drivers/i2c/busses/i2c-highlander.c

   1 /*
   2  * Renesas Solutions Highlander FPGA I2C/SMBus support.
   3  *
   4  * Supported devices: R0P7780LC0011RL, R0P7785LC0011RL
   5  *
   6  * Copyright (C) 2008  Paul Mundt
   7  * Copyright (C) 2008  Renesas Solutions Corp.
   8  * Copyright (C) 2008  Atom Create Engineering Co., Ltd.
   9  *
  10  * This file is subject to the terms and conditions of the GNU General
  11  * Public License version 2. See the file "COPYING" in the main directory
  12  * of this archive for more details.
  13  */
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/i2c.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/completion.h>
  20 #include <linux/io.h>
  21 #include <linux/delay.h>
  22 #include <linux/slab.h>
  23
  24 #define SMCR            0x00
  25 #define SMCR_START      (1 << 0)
  26 #define SMCR_IRIC       (1 << 1)
  27 #define SMCR_BBSY       (1 << 2)
  28 #define SMCR_ACKE       (1 << 3)
  29 #define SMCR_RST        (1 << 4)
  30 #define SMCR_IEIC       (1 << 6)
  31
  32 #define SMSMADR         0x02
  33
  34 #define SMMR            0x04
  35 #define SMMR_MODE0      (1 << 0)
  36 #define SMMR_MODE1      (1 << 1)
  37 #define SMMR_CAP        (1 << 3)
  38 #define SMMR_TMMD       (1 << 4)
  39 #define SMMR_SP         (1 << 7)
  40
  41 #define SMSADR          0x06
  42 #define SMTRDR          0x46
  43
  44 struct highlander_i2c_dev {
  45         struct device           *dev;
  46         void __iomem            *base;
  47         struct i2c_adapter      adapter;
  48         struct completion       cmd_complete;
  49         unsigned long           last_read_time;
  50         int                     irq;
  51         u8                      *buf;
  52         size_t                  buf_len;
  53 };
  54
  55 static bool iic_force_poll, iic_force_normal;
  56 static int iic_timeout = 1000, iic_read_delay;
  57
  58 static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev)
  59 {
  60         iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR);
  61 }
  62
  63 static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev)
  64 {
  65         iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR);
  66 }
  67
  68 static inline void highlander_i2c_start(struct highlander_i2c_dev *dev)
  69 {
  70         iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR);
  71 }
  72
  73 static inline void highlander_i2c_done(struct highlander_i2c_dev *dev)
  74 {
  75         iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR);
  76 }
  77
  78 static void highlander_i2c_setup(struct highlander_i2c_dev *dev)
  79 {
  80         u16 smmr;
  81
  82         smmr = ioread16(dev->base + SMMR);
  83         smmr |= SMMR_TMMD;
  84
  85         if (iic_force_normal)
  86                 smmr &= ~SMMR_SP;
  87         else
  88                 smmr |= SMMR_SP;
  89
  90         iowrite16(smmr, dev->base + SMMR);
  91 }
  92
  93 static void smbus_write_data(u8 *src, u16 *dst, int len)
  94 {
  95         for (; len > 1; len -= 2) {
  96                 *dst++ = be16_to_cpup((__be16 *)src);
  97                 src += 2;
  98         }
  99
 100         if (len)
 101                 *dst = *src << 8;
 102 }
 103
 104 static void smbus_read_data(u16 *src, u8 *dst, int len)
 105 {
 106         for (; len > 1; len -= 2) {
 107                 *(__be16 *)dst = cpu_to_be16p(src++);
 108                 dst += 2;
 109         }
 110
 111         if (len)
 112                 *dst = *src >> 8;
 113 }
 114
 115 static void highlander_i2c_command(struct highlander_i2c_dev *dev,
 116                                    u8 command, int len)
 117 {
 118         unsigned int i;
 119         u16 cmd = (command << 8) | command;
 120
 121         for (i = 0; i < len; i += 2) {
 122                 if (len - i == 1)
 123                         cmd = command << 8;
