drivers/spi/spi_txx9.c

   1 /*
   2  * spi_txx9.c - TXx9 SPI controller driver.
   3  *
   4  * Based on linux/arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c
   5  * Copyright (C) 2000-2001 Toshiba Corporation
   6  *
   7  * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
   8  * terms of the GNU General Public License version 2. This program is
   9  * licensed "as is" without any warranty of any kind, whether express
  10  * or implied.
  11  *
  12  * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
  13  *
  14  * Convert to generic SPI framework - Atsushi Nemoto (anemo@mba.ocn.ne.jp)
  15  */
  16 #include <linux/init.h>
  17 #include <linux/delay.h>
  18 #include <linux/errno.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/sched.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/err.h>
  26 #include <linux/clk.h>
  27 #include <linux/io.h>
  28 #include <asm/gpio.h>
  29
  30
  31 #define SPI_FIFO_SIZE 4
  32 #define SPI_MAX_DIVIDER 0xff    /* Max. value for SPCR1.SER */
  33 #define SPI_MIN_DIVIDER 1       /* Min. value for SPCR1.SER */
  34
  35 #define TXx9_SPMCR              0x00
  36 #define TXx9_SPCR0              0x04
  37 #define TXx9_SPCR1              0x08
  38 #define TXx9_SPFS               0x0c
  39 #define TXx9_SPSR               0x14
  40 #define TXx9_SPDR               0x18
  41
  42 /* SPMCR : SPI Master Control */
  43 #define TXx9_SPMCR_OPMODE       0xc0
  44 #define TXx9_SPMCR_CONFIG       0x40
  45 #define TXx9_SPMCR_ACTIVE       0x80
  46 #define TXx9_SPMCR_SPSTP        0x02
  47 #define TXx9_SPMCR_BCLR         0x01
  48
  49 /* SPCR0 : SPI Control 0 */
  50 #define TXx9_SPCR0_TXIFL_MASK   0xc000
  51 #define TXx9_SPCR0_RXIFL_MASK   0x3000
  52 #define TXx9_SPCR0_SIDIE        0x0800
  53 #define TXx9_SPCR0_SOEIE        0x0400
  54 #define TXx9_SPCR0_RBSIE        0x0200
  55 #define TXx9_SPCR0_TBSIE        0x0100
  56 #define TXx9_SPCR0_IFSPSE       0x0010
  57 #define TXx9_SPCR0_SBOS         0x0004
  58 #define TXx9_SPCR0_SPHA         0x0002
  59 #define TXx9_SPCR0_SPOL         0x0001
  60
  61 /* SPSR : SPI Status */
  62 #define TXx9_SPSR_TBSI          0x8000
  63 #define TXx9_SPSR_RBSI          0x4000
  64 #define TXx9_SPSR_TBS_MASK      0x3800
  65 #define TXx9_SPSR_RBS_MASK      0x0700
  66 #define TXx9_SPSR_SPOE          0x0080
  67 #define TXx9_SPSR_IFSD          0x0008
  68 #define TXx9_SPSR_SIDLE         0x0004
  69 #define TXx9_SPSR_STRDY         0x0002
  70 #define TXx9_SPSR_SRRDY         0x0001
  71
  72
  73 struct txx9spi {
  74         struct workqueue_struct *workqueue;
  75         struct work_struct work;
  76         spinlock_t lock;        /* protect 'queue' */
  77         struct list_head queue;
  78         wait_queue_head_t waitq;
  79         void __iomem *membase;
  80         int baseclk;
  81         struct clk *clk;
  82         u32 max_speed_hz, min_speed_hz;
  83         int last_chipselect;
  84         int last_chipselect_val;
  85 };
  86
  87 static u32 txx9spi_rd(struct txx9spi *c, int reg)
  88 {
  89         return __raw_readl(c->membase + reg);
  90 }
  91 static void txx9spi_wr(struct txx9spi *c, u32 val, int reg)
  92 {
  93         __raw_writel(val, c->membase + reg);
  94 }
  95
  96 static void txx9spi_cs_func(struct spi_device *spi, struct txx9spi *c,
  97                 int on, unsigned int cs_delay)
  98 {
  99         int val = (spi->mode & SPI_CS_HIGH) ? on : !on;
 100         if (on) {
 101                 /* deselect the chip with cs_change hint in last transfer */
 102                 if (c->last_chipselect >= 0)
 103                         gpio_set_value(c->last_chipselect,
 104                                         !c->last_chipselect_val);
 105                 c->last_chipselect = spi->chip_select;
 106                 c->last_chipselect_val = val;
 107         } else {
 108                 c->last_chipselect = -1;
 109                 ndelay(cs_delay);       /* CS Hold Time */
 110         }
 111         gpio_set_value(spi->chip_select, val);
 112         ndelay(cs_delay);       /* CS Setup Time / CS Recovery Time */
 113 }
 114
 115 static int txx9spi_setup(struct spi_device *spi)
 116 {
 117         struct txx9spi *c = spi_master_get_devdata(spi->master);
 118         u8 bits_per_word;
 119
 120         if (!spi->max_speed_hz
 121                         || spi->max_speed_hz > c->max_speed_hz
 122                         || spi->max_speed_hz < c->min_speed_hz)
 123                 return -EINVAL;
 124
 125         bits_per_word = spi->bits_per_word;
 126         if (bits_per_word != 8 && bits_per_word != 16)
 127                 return -EINVAL;
