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