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