 128
 129         if (gpio_direction_output(spi->chip_select,
 130                         !(spi->mode & SPI_CS_HIGH))) {
 131                 dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n");
 132                 return -EINVAL;
 133         }
 134
 135         /* deselect chip */
 136         spin_lock(&c->lock);
 137         txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz);
 138         spin_unlock(&c->lock);
 139
 140         return 0;
 141 }
 142
 143 static irqreturn_t txx9spi_interrupt(int irq, void *dev_id)
 144 {
 145         struct txx9spi *c = dev_id;
 146
 147         /* disable rx intr */
 148         txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE,
 149                         TXx9_SPCR0);
 150         wake_up(&c->waitq);
 151         return IRQ_HANDLED;
 152 }
 153
 154 static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
 155 {
 156         struct spi_device *spi = m->spi;
 157         struct spi_transfer *t;
 158         unsigned int cs_delay;
 159         unsigned int cs_change = 1;
 160         int status = 0;
 161         u32 mcr;
 162         u32 prev_speed_hz = 0;
 163         u8 prev_bits_per_word = 0;
 164
 165         /* CS setup/hold/recovery time in nsec */
 166         cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz;
 167
 168         mcr = txx9spi_rd(c, TXx9_SPMCR);
 169         if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) {
 170                 dev_err(&spi->dev, "Bad mode.\n");
 171                 status = -EIO;
 172                 goto exit;
 173         }
 174         mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
 175
 176         /* enter config mode */
 177         txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
 178         txx9spi_wr(c, TXx9_SPCR0_SBOS
 179                         | ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0)
 180                         | ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0)
 181                         | 0x08,
 182                         TXx9_SPCR0);
 183
 184         list_for_each_entry (t, &m->transfers, transfer_list) {
 185                 const void *txbuf = t->tx_buf;
 186                 void *rxbuf = t->rx_buf;
 187                 u32 data;
 188                 unsigned int len = t->len;
 189                 unsigned int wsize;
 190                 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
 191                 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
 192
 193                 bits_per_word = bits_per_word ? : 8;
 194                 wsize = bits_per_word >> 3; /* in bytes */
 195
 196                 if (prev_speed_hz != speed_hz
 197                                 || prev_bits_per_word != bits_per_word) {
 198                         int n = DIV_ROUND_UP(c->baseclk, speed_hz) - 1;
 199                         n = clamp(n, SPI_MIN_DIVIDER, SPI_MAX_DIVIDER);
 200                         /* enter config mode */
 201                         txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR,
 202                                         TXx9_SPMCR);
 203                         txx9spi_wr(c, (n << 8) | bits_per_word, TXx9_SPCR1);
 204                         /* enter active mode */
 205                         txx9spi_wr(c, mcr | TXx9_SPMCR_ACTIVE, TXx9_SPMCR);
 206
 207                         prev_speed_hz = speed_hz;
 208                         prev_bits_per_word = bits_per_word;
 209                 }
 210
 211                 if (cs_change)
 212                         txx9spi_cs_func(spi, c, 1, cs_delay);
 213                 cs_change = t->cs_change;
 214                 while (len) {
 215                         unsigned int count = SPI_FIFO_SIZE;
 216                         int i;
 217                         u32 cr0;
 218
 219                         if (len < count * wsize)
 220                                 count = len / wsize;
 221                         /* now tx must be idle... */
 222                         while (!(txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_SIDLE))
 223                                 cpu_relax();
 224                         cr0 = txx9spi_rd(c, TXx9_SPCR0);
 225                         cr0 &= ~TXx9_SPCR0_RXIFL_MASK;
 226                         cr0 |= (count - 1) << 12;
 227                         /* enable rx intr */
 228                         cr0 |= TXx9_SPCR0_RBSIE;
 229                         txx9spi_wr(c, cr0, TXx9_SPCR0);
 230                         /* send */
 231                         for (i = 0; i < count; i++) {
 232                                 if (txbuf) {
