drivers/spi/spi-omap-100k.c

   1 /*
   2  * OMAP7xx SPI 100k controller driver
   3  * Author: Fabrice Crohas <fcrohas@gmail.com>
   4  * from original omap1_mcspi driver
   5  *
   6  * Copyright (C) 2005, 2006 Nokia Corporation
   7  * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
   8  *              Juha Yrj�l� <juha.yrjola@nokia.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  */
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/module.h>
  29 #include <linux/device.h>
  30 #include <linux/delay.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/err.h>
  33 #include <linux/clk.h>
  34 #include <linux/io.h>
  35 #include <linux/gpio.h>
  36 #include <linux/slab.h>
  37
  38 #include <linux/spi/spi.h>
  39
  40 #define OMAP1_SPI100K_MAX_FREQ          48000000
  41
  42 #define ICR_SPITAS      (OMAP7XX_ICR_BASE + 0x12)
  43
  44 #define SPI_SETUP1      0x00
  45 #define SPI_SETUP2      0x02
  46 #define SPI_CTRL        0x04
  47 #define SPI_STATUS      0x06
  48 #define SPI_TX_LSB      0x08
  49 #define SPI_TX_MSB      0x0a
  50 #define SPI_RX_LSB      0x0c
  51 #define SPI_RX_MSB      0x0e
  52
  53 #define SPI_SETUP1_INT_READ_ENABLE      (1UL << 5)
  54 #define SPI_SETUP1_INT_WRITE_ENABLE     (1UL << 4)
  55 #define SPI_SETUP1_CLOCK_DIVISOR(x)     ((x) << 1)
  56 #define SPI_SETUP1_CLOCK_ENABLE         (1UL << 0)
  57
  58 #define SPI_SETUP2_ACTIVE_EDGE_FALLING  (0UL << 0)
  59 #define SPI_SETUP2_ACTIVE_EDGE_RISING   (1UL << 0)
  60 #define SPI_SETUP2_NEGATIVE_LEVEL       (0UL << 5)
  61 #define SPI_SETUP2_POSITIVE_LEVEL       (1UL << 5)
  62 #define SPI_SETUP2_LEVEL_TRIGGER        (0UL << 10)
  63 #define SPI_SETUP2_EDGE_TRIGGER         (1UL << 10)
  64
  65 #define SPI_CTRL_SEN(x)                 ((x) << 7)
  66 #define SPI_CTRL_WORD_SIZE(x)           (((x) - 1) << 2)
  67 #define SPI_CTRL_WR                     (1UL << 1)
  68 #define SPI_CTRL_RD                     (1UL << 0)
  69
  70 #define SPI_STATUS_WE                   (1UL << 1)
  71 #define SPI_STATUS_RD                   (1UL << 0)
  72
  73 #define WRITE 0
  74 #define READ  1
  75
  76
  77 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
  78  * cache operations; better heuristics consider wordsize and bitrate.
  79  */
  80 #define DMA_MIN_BYTES                   8
  81
  82 #define SPI_RUNNING     0
  83 #define SPI_SHUTDOWN    1
  84
  85 struct omap1_spi100k {
  86         struct clk              *ick;
  87         struct clk              *fck;
  88
  89         /* Virtual base address of the controller */
  90         void __iomem            *base;
  91 };
  92
  93 struct omap1_spi100k_cs {
  94         void __iomem            *base;
  95         int                     word_len;
  96 };
  97
  98 static void spi100k_enable_clock(struct spi_master *master)
  99 {
 100         unsigned int val;
 101         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 102
 103         /* enable SPI */
 104         val = readw(spi100k->base + SPI_SETUP1);
 105         val |= SPI_SETUP1_CLOCK_ENABLE;
 106         writew(val, spi100k->base + SPI_SETUP1);
 107 }
 108
 109 static void spi100k_disable_clock(struct spi_master *master)
 110 {
 111         unsigned int val;
 112         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 113
 114         /* disable SPI */
 115         val = readw(spi100k->base + SPI_SETUP1);
 116         val &= ~SPI_SETUP1_CLOCK_ENABLE;
 117         writew(val, spi100k->base + SPI_SETUP1);
 118 }
 119
 120 static void spi100k_write_data(struct spi_master *master, int len, int data)
 121 {
 122         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 123
 124         /* write 16-bit word, shifting 8-bit data if necessary */
 125         if (len <= 8) {
 126                 data <<= 8;
 127                 len = 16;
 128         }
 129
 130         spi100k_enable_clock(master);
 131         writew(data , spi100k->base + SPI_TX_MSB);
 132
 133         writew(SPI_CTRL_SEN(0) |
 134                SPI_CTRL_WORD_SIZE(len) |
 135                SPI_CTRL_WR,
 136                spi100k->base + SPI_CTRL);
 137
 138         /* Wait for bit ack send change */
 139         while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE)
 140                 ;
 141         udelay(1000);
 142
 143         spi100k_disable_clock(master);
 144 }
 145
 146 static int spi100k_read_data(struct spi_master *master, int len)
 147 {
 148         int dataH, dataL;
 149         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 150
 151         /* Always do at least 16 bits */
 152         if (len <= 8)
 153                 len = 16;
 154
 155         spi100k_enable_clock(master);
 156         writew(SPI_CTRL_SEN(0) |
 157                SPI_CTRL_WORD_SIZE(len) |
 158                SPI_CTRL_RD,
 159                spi100k->base + SPI_CTRL);
 160
 161         while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD)
 162                 ;
 163         udelay(1000);
 164
 165         dataL = readw(spi100k->base + SPI_RX_LSB);
 166         dataH = readw(spi100k->base + SPI_RX_MSB);
 167         spi100k_disable_clock(master);
 168
 169         return dataL;
 170 }
 171
 172 static void spi100k_open(struct spi_master *master)
 173 {
 174         /* get control of SPI */
 175         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 176
 177         writew(SPI_SETUP1_INT_READ_ENABLE |
