drivers/spi/spi_mpc83xx.c

   1 /*
   2  * MPC83xx SPI controller driver.
   3  *
   4  * Maintainer: Kumar Gala
   5  *
   6  * Copyright (C) 2006 Polycom, Inc.
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/completion.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/delay.h>
  20 #include <linux/irq.h>
  21 #include <linux/device.h>
  22 #include <linux/spi/spi.h>
  23 #include <linux/spi/spi_bitbang.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/fsl_devices.h>
  26
  27 #include <asm/irq.h>
  28 #include <asm/io.h>
  29
  30 /* SPI Controller registers */
  31 struct mpc83xx_spi_reg {
  32         u8 res1[0x20];
  33         __be32 mode;
  34         __be32 event;
  35         __be32 mask;
  36         __be32 command;
  37         __be32 transmit;
  38         __be32 receive;
  39 };
  40
  41 /* SPI Controller mode register definitions */
  42 #define SPMODE_CI_INACTIVEHIGH  (1 << 29)
  43 #define SPMODE_CP_BEGIN_EDGECLK (1 << 28)
  44 #define SPMODE_DIV16            (1 << 27)
  45 #define SPMODE_REV              (1 << 26)
  46 #define SPMODE_MS               (1 << 25)
  47 #define SPMODE_ENABLE           (1 << 24)
  48 #define SPMODE_LEN(x)           ((x) << 20)
  49 #define SPMODE_PM(x)            ((x) << 16)
  50
  51 /*
  52  * Default for SPI Mode:
  53  *      SPI MODE 0 (inactive low, phase middle, MSB, 8-bit length, slow clk
  54  */
  55 #define SPMODE_INIT_VAL (SPMODE_CI_INACTIVEHIGH | SPMODE_DIV16 | SPMODE_REV | \
  56                          SPMODE_MS | SPMODE_LEN(7) | SPMODE_PM(0xf))
  57
  58 /* SPIE register values */
  59 #define SPIE_NE         0x00000200      /* Not empty */
  60 #define SPIE_NF         0x00000100      /* Not full */
  61
  62 /* SPIM register values */
  63 #define SPIM_NE         0x00000200      /* Not empty */
  64 #define SPIM_NF         0x00000100      /* Not full */
  65
  66 /* SPI Controller driver's private data. */
  67 struct mpc83xx_spi {
  68         /* bitbang has to be first */
  69         struct spi_bitbang bitbang;
  70         struct completion done;
  71
  72         struct mpc83xx_spi_reg __iomem *base;
  73
  74         /* rx & tx bufs from the spi_transfer */
  75         const void *tx;
  76         void *rx;
  77
  78         /* functions to deal with different sized buffers */
  79         void (*get_rx) (u32 rx_data, struct mpc83xx_spi *);
  80         u32(*get_tx) (struct mpc83xx_spi *);
  81
  82         unsigned int count;
  83         u32 irq;
  84
  85         unsigned nsecs;         /* (clock cycle time)/2 */
  86
  87         u32 sysclk;
  88         void (*activate_cs) (u8 cs, u8 polarity);
  89         void (*deactivate_cs) (u8 cs, u8 polarity);
  90 };
  91
  92 static inline void mpc83xx_spi_write_reg(__be32 __iomem * reg, u32 val)
  93 {
  94         out_be32(reg, val);
  95 }
  96
  97 static inline u32 mpc83xx_spi_read_reg(__be32 __iomem * reg)
  98 {
  99         return in_be32(reg);
 100 }
 101
 102 #define MPC83XX_SPI_RX_BUF(type)                                          \
 103 void mpc83xx_spi_rx_buf_##type(u32 data, struct mpc83xx_spi *mpc83xx_spi) \
 104 {                                                                         \
 105         type * rx = mpc83xx_spi->rx;                                      \
 106         *rx++ = (type)data;                                               \
 107         mpc83xx_spi->rx = rx;                                             \
 108 }
 109
 110 #define MPC83XX_SPI_TX_BUF(type)                                \
 111 u32 mpc83xx_spi_tx_buf_##type(struct mpc83xx_spi *mpc83xx_spi)  \
 112 {                                                               \
 113         u32 data;                                               \
 114         const type * tx = mpc83xx_spi->tx;                      \
 115         data = *tx++;                                           \
 116         mpc83xx_spi->tx = tx;                                   \
 117         return data;                                            \
 118 }
 119
 120 MPC83XX_SPI_RX_BUF(u8)
 121 MPC83XX_SPI_RX_BUF(u16)
 122 MPC83XX_SPI_RX_BUF(u32)
 123 MPC83XX_SPI_TX_BUF(u8)
 124 MPC83XX_SPI_TX_BUF(u16)
 125 MPC83XX_SPI_TX_BUF(u32)
 126
 127 static void mpc83xx_spi_chipselect(struct spi_device *spi, int value)
 128 {
 129         struct mpc83xx_spi *mpc83xx_spi;
 130         u8 pol = spi->mode & SPI_CS_HIGH ? 1 : 0;
 131
 132         mpc83xx_spi = spi_master_get_devdata(spi->master);
 133
 134         if (value == BITBANG_CS_INACTIVE) {
 135                 if (mpc83xx_spi->deactivate_cs)
 136                         mpc83xx_spi->deactivate_cs(spi->chip_select, pol);
 137         }
 138
 139         if (value == BITBANG_CS_ACTIVE) {
