target/linux/brcm63xx/files/drivers/spi/bcm63xx_spi.c

   1 /*
   2  * Broadcom BCM63xx SPI controller support
   3  *
   4  * Copyright (C) 2009 Florian Fainelli <florian@openwrt.org>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the
  18  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/init.h>
  23 #include <linux/clk.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/delay.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spi/spi.h>
  29 #include <linux/spi/spi_bitbang.h>
  30 #include <linux/gpio.h>
  31 #include <linux/completion.h>
  32 #include <linux/err.h>
  33
  34 #include <bcm63xx_io.h>
  35 #include <bcm63xx_regs.h>
  36 #include <bcm63xx_dev_spi.h>
  37
  38 #define PFX             KBUILD_MODNAME
  39 #define DRV_VER         "0.1.2"
  40
  41 struct bcm63xx_spi {
  42         /* bitbang has to be first */
  43         struct spi_bitbang      bitbang;
  44         struct completion       done;
  45
  46         void __iomem            *regs;
  47         int                     irq;
  48
  49         /* Platform data */
  50         u32                     speed_hz;
  51         unsigned                fifo_size;
  52
  53         /* Data buffers */
  54         const unsigned char     *tx_ptr;
  55         unsigned char           *rx_ptr;
  56         int                     remaining_bytes;
  57
  58         struct clk              *clk;
  59         struct resource         *ioarea;
  60         struct platform_device  *pdev;
  61 };
  62
  63 static void bcm63xx_spi_chipselect(struct spi_device *spi, int is_on)
  64 {
  65         struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
  66         u16 val;
  67
  68         val = bcm_spi_readw(bs->regs, SPI_CMD);
  69         if (is_on == BITBANG_CS_INACTIVE)
  70                 val |= SPI_CMD_NOOP;
  71         else if (is_on == BITBANG_CS_ACTIVE)
  72                 val |= (1 << spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
  73
  74         bcm_spi_writew(val, bs->regs, SPI_CMD);
  75 }
  76
  77 static int bcm63xx_spi_setup_transfer(struct spi_device *spi,
  78                                         struct spi_transfer *t)
  79 {
  80         u8 bits_per_word;
  81         u8 clk_cfg;
  82         u32 hz;
  83         unsigned int div;
  84
  85         struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
  86
  87         bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
  88         hz = (t) ? t->speed_hz : spi->max_speed_hz;
  89         if (bits_per_word != 8) {
  90                 dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
  91                         __func__, bits_per_word);
  92                 return -EINVAL;
  93         }
  94
  95         if (spi->chip_select > spi->master->num_chipselect) {
  96                 dev_err(&spi->dev, "%s, unsupported slave %d\n",
  97                         __func__, spi->chip_select);
  98                 return -EINVAL;
  99         }
 100
 101         /* Check clock setting */
 102         div = (bs->speed_hz / hz);
 103         switch (div) {
 104         case 2:
 105                 clk_cfg = SPI_CLK_25MHZ;
 106                 break;
 107         case 4:
 108                 clk_cfg = SPI_CLK_12_50MHZ;
 109                 break;
 110         case 8:
 111                 clk_cfg = SPI_CLK_6_250MHZ;
 112                 break;
 113         case 16:
 114                 clk_cfg = SPI_CLK_3_125MHZ;
 115                 break;
 116         case 32:
 117                 clk_cfg = SPI_CLK_1_563MHZ;
 118                 break;
 119         case 128:
 120                 clk_cfg = SPI_CLK_0_781MHZ;
 121                 break;
 122         case 64:
 123         default:
 124                 /* Set to slowest mode for compatibility */
 125                 clk_cfg = SPI_CLK_0_781MHZ;
