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/config.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/sched.h>
  20 #include <linux/init.h>
  21 #include <linux/pci.h>
  22 #include <linux/platform_device.h>
  23
  24 #include <asm/io.h>
  25 #include <linux/fsl_devices.h>
  26 #include <linux/i2c.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/delay.h>
  29
  30 #define MPC_I2C_ADDR  0x00
  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 #define MPC_I2C_REGION 0x20
  37
  38 #define CCR_MEN  0x80
  39 #define CCR_MIEN 0x40
  40 #define CCR_MSTA 0x20
  41 #define CCR_MTX  0x10
  42 #define CCR_TXAK 0x08
  43 #define CCR_RSTA 0x04
  44
  45 #define CSR_MCF  0x80
  46 #define CSR_MAAS 0x40
  47 #define CSR_MBB  0x20
  48 #define CSR_MAL  0x10
  49 #define CSR_SRW  0x04
  50 #define CSR_MIF  0x02
  51 #define CSR_RXAK 0x01
  52
  53 struct mpc_i2c {
  54         void __iomem *base;
  55         u32 interrupt;
  56         wait_queue_head_t queue;
  57         struct i2c_adapter adap;
  58         int irq;
  59         u32 flags;
  60 };
  61
  62 static __inline__ void writeccr(struct mpc_i2c *i2c, u32 x)
  63 {
  64         writeb(x, i2c->base + MPC_I2C_CR);
  65 }
  66
  67 static irqreturn_t mpc_i2c_isr(int irq, void *dev_id, struct pt_regs *regs)
  68 {
  69         struct mpc_i2c *i2c = dev_id;
  70         if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
  71                 /* Read again to allow register to stabilise */
  72                 i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
  73                 writeb(0, i2c->base + MPC_I2C_SR);
  74                 wake_up_interruptible(&i2c->queue);
  75         }
  76         return IRQ_HANDLED;
  77 }
  78
  79 static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
  80 {
  81         unsigned long orig_jiffies = jiffies;
  82         u32 x;
  83         int result = 0;
  84
  85         if (i2c->irq == 0)
  86         {
  87                 while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
  88                         schedule();
  89                         if (time_after(jiffies, orig_jiffies + timeout)) {
  90                                 pr_debug("I2C: timeout\n");
  91                                 result = -EIO;
  92                                 break;
  93                         }
  94                 }
  95                 x = readb(i2c->base + MPC_I2C_SR);
  96                 writeb(0, i2c->base + MPC_I2C_SR);
  97         } else {
  98                 /* Interrupt mode */
  99                 result = wait_event_interruptible_timeout(i2c->queue,
 100                         (i2c->interrupt & CSR_MIF), timeout * HZ);
 101
 102                 if (unlikely(result < 0))
 103                         pr_debug("I2C: wait interrupted\n");
 104                 else if (unlikely(!(i2c->interrupt & CSR_MIF))) {
 105                         pr_debug("I2C: wait timeout\n");
 106                         result = -ETIMEDOUT;
 107                 }
 108
 109                 x = i2c->interrupt;
 110                 i2c->interrupt = 0;
 111         }
 112
 113         if (result < 0)
 114                 return result;
 115
 116         if (!(x & CSR_MCF)) {
 117                 pr_debug("I2C: unfinished\n");
 118                 return -EIO;
 119         }
 120
 121         if (x & CSR_MAL) {
 122                 pr_debug("I2C: MAL\n");
 123                 return -EIO;
 124         }
 125
 126         if (writing && (x & CSR_RXAK)) {
 127                 pr_debug("I2C: No RXAK\n");
 128                 /* generate stop */
 129                 writeccr(i2c, CCR_MEN);
 130                 return -EIO;
 131         }
 132         return 0;
 133 }
 134
 135 static void mpc_i2c_setclock(struct mpc_i2c *i2c)
 136 {
 137         /* Set clock and filters */
 138         if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
 139                 writeb(0x31, i2c->base + MPC_I2C_FDR);
 140                 writeb(0x10, i2c->base + MPC_I2C_DFSRR);
 141         } else if (i2c->flags & FSL_I2C_DEV_CLOCK_5200)
 142                 writeb(0x3f, i2c->base + MPC_I2C_FDR);
 143         else