 233                                         data = (wsize == 1)
 234                                                 ? *(const u8 *)txbuf
 235                                                 : *(const u16 *)txbuf;
 236                                         txx9spi_wr(c, data, TXx9_SPDR);
 237                                         txbuf += wsize;
 238                                 } else
 239                                         txx9spi_wr(c, 0, TXx9_SPDR);
 240                         }
 241                         /* wait all rx data */
 242                         wait_event(c->waitq,
 243                                 txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_RBSI);
 244                         /* receive */
 245                         for (i = 0; i < count; i++) {
 246                                 data = txx9spi_rd(c, TXx9_SPDR);
 247                                 if (rxbuf) {
 248                                         if (wsize == 1)
 249                                                 *(u8 *)rxbuf = data;
 250                                         else
 251                                                 *(u16 *)rxbuf = data;
 252                                         rxbuf += wsize;
 253                                 }
 254                         }
 255                         len -= count * wsize;
 256                 }
 257                 m->actual_length += t->len;
 258                 if (t->delay_usecs)
 259                         udelay(t->delay_usecs);
 260
 261                 if (!cs_change)
 262                         continue;
 263                 if (t->transfer_list.next == &m->transfers)
 264                         break;
 265                 /* sometimes a short mid-message deselect of the chip
 266                  * may be needed to terminate a mode or command
 267                  */
 268                 txx9spi_cs_func(spi, c, 0, cs_delay);
 269         }
 270
 271 exit:
 272         m->status = status;
 273         m->complete(m->context);
 274
 275         /* normally deactivate chipselect ... unless no error and
 276          * cs_change has hinted that the next message will probably
 277          * be for this chip too.
 278          */
 279         if (!(status == 0 && cs_change))
 280                 txx9spi_cs_func(spi, c, 0, cs_delay);
 281
 282         /* enter config mode */
 283         txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
 284 }
 285
 286 static void txx9spi_work(struct work_struct *work)
 287 {
 288         struct txx9spi *c = container_of(work, struct txx9spi, work);
 289         unsigned long flags;
 290
 291         spin_lock_irqsave(&c->lock, flags);
 292         while (!list_empty(&c->queue)) {
 293                 struct spi_message *m;
 294
 295                 m = container_of(c->queue.next, struct spi_message, queue);
 296                 list_del_init(&m->queue);
 297                 spin_unlock_irqrestore(&c->lock, flags);
 298
 299                 txx9spi_work_one(c, m);
 300
 301                 spin_lock_irqsave(&c->lock, flags);
 302         }
 303         spin_unlock_irqrestore(&c->lock, flags);
 304 }
 305
 306 static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m)
 307 {
 308         struct spi_master *master = spi->master;
 309         struct txx9spi *c = spi_master_get_devdata(master);
 310         struct spi_transfer *t;
 311         unsigned long flags;
 312
 313         m->actual_length = 0;
 314
 315         /* check each transfer's parameters */
 316         list_for_each_entry (t, &m->transfers, transfer_list) {
 317                 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
 318                 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
 319
 320                 bits_per_word = bits_per_word ? : 8;
 321                 if (!t->tx_buf && !t->rx_buf && t->len)
 322                         return -EINVAL;
 323                 if (bits_per_word != 8 && bits_per_word != 16)
 324                         return -EINVAL;
 325                 if (t->len & ((bits_per_word >> 3) - 1))
 326                         return -EINVAL;
 327                 if (speed_hz < c->min_speed_hz || speed_hz > c->max_speed_hz)
 328                         return -EINVAL;
 329         }
 330
 331         spin_lock_irqsave(&c->lock, flags);
 332         list_add_tail(&m->queue, &c->queue);
 333         queue_work(c->workqueue, &c->work);
 334         spin_unlock_irqrestore(&c->lock, flags);
 335
 336         return 0;
 337 }
 338
 339 static int __init txx9spi_probe(struct platform_device *dev)
 340 {
 341         struct spi_master *master;