 126                 break;
 127         }
 128
 129         bcm_spi_writeb(clk_cfg, bs->regs, SPI_CLK_CFG);
 130         dev_dbg(&spi->dev, "Setting clock register to %d (hz %d, cmd %02x)\n",
 131                                                                 div, hz, clk_cfg);
 132
 133         return 0;
 134 }
 135
 136 /* the spi->mode bits understood by this driver: */
 137 #define MODEBITS (SPI_CPOL | SPI_CPHA)
 138
 139 static int bcm63xx_spi_setup(struct spi_device *spi)
 140 {
 141         struct spi_bitbang *bitbang;
 142         struct bcm63xx_spi *bs;
 143         int retval;
 144
 145         bs = spi_master_get_devdata(spi->master);
 146         bitbang = &bs->bitbang;
 147
 148         if (!spi->bits_per_word)
 149                 spi->bits_per_word = 8;
 150
 151         if (spi->mode & ~MODEBITS) {
 152                 dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
 153                         __func__, spi->mode & ~MODEBITS);
 154                 return -EINVAL;
 155         }
 156
 157         retval = bcm63xx_spi_setup_transfer(spi, NULL);
 158         if (retval < 0) {
 159                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
 160                         spi->mode & ~MODEBITS);
 161                 return retval;
 162         }
 163
 164         dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
 165                 __func__, spi->mode & MODEBITS, spi->bits_per_word, 0);
 166
 167         return 0;
 168 }
 169
 170 /* Fill the TX FIFO with as many bytes as possible */
 171 static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
 172 {
 173         u8 tail;
 174
 175         /* Fill the Tx FIFO with as many bytes as possible */
 176         tail = bcm_spi_readb(bs->regs, SPI_MSG_TAIL);
 177         while ((tail < bs->fifo_size) && (bs->remaining_bytes > 0)) {
 178                 if (bs->tx_ptr)
 179                         bcm_spi_writeb(*bs->tx_ptr++, bs->regs, SPI_MSG_DATA);
 180                 else
 181                         bcm_spi_writeb(0, bs->regs, SPI_MSG_DATA);
 182                 bs->remaining_bytes--;
 183                 tail = bcm_spi_readb(bs->regs, SPI_MSG_TAIL);
 184         }
 185 }
 186
 187 static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 188 {
 189         struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
 190         u8 msg_ctl;
 191         u16 cmd;
 192
 193         dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
 194                                 t->tx_buf, t->rx_buf, t->len);
 195
 196         /* Transmitter is inhibited */
 197         bs->tx_ptr = t->tx_buf;
 198         bs->rx_ptr = t->rx_buf;
 199         bs->remaining_bytes = t->len;
 200         init_completion(&bs->done);
 201
 202         bcm63xx_spi_fill_tx_fifo(bs);
 203
 204         /* Enable the command done interrupt which
 205          * we use to determine completion of a command */
 206         bcm_spi_writeb(SPI_INTR_CMD_DONE, bs->regs, SPI_INT_MASK);
 207
 208         /* Fill in the Message control register */
 209         msg_ctl = bcm_spi_readb(bs->regs, SPI_MSG_CTL);
 210         msg_ctl |= (t->len << SPI_BYTE_CNT_SHIFT);
 211         msg_ctl |= (SPI_FD_RW << SPI_MSG_TYPE_SHIFT);
 212         bcm_spi_writeb(msg_ctl, bs->regs, SPI_MSG_CTL);
 213
 214         /* Issue the transfer */
 215         cmd = bcm_spi_readb(bs->regs, SPI_CMD);
 216         cmd |= SPI_CMD_START_IMMEDIATE;
 217         cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
 218         bcm_spi_writeb(cmd, bs->regs, SPI_CMD);
 219
 220         wait_for_completion(&bs->done);
 221
 222         /* Disable the CMD_DONE interrupt */
 223         bcm_spi_writeb(~(SPI_INTR_CMD_DONE), bs->regs, SPI_INT_MASK);
 224
 225         return t->len - bs->remaining_bytes;
 226 }
 227
