drivers/spi/spi-mpc52xx-psc.c

   1 /*
   2  * MPC52xx PSC in SPI mode driver.
   3  *
   4  * Maintainer: Dragos Carp
   5  *
   6  * Copyright (C) 2006 TOPTICA Photonics AG.
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/errno.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/workqueue.h>
  21 #include <linux/completion.h>
  22 #include <linux/io.h>
  23 #include <linux/delay.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/fsl_devices.h>
  26 #include <linux/slab.h>
  27
  28 #include <asm/mpc52xx.h>
  29 #include <asm/mpc52xx_psc.h>
  30
  31 #define MCLK 20000000 /* PSC port MClk in hz */
  32
  33 struct mpc52xx_psc_spi {
  34         /* fsl_spi_platform data */
  35         void (*cs_control)(struct spi_device *spi, bool on);
  36         u32 sysclk;
  37
  38         /* driver internal data */
  39         struct mpc52xx_psc __iomem *psc;
  40         struct mpc52xx_psc_fifo __iomem *fifo;
  41         unsigned int irq;
  42         u8 bits_per_word;
  43         u8 busy;
  44
  45         struct workqueue_struct *workqueue;
  46         struct work_struct work;
  47
  48         struct list_head queue;
  49         spinlock_t lock;
  50
  51         struct completion done;
  52 };
  53
  54 /* controller state */
  55 struct mpc52xx_psc_spi_cs {
  56         int bits_per_word;
  57         int speed_hz;
  58 };
  59
  60 /* set clock freq, clock ramp, bits per work
  61  * if t is NULL then reset the values to the default values
  62  */
  63 static int mpc52xx_psc_spi_transfer_setup(struct spi_device *spi,
  64                 struct spi_transfer *t)
  65 {
  66         struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
  67
  68         cs->speed_hz = (t && t->speed_hz)
  69                         ? t->speed_hz : spi->max_speed_hz;
  70         cs->bits_per_word = (t && t->bits_per_word)
  71                         ? t->bits_per_word : spi->bits_per_word;
  72         cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
  73         return 0;
  74 }
  75
  76 static void mpc52xx_psc_spi_activate_cs(struct spi_device *spi)
  77 {
  78         struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
  79         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
  80         struct mpc52xx_psc __iomem *psc = mps->psc;
  81         u32 sicr;
  82         u16 ccr;
  83
  84         sicr = in_be32(&psc->sicr);
  85
  86         /* Set clock phase and polarity */
  87         if (spi->mode & SPI_CPHA)
  88                 sicr |= 0x00001000;
  89         else
  90                 sicr &= ~0x00001000;
  91         if (spi->mode & SPI_CPOL)
  92                 sicr |= 0x00002000;
  93         else
  94                 sicr &= ~0x00002000;
  95
  96         if (spi->mode & SPI_LSB_FIRST)
  97                 sicr |= 0x10000000;
  98         else
  99                 sicr &= ~0x10000000;
 100         out_be32(&psc->sicr, sicr);
 101
 102         /* Set clock frequency and bits per word
 103          * Because psc->ccr is defined as 16bit register instead of 32bit
 104          * just set the lower byte of BitClkDiv
 105          */
 106         ccr = in_be16((u16 __iomem *)&psc->ccr);
 107         ccr &= 0xFF00;
 108         if (cs->speed_hz)
 109                 ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
 110         else /* by default SPI Clk 1MHz */
 111                 ccr |= (MCLK / 1000000 - 1) & 0xFF;
 112         out_be16((u16 __iomem *)&psc->ccr, ccr);
 113         mps->bits_per_word = cs->bits_per_word;
 114
 115         if (mps->cs_control)
 116                 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
 117 }
 118
 119 static void mpc52xx_psc_spi_deactivate_cs(struct spi_device *spi)
 120 {
 121         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 122
 123         if (mps->cs_control)
 124                 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
 125 }
 126
 127 #define MPC52xx_PSC_BUFSIZE (MPC52xx_PSC_RFNUM_MASK + 1)
 128 /* wake up when 80% fifo full */
 129 #define MPC52xx_PSC_RFALARM (MPC52xx_PSC_BUFSIZE * 20 / 100)
 130
 131 static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
 132                                                 struct spi_transfer *t)
 133 {
 134         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 135         struct mpc52xx_psc __iomem *psc = mps->psc;
 136         struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
 137         unsigned rb = 0;        /* number of bytes receieved */
 138         unsigned sb = 0;        /* number of bytes sent */
 139         unsigned char *rx_buf = (unsigned char *)t->rx_buf;
 140         unsigned char *tx_buf = (unsigned char *)t->tx_buf;
 141         unsigned rfalarm;
 142         unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
 143         unsigned recv_at_once;
 144         int last_block = 0;
 145
