drivers/spi/spi-bcm63xx.c

   1 /*
   2  * Broadcom BCM63xx SPI controller support
   3  *
   4  * Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
   5  * Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the
  19  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/init.h>
  24 #include <linux/clk.h>
  25 #include <linux/io.h>
  26 #include <linux/module.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/delay.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/completion.h>
  32 #include <linux/err.h>
  33 #include <linux/workqueue.h>
  34 #include <linux/pm_runtime.h>
  35
  36 #include <bcm63xx_dev_spi.h>
  37
  38 #define PFX             KBUILD_MODNAME
  39
  40 #define BCM63XX_SPI_MAX_PREPEND         15
  41
  42 struct bcm63xx_spi {
  43         struct completion       done;
  44
  45         void __iomem            *regs;
  46         int                     irq;
  47
  48         /* Platform data */
  49         unsigned                fifo_size;
  50         unsigned int            msg_type_shift;
  51         unsigned int            msg_ctl_width;
  52
  53         /* data iomem */
  54         u8 __iomem              *tx_io;
  55         const u8 __iomem        *rx_io;
  56
  57         struct clk              *clk;
  58         struct platform_device  *pdev;
  59 };
  60
  61 static inline u8 bcm_spi_readb(struct bcm63xx_spi *bs,
  62                                 unsigned int offset)
  63 {
  64         return bcm_readb(bs->regs + bcm63xx_spireg(offset));
  65 }
  66
  67 static inline u16 bcm_spi_readw(struct bcm63xx_spi *bs,
  68                                 unsigned int offset)
  69 {
  70         return bcm_readw(bs->regs + bcm63xx_spireg(offset));
  71 }
  72
  73 static inline void bcm_spi_writeb(struct bcm63xx_spi *bs,
  74                                   u8 value, unsigned int offset)
  75 {
  76         bcm_writeb(value, bs->regs + bcm63xx_spireg(offset));
  77 }
  78
  79 static inline void bcm_spi_writew(struct bcm63xx_spi *bs,
  80                                   u16 value, unsigned int offset)
  81 {
  82         bcm_writew(value, bs->regs + bcm63xx_spireg(offset));
  83 }
  84
  85 static const unsigned bcm63xx_spi_freq_table[SPI_CLK_MASK][2] = {
  86         { 20000000, SPI_CLK_20MHZ },
  87         { 12500000, SPI_CLK_12_50MHZ },
  88         {  6250000, SPI_CLK_6_250MHZ },
  89         {  3125000, SPI_CLK_3_125MHZ },
  90         {  1563000, SPI_CLK_1_563MHZ },
  91         {   781000, SPI_CLK_0_781MHZ },
  92         {   391000, SPI_CLK_0_391MHZ }
  93 };
  94
  95 static void bcm63xx_spi_setup_transfer(struct spi_device *spi,
  96                                       struct spi_transfer *t)
  97 {
  98         struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
  99         u8 clk_cfg, reg;
 100         int i;
 101
 102         /* Find the closest clock configuration */
 103         for (i = 0; i < SPI_CLK_MASK; i++) {
 104                 if (t->speed_hz >= bcm63xx_spi_freq_table[i][0]) {
 105                         clk_cfg = bcm63xx_spi_freq_table[i][1];
 106                         break;
 107                 }
 108         }
 109
 110         /* No matching configuration found, default to lowest */
 111         if (i == SPI_CLK_MASK)
 112                 clk_cfg = SPI_CLK_0_391MHZ;
 113
 114         /* clear existing clock configuration bits of the register */
 115         reg = bcm_spi_readb(bs, SPI_CLK_CFG);
 116         reg &= ~SPI_CLK_MASK;
 117         reg |= clk_cfg;
 118
 119         bcm_spi_writeb(bs, reg, SPI_CLK_CFG);
 120         dev_dbg(&spi->dev, "Setting clock register to %02x (hz %d)\n",
 121                 clk_cfg, t->speed_hz);
 122 }
 123
 124 /* the spi->mode bits understood by this driver: */
 125 #define MODEBITS (SPI_CPOL | SPI_CPHA)
 126
 127 static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *first,
 128                                 unsigned int num_transfers)
 129 {
 130         struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
 131         u16 msg_ctl;
 132         u16 cmd;
 133         u8 rx_tail;
 134         unsigned int i, timeout = 0, prepend_len = 0, len = 0;
 135         struct spi_transfer *t = first;
