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/platform_device.h>
  21
  22 #include <asm/io.h>
  23 #include <linux/fsl_devices.h>
  24 #include <linux/i2c.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/delay.h>
  27
  28 #define MPC_I2C_ADDR  0x00
  29 #define MPC_I2C_FDR     0x04
  30 #define MPC_I2C_CR      0x08
  31 #define MPC_I2C_SR      0x0c
  32 #define MPC_I2C_DR      0x10
  33 #define MPC_I2C_DFSRR 0x14
  34 #define MPC_I2C_REGION 0x20
  35
  36 #define CCR_MEN  0x80
  37 #define CCR_MIEN 0x40
  38 #define CCR_MSTA 0x20
  39 #define CCR_MTX  0x10
  40 #define CCR_TXAK 0x08
  41 #define CCR_RSTA 0x04
  42
  43 #define CSR_MCF  0x80
  44 #define CSR_MAAS 0x40
  45 #define CSR_MBB  0x20
  46 #define CSR_MAL  0x10
  47 #define CSR_SRW  0x04
  48 #define CSR_MIF  0x02
  49 #define CSR_RXAK 0x01
  50
  51 struct mpc_i2c {
  52         void __iomem *base;
  53         u32 interrupt;
  54         wait_queue_head_t queue;
  55         struct i2c_adapter adap;
  56         int irq;
  57         u32 flags;
  58 };
  59
  60 static __inline__ void writeccr(struct mpc_i2c *i2c, u32 x)
  61 {
  62         writeb(x, i2c->base + MPC_I2C_CR);
  63 }
  64
  65 static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
  66 {
  67         struct mpc_i2c *i2c = dev_id;
  68         if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
  69                 /* Read again to allow register to stabilise */
  70                 i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
  71                 writeb(0, i2c->base + MPC_I2C_SR);
  72                 wake_up_interruptible(&i2c->queue);
  73         }
  74         return IRQ_HANDLED;
  75 }
  76
  77 /* Sometimes 9th clock pulse isn't generated, and slave doesn't release
  78  * the bus, because it wants to send ACK.
  79  * Following sequence of enabling/disabling and sending start/stop generates
  80  * the pulse, so it's all OK.
  81  */
  82 static void mpc_i2c_fixup(struct mpc_i2c *i2c)
  83 {
  84         writeccr(i2c, 0);
  85         udelay(30);
  86         writeccr(i2c, CCR_MEN);
  87         udelay(30);
  88         writeccr(i2c, CCR_MSTA | CCR_MTX);
  89         udelay(30);
  90         writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
  91         udelay(30);
  92         writeccr(i2c, CCR_MEN);
  93         udelay(30);
  94 }
  95
  96 static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
  97 {
  98         unsigned long orig_jiffies = jiffies;
  99         u32 x;
 100         int result = 0;
 101
 102         if (i2c->irq == NO_IRQ)
 103         {
 104                 while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
 105                         schedule();
 106                         if (time_after(jiffies, orig_jiffies + timeout)) {
 107                                 pr_debug("I2C: timeout\n");
 108                                 writeccr(i2c, 0);
 109                                 result = -EIO;
 110                                 break;
 111                         }
 112                 }
 113                 x = readb(i2c->base + MPC_I2C_SR);
 114                 writeb(0, i2c->base + MPC_I2C_SR);
 115         } else {
 116                 /* Interrupt mode */
 117                 result = wait_event_interruptible_timeout(i2c->queue,
 118                         (i2c->interrupt & CSR_MIF), timeout * HZ);
 119
 120                 if (unlikely(result < 0)) {
 121                         pr_debug("I2C: wait interrupted\n");
 122                         writeccr(i2c, 0);
 123                 } else if (unlikely(!(i2c->interrupt & CSR_MIF))) {
 124                         pr_debug("I2C: wait timeout\n");
 125                         writeccr(i2c, 0);
 126                         result = -ETIMEDOUT;
 127                 }
 128
 129                 x = i2c->interrupt;
 130                 i2c->interrupt = 0;
 131         }
 132
 133         if (result < 0)
 134                 return result;
 135
 136         if (!(x & CSR_MCF)) {
 137                 pr_debug("I2C: unfinished\n");
 138                 return -EIO;
 139         }
 140
 141         if (x & CSR_MAL) {
 142                 pr_debug("I2C: MAL\n");
 143                 return -EIO;
 144         }
 145
 146         if (writing && (x & CSR_RXAK)) {
 147                 pr_debug("I2C: No RXAK\n");
 148                 /* generate stop */
 149                 writeccr(i2c, CCR_MEN);
 150                 return -EIO;
 151         }
 152         return 0;
 153 }
 154
 155 static void mpc_i2c_setclock(struct mpc_i2c *i2c)
 156 {
 157         /* Set clock and filters */
 158         if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