 140                 u32 regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
 141                 u32 len = spi->bits_per_word;
 142                 if (len == 32)
 143                         len = 0;
 144                 else
 145                         len = len - 1;
 146
 147                 /* mask out bits we are going to set */
 148                 regval &= ~0x38ff0000;
 149
 150                 if (spi->mode & SPI_CPHA)
 151                         regval |= SPMODE_CP_BEGIN_EDGECLK;
 152                 if (spi->mode & SPI_CPOL)
 153                         regval |= SPMODE_CI_INACTIVEHIGH;
 154
 155                 regval |= SPMODE_LEN(len);
 156
 157                 if ((mpc83xx_spi->sysclk / spi->max_speed_hz) >= 64) {
 158                         u8 pm = mpc83xx_spi->sysclk / (spi->max_speed_hz * 64);
 159                         regval |= SPMODE_PM(pm) | SPMODE_DIV16;
 160                 } else {
 161                         u8 pm = mpc83xx_spi->sysclk / (spi->max_speed_hz * 4);
 162                         regval |= SPMODE_PM(pm);
 163                 }
 164
 165                 mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval);
 166                 if (mpc83xx_spi->activate_cs)
 167                         mpc83xx_spi->activate_cs(spi->chip_select, pol);
 168         }
 169 }
 170
 171 static
 172 int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 173 {
 174         struct mpc83xx_spi *mpc83xx_spi;
 175         u32 regval;
 176         u8 bits_per_word;
 177         u32 hz;
 178
 179         mpc83xx_spi = spi_master_get_devdata(spi->master);
 180
 181         if (t) {
 182                 bits_per_word = t->bits_per_word;
 183                 hz = t->speed_hz;
 184         } else {
 185                 bits_per_word = 0;
 186                 hz = 0;
 187         }
 188
 189         /* spi_transfer level calls that work per-word */
 190         if (!bits_per_word)
 191                 bits_per_word = spi->bits_per_word;
 192
 193         /* Make sure its a bit width we support [4..16, 32] */
 194         if ((bits_per_word < 4)
 195             || ((bits_per_word > 16) && (bits_per_word != 32)))
 196                 return -EINVAL;
 197
 198         if (bits_per_word <= 8) {
 199                 mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u8;
 200                 mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u8;
 201         } else if (bits_per_word <= 16) {
 202                 mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u16;
 203                 mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u16;
 204         } else if (bits_per_word <= 32) {
 205                 mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u32;
 206                 mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u32;
 207         } else
 208                 return -EINVAL;
 209
 210         /* nsecs = (clock period)/2 */
 211         if (!hz)
 212                 hz = spi->max_speed_hz;
 213         mpc83xx_spi->nsecs = (1000000000 / 2) / hz;
 214         if (mpc83xx_spi->nsecs > MAX_UDELAY_MS * 1000)
 215                 return -EINVAL;
 216
 217         if (bits_per_word == 32)
 218                 bits_per_word = 0;
 219         else
 220                 bits_per_word = bits_per_word - 1;
 221
 222         regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
 223
 224         /* Mask out bits_per_wordgth */
 225         regval &= 0xff0fffff;
 226         regval |= SPMODE_LEN(bits_per_word);
 227
 228         mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval);
 229
 230         return 0;
 231 }
 232
 233 static int mpc83xx_spi_setup(struct spi_device *spi)
 234 {
 235         struct spi_bitbang *bitbang;
 236         struct mpc83xx_spi *mpc83xx_spi;
 237         int retval;
 238
 239         if (!spi->max_speed_hz)
 240                 return -EINVAL;
 241
 242         bitbang = spi_master_get_devdata(spi->master);
 243         mpc83xx_spi = spi_master_get_devdata(spi->master);
 244
 245         if (!spi->bits_per_word)
 246                 spi->bits_per_word = 8;
 247
 248         retval = mpc83xx_spi_setup_transfer(spi, NULL);
 249         if (retval < 0)
 250                 return retval;
 251
 252         dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n",
 253                 __FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA),
 254                 spi->bits_per_word, 2 * mpc83xx_spi->nsecs);
 255
 256         /* NOTE we _need_ to call chipselect() early, ideally with adapter
 257          * setup, unless the hardware defaults cooperate to avoid confusion
 258          * between normal (active low) and inverted chipselects.