 136         bool do_rx = false;
 137         bool do_tx = false;
 138
 139         /* Disable the CMD_DONE interrupt */
 140         bcm_spi_writeb(bs, 0, SPI_INT_MASK);
 141
 142         dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
 143                 t->tx_buf, t->rx_buf, t->len);
 144
 145         if (num_transfers > 1 && t->tx_buf && t->len <= BCM63XX_SPI_MAX_PREPEND)
 146                 prepend_len = t->len;
 147
 148         /* prepare the buffer */
 149         for (i = 0; i < num_transfers; i++) {
 150                 if (t->tx_buf) {
 151                         do_tx = true;
 152                         memcpy_toio(bs->tx_io + len, t->tx_buf, t->len);
 153
 154                         /* don't prepend more than one tx */
 155                         if (t != first)
 156                                 prepend_len = 0;
 157                 }
 158
 159                 if (t->rx_buf) {
 160                         do_rx = true;
 161                         /* prepend is half-duplex write only */
 162                         if (t == first)
 163                                 prepend_len = 0;
 164                 }
 165
 166                 len += t->len;
 167
 168                 t = list_entry(t->transfer_list.next, struct spi_transfer,
 169                                transfer_list);
 170         }
 171
 172         len -= prepend_len;
 173
 174         init_completion(&bs->done);
 175
 176         /* Fill in the Message control register */
 177         msg_ctl = (len << SPI_BYTE_CNT_SHIFT);
 178
 179         if (do_rx && do_tx && prepend_len == 0)
 180                 msg_ctl |= (SPI_FD_RW << bs->msg_type_shift);
 181         else if (do_rx)
 182                 msg_ctl |= (SPI_HD_R << bs->msg_type_shift);
 183         else if (do_tx)
 184                 msg_ctl |= (SPI_HD_W << bs->msg_type_shift);
 185
 186         switch (bs->msg_ctl_width) {
 187         case 8:
 188                 bcm_spi_writeb(bs, msg_ctl, SPI_MSG_CTL);
 189                 break;
 190         case 16:
 191                 bcm_spi_writew(bs, msg_ctl, SPI_MSG_CTL);
 192                 break;
 193         }
 194
 195         /* Issue the transfer */
 196         cmd = SPI_CMD_START_IMMEDIATE;
 197         cmd |= (prepend_len << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
 198         cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
 199         bcm_spi_writew(bs, cmd, SPI_CMD);
 200
 201         /* Enable the CMD_DONE interrupt */
 202         bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
 203
 204         timeout = wait_for_completion_timeout(&bs->done, HZ);
 205         if (!timeout)
 206                 return -ETIMEDOUT;
 207
 208         /* read out all data */
 209         rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
 210
 211         if (do_rx && rx_tail != len)
 212                 return -EIO;
 213
 214         if (!rx_tail)
 215                 return 0;
 216
 217         len = 0;
 218         t = first;
 219         /* Read out all the data */
 220         for (i = 0; i < num_transfers; i++) {
 221                 if (t->rx_buf)
 222                         memcpy_fromio(t->rx_buf, bs->rx_io + len, t->len);
 223
 224                 if (t != first || prepend_len == 0)
 225                         len += t->len;
 226
 227                 t = list_entry(t->transfer_list.next, struct spi_transfer,
 228                                transfer_list);
 229         }
 230
 231         return 0;
 232 }
 233
 234 static int bcm63xx_spi_transfer_one(struct spi_master *master,
 235                                         struct spi_message *m)
 236 {
 237         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 238         struct spi_transfer *t, *first = NULL;
 239         struct spi_device *spi = m->spi;
 240         int status = 0;
 241         unsigned int n_transfers = 0, total_len = 0;
 242         bool can_use_prepend = false;
 243
 244         /*
 245          * This SPI controller does not support keeping CS active after a
 246          * transfer.
 247          * Work around this by merging as many transfers we can into one big
 248          * full-duplex transfers.
