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 == 0)
 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;
 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         if (i2c_wait(i2c, timeout, 1) < 0)
 196                 return -1;
 197
 198         for (i = 0; i < length; i++) {
 199                 /* Write data byte */
 200                 writeb(data[i], i2c->base + MPC_I2C_DR);
 201
 202                 if (i2c_wait(i2c, timeout, 1) < 0)
 203                         return -1;
 204         }
 205
 206         return 0;
 207 }
 208
 209 static int mpc_read(struct mpc_i2c *i2c, int target,
 210                     u8 * data, int length, int restart)
 211 {
 212         unsigned timeout = i2c->adap.timeout;
 213         int i;
 214         u32 flags = restart ? CCR_RSTA : 0;
 215
 216         /* Start with MEN */
 217         if (!restart)
 218                 writeccr(i2c, CCR_MEN);
 219         /* Switch to read - restart */
 220         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 221         /* Write target address byte - this time with the read flag set */
 222         writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
 223
 224         if (i2c_wait(i2c, timeout, 1) < 0)
 225                 return -1;
 226
 227         if (length) {
 228                 if (length == 1)
 229                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 230                 else
 231                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
 232                 /* Dummy read */
 233                 readb(i2c->base + MPC_I2C_DR);
 234         }
 235
 236         for (i = 0; i < length; i++) {
 237                 if (i2c_wait(i2c, timeout, 0) < 0)
 238                         return -1;
 239
 240                 /* Generate txack on next to last byte */
 241                 if (i == length - 2)
 242                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 243                 /* Generate stop on last byte */
 244                 if (i == length - 1)
 245                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
 246                 data[i] = readb(i2c->base + MPC_I2C_DR);
 247         }
 248
 249         return length;
 250 }
 251
 252 static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 253 {
 254         struct i2c_msg *pmsg;
 255         int i;
 256         int ret = 0;
 257         unsigned long orig_jiffies = jiffies;
 258         struct mpc_i2c *i2c = i2c_get_adapdata(adap);
 259
 260         mpc_i2c_start(i2c);
 261
 262         /* Allow bus up to 1s to become not busy */
 263         while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
 264                 if (signal_pending(current)) {
 265                         pr_debug("I2C: Interrupted\n");
 266                         writeccr(i2c, 0);
 267                         return -EINTR;
 268                 }
 269                 if (time_after(jiffies, orig_jiffies + HZ)) {
 270                         pr_debug("I2C: timeout\n");
 271                         if (readb(i2c->base + MPC_I2C_SR) ==
 272                             (CSR_MCF | CSR_MBB | CSR_RXAK))
 273                                 mpc_i2c_fixup(i2c);
 274                         return -EIO;
 275                 }
 276                 schedule();
 277         }
 278
 279         for (i = 0; ret >= 0 && i < num; i++) {
 280                 pmsg = &msgs[i];
 281                 pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 282                          pmsg->flags & I2C_M_RD ? "read" : "write",
 283                          pmsg->len, pmsg->addr, i + 1, num);
 284                 if (pmsg->flags & I2C_M_RD)
 285                         ret =
 286                             mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 287                 else
 288                         ret =
 289                             mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 290         }
 291         mpc_i2c_stop(i2c);
 292         return (ret < 0) ? ret : num;
 293 }
 294
 295 static u32 mpc_functionality(struct i2c_adapter *adap)
 296 {
 297         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 298 }
 299
 300 static const struct i2c_algorithm mpc_algo = {
 301         .master_xfer = mpc_xfer,
 302         .functionality = mpc_functionality,
 303 };
 304
 305 static struct i2c_adapter mpc_ops = {
 306         .owner = THIS_MODULE,
 307         .name = "MPC adapter",
 308         .id = I2C_HW_MPC107,
 309         .algo = &mpc_algo,
 310         .class = I2C_CLASS_HWMON,
 311         .timeout = 1,
 312         .retries = 1
 313 };
 314
 315 static int fsl_i2c_probe(struct platform_device *pdev)
 316 {
 317         int result = 0;
 318         struct mpc_i2c *i2c;
 319         struct fsl_i2c_platform_data *pdata;
 320         struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 321
 322         pdata = (struct fsl_i2c_platform_data *) pdev->dev.platform_data;
 323
 324         if (!(i2c = kzalloc(sizeof(*i2c), GFP_KERNEL))) {
 325                 return -ENOMEM;
 326         }
 327
 328         i2c->irq = platform_get_irq(pdev, 0);
 329         if (i2c->irq < 0) {
 330                 result = -ENXIO;
 331                 goto fail_get_irq;
 332         }
 333         i2c->flags = pdata->device_flags;
 334         init_waitqueue_head(&i2c->queue);
 335
 336         i2c->base = ioremap((phys_addr_t)r->start, MPC_I2C_REGION);
 337
 338         if (!i2c->base) {
 339                 printk(KERN_ERR "i2c-mpc - failed to map controller\n");
 340                 result = -ENOMEM;
 341                 goto fail_map;
 342         }
 343
 344         if (i2c->irq != 0)
 345                 if ((result = request_irq(i2c->irq, mpc_i2c_isr,
 346                                           IRQF_SHARED, "i2c-mpc", i2c)) < 0) {
 347                         printk(KERN_ERR
 348                                "i2c-mpc - failed to attach interrupt\n");
 349                         goto fail_irq;
 350                 }
 351
 352         mpc_i2c_setclock(i2c);
 353         platform_set_drvdata(pdev, i2c);
 354
 355         i2c->adap = mpc_ops;
 356         i2c->adap.nr = pdev->id;
 357         i2c_set_adapdata(&i2c->adap, i2c);
 358         i2c->adap.dev.parent = &pdev->dev;
 359         if ((result = i2c_add_numbered_adapter(&i2c->adap)) < 0) {
 360                 printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
 361                 goto fail_add;
 362         }
 363
 364         return result;
 365
 366       fail_add:
 367         if (i2c->irq != 0)
 368                 free_irq(i2c->irq, i2c);
 369       fail_irq:
 370         iounmap(i2c->base);
 371       fail_map:
 372       fail_get_irq:
 373         kfree(i2c);
 374         return result;
 375 };
 376
 377 static int fsl_i2c_remove(struct platform_device *pdev)
 378 {
 379         struct mpc_i2c *i2c = platform_get_drvdata(pdev);
 380
 381         i2c_del_adapter(&i2c->adap);
 382         platform_set_drvdata(pdev, NULL);
 383
 384         if (i2c->irq != 0)
 385                 free_irq(i2c->irq, i2c);
 386
 387         iounmap(i2c->base);
 388         kfree(i2c);
 389         return 0;
 390 };
 391
 392 /* Structure for a device driver */
 393 static struct platform_driver fsl_i2c_driver = {
 394         .probe = fsl_i2c_probe,
 395         .remove = fsl_i2c_remove,
 396         .driver = {
 397                 .owner = THIS_MODULE,
 398                 .name = "fsl-i2c",
 399         },
 400 };
 401
 402 static int __init fsl_i2c_init(void)
 403 {
 404         return platform_driver_register(&fsl_i2c_driver);
 405 }
 406
 407 static void __exit fsl_i2c_exit(void)
 408 {
 409         platform_driver_unregister(&fsl_i2c_driver);
 410 }
 411
 412 module_init(fsl_i2c_init);
 413 module_exit(fsl_i2c_exit);
 414
 415 MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
 416 MODULE_DESCRIPTION
 417     ("I2C-Bus adapter for MPC107 bridge and MPC824x/85xx/52xx processors");
 418 MODULE_LICENSE("GPL");