 144                 writel(0x1031, i2c->base + MPC_I2C_FDR);
 145 }
 146
 147 static void mpc_i2c_start(struct mpc_i2c *i2c)
 148 {
 149         /* Clear arbitration */
 150         writeb(0, i2c->base + MPC_I2C_SR);
 151         /* Start with MEN */
 152         writeccr(i2c, CCR_MEN);
 153 }
 154
 155 static void mpc_i2c_stop(struct mpc_i2c *i2c)
 156 {
 157         writeccr(i2c, CCR_MEN);
 158 }
 159
 160 static int mpc_write(struct mpc_i2c *i2c, int target,
 161                      const u8 * data, int length, int restart)
 162 {
 163         int i;
 164         unsigned timeout = i2c->adap.timeout;
 165         u32 flags = restart ? CCR_RSTA : 0;
 166
 167         /* Start with MEN */
 168         if (!restart)
 169                 writeccr(i2c, CCR_MEN);
 170         /* Start as master */
 171         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 172         /* Write target byte */
 173         writeb((target << 1), i2c->base + MPC_I2C_DR);
 174
 175         if (i2c_wait(i2c, timeout, 1) < 0)
 176                 return -1;
 177
 178         for (i = 0; i < length; i++) {
 179                 /* Write data byte */
 180                 writeb(data[i], i2c->base + MPC_I2C_DR);
 181
 182                 if (i2c_wait(i2c, timeout, 1) < 0)
 183                         return -1;
 184         }
 185
 186         return 0;
 187 }
 188
 189 static int mpc_read(struct mpc_i2c *i2c, int target,
 190                     u8 * data, int length, int restart)
 191 {
 192         unsigned timeout = i2c->adap.timeout;
 193         int i;
 194         u32 flags = restart ? CCR_RSTA : 0;
 195
 196         /* Start with MEN */
 197         if (!restart)
 198                 writeccr(i2c, CCR_MEN);
 199         /* Switch to read - restart */
 200         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 201         /* Write target address byte - this time with the read flag set */
 202         writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
 203
 204         if (i2c_wait(i2c, timeout, 1) < 0)
 205                 return -1;
 206
 207         if (length) {
 208                 if (length == 1)
 209                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 210                 else
 211                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
 212                 /* Dummy read */
 213                 readb(i2c->base + MPC_I2C_DR);
 214         }
 215
 216         for (i = 0; i < length; i++) {
 217                 if (i2c_wait(i2c, timeout, 0) < 0)
 218                         return -1;
 219
 220                 /* Generate txack on next to last byte */
 221                 if (i == length - 2)
 222                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 223                 /* Generate stop on last byte */
 224                 if (i == length - 1)
 225                         writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
 226                 data[i] = readb(i2c->base + MPC_I2C_DR);
 227         }
 228
 229         return length;
 230 }
 231
 232 static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 233 {
 234         struct i2c_msg *pmsg;
 235         int i;
 236         int ret = 0;
 237         unsigned long orig_jiffies = jiffies;
 238         struct mpc_i2c *i2c = i2c_get_adapdata(adap);
 239
 240         mpc_i2c_start(i2c);
 241
 242         /* Allow bus up to 1s to become not busy */
 243         while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
 244                 if (signal_pending(current)) {
 245                         pr_debug("I2C: Interrupted\n");
 246                         return -EINTR;
 247                 }
 248                 if (time_after(jiffies, orig_jiffies + HZ)) {
 249                         pr_debug("I2C: timeout\n");
 250                         return -EIO;
 251                 }
 252                 schedule();
 253         }
 254
 255         for (i = 0; ret >= 0 && i < num; i++) {
 256                 pmsg = &msgs[i];
 257                 pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 258                          pmsg->flags & I2C_M_RD ? "read" : "write",
 259                          pmsg->len, pmsg->addr, i + 1, num);