 178                SPI_SETUP1_INT_WRITE_ENABLE |
 179                SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
 180
 181         /* configure clock and interrupts */
 182         writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
 183                SPI_SETUP2_NEGATIVE_LEVEL |
 184                SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
 185 }
 186
 187 static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
 188 {
 189         if (enable)
 190                 writew(0x05fc, spi100k->base + SPI_CTRL);
 191         else
 192                 writew(0x05fd, spi100k->base + SPI_CTRL);
 193 }
 194
 195 static unsigned
 196 omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 197 {
 198         struct omap1_spi100k_cs *cs = spi->controller_state;
 199         unsigned int            count, c;
 200         int                     word_len;
 201
 202         count = xfer->len;
 203         c = count;
 204         word_len = cs->word_len;
 205
 206         if (word_len <= 8) {
 207                 u8              *rx;
 208                 const u8        *tx;
 209
 210                 rx = xfer->rx_buf;
 211                 tx = xfer->tx_buf;
 212                 do {
 213                         c -= 1;
 214                         if (xfer->tx_buf != NULL)
 215                                 spi100k_write_data(spi->master, word_len, *tx++);
 216                         if (xfer->rx_buf != NULL)
 217                                 *rx++ = spi100k_read_data(spi->master, word_len);
 218                 } while (c);
 219         } else if (word_len <= 16) {
 220                 u16             *rx;
 221                 const u16       *tx;
 222
 223                 rx = xfer->rx_buf;
 224                 tx = xfer->tx_buf;
 225                 do {
 226                         c -= 2;
 227                         if (xfer->tx_buf != NULL)
 228                                 spi100k_write_data(spi->master, word_len, *tx++);
 229                         if (xfer->rx_buf != NULL)
 230                                 *rx++ = spi100k_read_data(spi->master, word_len);
 231                 } while (c);
 232         } else if (word_len <= 32) {
 233                 u32             *rx;
 234                 const u32       *tx;
 235
 236                 rx = xfer->rx_buf;
 237                 tx = xfer->tx_buf;
 238                 do {
 239                         c -= 4;
 240                         if (xfer->tx_buf != NULL)
 241                                 spi100k_write_data(spi->master, word_len, *tx);
 242                         if (xfer->rx_buf != NULL)
 243                                 *rx = spi100k_read_data(spi->master, word_len);
 244                 } while (c);
 245         }
 246         return count - c;
 247 }
 248
 249 /* called only when no transfer is active to this device */
 250 static int omap1_spi100k_setup_transfer(struct spi_device *spi,
 251                 struct spi_transfer *t)
 252 {
 253         struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
 254         struct omap1_spi100k_cs *cs = spi->controller_state;
 255         u8 word_len = spi->bits_per_word;
 256
 257         if (t != NULL && t->bits_per_word)
 258                 word_len = t->bits_per_word;
 259         if (!word_len)
 260                 word_len = 8;
 261
 262         if (spi->bits_per_word > 32)
 263                 return -EINVAL;
 264         cs->word_len = word_len;
 265
 266         /* SPI init before transfer */
 267         writew(0x3e , spi100k->base + SPI_SETUP1);
 268         writew(0x00 , spi100k->base + SPI_STATUS);
 269         writew(0x3e , spi100k->base + SPI_CTRL);
 270
 271         return 0;
 272 }
 273
 274 /* the spi->mode bits understood by this driver: */
 275 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 276
 277 static int omap1_spi100k_setup(struct spi_device *spi)
 278 {
 279         int                     ret;
 280         struct omap1_spi100k    *spi100k;
 281         struct omap1_spi100k_cs *cs = spi->controller_state;
 282
 283         spi100k = spi_master_get_devdata(spi->master);
 284
 285         if (!cs) {
 286                 cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
 287                 if (!cs)
 288                         return -ENOMEM;
 289                 cs->base = spi100k->base + spi->chip_select * 0x14;
 290                 spi->controller_state = cs;
 291         }
 292
 293         spi100k_open(spi->master);
 294
 295         clk_prepare_enable(spi100k->ick);
 296         clk_prepare_enable(spi100k->fck);
 297
 298         ret = omap1_spi100k_setup_transfer(spi, NULL);
 299
 300         clk_disable_unprepare(spi100k->ick);
 301         clk_disable_unprepare(spi100k->fck);
 302
 303         return ret;
 304 }
 305
 306 static int omap1_spi100k_prepare_hardware(struct spi_master *master)
 307 {
 308         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 309
 310         clk_prepare_enable(spi100k->ick);
 311         clk_prepare_enable(spi100k->fck);
 312
 313         return 0;
 314 }
 315
 316 static int omap1_spi100k_transfer_one_message(struct spi_master *master,
 317                                               struct spi_message *m)
 318 {
 319         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 320         struct spi_device *spi = m->spi;
 321         struct spi_transfer *t = NULL;