 259          */
 260
 261         /* deselect chip (low or high) */
 262         spin_lock(&bitbang->lock);
 263         if (!bitbang->busy) {
 264                 bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
 265                 ndelay(mpc83xx_spi->nsecs);
 266         }
 267         spin_unlock(&bitbang->lock);
 268
 269         return 0;
 270 }
 271
 272 static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 273 {
 274         struct mpc83xx_spi *mpc83xx_spi;
 275         u32 word;
 276
 277         mpc83xx_spi = spi_master_get_devdata(spi->master);
 278
 279         mpc83xx_spi->tx = t->tx_buf;
 280         mpc83xx_spi->rx = t->rx_buf;
 281         mpc83xx_spi->count = t->len;
 282         INIT_COMPLETION(mpc83xx_spi->done);
 283
 284         /* enable rx ints */
 285         mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, SPIM_NE);
 286
 287         /* transmit word */
 288         word = mpc83xx_spi->get_tx(mpc83xx_spi);
 289         mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, word);
 290
 291         wait_for_completion(&mpc83xx_spi->done);
 292
 293         /* disable rx ints */
 294         mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0);
 295
 296         return t->len - mpc83xx_spi->count;
 297 }
 298
 299 irqreturn_t mpc83xx_spi_irq(s32 irq, void *context_data,
 300                             struct pt_regs * ptregs)
 301 {
 302         struct mpc83xx_spi *mpc83xx_spi = context_data;
 303         u32 event;
 304         irqreturn_t ret = IRQ_NONE;
 305
 306         /* Get interrupt events(tx/rx) */
 307         event = mpc83xx_spi_read_reg(&mpc83xx_spi->base->event);
 308
 309         /* We need handle RX first */
 310         if (event & SPIE_NE) {
 311                 u32 rx_data = mpc83xx_spi_read_reg(&mpc83xx_spi->base->receive);
 312
 313                 if (mpc83xx_spi->rx)
 314                         mpc83xx_spi->get_rx(rx_data, mpc83xx_spi);
 315
 316                 ret = IRQ_HANDLED;
 317         }
 318
 319         if ((event & SPIE_NF) == 0)
 320                 /* spin until TX is done */
 321                 while (((event =
 322                          mpc83xx_spi_read_reg(&mpc83xx_spi->base->event)) &
 323                                                 SPIE_NF) == 0)
 324                          cpu_relax();
 325
 326         mpc83xx_spi->count -= 1;
 327         if (mpc83xx_spi->count) {
 328                 if (mpc83xx_spi->tx) {
 329                         u32 word = mpc83xx_spi->get_tx(mpc83xx_spi);
 330                         mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit,
 331                                               word);
 332                 }
 333         } else {
 334                 complete(&mpc83xx_spi->done);
 335         }
 336
 337         /* Clear the events */
 338         mpc83xx_spi_write_reg(&mpc83xx_spi->base->event, event);
 339
 340         return ret;
 341 }
 342
 343 static int __init mpc83xx_spi_probe(struct platform_device *dev)
 344 {
 345         struct spi_master *master;
 346         struct mpc83xx_spi *mpc83xx_spi;
 347         struct fsl_spi_platform_data *pdata;
 348         struct resource *r;
 349         u32 regval;
 350         int ret = 0;
 351
 352         /* Get resources(memory, IRQ) associated with the device */
 353         master = spi_alloc_master(&dev->dev, sizeof(struct mpc83xx_spi));
 354
 355         if (master == NULL) {
 356                 ret = -ENOMEM;
 357                 goto err;
 358         }
 359
 360         platform_set_drvdata(dev, master);
 361         pdata = dev->dev.platform_data;
 362
 363         if (pdata == NULL) {
 364                 ret = -ENODEV;
 365                 goto free_master;
 366         }
 367
 368         r = platform_get_resource(dev, IORESOURCE_MEM, 0);
 369         if (r == NULL) {
 370                 ret = -ENODEV;
 371                 goto free_master;
 372         }
 373