 146         if (!t->tx_buf && !t->rx_buf && t->len)
 147                 return -EINVAL;
 148
 149         /* enable transmiter/receiver */
 150         out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
 151         while (rb < t->len) {
 152                 if (t->len - rb > MPC52xx_PSC_BUFSIZE) {
 153                         rfalarm = MPC52xx_PSC_RFALARM;
 154                         last_block = 0;
 155                 } else {
 156                         send_at_once = t->len - sb;
 157                         rfalarm = MPC52xx_PSC_BUFSIZE - (t->len - rb);
 158                         last_block = 1;
 159                 }
 160
 161                 dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
 162                 for (; send_at_once; sb++, send_at_once--) {
 163                         /* set EOF flag before the last word is sent */
 164                         if (send_at_once == 1 && last_block)
 165                                 out_8(&psc->ircr2, 0x01);
 166
 167                         if (tx_buf)
 168                                 out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
 169                         else
 170                                 out_8(&psc->mpc52xx_psc_buffer_8, 0);
 171                 }
 172
 173
 174                 /* enable interrupts and wait for wake up
 175                  * if just one byte is expected the Rx FIFO genererates no
 176                  * FFULL interrupt, so activate the RxRDY interrupt
 177                  */
 178                 out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
 179                 if (t->len - rb == 1) {
 180                         out_8(&psc->mode, 0);
 181                 } else {
 182                         out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
 183                         out_be16(&fifo->rfalarm, rfalarm);
 184                 }
 185                 out_be16(&psc->mpc52xx_psc_imr, MPC52xx_PSC_IMR_RXRDY);
 186                 wait_for_completion(&mps->done);
 187                 recv_at_once = in_be16(&fifo->rfnum);
 188                 dev_dbg(&spi->dev, "%d bytes received\n", recv_at_once);
 189
 190                 send_at_once = recv_at_once;
 191                 if (rx_buf) {
 192                         for (; recv_at_once; rb++, recv_at_once--)
 193                                 rx_buf[rb] = in_8(&psc->mpc52xx_psc_buffer_8);
 194                 } else {
 195                         for (; recv_at_once; rb++, recv_at_once--)
 196                                 in_8(&psc->mpc52xx_psc_buffer_8);
 197                 }
 198         }
 199         /* disable transmiter/receiver */
 200         out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
 201
 202         return 0;
 203 }
 204
 205 static void mpc52xx_psc_spi_work(struct work_struct *work)
 206 {
 207         struct mpc52xx_psc_spi *mps =
 208                 container_of(work, struct mpc52xx_psc_spi, work);
 209
 210         spin_lock_irq(&mps->lock);
 211         mps->busy = 1;
 212         while (!list_empty(&mps->queue)) {
 213                 struct spi_message *m;
 214                 struct spi_device *spi;
 215                 struct spi_transfer *t = NULL;
 216                 unsigned cs_change;
 217                 int status;
 218
 219                 m = container_of(mps->queue.next, struct spi_message, queue);
 220                 list_del_init(&m->queue);
 221                 spin_unlock_irq(&mps->lock);
 222
 223                 spi = m->spi;
 224                 cs_change = 1;
 225                 status = 0;
 226                 list_for_each_entry (t, &m->transfers, transfer_list) {
 227                         if (t->bits_per_word || t->speed_hz) {
 228                                 status = mpc52xx_psc_spi_transfer_setup(spi, t);
 229                                 if (status < 0)
 230                                         break;
 231                         }
 232
 233                         if (cs_change)
 234                                 mpc52xx_psc_spi_activate_cs(spi);
 235                         cs_change = t->cs_change;
 236
 237                         status = mpc52xx_psc_spi_transfer_rxtx(spi, t);
 238                         if (status)
 239                                 break;
 240                         m->actual_length += t->len;
 241
 242                         if (t->delay_usecs)
 243                                 udelay(t->delay_usecs);
 244
 245                         if (cs_change)
 246                                 mpc52xx_psc_spi_deactivate_cs(spi);
 247                 }
 248
 249                 m->status = status;
 250                 if (m->complete)
 251                         m->complete(m->context);
 252
 253                 if (status || !cs_change)
 254                         mpc52xx_psc_spi_deactivate_cs(spi);
