if (readb(i2c->base + MPC_I2C_SR) ==
 277                             (CSR_MCF | CSR_MBB | CSR_RXAK))
 278                                 mpc_i2c_fixup(i2c);
 279                         return -EIO;
 280                 }
 281                 schedule();
 282         }
 283
 284         for (i = 0; ret >= 0 && i < num; i++) {
 285                 pmsg = &msgs[i];
 286                 pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 287                          pmsg->flags & I2C_M_RD ? "read" : "write",
 288                          pmsg->len, pmsg->addr, i + 1, num);
 289                 if (pmsg->flags & I2C_M_RD)
 290                         ret =
 291                             mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 292                 else
 293                         ret =
 294                             mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 295         }
 296         mpc_i2c_stop(i2c);
 297         return (ret < 0) ? ret : num;
 298 }
 299
 300 static u32 mpc_functionality(struct i2c_adapter *adap)
 301 {
 302         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 303 }
 304
 305 static const struct i2c_algorithm mpc_algo = {
 306         .master_xfer = mpc_xfer,
 307         .functionality = mpc_functionality,
 308 };
 309
 310 static struct i2c_adapter mpc_ops = {
 311         .owner = THIS_MODULE,
 312         .name = "MPC adapter",
 313         .algo = &mpc_algo,
 314         .timeout = 1,
 315 };
 316
 317 static int __devinit fsl_i2c_probe(struct of_device *op, const struct of_device_id *match)
 318 {
 319         int result = 0;
 320         struct mpc_i2c *i2c;
 321
 322         i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
 323         if (!i2c)
 324                 return -ENOMEM;
 325
 326         if (of_get_property(op->node, "dfsrr", NULL))
 327                 i2c->flags |= FSL_I2C_DEV_SEPARATE_DFSRR;
 328
 329         if (of_device_is_compatible(op->node, "fsl,mpc5200-i2c") ||
 330                         of_device_is_compatible(op->node, "mpc5200-i2c"))
 331                 i2c->flags |= FSL_I2C_DEV_CLOCK_5200;
 332
 333         init_waitqueue_head(&i2c->queue);
 334
 335         i2c->base = of_iomap(op->node, 0);
 336         if (!i2c->base) {
 337                 printk(KERN_ERR "i2c-mpc - failed to map controller\n");
 338                 result = -ENOMEM;
 339                 goto fail_map;
 340         }
 341
 342         i2c->irq = irq_of_parse_and_map(op->node, 0);
 343         if (i2c->irq != NO_IRQ) { /* i2c->irq = NO_IRQ implies polling */
 344                 result = request_irq(i2c->irq, mpc_i2c_isr,
 345                                      IRQF_SHARED, "i2c-mpc", i2c);
 346                 if (result < 0) {
 347                         printk(KERN_ERR "i2c-mpc - failed to attach interrupt\n");
 348                         goto fail_request;
 349                 }
 350         }
 351
 352         mpc_i2c_setclock(i2c);
 353
 354         dev_set_drvdata(&op->dev, i2c);
 355
 356         i2c->adap = mpc_ops;
 357         i2c_set_adapdata(&i2c->adap, i2c);
 358         i2c->adap.dev.parent = &op->dev;
 359
 360         result = i2c_add_adapter(&i2c->adap);
 361         if (result < 0) {
 362                 printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
 363                 goto fail_add;
 364         }
 365         of_register_i2c_devices(&i2c->adap, op->node);
 366
 367         return result;
 368
 369  fail_add:
 370         dev_set_drvdata(&op->dev, NULL);
 371         free_irq(i2c->irq, i2c);
 372  fail_request:
 373         irq_dispose_mapping(i2c->irq);
 374         iounmap(i2c->base);
 375  fail_map:
 376         kfree(i2c);
 377         return result;
 378 };
 379
 380 static int __devexit fsl_i2c_remove(struct of_device *op)
 381 {
 382         struct mpc_i2c *i2c = dev_get_drvdata(&op->dev);
 383
 384         i2c_del_adapter(&i2c->adap);
 385         dev_set_drvdata(&op->dev, NULL);
 386
 387         if (i2c->irq != NO_IRQ)
 388                 free_irq(i2c->irq, i2c);
 389
 390         irq_dispose_mapping(i2c->irq);
 391         iounmap(i2c->base);
 392         kfree(i2c);
 393         return 0;
 394 };
 395
 396 static const struct of_device_id mpc_i2c_of_match[] = {
 397         {.compatible = "fsl-i2c",},
 398         {},
 399 };
 400 MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);
 401
 402
 403 /* Structure for a device driver */
 404 static struct of_platform_driver mpc_i2c_driver = {
 405         .match_table    = mpc_i2c_of_match,
 406         .probe          = fsl_i2c_probe,
 407         .remove         = __devexit_p(fsl_i2c_remove),
 408         .driver         = {
 409                 .owner  = THIS_MODULE,
 410                 .name   = DRV_NAME,
 411         },
 412 };
 413
 414 static int __init fsl_i2c_init(void)
 415 {
 416         int rv;
 417
 418         rv = of_register_platform_driver(&mpc_i2c_driver);
 419         if (rv)
 420                 printk(KERN_ERR DRV_NAME
 421                        " of_register_platform_driver failed (%i)\n", rv);
 422         return rv;
 423 }
 424
 425 static void __exit fsl_i2c_exit(void)
 426 {
 427         of_unregister_platform_driver(&mpc_i2c_driver);
 428 }
 429
 430 module_init(fsl_i2c_init);
 431 module_exit(fsl_i2c_exit);
 432
 433 MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
 434 MODULE_DESCRIPTION
 435     ("I2C-Bus adapter for MPC107 bridge and MPC824x/85xx/52xx processors");
 436 MODULE_LICENSE("GPL");