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         init_completion(&bs->done);
 173
 174         /* Fill in the Message control register */
 175         msg_ctl = (len << SPI_BYTE_CNT_SHIFT);
 176
 177         if (do_rx && do_tx && prepend_len == 0)
 178                 msg_ctl |= (SPI_FD_RW << bs->msg_type_shift);
 179         else if (do_rx)
 180                 msg_ctl |= (SPI_HD_R << bs->msg_type_shift);
 181         else if (do_tx)
 182                 msg_ctl |= (SPI_HD_W << bs->msg_type_shift);
 183
 184         switch (bs->msg_ctl_width) {
 185         case 8:
 186                 bcm_spi_writeb(bs, msg_ctl, SPI_MSG_CTL);
 187                 break;
 188         case 16:
 189                 bcm_spi_writew(bs, msg_ctl, SPI_MSG_CTL);
 190                 break;
 191         }
 192
 193         /* Issue the transfer */
 194         cmd = SPI_CMD_START_IMMEDIATE;
 195         cmd |= (prepend_len << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
 196         cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
 197         bcm_spi_writew(bs, cmd, SPI_CMD);
 198
 199         /* Enable the CMD_DONE interrupt */
 200         bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
 201
 202         timeout = wait_for_completion_timeout(&bs->done, HZ);
 203         if (!timeout)
 204                 return -ETIMEDOUT;
 205
 206         if (!do_rx)
 207                 return 0;
 208
 209         len = 0;
 210         t = first;
 211         /* Read out all the data */
 212         for (i = 0; i < num_transfers; i++) {
 213                 if (t->rx_buf)
 214                         memcpy_fromio(t->rx_buf, bs->rx_io + len, t->len);
 215
 216                 if (t != first || prepend_len == 0)
 217                         len += t->len;
 218
 219                 t = list_entry(t->transfer_list.next, struct spi_transfer,
 220                                transfer_list);
 221         }
 222
 223         return 0;
 224 }
 225
 226 static int bcm63xx_spi_transfer_one(struct spi_master *master,
 227                                         struct spi_message *m)
 228 {
 229         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 230         struct spi_transfer *t, *first = NULL;
 231         struct spi_device *spi = m->spi;
 232         int status = 0;
 233         unsigned int n_transfers = 0, total_len = 0;
 234         bool can_use_prepend = false;
 235
 236         /*
 237          * This SPI controller does not support keeping CS active after a
 238          * transfer.
 239          * Work around this by merging as many transfers we can into one big
 240          * full-duplex transfers.
 241          */
 242         list_for_each_entry(t, &m->transfers, transfer_list) {
 243                 if (!first)
 244                         first = t;
 245
 246                 n_transfers++;
 247                 total_len += t->len;
 248
 249                 if (n_transfers == 2 && !first->rx_buf && !t->tx_buf &&
 250                     first->len <= BCM63XX_SPI_MAX_PREPEND)
 251                         can_use_prepend = true;
 252                 else if (can_use_prepend && t->tx_buf)
 253                         can_use_prepend = false;
 254
 255                 /* we can only transfer one fifo worth of data */
 256                 if ((can_use_prepend &&
 257                      total_len > (bs->fifo_size + BCM63XX_SPI_MAX_PREPEND)) ||
 258                     (!can_use_prepend && total_len > bs->fifo_size)) {
 259                         dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
 260                                 total_len, bs->fifo_size);
 261                         status = -EINVAL;
 262                         goto exit;
 263                 }
 264
 265                 /* all combined transfers have to have the same speed */
 266                 if (t->speed_hz != first->speed_hz) {
 267                         dev_err(&spi->dev, "unable to change speed between transfers\n");
 268                         status = -EINVAL;
 269                         goto exit;
 270                 }
 271
 272                 /* CS will be deasserted directly after transfer */
 273                 if (t->delay_usecs) {
 274                         dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
 275                         status = -EINVAL;
 276                         goto exit;
 277                 }
 278
 279                 if (t->cs_change ||
 280                     list_is_last(&t->transfer_list, &m->transfers)) {
 281                         /* configure adapter for a new transfer */
 282                         bcm63xx_spi_setup_transfer(spi, first);
 283
 284                         /* send the data */
 285                         status = bcm63xx_txrx_bufs(spi, first, n_transfers);
 286                         if (status)
 287                                 goto exit;
 288
 289                         m->actual_length += total_len;
 290
 291                         first = NULL;
 292                         n_transfers = 0;
 293                         total_len = 0;
 294                         can_use_prepend = false;
 295                 }
 296         }
 297 exit:
 298         m->status = status;
 299         spi_finalize_current_message(master);
 300
 301         return 0;
 302 }
 303
 304 /* This driver supports single master mode only. Hence
 305  * CMD_DONE is the only interrupt we care about
 306  */
 307 static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
 308 {
 309         struct spi_master *master = (struct spi_master *)dev_id;
 310         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 311         u8 intr;
 312
 313         /* Read interupts and clear them immediately */
 314         intr = bcm_spi_readb(bs, SPI_INT_STATUS);