 255
 256                 mpc52xx_psc_spi_transfer_setup(spi, NULL);
 257
 258                 spin_lock_irq(&mps->lock);
 259         }
 260         mps->busy = 0;
 261         spin_unlock_irq(&mps->lock);
 262 }
 263
 264 static int mpc52xx_psc_spi_setup(struct spi_device *spi)
 265 {
 266         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 267         struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
 268         unsigned long flags;
 269
 270         if (spi->bits_per_word%8)
 271                 return -EINVAL;
 272
 273         if (!cs) {
 274                 cs = kzalloc(sizeof *cs, GFP_KERNEL);
 275                 if (!cs)
 276                         return -ENOMEM;
 277                 spi->controller_state = cs;
 278         }
 279
 280         cs->bits_per_word = spi->bits_per_word;
 281         cs->speed_hz = spi->max_speed_hz;
 282
 283         spin_lock_irqsave(&mps->lock, flags);
 284         if (!mps->busy)
 285                 mpc52xx_psc_spi_deactivate_cs(spi);
 286         spin_unlock_irqrestore(&mps->lock, flags);
 287
 288         return 0;
 289 }
 290
 291 static int mpc52xx_psc_spi_transfer(struct spi_device *spi,
 292                 struct spi_message *m)
 293 {
 294         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
 295         unsigned long flags;
 296
 297         m->actual_length = 0;
 298         m->status = -EINPROGRESS;
 299
 300         spin_lock_irqsave(&mps->lock, flags);
 301         list_add_tail(&m->queue, &mps->queue);
 302         queue_work(mps->workqueue, &mps->work);
 303         spin_unlock_irqrestore(&mps->lock, flags);
 304
 305         return 0;
 306 }
 307
 308 static void mpc52xx_psc_spi_cleanup(struct spi_device *spi)
 309 {
 310         kfree(spi->controller_state);
 311 }
 312
 313 static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)
 314 {
 315         struct mpc52xx_psc __iomem *psc = mps->psc;
 316         struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
 317         u32 mclken_div;
 318         int ret;
 319
 320         /* default sysclk is 512MHz */
 321         mclken_div = (mps->sysclk ? mps->sysclk : 512000000) / MCLK;
 322         ret = mpc52xx_set_psc_clkdiv(psc_id, mclken_div);
 323         if (ret)
 324                 return ret;
 325
 326         /* Reset the PSC into a known state */
 327         out_8(&psc->command, MPC52xx_PSC_RST_RX);
 328         out_8(&psc->command, MPC52xx_PSC_RST_TX);
 329         out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
 330
 331         /* Disable interrupts, interrupts are based on alarm level */
 332         out_be16(&psc->mpc52xx_psc_imr, 0);
 333         out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
 334         out_8(&fifo->rfcntl, 0);
 335         out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
 336
 337         /* Configure 8bit codec mode as a SPI master and use EOF flags */
 338         /* SICR_SIM_CODEC8|SICR_GENCLK|SICR_SPI|SICR_MSTR|SICR_USEEOF */
 339         out_be32(&psc->sicr, 0x0180C800);
 340         out_be16((u16 __iomem *)&psc->ccr, 0x070F); /* default SPI Clk 1MHz */
 341
 342         /* Set 2ms DTL delay */
 343         out_8(&psc->ctur, 0x00);
 344         out_8(&psc->ctlr, 0x84);
 345
 346         mps->bits_per_word = 8;
 347
 348         return 0;
 349 }
 350
 351 static irqreturn_t mpc52xx_psc_spi_isr(int irq, void *dev_id)
 352 {
 353         struct mpc52xx_psc_spi *mps = (struct mpc52xx_psc_spi *)dev_id;
 354         struct mpc52xx_psc __iomem *psc = mps->psc;
 355
 356         /* disable interrupt and wake up the work queue */
 357         if (in_be16(&psc->mpc52xx_psc_isr) & MPC52xx_PSC_IMR_RXRDY) {
 358                 out_be16(&psc->mpc52xx_psc_imr, 0);
 359                 complete(&mps->done);
 360                 return IRQ_HANDLED;
 361         }
 362         return IRQ_NONE;
 363 }
 364
 365 /* bus_num is used only for the case dev->platform_data == NULL */
 366 static int mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
 367                                 u32 size, unsigned int irq, s16 bus_num)
 368 {
 369         struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
 370         struct mpc52xx_psc_spi *mps;
 371         struct spi_master *master;
 372         int ret;
 373
 374         master = spi_alloc_master(dev, sizeof *mps);
 375         if (master == NULL)
 376                 return -ENOMEM;
 377
 378         dev_set_drvdata(dev, master);
 379         mps = spi_master_get_devdata(master);
 380
 381         /* the spi->mode bits understood by this driver: */
 382         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
 383
 384         mps->irq = irq;
 385         if (pdata == NULL) {
 386                 dev_warn(dev,
 387                          "probe called without platform data, no cs_control function will be called\n");