 260                 if (pmsg->flags & I2C_M_RD)
 261                         ret =
 262                             mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 263                 else
 264                         ret =
 265                             mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 266         }
 267         mpc_i2c_stop(i2c);
 268         return (ret < 0) ? ret : num;
 269 }
 270
 271 static u32 mpc_functionality(struct i2c_adapter *adap)
 272 {
 273         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 274 }
 275
 276 static struct i2c_algorithm mpc_algo = {
 277         .master_xfer = mpc_xfer,
 278         .functionality = mpc_functionality,
 279 };
 280
 281 static struct i2c_adapter mpc_ops = {
 282         .owner = THIS_MODULE,
 283         .name = "MPC adapter",
 284         .id = I2C_HW_MPC107,
 285         .algo = &mpc_algo,
 286         .class = I2C_CLASS_HWMON,
 287         .timeout = 1,
 288         .retries = 1
 289 };
 290
 291 static int fsl_i2c_probe(struct device *device)
 292 {
 293         int result = 0;
 294         struct mpc_i2c *i2c;
 295         struct platform_device *pdev = to_platform_device(device);
 296         struct fsl_i2c_platform_data *pdata;
 297         struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 298
 299         pdata = (struct fsl_i2c_platform_data *) pdev->dev.platform_data;
 300
 301         if (!(i2c = kzalloc(sizeof(*i2c), GFP_KERNEL))) {
 302                 return -ENOMEM;
 303         }
 304
 305         i2c->irq = platform_get_irq(pdev, 0);
 306         i2c->flags = pdata->device_flags;
 307         init_waitqueue_head(&i2c->queue);
 308
 309         i2c->base = ioremap((phys_addr_t)r->start, MPC_I2C_REGION);
 310
 311         if (!i2c->base) {
 312                 printk(KERN_ERR "i2c-mpc - failed to map controller\n");
 313                 result = -ENOMEM;
 314                 goto fail_map;
 315         }
 316
 317         if (i2c->irq != 0)
 318                 if ((result = request_irq(i2c->irq, mpc_i2c_isr,
 319                                           SA_SHIRQ, "i2c-mpc", i2c)) < 0) {
 320                         printk(KERN_ERR
 321                                "i2c-mpc - failed to attach interrupt\n");
 322                         goto fail_irq;
 323                 }
 324
 325         mpc_i2c_setclock(i2c);
 326         dev_set_drvdata(device, i2c);
 327
 328         i2c->adap = mpc_ops;
 329         i2c_set_adapdata(&i2c->adap, i2c);
 330         i2c->adap.dev.parent = &pdev->dev;
 331         if ((result = i2c_add_adapter(&i2c->adap)) < 0) {
 332                 printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
 333                 goto fail_add;
 334         }
 335
 336         return result;
 337
 338       fail_add:
 339         if (i2c->irq != 0)
 340                 free_irq(i2c->irq, NULL);
 341       fail_irq:
 342         iounmap(i2c->base);
 343       fail_map:
 344         kfree(i2c);
 345         return result;
 346 };
 347
 348 static int fsl_i2c_remove(struct device *device)
 349 {
 350         struct mpc_i2c *i2c = dev_get_drvdata(device);
 351
 352         i2c_del_adapter(&i2c->adap);
 353         dev_set_drvdata(device, NULL);
 354
 355         if (i2c->irq != 0)
 356                 free_irq(i2c->irq, i2c);
 357
 358         iounmap(i2c->base);
 359         kfree(i2c);
 360         return 0;
 361 };
 362
 363 /* Structure for a device driver */
 364 static struct device_driver fsl_i2c_driver = {
 365         .owner = THIS_MODULE,
 366         .name = "fsl-i2c",
 367         .bus = &platform_bus_type,
 368         .probe = fsl_i2c_probe,
 369         .remove = fsl_i2c_remove,
 370 };
 371
 372 static int __init fsl_i2c_init(void)
 373 {
 374         return driver_register(&fsl_i2c_driver);
 375 }
 376
 377 static void __exit fsl_i2c_exit(void)
 378 {
 379         driver_unregister(&fsl_i2c_driver);
 380 }
 381
 382 module_init(fsl_i2c_init);
 383 module_exit(fsl_i2c_exit);
 384
 385 MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
 386 MODULE_DESCRIPTION
 387     ("I2C-Bus adapter for MPC107 bridge and MPC824x/85xx/52xx processors");
 388 MODULE_LICENSE("GPL");