 322         int cs_active = 0;
 323         int par_override = 0;
 324         int status = 0;
 325
 326         list_for_each_entry(t, &m->transfers, transfer_list) {
 327                 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 328                         status = -EINVAL;
 329                         break;
 330                 }
 331                 if (par_override || t->speed_hz || t->bits_per_word) {
 332                         par_override = 1;
 333                         status = omap1_spi100k_setup_transfer(spi, t);
 334                         if (status < 0)
 335                                 break;
 336                         if (!t->speed_hz && !t->bits_per_word)
 337                                 par_override = 0;
 338                 }
 339
 340                 if (!cs_active) {
 341                         omap1_spi100k_force_cs(spi100k, 1);
 342                         cs_active = 1;
 343                 }
 344
 345                 if (t->len) {
 346                         unsigned count;
 347
 348                         count = omap1_spi100k_txrx_pio(spi, t);
 349                         m->actual_length += count;
 350
 351                         if (count != t->len) {
 352                                 status = -EIO;
 353                                 break;
 354                         }
 355                 }
 356
 357                 if (t->delay_usecs)
 358                         udelay(t->delay_usecs);
 359
 360                 /* ignore the "leave it on after last xfer" hint */
 361
 362                 if (t->cs_change) {
 363                         omap1_spi100k_force_cs(spi100k, 0);
 364                         cs_active = 0;
 365                 }
 366         }
 367
 368         /* Restore defaults if they were overriden */
 369         if (par_override) {
 370                 par_override = 0;
 371                 status = omap1_spi100k_setup_transfer(spi, NULL);
 372         }
 373
 374         if (cs_active)
 375                 omap1_spi100k_force_cs(spi100k, 0);
 376
 377         m->status = status;
 378
 379         spi_finalize_current_message(master);
 380
 381         return status;
 382 }
 383
 384 static int omap1_spi100k_unprepare_hardware(struct spi_master *master)
 385 {
 386         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 387
 388         clk_disable_unprepare(spi100k->ick);
 389         clk_disable_unprepare(spi100k->fck);
 390
 391         return 0;
 392 }
 393
 394 static int omap1_spi100k_probe(struct platform_device *pdev)
 395 {
 396         struct spi_master       *master;
 397         struct omap1_spi100k    *spi100k;
 398         int                     status = 0;
 399
 400         if (!pdev->id)
 401                 return -EINVAL;
 402
 403         master = spi_alloc_master(&pdev->dev, sizeof(*spi100k));
 404         if (master == NULL) {
 405                 dev_dbg(&pdev->dev, "master allocation failed\n");
 406                 return -ENOMEM;
 407         }
 408
 409         if (pdev->id != -1)
 410                 master->bus_num = pdev->id;
 411
 412         master->setup = omap1_spi100k_setup;
 413         master->transfer_one_message = omap1_spi100k_transfer_one_message;
 414         master->prepare_transfer_hardware = omap1_spi100k_prepare_hardware;
 415         master->unprepare_transfer_hardware = omap1_spi100k_unprepare_hardware;
 416         master->cleanup = NULL;
 417         master->num_chipselect = 2;
 418         master->mode_bits = MODEBITS;
 419         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 420         master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16);
 421         master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ;
 422
 423         spi100k = spi_master_get_devdata(master);
 424
 425         /*
 426          * The memory region base address is taken as the platform_data.
 427          * You should allocate this with ioremap() before initializing
 428          * the SPI.
 429          */
 430         spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev);
 431
 432         spi100k->ick = devm_clk_get(&pdev->dev, "ick");
 433         if (IS_ERR(spi100k->ick)) {
 434                 dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
 435                 status = PTR_ERR(spi100k->ick);
 436                 goto err;
 437         }
 438
 439         spi100k->fck = devm_clk_get(&pdev->dev, "fck");
 440         if (IS_ERR(spi100k->fck)) {
 441                 dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
 442                 status = PTR_ERR(spi100k->fck);
 443                 goto err;
 444         }
 445
 446         status = devm_spi_register_master(&pdev->dev, master);
 447         if (status < 0)
 448                 goto err;
 449
 450         return status;
 451
 452 err:
 453         spi_master_put(master);
 454         return status;
 455 }
 456
 457 static struct platform_driver omap1_spi100k_driver = {
 458         .driver = {
 459                 .name           = "omap1_spi100k",
 460                 .owner          = THIS_MODULE,
 461         },
 462         .probe          = omap1_spi100k_probe,
 463 };
 464
 465 module_platform_driver(omap1_spi100k_driver);
 466
 467 MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
 468 MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
 469 MODULE_LICENSE("GPL");