 388                 mps->cs_control = NULL;
 389                 mps->sysclk = 0;
 390                 master->bus_num = bus_num;
 391                 master->num_chipselect = 255;
 392         } else {
 393                 mps->cs_control = pdata->cs_control;
 394                 mps->sysclk = pdata->sysclk;
 395                 master->bus_num = pdata->bus_num;
 396                 master->num_chipselect = pdata->max_chipselect;
 397         }
 398         master->setup = mpc52xx_psc_spi_setup;
 399         master->transfer = mpc52xx_psc_spi_transfer;
 400         master->cleanup = mpc52xx_psc_spi_cleanup;
 401         master->dev.of_node = dev->of_node;
 402
 403         mps->psc = ioremap(regaddr, size);
 404         if (!mps->psc) {
 405                 dev_err(dev, "could not ioremap I/O port range\n");
 406                 ret = -EFAULT;
 407                 goto free_master;
 408         }
 409         /* On the 5200, fifo regs are immediately ajacent to the psc regs */
 410         mps->fifo = ((void __iomem *)mps->psc) + sizeof(struct mpc52xx_psc);
 411
 412         ret = request_irq(mps->irq, mpc52xx_psc_spi_isr, 0, "mpc52xx-psc-spi",
 413                                 mps);
 414         if (ret)
 415                 goto free_master;
 416
 417         ret = mpc52xx_psc_spi_port_config(master->bus_num, mps);
 418         if (ret < 0) {
 419                 dev_err(dev, "can't configure PSC! Is it capable of SPI?\n");
 420                 goto free_irq;
 421         }
 422
 423         spin_lock_init(&mps->lock);
 424         init_completion(&mps->done);
 425         INIT_WORK(&mps->work, mpc52xx_psc_spi_work);
 426         INIT_LIST_HEAD(&mps->queue);
 427
 428         mps->workqueue = create_singlethread_workqueue(
 429                 dev_name(master->dev.parent));
 430         if (mps->workqueue == NULL) {
 431                 ret = -EBUSY;
 432                 goto free_irq;
 433         }
 434
 435         ret = spi_register_master(master);
 436         if (ret < 0)
 437                 goto unreg_master;
 438
 439         return ret;
 440
 441 unreg_master:
 442         destroy_workqueue(mps->workqueue);
 443 free_irq:
 444         free_irq(mps->irq, mps);
 445 free_master:
 446         if (mps->psc)
 447                 iounmap(mps->psc);
 448         spi_master_put(master);
 449
 450         return ret;
 451 }
 452
 453 static int mpc52xx_psc_spi_of_probe(struct platform_device *op)
 454 {
 455         const u32 *regaddr_p;
 456         u64 regaddr64, size64;
 457         s16 id = -1;
 458
 459         regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL);
 460         if (!regaddr_p) {
 461                 dev_err(&op->dev, "Invalid PSC address\n");
 462                 return -EINVAL;
 463         }
 464         regaddr64 = of_translate_address(op->dev.of_node, regaddr_p);
 465
 466         /* get PSC id (1..6, used by port_config) */
 467         if (op->dev.platform_data == NULL) {
 468                 const u32 *psc_nump;
 469
 470                 psc_nump = of_get_property(op->dev.of_node, "cell-index", NULL);
 471                 if (!psc_nump || *psc_nump > 5) {
 472                         dev_err(&op->dev, "Invalid cell-index property\n");
 473                         return -EINVAL;
 474                 }
 475                 id = *psc_nump + 1;
 476         }
 477
 478         return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
 479                                 irq_of_parse_and_map(op->dev.of_node, 0), id);
 480 }
 481
 482 static int mpc52xx_psc_spi_of_remove(struct platform_device *op)
 483 {
 484         struct spi_master *master = spi_master_get(platform_get_drvdata(op));
 485         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(master);
 486
 487         flush_workqueue(mps->workqueue);
 488         destroy_workqueue(mps->workqueue);
 489         spi_unregister_master(master);
 490         free_irq(mps->irq, mps);
 491         if (mps->psc)
 492                 iounmap(mps->psc);
 493         spi_master_put(master);
 494
 495         return 0;
 496 }
 497
 498 static const struct of_device_id mpc52xx_psc_spi_of_match[] = {
 499         { .compatible = "fsl,mpc5200-psc-spi", },
 500         { .compatible = "mpc5200-psc-spi", }, /* old */
 501         {}
 502 };
 503
 504 MODULE_DEVICE_TABLE(of, mpc52xx_psc_spi_of_match);
 505
 506 static struct platform_driver mpc52xx_psc_spi_of_driver = {
 507         .probe = mpc52xx_psc_spi_of_probe,
 508         .remove = mpc52xx_psc_spi_of_remove,
 509         .driver = {
 510                 .name = "mpc52xx-psc-spi",
 511                 .of_match_table = mpc52xx_psc_spi_of_match,
 512         },
 513 };
 514 module_platform_driver(mpc52xx_psc_spi_of_driver);
 515
 516 MODULE_AUTHOR("Dragos Carp");
 517 MODULE_DESCRIPTION("MPC52xx PSC SPI Driver");
 518 MODULE_LICENSE("GPL");