 315         bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
 316         bcm_spi_writeb(bs, 0, SPI_INT_MASK);
 317
 318         /* A transfer completed */
 319         if (intr & SPI_INTR_CMD_DONE)
 320                 complete(&bs->done);
 321
 322         return IRQ_HANDLED;
 323 }
 324
 325
 326 static int bcm63xx_spi_probe(struct platform_device *pdev)
 327 {
 328         struct resource *r;
 329         struct device *dev = &pdev->dev;
 330         struct bcm63xx_spi_pdata *pdata = dev_get_platdata(&pdev->dev);
 331         int irq;
 332         struct spi_master *master;
 333         struct clk *clk;
 334         struct bcm63xx_spi *bs;
 335         int ret;
 336
 337         irq = platform_get_irq(pdev, 0);
 338         if (irq < 0) {
 339                 dev_err(dev, "no irq\n");
 340                 return -ENXIO;
 341         }
 342
 343         clk = devm_clk_get(dev, "spi");
 344         if (IS_ERR(clk)) {
 345                 dev_err(dev, "no clock for device\n");
 346                 return PTR_ERR(clk);
 347         }
 348
 349         master = spi_alloc_master(dev, sizeof(*bs));
 350         if (!master) {
 351                 dev_err(dev, "out of memory\n");
 352                 return -ENOMEM;
 353         }
 354
 355         bs = spi_master_get_devdata(master);
 356
 357         platform_set_drvdata(pdev, master);
 358         bs->pdev = pdev;
 359
 360         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 361         bs->regs = devm_ioremap_resource(&pdev->dev, r);
 362         if (IS_ERR(bs->regs)) {
 363                 ret = PTR_ERR(bs->regs);
 364                 goto out_err;
 365         }
 366
 367         bs->irq = irq;
 368         bs->clk = clk;
 369         bs->fifo_size = pdata->fifo_size;
 370
 371         ret = devm_request_irq(&pdev->dev, irq, bcm63xx_spi_interrupt, 0,
 372                                                         pdev->name, master);
 373         if (ret) {
 374                 dev_err(dev, "unable to request irq\n");
 375                 goto out_err;
 376         }
 377
 378         master->bus_num = pdata->bus_num;
 379         master->num_chipselect = pdata->num_chipselect;
 380         master->transfer_one_message = bcm63xx_spi_transfer_one;
 381         master->mode_bits = MODEBITS;
 382         master->bits_per_word_mask = SPI_BPW_MASK(8);
 383         master->auto_runtime_pm = true;
 384         bs->msg_type_shift = pdata->msg_type_shift;
 385         bs->msg_ctl_width = pdata->msg_ctl_width;
 386         bs->tx_io = (u8 *)(bs->regs + bcm63xx_spireg(SPI_MSG_DATA));
 387         bs->rx_io = (const u8 *)(bs->regs + bcm63xx_spireg(SPI_RX_DATA));
 388
 389         switch (bs->msg_ctl_width) {
 390         case 8:
 391         case 16:
 392                 break;
 393         default:
 394                 dev_err(dev, "unsupported MSG_CTL width: %d\n",
 395                          bs->msg_ctl_width);
 396                 goto out_err;
 397         }
 398
 399         /* Initialize hardware */
 400         ret = clk_prepare_enable(bs->clk);
 401         if (ret)
 402                 goto out_err;
 403
 404         bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
 405
 406         /* register and we are done */
 407         ret = devm_spi_register_master(dev, master);
 408         if (ret) {
 409                 dev_err(dev, "spi register failed\n");
 410                 goto out_clk_disable;
 411         }
 412
 413         dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d)\n",
 414                  r->start, irq, bs->fifo_size);
 415
 416         return 0;
 417
 418 out_clk_disable:
 419         clk_disable_unprepare(clk);
 420 out_err:
 421         spi_master_put(master);
 422         return ret;
 423 }
 424
 425 static int bcm63xx_spi_remove(struct platform_device *pdev)
 426 {
 427         struct spi_master *master = platform_get_drvdata(pdev);
 428         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 429
 430         /* reset spi block */
 431         bcm_spi_writeb(bs, 0, SPI_INT_MASK);
 432
 433         /* HW shutdown */
 434         clk_disable_unprepare(bs->clk);
 435
 436         return 0;
 437 }
 438
 439 #ifdef CONFIG_PM_SLEEP
 440 static int bcm63xx_spi_suspend(struct device *dev)
 441 {
 442         struct spi_master *master = dev_get_drvdata(dev);
 443         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 444
 445         spi_master_suspend(master);
 446
 447         clk_disable_unprepare(bs->clk);
 448
 449         return 0;
 450 }
 451
 452 static int bcm63xx_spi_resume(struct device *dev)
 453 {
 454         struct spi_master *master = dev_get_drvdata(dev);
 455         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 456         int ret;
 457
 458         ret = clk_prepare_enable(bs->clk);
 459         if (ret)
 460                 return ret;
 461
 462         spi_master_resume(master);
 463
 464         return 0;
 465 }
 466 #endif
 467
 468 static const struct dev_pm_ops bcm63xx_spi_pm_ops = {
 469         SET_SYSTEM_SLEEP_PM_OPS(bcm63xx_spi_suspend, bcm63xx_spi_resume)
 470 };
 471
 472 static struct platform_driver bcm63xx_spi_driver = {
 473         .driver = {
 474                 .name   = "bcm63xx-spi",
 475                 .owner  = THIS_MODULE,
 476                 .pm     = &bcm63xx_spi_pm_ops,
 477         },
 478         .probe          = bcm63xx_spi_probe,
 479         .remove         = bcm63xx_spi_remove,
 480 };
 481
 482 module_platform_driver(bcm63xx_spi_driver);
 483
 484 MODULE_ALIAS("platform:bcm63xx_spi");
 485 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 486 MODULE_AUTHOR("Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>");
 487 MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
 488 MODULE_LICENSE("GPL");