 124                 iowrite16(cmd, dev->base + SMSADR + i);
 125                 dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd);
 126         }
 127 }
 128
 129 static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev)
 130 {
 131         unsigned long timeout;
 132
 133         timeout = jiffies + msecs_to_jiffies(iic_timeout);
 134         while (ioread16(dev->base + SMCR) & SMCR_BBSY) {
 135                 if (time_after(jiffies, timeout)) {
 136                         dev_warn(dev->dev, "timeout waiting for bus ready\n");
 137                         return -ETIMEDOUT;
 138                 }
 139
 140                 msleep(1);
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int highlander_i2c_reset(struct highlander_i2c_dev *dev)
 147 {
 148         iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR);
 149         return highlander_i2c_wait_for_bbsy(dev);
 150 }
 151
 152 static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev)
 153 {
 154         u16 tmp = ioread16(dev->base + SMCR);
 155
 156         if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) {
 157                 dev_warn(dev->dev, "ack abnormality\n");
 158                 return highlander_i2c_reset(dev);
 159         }
 160
 161         return 0;
 162 }
 163
 164 static irqreturn_t highlander_i2c_irq(int irq, void *dev_id)
 165 {
 166         struct highlander_i2c_dev *dev = dev_id;
 167
 168         highlander_i2c_done(dev);
 169         complete(&dev->cmd_complete);
 170
 171         return IRQ_HANDLED;
 172 }
 173
 174 static void highlander_i2c_poll(struct highlander_i2c_dev *dev)
 175 {
 176         unsigned long timeout;
 177         u16 smcr;
 178
 179         timeout = jiffies + msecs_to_jiffies(iic_timeout);
 180         for (;;) {
 181                 smcr = ioread16(dev->base + SMCR);
 182
 183                 /*
 184                  * Don't bother checking ACKE here, this and the reset
 185                  * are handled in highlander_i2c_wait_xfer_done() when
 186                  * waiting for the ACK.
 187                  */
 188
 189                 if (smcr & SMCR_IRIC)
 190                         return;
 191                 if (time_after(jiffies, timeout))
 192                         break;
 193
 194                 cpu_relax();
 195                 cond_resched();
 196         }
 197
 198         dev_err(dev->dev, "polling timed out\n");
 199 }
 200
 201 static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev)
 202 {
 203         if (dev->irq)
 204                 wait_for_completion_timeout(&dev->cmd_complete,
 205                                           msecs_to_jiffies(iic_timeout));
 206         else
 207                 /* busy looping, the IRQ of champions */
 208                 highlander_i2c_poll(dev);
 209
 210         return highlander_i2c_wait_for_ack(dev);
 211 }
 212
 213 static int highlander_i2c_read(struct highlander_i2c_dev *dev)
 214 {
 215         int i, cnt;
 216         u16 data[16];
 217
 218         if (highlander_i2c_wait_for_bbsy(dev))
 219                 return -EAGAIN;
 220
 221         highlander_i2c_start(dev);
 222
 223         if (highlander_i2c_wait_xfer_done(dev)) {
 224                 dev_err(dev->dev, "Arbitration loss\n");
 225                 return -EAGAIN;
 226         }
 227
 228         /*
 229          * The R0P7780LC0011RL FPGA needs a significant delay between
 230          * data read cycles, otherwise the transceiver gets confused and
 231          * garbage is returned when the read is subsequently aborted.
 232          *
 233          * It is not sufficient to wait for BBSY.
 234          *
 235          * While this generally only applies to the older SH7780-based
 236          * Highlanders, the same issue can be observed on SH7785 ones,
 237          * albeit less frequently. SH7780-based Highlanders may need
 238          * this to be as high as 1000 ms.