 228 /* This driver supports single master mode only. Hence
 229  * CMD_DONE is the only interrupt we care about
 230  */
 231 static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
 232 {
 233         struct spi_master *master = (struct spi_master *)dev_id;
 234         struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 235         u8 intr;
 236         u16 cmd;
 237
 238         /* Read interupts and clear them immediately */
 239         intr = bcm_spi_readb(bs->regs, SPI_INT_STATUS);
 240         bcm_spi_writeb(SPI_INTR_CLEAR_ALL, bs->regs, SPI_INT_STATUS);
 241
 242         /* A tansfer completed */
 243         if (intr & SPI_INTR_CMD_DONE) {
 244                 u8 rx_empty;
 245
 246                 rx_empty = bcm_spi_readb(bs->regs, SPI_ST);
 247                 /* Read out all the data */
 248                 while ((rx_empty & SPI_RX_EMPTY) == 0) {
 249                         u8 data;
 250
 251                         data = bcm_spi_readb(bs->regs, SPI_RX_DATA);
 252                         if (bs->rx_ptr)
 253                                 *bs->rx_ptr++ = data;
 254
 255                         rx_empty = bcm_spi_readb(bs->regs, SPI_RX_EMPTY);
 256                 }
 257
 258                 /* See if there is more data to send */
 259                 if (bs->remaining_bytes > 0) {
 260                         bcm63xx_spi_fill_tx_fifo(bs);
 261
 262                         /* Start the transfer */
 263                         cmd = bcm_spi_readb(bs->regs, SPI_CMD);
 264                         cmd |= SPI_CMD_START_IMMEDIATE;
 265                         cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
 266                         bcm_spi_writeb(cmd, bs->regs, SPI_CMD);
 267                 } else
 268                         complete(&bs->done);
 269         }
 270
 271         return IRQ_HANDLED;
 272 }
 273
 274
 275 static int __init bcm63xx_spi_probe(struct platform_device *pdev)
 276 {
 277         struct resource *r;
 278         struct bcm63xx_spi_pdata *pdata = pdev->dev.platform_data;
 279         int irq;
 280         struct spi_master *master;
 281         struct clk *clk;
 282         struct bcm63xx_spi *bs;
 283         int ret;
 284
 285         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 286         if (!r) {
 287                 ret = -ENXIO;
 288                 goto out;
 289         }
 290
 291         irq = platform_get_irq(pdev, 0);
 292         if (irq < 0) {
 293                 ret = -ENXIO;
 294                 goto out;
 295         }
 296
 297         clk = clk_get(&pdev->dev, "spi");
 298         if (IS_ERR(clk)) {
 299                 dev_err(&pdev->dev, "No clock for device\n");
 300                 ret = -ENODEV;
 301                 goto out;
 302         }
 303
 304         master = spi_alloc_master(&pdev->dev, sizeof(struct bcm63xx_spi));
 305         if (!master) {
 306                 ret = -ENOMEM;
 307                 goto out_free;
 308         }
 309
 310         bs = spi_master_get_devdata(master);
 311         bs->bitbang.master = spi_master_get(master);
 312         bs->bitbang.chipselect = bcm63xx_spi_chipselect;
 313         bs->bitbang.setup_transfer = bcm63xx_spi_setup_transfer;
 314         bs->bitbang.txrx_bufs = bcm63xx_txrx_bufs;
 315         bs->bitbang.master->setup = bcm63xx_spi_setup;
 316         init_completion(&bs->done);
 317
 318         platform_set_drvdata(pdev, master);
 319         bs->pdev = pdev;
 320
 321         if (!request_mem_region(r->start,
 322                         r->end - r->start, PFX)) {
 323                 ret = -ENXIO;
 324                 goto out_free;
 325         }
 326
 327         bs->regs = ioremap_nocache(r->start, r->end - r->start);
 328         if (!bs->regs) {
 329                 printk(KERN_ERR PFX " unable to ioremap regs\n");