 159                 writeb(0x31, i2c->base + MPC_I2C_FDR);
 160                 writeb(0x10, i2c->base + MPC_I2C_DFSRR);
 161         } else if (i2c->flags & FSL_I2C_DEV_CLOCK_5200)
 162                 writeb(0x3f, i2c->base + MPC_I2C_FDR);
 163         else
 164                 writel(0x1031, i2c->base + MPC_I2C_FDR);
 165 }
 166
 167 static void mpc_i2c_start(struct mpc_i2c *i2c)
 168 {
 169         /* Clear arbitration */
 170         writeb(0, i2c->base + MPC_I2C_SR);
 171         /* Start with MEN */
 172         writeccr(i2c, CCR_MEN);
 173 }
 174
 175 static void mpc_i2c_stop(struct mpc_i2c *i2c)
 176 {
 177         writeccr(i2c, CCR_MEN);
 178 }
 179
 180 static int mpc_write(struct mpc_i2c *i2c, int target,
 181                      const u8 * data, int length, int restart)
 182 {
 183         int i, result;
 184         unsigned timeout = i2c->adap.timeout;
 185         u32 flags = restart ? CCR_RSTA : 0;
 186
 187         /* Start with MEN */
 188         if (!restart)
 189                 writeccr(i2c, CCR_MEN);
 190         /* Start as master */
 191         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 192         /* Write target byte */
 193         writeb((target << 1), i2c->base + MPC_I2C_DR);
 194
 195         result = i2c_wait(i2c, timeout, 1);
 196         if (result < 0)
 197                 return result;
 198
 199         for (i = 0; i < length; i++) {
 200                 /* Write data byte */
 201                 writeb(data[i], i2c->base + MPC_I2C_DR);
 202
 203                 result = i2c_wait(i2c, timeout, 1);
 204                 if (result < 0)
 205                         return result;
 206         }
 207
 208         return 0;
 209 }
 210
 211 static int mpc_read(struct mpc_i2c *i2c, int target,
 212                     u8 * data, int length, int restart)
 213 {
 214         unsigned timeout = i2c->adap.timeout;
 215         int i, result;
 216         u32 flags = restart ? CCR_RSTA : 0;
 217
 218         /* Start with MEN */
 219         if (!restart)
 220                 writeccr(i2c, CCR_MEN);
 221         /* Switch to read - restart */
 222         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 223         /* Write target address byte - this time with the read flag set */
 224         writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
 225
 226         result = i2c_wait(i2c, timeout, 1);
 227         if (result < 0)
 228                 return result;
 229
 230         if (length) {
 231                 if (length == 1)
 232                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 233                 else
 234                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
 235                 /* Dummy read */
 236                 readb(i2c->base + MPC_I2C_DR);
 237         }
 238
 239         for (i = 0; i < length; i++) {
 240                 result = i2c_wait(i2c, timeout, 0);
 241                 if (result < 0)
 242                         return result;
 243
 244                 /* Generate txack on next to last byte */
 245                 if (i == length - 2)
 246                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 247                 /* Generate stop on last byte */
 248                 if (i == length - 1)
 249                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
 250                 data[i] = readb(i2c->base + MPC_I2C_DR);
 251         }
 252
 253         return length;
 254 }
 255
 256 static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 257 {
 258         struct i2c_msg *pmsg;
 259         int i;
 260         int ret = 0;
 261         unsigned long orig_jiffies = jiffies;
 262         struct mpc_i2c *i2c = i2c_get_adapdata(adap);
 263
 264         mpc_i2c_start(i2c);
 265
 266         /* Allow bus up to 1s to become not busy */
 267         while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
 268                 if (signal_pending(current)) {
 269                         pr_debug("I2C: Interrupted\n");
 270                         writeccr(i2c, 0);
 271                         return -EINTR;
 272                 }
 273                 if (time_after(jiffies, orig_jiffies + HZ)) {
 274                         pr_debug("I2C: timeout\n");
 275                         if (readb(i2c->base + MPC_I2C_SR) ==
 276                             (CSR_MCF | CSR_MBB | CSR_RXAK))
 277                                 mpc_i2c_fixup(i2c);
 278                         return -EIO;
 279                 }
 280                 schedule();
 281         }
 282
 283         for (i = 0; ret >= 0 && i < num; i++) {
 284                 pmsg = &msgs[i];