 239          */
 240         if (iic_read_delay && time_before(jiffies, dev->last_read_time +
 241                                  msecs_to_jiffies(iic_read_delay)))
 242                 msleep(jiffies_to_msecs((dev->last_read_time +
 243                                 msecs_to_jiffies(iic_read_delay)) - jiffies));
 244
 245         cnt = (dev->buf_len + 1) >> 1;
 246         for (i = 0; i < cnt; i++) {
 247                 data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16)));
 248                 dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]);
 249         }
 250
 251         smbus_read_data(data, dev->buf, dev->buf_len);
 252
 253         dev->last_read_time = jiffies;
 254
 255         return 0;
 256 }
 257
 258 static int highlander_i2c_write(struct highlander_i2c_dev *dev)
 259 {
 260         int i, cnt;
 261         u16 data[16];
 262
 263         smbus_write_data(dev->buf, data, dev->buf_len);
 264
 265         cnt = (dev->buf_len + 1) >> 1;
 266         for (i = 0; i < cnt; i++) {
 267                 iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16)));
 268                 dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]);
 269         }
 270
 271         if (highlander_i2c_wait_for_bbsy(dev))
 272                 return -EAGAIN;
 273
 274         highlander_i2c_start(dev);
 275
 276         return highlander_i2c_wait_xfer_done(dev);
 277 }
 278
 279 static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
 280                                   unsigned short flags, char read_write,
 281                                   u8 command, int size,
 282                                   union i2c_smbus_data *data)
 283 {
 284         struct highlander_i2c_dev *dev = i2c_get_adapdata(adap);
 285         u16 tmp;
 286
 287         init_completion(&dev->cmd_complete);
 288
 289         dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n",
 290                 addr, command, read_write, size);
 291
 292         /*
 293          * Set up the buffer and transfer size
 294          */
 295         switch (size) {
 296         case I2C_SMBUS_BYTE_DATA:
 297                 dev->buf = &data->byte;
 298                 dev->buf_len = 1;
 299                 break;
 300         case I2C_SMBUS_I2C_BLOCK_DATA:
 301                 dev->buf = &data->block[1];
 302                 dev->buf_len = data->block[0];
 303                 break;
 304         default:
 305                 dev_err(dev->dev, "unsupported command %d\n", size);
 306                 return -EINVAL;
 307         }
 308
 309         /*
 310          * Encode the mode setting
 311          */
 312         tmp = ioread16(dev->base + SMMR);
 313         tmp &= ~(SMMR_MODE0 | SMMR_MODE1);
 314
 315         switch (dev->buf_len) {
 316         case 1:
 317                 /* default */
 318                 break;
 319         case 8:
 320                 tmp |= SMMR_MODE0;
 321                 break;
 322         case 16:
 323                 tmp |= SMMR_MODE1;
 324                 break;
 325         case 32:
 326                 tmp |= (SMMR_MODE0 | SMMR_MODE1);
 327                 break;
 328         default:
 329                 dev_err(dev->dev, "unsupported xfer size %d\n", dev->buf_len);
 330                 return -EINVAL;
 331         }
 332
 333         iowrite16(tmp, dev->base + SMMR);
 334
 335         /* Ensure we're in a sane state */
 336         highlander_i2c_done(dev);
 337
 338         /* Set slave address */
 339         iowrite16((addr << 1) | read_write, dev->base + SMSMADR);
 340
 341         highlander_i2c_command(dev, command, dev->buf_len);
 342
 343         if (read_write == I2C_SMBUS_READ)
 344                 return highlander_i2c_read(dev);
 345         else
 346                 return highlander_i2c_write(dev);
 347 }
 348
 349 static u32 highlander_i2c_func(struct i2c_adapter *adapter)
 350 {
 351         return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
 352 }
 353
 354 static const struct i2c_algorithm highlander_i2c_algo = {
 355         .smbus_xfer     = highlander_i2c_smbus_xfer,
 356         .functionality  = highlander_i2c_func,