 342         struct txx9spi *c;
 343         struct resource *res;
 344         int ret = -ENODEV;
 345         u32 mcr;
 346         int irq;
 347
 348         master = spi_alloc_master(&dev->dev, sizeof(*c));
 349         if (!master)
 350                 return ret;
 351         c = spi_master_get_devdata(master);
 352         platform_set_drvdata(dev, master);
 353
 354         INIT_WORK(&c->work, txx9spi_work);
 355         spin_lock_init(&c->lock);
 356         INIT_LIST_HEAD(&c->queue);
 357         init_waitqueue_head(&c->waitq);
 358
 359         c->clk = clk_get(&dev->dev, "spi-baseclk");
 360         if (IS_ERR(c->clk)) {
 361                 ret = PTR_ERR(c->clk);
 362                 c->clk = NULL;
 363                 goto exit;
 364         }
 365         ret = clk_enable(c->clk);
 366         if (ret) {
 367                 clk_put(c->clk);
 368                 c->clk = NULL;
 369                 goto exit;
 370         }
 371         c->baseclk = clk_get_rate(c->clk);
 372         c->min_speed_hz = DIV_ROUND_UP(c->baseclk, SPI_MAX_DIVIDER + 1);
 373         c->max_speed_hz = c->baseclk / (SPI_MIN_DIVIDER + 1);
 374
 375         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 376         if (!res)
 377                 goto exit_busy;
 378         if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
 379                                      "spi_txx9"))
 380                 goto exit_busy;
 381         c->membase = devm_ioremap(&dev->dev, res->start, resource_size(res));
 382         if (!c->membase)
 383                 goto exit_busy;
 384
 385         /* enter config mode */
 386         mcr = txx9spi_rd(c, TXx9_SPMCR);
 387         mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
 388         txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
 389
 390         irq = platform_get_irq(dev, 0);
 391         if (irq < 0)
 392                 goto exit_busy;
 393         ret = devm_request_irq(&dev->dev, irq, txx9spi_interrupt, 0,
 394                                "spi_txx9", c);
 395         if (ret)
 396                 goto exit;
 397
 398         c->workqueue = create_singlethread_workqueue(
 399                                 dev_name(master->dev.parent));
 400         if (!c->workqueue)
 401                 goto exit_busy;
 402         c->last_chipselect = -1;
 403
 404         dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n",
 405                  (unsigned long long)res->start, irq,
 406                  (c->baseclk + 500000) / 1000000);
 407
 408         /* the spi->mode bits understood by this driver: */
 409         master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA;
 410
 411         master->bus_num = dev->id;
 412         master->setup = txx9spi_setup;
 413         master->transfer = txx9spi_transfer;
 414         master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */
 415
 416         ret = spi_register_master(master);
 417         if (ret)
 418                 goto exit;
 419         return 0;
 420 exit_busy:
 421         ret = -EBUSY;
 422 exit:
 423         if (c->workqueue)
 424                 destroy_workqueue(c->workqueue);
 425         if (c->clk) {
 426                 clk_disable(c->clk);
 427                 clk_put(c->clk);
 428         }
 429         platform_set_drvdata(dev, NULL);
 430         spi_master_put(master);
 431         return ret;
 432 }
 433
 434 static int __exit txx9spi_remove(struct platform_device *dev)
 435 {
 436         struct spi_master *master = spi_master_get(platform_get_drvdata(dev));
 437         struct txx9spi *c = spi_master_get_devdata(master);
 438
 439         spi_unregister_master(master);
 440         platform_set_drvdata(dev, NULL);
 441         destroy_workqueue(c->workqueue);
 442         clk_disable(c->clk);
 443         clk_put(c->clk);
 444         spi_master_put(master);
 445         return 0;
 446 }
 447
 448 /* work with hotplug and coldplug */
 449 MODULE_ALIAS("platform:spi_txx9");
 450
 451 static struct platform_driver txx9spi_driver = {
 452         .remove = __exit_p(txx9spi_remove),
 453         .driver = {
 454                 .name = "spi_txx9",
 455                 .owner = THIS_MODULE,
 456         },
 457 };
 458
 459 static int __init txx9spi_init(void)
 460 {
 461         return platform_driver_probe(&txx9spi_driver, txx9spi_probe);
 462 }
 463 subsys_initcall(txx9spi_init);
 464
 465 static void __exit txx9spi_exit(void)
 466 {
 467         platform_driver_unregister(&txx9spi_driver);
 468 }
 469 module_exit(txx9spi_exit);
 470
 471 MODULE_DESCRIPTION("TXx9 SPI Driver");
 472 MODULE_LICENSE("GPL");