 249          */
 250         list_for_each_entry(t, &m->transfers, transfer_list) {
 251                 if (!first)
 252                         first = t;
 253
 254                 n_transfers++;
 255                 total_len += t->len;
 256
 257                 if (n_transfers == 2 && !first->rx_buf && !t->tx_buf &&
 258                     first->len <= BCM63XX_SPI_MAX_PREPEND)
 259                         can_use_prepend = true;
 260                 else if (can_use_prepend && t->tx_buf)
 261                         can_use_prepend = false;
 262
 263                 /* we can only transfer one fifo worth of data */
 264                 if ((can_use_prepend &&
 265                      total_len > (bs->fifo_size + BCM63XX_SPI_MAX_PREPEND)) ||
 266                     (!can_use_prepend && total_len > bs->fifo_size)) {
 267                         dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
 268                                 total_len, bs->fifo_size);
 269                         status = -EINVAL;
 270                         goto exit;
 271                 }
 272
 273                 /* all combined transfers have to have the same speed */
 274                 if (t->speed_hz != first->speed_hz) {
 275                         dev_err(&spi->dev, "unable to change speed between transfers\n");
 276                         status = -EINVAL;
 277                         goto exit;
 278                 }
 279
 280                 /* CS will be deasserted directly after transfer */
 281                 if (t->delay_usecs) {
 282                         dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
 283                         status = -EINVAL;
 284                         goto exit;
 285                 }
 286
 287                 if (t->cs_change ||
 288                     list_is_last(&t->transfer_list, &m->transfers)) {
 289                         /* configure adapter for a new transfer */
 290                         bcm63xx_spi_setup_transfer(spi, first);
 291
 292                         /* send the data */
 293                         status = bcm63xx_txrx_bufs(spi, first, n_transfers);
 294                         if (status)
 295                                 goto exit;
 296
 297                         m->actual_length += total_len;
 298
 299                         first = NULL;
 300                         n_transfers = 0;
 301                         total_len = 0;
 302                         can_use_prepend = false;
 303                 }
 304         }
 305 exit:
 306         m->status = status;
 307         spi_finalize_current_message(master);
 308
 309         return 0;
 310 }
 311
 312 /* This driver supports single master mode only. Hence
 313  * CMD_DONE is the only interrupt we care about
 314  */
 315 static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
 316 {
 317         struct spi_master *master = (struct spi_master *)dev_id;
 318         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 319         u8 intr;
 320
 321         /* Read interupts and clear them immediately */
 322         intr = bcm_spi_readb(bs, SPI_INT_STATUS);
 323         bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
 324         bcm_spi_writeb(bs, 0, SPI_INT_MASK);
 325
 326         /* A transfer completed */
 327         if (intr & SPI_INTR_CMD_DONE)
 328                 complete(&bs->done);
 329
 330         return IRQ_HANDLED;
 331 }
 332
 333
 334 static int bcm63xx_spi_probe(struct platform_device *pdev)
 335 {
 336         struct resource *r;
 337         struct device *dev = &pdev->dev;
 338         struct bcm63xx_spi_pdata *pdata = dev_get_platdata(&pdev->dev);
 339         int irq;
 340         struct spi_master *master;
 341         struct clk *clk;
 342         struct bcm63xx_spi *bs;
 343         int ret;
 344
 345         irq = platform_get_irq(pdev, 0);
 346         if (irq < 0) {
 347                 dev_err(dev, "no irq\n");
 348                 ret = -ENXIO;
 349                 goto out;
 350         }
 351
 352         clk = clk_get(dev, "spi");
 353         if (IS_ERR(clk)) {
 354                 dev_err(dev, "no clock for device\n");
 355                 ret = PTR_ERR(clk);
 356                 goto out;
 357         }
 358
 359         master = spi_alloc_master(dev, sizeof(*bs));
 360         if (!master) {
 361                 dev_err(dev, "out of memory\n");
 362                 ret = -ENOMEM;
 363                 goto out_clk;
 364         }
 365
 366         bs = spi_master_get_devdata(master);