 357 };
 358
 359 static int highlander_i2c_probe(struct platform_device *pdev)
 360 {
 361         struct highlander_i2c_dev *dev;
 362         struct i2c_adapter *adap;
 363         struct resource *res;
 364         int ret;
 365
 366         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 367         if (unlikely(!res)) {
 368                 dev_err(&pdev->dev, "no mem resource\n");
 369                 return -ENODEV;
 370         }
 371
 372         dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL);
 373         if (unlikely(!dev))
 374                 return -ENOMEM;
 375
 376         dev->base = ioremap_nocache(res->start, resource_size(res));
 377         if (unlikely(!dev->base)) {
 378                 ret = -ENXIO;
 379                 goto err;
 380         }
 381
 382         dev->dev = &pdev->dev;
 383         platform_set_drvdata(pdev, dev);
 384
 385         dev->irq = platform_get_irq(pdev, 0);
 386         if (iic_force_poll)
 387                 dev->irq = 0;
 388
 389         if (dev->irq) {
 390                 ret = request_irq(dev->irq, highlander_i2c_irq, 0,
 391                                   pdev->name, dev);
 392                 if (unlikely(ret))
 393                         goto err_unmap;
 394
 395                 highlander_i2c_irq_enable(dev);
 396         } else {
 397                 dev_notice(&pdev->dev, "no IRQ, using polling mode\n");
 398                 highlander_i2c_irq_disable(dev);
 399         }
 400
 401         dev->last_read_time = jiffies;  /* initial read jiffies */
 402
 403         highlander_i2c_setup(dev);
 404
 405         adap = &dev->adapter;
 406         i2c_set_adapdata(adap, dev);
 407         adap->owner = THIS_MODULE;
 408         adap->class = I2C_CLASS_HWMON;
 409         strlcpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name));
 410         adap->algo = &highlander_i2c_algo;
 411         adap->dev.parent = &pdev->dev;
 412         adap->nr = pdev->id;
 413
 414         /*
 415          * Reset the adapter
 416          */
 417         ret = highlander_i2c_reset(dev);
 418         if (unlikely(ret)) {
 419                 dev_err(&pdev->dev, "controller didn't come up\n");
 420                 goto err_free_irq;
 421         }
 422
 423         ret = i2c_add_numbered_adapter(adap);
 424         if (unlikely(ret)) {
 425                 dev_err(&pdev->dev, "failure adding adapter\n");
 426                 goto err_free_irq;
 427         }
 428
 429         return 0;
 430
 431 err_free_irq:
 432         if (dev->irq)
 433                 free_irq(dev->irq, dev);
 434 err_unmap:
 435         iounmap(dev->base);
 436 err:
 437         kfree(dev);
 438
 439         return ret;
 440 }
 441
 442 static int highlander_i2c_remove(struct platform_device *pdev)
 443 {
 444         struct highlander_i2c_dev *dev = platform_get_drvdata(pdev);
 445
 446         i2c_del_adapter(&dev->adapter);
 447
 448         if (dev->irq)
 449                 free_irq(dev->irq, dev);
 450
 451         iounmap(dev->base);
 452         kfree(dev);
 453
 454         return 0;
 455 }
 456
 457 static struct platform_driver highlander_i2c_driver = {
 458         .driver         = {
 459                 .name   = "i2c-highlander",
 460                 .owner  = THIS_MODULE,
 461         },
 462
 463         .probe          = highlander_i2c_probe,
 464         .remove         = highlander_i2c_remove,
 465 };
 466
 467 module_platform_driver(highlander_i2c_driver);
 468
 469 MODULE_AUTHOR("Paul Mundt");
 470 MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter");
 471 MODULE_LICENSE("GPL v2");
 472
 473 module_param(iic_force_poll, bool, 0);
 474 module_param(iic_force_normal, bool, 0);
 475 module_param(iic_timeout, int, 0);
 476 module_param(iic_read_delay, int, 0);
 477
 478 MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
 479 MODULE_PARM_DESC(iic_force_normal,
 480                  "Force normal mode (100 kHz), default is fast mode (400 kHz)");
 481 MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)");
 482 MODULE_PARM_DESC(iic_read_delay,
 483                  "Delay between data read cycles (default 0 ms)");