 374         mpc83xx_spi = spi_master_get_devdata(master);
 375         mpc83xx_spi->bitbang.master = spi_master_get(master);
 376         mpc83xx_spi->bitbang.chipselect = mpc83xx_spi_chipselect;
 377         mpc83xx_spi->bitbang.setup_transfer = mpc83xx_spi_setup_transfer;
 378         mpc83xx_spi->bitbang.txrx_bufs = mpc83xx_spi_bufs;
 379         mpc83xx_spi->sysclk = pdata->sysclk;
 380         mpc83xx_spi->activate_cs = pdata->activate_cs;
 381         mpc83xx_spi->deactivate_cs = pdata->deactivate_cs;
 382         mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u8;
 383         mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u8;
 384
 385         mpc83xx_spi->bitbang.master->setup = mpc83xx_spi_setup;
 386         init_completion(&mpc83xx_spi->done);
 387
 388         mpc83xx_spi->base = ioremap(r->start, r->end - r->start + 1);
 389         if (mpc83xx_spi->base == NULL) {
 390                 ret = -ENOMEM;
 391                 goto put_master;
 392         }
 393
 394         mpc83xx_spi->irq = platform_get_irq(dev, 0);
 395
 396         if (mpc83xx_spi->irq < 0) {
 397                 ret = -ENXIO;
 398                 goto unmap_io;
 399         }
 400
 401         /* Register for SPI Interrupt */
 402         ret = request_irq(mpc83xx_spi->irq, mpc83xx_spi_irq,
 403                           0, "mpc83xx_spi", mpc83xx_spi);
 404
 405         if (ret != 0)
 406                 goto unmap_io;
 407
 408         master->bus_num = pdata->bus_num;
 409         master->num_chipselect = pdata->max_chipselect;
 410
 411         /* SPI controller initializations */
 412         mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, 0);
 413         mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0);
 414         mpc83xx_spi_write_reg(&mpc83xx_spi->base->command, 0);
 415         mpc83xx_spi_write_reg(&mpc83xx_spi->base->event, 0xffffffff);
 416
 417         /* Enable SPI interface */
 418         regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
 419         mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval);
 420
 421         ret = spi_bitbang_start(&mpc83xx_spi->bitbang);
 422
 423         if (ret != 0)
 424                 goto free_irq;
 425
 426         printk(KERN_INFO
 427                "%s: MPC83xx SPI Controller driver at 0x%p (irq = %d)\n",
 428                dev->dev.bus_id, mpc83xx_spi->base, mpc83xx_spi->irq);
 429
 430         return ret;
 431
 432 free_irq:
 433         free_irq(mpc83xx_spi->irq, mpc83xx_spi);
 434 unmap_io:
 435         iounmap(mpc83xx_spi->base);
 436 put_master:
 437         spi_master_put(master);
 438 free_master:
 439         kfree(master);
 440 err:
 441         return ret;
 442 }
 443
 444 static int __devexit mpc83xx_spi_remove(struct platform_device *dev)
 445 {
 446         struct mpc83xx_spi *mpc83xx_spi;
 447         struct spi_master *master;
 448
 449         master = platform_get_drvdata(dev);
 450         mpc83xx_spi = spi_master_get_devdata(master);
 451
 452         spi_bitbang_stop(&mpc83xx_spi->bitbang);
 453         free_irq(mpc83xx_spi->irq, mpc83xx_spi);
 454         iounmap(mpc83xx_spi->base);
 455         spi_master_put(mpc83xx_spi->bitbang.master);
 456
 457         return 0;
 458 }
 459
 460 static struct platform_driver mpc83xx_spi_driver = {
 461         .probe = mpc83xx_spi_probe,
 462         .remove = __devexit_p(mpc83xx_spi_remove),
 463         .driver = {
 464                    .name = "mpc83xx_spi",
 465         },
 466 };
 467
 468 static int __init mpc83xx_spi_init(void)
 469 {
 470         return platform_driver_register(&mpc83xx_spi_driver);
 471 }
 472
 473 static void __exit mpc83xx_spi_exit(void)
 474 {
 475         platform_driver_unregister(&mpc83xx_spi_driver);
 476 }
 477
 478 module_init(mpc83xx_spi_init);
 479 module_exit(mpc83xx_spi_exit);
 480
 481 MODULE_AUTHOR("Kumar Gala");
 482 MODULE_DESCRIPTION("Simple MPC83xx SPI Driver");
 483 MODULE_LICENSE("GPL");