 367
 368         platform_set_drvdata(pdev, master);
 369         bs->pdev = pdev;
 370
 371         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 372         bs->regs = devm_ioremap_resource(&pdev->dev, r);
 373         if (IS_ERR(bs->regs)) {
 374                 ret = PTR_ERR(bs->regs);
 375                 goto out_err;
 376         }
 377
 378         bs->irq = irq;
 379         bs->clk = clk;
 380         bs->fifo_size = pdata->fifo_size;
 381
 382         ret = devm_request_irq(&pdev->dev, irq, bcm63xx_spi_interrupt, 0,
 383                                                         pdev->name, master);
 384         if (ret) {
 385                 dev_err(dev, "unable to request irq\n");
 386                 goto out_err;
 387         }
 388
 389         master->bus_num = pdata->bus_num;
 390         master->num_chipselect = pdata->num_chipselect;
 391         master->transfer_one_message = bcm63xx_spi_transfer_one;
 392         master->mode_bits = MODEBITS;
 393         master->bits_per_word_mask = SPI_BPW_MASK(8);
 394         master->auto_runtime_pm = true;
 395         bs->msg_type_shift = pdata->msg_type_shift;
 396         bs->msg_ctl_width = pdata->msg_ctl_width;
 397         bs->tx_io = (u8 *)(bs->regs + bcm63xx_spireg(SPI_MSG_DATA));
 398         bs->rx_io = (const u8 *)(bs->regs + bcm63xx_spireg(SPI_RX_DATA));
 399
 400         switch (bs->msg_ctl_width) {
 401         case 8:
 402         case 16:
 403                 break;
 404         default:
 405                 dev_err(dev, "unsupported MSG_CTL width: %d\n",
 406                          bs->msg_ctl_width);
 407                 goto out_err;
 408         }
 409
 410         /* Initialize hardware */
 411         clk_prepare_enable(bs->clk);
 412         bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
 413
 414         /* register and we are done */
 415         ret = devm_spi_register_master(dev, master);
 416         if (ret) {
 417                 dev_err(dev, "spi register failed\n");
 418                 goto out_clk_disable;
 419         }
 420
 421         dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d)\n",
 422                  r->start, irq, bs->fifo_size);
 423
 424         return 0;
 425
 426 out_clk_disable:
 427         clk_disable_unprepare(clk);
 428 out_err:
 429         spi_master_put(master);
 430 out_clk:
 431         clk_put(clk);
 432 out:
 433         return ret;
 434 }
 435
 436 static int bcm63xx_spi_remove(struct platform_device *pdev)
 437 {
 438         struct spi_master *master = platform_get_drvdata(pdev);
 439         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 440
 441         /* reset spi block */
 442         bcm_spi_writeb(bs, 0, SPI_INT_MASK);
 443
 444         /* HW shutdown */
 445         clk_disable_unprepare(bs->clk);
 446         clk_put(bs->clk);
 447
 448         return 0;
 449 }
 450
 451 #ifdef CONFIG_PM
 452 static int bcm63xx_spi_suspend(struct device *dev)
 453 {
 454         struct spi_master *master = dev_get_drvdata(dev);
 455         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 456
 457         spi_master_suspend(master);
 458
 459         clk_disable_unprepare(bs->clk);
 460
 461         return 0;
 462 }
 463
 464 static int bcm63xx_spi_resume(struct device *dev)
 465 {
 466         struct spi_master *master = dev_get_drvdata(dev);
 467         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 468
 469         clk_prepare_enable(bs->clk);
 470
 471         spi_master_resume(master);
 472
 473         return 0;
 474 }
 475
 476 static const struct dev_pm_ops bcm63xx_spi_pm_ops = {
 477         .suspend        = bcm63xx_spi_suspend,
 478         .resume         = bcm63xx_spi_resume,
 479 };
 480
 481 #define BCM63XX_SPI_PM_OPS      (&bcm63xx_spi_pm_ops)
 482 #else
 483 #define BCM63XX_SPI_PM_OPS      NULL
 484 #endif
 485
 486 static struct platform_driver bcm63xx_spi_driver = {
 487         .driver = {
 488                 .name   = "bcm63xx-spi",
 489                 .owner  = THIS_MODULE,
 490                 .pm     = BCM63XX_SPI_PM_OPS,
 491         },
 492         .probe          = bcm63xx_spi_probe,
 493         .remove         = bcm63xx_spi_remove,
 494 };
 495
 496 module_platform_driver(bcm63xx_spi_driver);
 497
 498 MODULE_ALIAS("platform:bcm63xx_spi");
 499 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 500 MODULE_AUTHOR("Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>");
 501 MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
 502 MODULE_LICENSE("GPL");