 285                 pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 286                          pmsg->flags & I2C_M_RD ? "read" : "write",
 287                          pmsg->len, pmsg->addr, i + 1, num);
 288                 if (pmsg->flags & I2C_M_RD)
 289                         ret =
 290                             mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 291                 else
 292                         ret =
 293                             mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 294         }
 295         mpc_i2c_stop(i2c);
 296         return (ret < 0) ? ret : num;
 297 }
 298
 299 static u32 mpc_functionality(struct i2c_adapter *adap)
 300 {
 301         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 302 }
 303
 304 static const struct i2c_algorithm mpc_algo = {
 305         .master_xfer = mpc_xfer,
 306         .functionality = mpc_functionality,
 307 };
 308
 309 static struct i2c_adapter mpc_ops = {
 310         .owner = THIS_MODULE,
 311         .name = "MPC adapter",
 312         .id = I2C_HW_MPC107,
 313         .algo = &mpc_algo,
 314         .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 315         .timeout = 1,
 316 };
 317
 318 static int fsl_i2c_probe(struct platform_device *pdev)
 319 {
 320         int result = 0;
 321         struct mpc_i2c *i2c;
 322         struct fsl_i2c_platform_data *pdata;
 323         struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 324
 325         pdata = (struct fsl_i2c_platform_data *) pdev->dev.platform_data;
 326
 327         i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
 328         if (!i2c)
 329                 return -ENOMEM;
 330
 331         i2c->irq = platform_get_irq(pdev, 0);
 332         if (i2c->irq < 0)
 333                 i2c->irq = NO_IRQ; /* Use polling */
 334
 335         i2c->flags = pdata->device_flags;
 336         init_waitqueue_head(&i2c->queue);
 337
 338         i2c->base = ioremap((phys_addr_t)r->start, MPC_I2C_REGION);
 339
 340         if (!i2c->base) {
 341                 printk(KERN_ERR "i2c-mpc - failed to map controller\n");
 342                 result = -ENOMEM;
 343                 goto fail_map;
 344         }
 345
 346         if (i2c->irq != NO_IRQ)
 347                 if ((result = request_irq(i2c->irq, mpc_i2c_isr,
 348                                           IRQF_SHARED, "i2c-mpc", i2c)) < 0) {
 349                         printk(KERN_ERR
 350                                "i2c-mpc - failed to attach interrupt\n");
 351                         goto fail_irq;
 352                 }
 353
 354         mpc_i2c_setclock(i2c);
 355         platform_set_drvdata(pdev, i2c);
 356
 357         i2c->adap = mpc_ops;
 358         i2c->adap.nr = pdev->id;
 359         i2c_set_adapdata(&i2c->adap, i2c);
 360         i2c->adap.dev.parent = &pdev->dev;
 361         if ((result = i2c_add_numbered_adapter(&i2c->adap)) < 0) {
 362                 printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
 363                 goto fail_add;
 364         }
 365
 366         return result;
 367
 368       fail_add:
 369         if (i2c->irq != NO_IRQ)
 370                 free_irq(i2c->irq, i2c);
 371       fail_irq:
 372         iounmap(i2c->base);
 373       fail_map:
 374         kfree(i2c);
 375         return result;
 376 };
 377
 378 static int fsl_i2c_remove(struct platform_device *pdev)
 379 {
 380         struct mpc_i2c *i2c = platform_get_drvdata(pdev);
 381
 382         i2c_del_adapter(&i2c->adap);
 383         platform_set_drvdata(pdev, NULL);
 384
 385         if (i2c->irq != NO_IRQ)
 386                 free_irq(i2c->irq, i2c);
 387
 388         iounmap(i2c->base);
 389         kfree(i2c);
 390         return 0;
 391 };
 392
 393 /* work with hotplug and coldplug */
 394 MODULE_ALIAS("platform:fsl-i2c");
 395
 396 /* Structure for a device driver */
 397 static struct platform_driver fsl_i2c_driver = {
 398         .probe = fsl_i2c_probe,
 399         .remove = fsl_i2c_remove,
 400         .driver = {
 401                 .owner = THIS_MODULE,
 402                 .name = "fsl-i2c",
 403         },
 404 };
 405
 406 static int __init fsl_i2c_init(void)
 407 {
 408         return platform_driver_register(&fsl_i2c_driver);
 409 }
 410
 411 static void __exit fsl_i2c_exit(void)
 412 {
 413         platform_driver_unregister(&fsl_i2c_driver);
 414 }
 415
 416 module_init(fsl_i2c_init);
 417 module_exit(fsl_i2c_exit);
 418
 419 MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
 420 MODULE_DESCRIPTION
 421     ("I2C-Bus adapter for MPC107 bridge and MPC824x/85xx/52xx processors");
 422 MODULE_LICENSE("GPL");