 330                 ret = -ENOMEM;
 331                 goto out_free;
 332         }
 333         bs->irq = irq;
 334         bs->clk = clk;
 335         bs->fifo_size = pdata->fifo_size;
 336
 337         ret = request_irq(irq, bcm63xx_spi_interrupt, 0,
 338                                 pdev->dev.bus_id, master);
 339         if (ret) {
 340                 printk(KERN_ERR PFX " unable to request irq\n");
 341                 goto out_unmap;
 342         }
 343
 344         master->bus_num = pdata->bus_num;
 345         master->num_chipselect = pdata->num_chipselect;
 346         bs->speed_hz = pdata->speed_hz;
 347
 348         /* Initialize hardware */
 349         clk_enable(bs->clk);
 350         bcm_spi_writew(SPI_CMD_HARD_RESET, bs->regs, SPI_CMD);
 351         bcm_spi_writeb(SPI_INTR_CLEAR_ALL, bs->regs, SPI_INT_MASK);
 352
 353         dev_info(&pdev->dev, PFX " at 0x%08x (irq %d, FIFOs size %d) v%s\n",
 354                                 r->start, irq, bs->fifo_size, DRV_VER);
 355
 356         ret = spi_bitbang_start(&bs->bitbang);
 357         if (ret) {
 358                 dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
 359                 goto out_reset_hw;
 360         }
 361
 362         return ret;
 363
 364 out_reset_hw:
 365         clk_disable(clk);
 366         free_irq(irq, master);
 367 out_unmap:
 368         iounmap(bs->regs);
 369 out_free:
 370         clk_put(clk);
 371         spi_master_put(master);
 372 out:
 373         return ret;
 374 }
 375
 376 static int __exit bcm63xx_spi_remove(struct platform_device *pdev)
 377 {
 378         struct spi_master       *master = platform_get_drvdata(pdev);
 379         struct bcm63xx_spi      *bs = spi_master_get_devdata(master);
 380
 381         spi_bitbang_stop(&bs->bitbang);
 382         clk_disable(bs->clk);
 383         clk_put(bs->clk);
 384         free_irq(bs->irq, master);
 385         iounmap(bs->regs);
 386         platform_set_drvdata(pdev, 0);
 387         spi_master_put(bs->bitbang.master);
 388
 389         return 0;
 390 }
 391
 392 #ifdef CONFIG_PM
 393 static int bcm63xx_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
 394 {
 395         struct spi_master       *master = platform_get_drvdata(pdev);
 396         struct bcm63xx_spi      *bs = spi_master_get_devdata(master);
 397
 398         clk_disable(bs->clk);
 399
 400         return 0;
 401 }
 402
 403 static int bcm63xx_spi_resume(struct platform_device *pdev)
 404 {
 405         struct bcm63xx_spi      *bs = spi_master_get_devdata(master);
 406         struct bcm63xx_spi      *bs = spi_master_get_devdata(master);
 407
 408         clk_enable(bs->clk);
 409
 410         return 0;
 411 }
 412 #else
 413 #define bcm63xx_spi_suspend     NULL
 414 #define bcm63xx_spi_resume      NULL
 415 #endif
 416
 417 static struct platform_driver bcm63xx_spi_driver = {
 418         .driver = {
 419                 .name   = "bcm63xx-spi",
 420                 .owner  = THIS_MODULE,
 421         },
 422         .probe          = bcm63xx_spi_probe,
 423         .remove         = bcm63xx_spi_remove,
 424         .suspend        = bcm63xx_spi_suspend,
 425         .resume         = bcm63xx_spi_resume,
 426 };
 427
 428
 429 static int __init bcm63xx_spi_init(void)
 430 {
 431         return platform_driver_register(&bcm63xx_spi_driver);
 432 }
 433
 434 static void __exit bcm63xx_spi_exit(void)
 435 {
 436         platform_driver_unregister(&bcm63xx_spi_driver);
 437 }
 438
 439 module_init(bcm63xx_spi_init);
 440 module_exit(bcm63xx_spi_exit);
 441
 442 MODULE_ALIAS("platform:bcm63xx_spi");
 443 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 444 MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
 445 MODULE_LICENSE("GPL");
 446 MODULE_VERSION(DRV_VER);