drivers/spi/spi_nuc900.c

   1 /* linux/drivers/spi/spi_nuc900.c
   2  *
   3  * Copyright (c) 2009 Nuvoton technology.
   4  * Wan ZongShun <mcuos.com@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10 */
  11
  12 #include <linux/init.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/delay.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/clk.h>
  20 #include <linux/device.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/gpio.h>
  23 #include <linux/io.h>
  24
  25 #include <linux/spi/spi.h>
  26 #include <linux/spi/spi_bitbang.h>
  27
  28 #include <mach/nuc900_spi.h>
  29
  30 /* usi registers offset */
  31 #define USI_CNT         0x00
  32 #define USI_DIV         0x04
  33 #define USI_SSR         0x08
  34 #define USI_RX0         0x10
  35 #define USI_TX0         0x10
  36
  37 /* usi register bit */
  38 #define ENINT           (0x01 << 17)
  39 #define ENFLG           (0x01 << 16)
  40 #define TXNUM           (0x03 << 8)
  41 #define TXNEG           (0x01 << 2)
  42 #define RXNEG           (0x01 << 1)
  43 #define LSB             (0x01 << 10)
  44 #define SELECTLEV       (0x01 << 2)
  45 #define SELECTPOL       (0x01 << 31)
  46 #define SELECTSLAVE     0x01
  47 #define GOBUSY          0x01
  48
  49 struct nuc900_spi {
  50         struct spi_bitbang       bitbang;
  51         struct completion        done;
  52         void __iomem            *regs;
  53         int                      irq;
  54         int                      len;
  55         int                      count;
  56         const unsigned char     *tx;
  57         unsigned char           *rx;
  58         struct clk              *clk;
  59         struct resource         *ioarea;
  60         struct spi_master       *master;
  61         struct spi_device       *curdev;
  62         struct device           *dev;
  63         struct nuc900_spi_info *pdata;
  64         spinlock_t              lock;
  65         struct resource         *res;
  66 };
  67
  68 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
  69 {
  70         return spi_master_get_devdata(sdev->master);
  71 }
  72
  73 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
  74 {
  75         struct nuc900_spi *hw = to_hw(spi);
  76         unsigned int val;
  77         unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
  78         unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
  79         unsigned long flags;
  80
  81         spin_lock_irqsave(&hw->lock, flags);
  82
  83         val = __raw_readl(hw->regs + USI_SSR);
  84
  85         if (!cs)
  86                 val &= ~SELECTLEV;
  87         else
  88                 val |= SELECTLEV;
  89
  90         if (!ssr)
  91                 val &= ~SELECTSLAVE;
  92         else
  93                 val |= SELECTSLAVE;
  94
  95         __raw_writel(val, hw->regs + USI_SSR);
  96
  97         val = __raw_readl(hw->regs + USI_CNT);
  98
  99         if (!cpol)
 100                 val &= ~SELECTPOL;
 101         else
 102                 val |= SELECTPOL;
 103
 104         __raw_writel(val, hw->regs + USI_CNT);
 105
 106         spin_unlock_irqrestore(&hw->lock, flags);
 107 }
 108
 109 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
 110 {
 111         switch (value) {
 112         case BITBANG_CS_INACTIVE:
 113                 nuc900_slave_select(spi, 0);
 114                 break;
 115
 116         case BITBANG_CS_ACTIVE:
 117                 nuc900_slave_select(spi, 1);
 118                 break;
 119         }
 120 }
 121
 122 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw,
 123                                                         unsigned int txnum)
 124 {
 125         unsigned int val;
 126         unsigned long flags;
 127
 128         spin_lock_irqsave(&hw->lock, flags);
 129
 130         val = __raw_readl(hw->regs + USI_CNT);
 131
 132         if (!txnum)
 133                 val &= ~TXNUM;
 134         else
 135                 val |= txnum << 0x08;
 136
 137         __raw_writel(val, hw->regs + USI_CNT);
 138
 139         spin_unlock_irqrestore(&hw->lock, flags);
 140
 141 }
 142
 143 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
 144                                                         unsigned int txbitlen)
 145 {
 146         unsigned int val;
 147         unsigned long flags;
 148
 149         spin_lock_irqsave(&hw->lock, flags);
 150
 151         val = __raw_readl(hw->regs + USI_CNT);
 152
 153         val |= (txbitlen << 0x03);
 154
 155         __raw_writel(val, hw->regs + USI_CNT);
 156
 157         spin_unlock_irqrestore(&hw->lock, flags);
 158 }
 159
 160 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
 161 {
 162         unsigned int val;
 163         unsigned long flags;
 164
 165         spin_lock_irqsave(&hw->lock, flags);
 166
 167         val = __raw_readl(hw->regs + USI_CNT);
 168
 169         val |= GOBUSY;
 170
 171         __raw_writel(val, hw->regs + USI_CNT);
 172
 173         spin_unlock_irqrestore(&hw->lock, flags);
 174 }
 175
 176 static int nuc900_spi_setupxfer(struct spi_device *spi,
 177                                  struct spi_transfer *t)
 178 {
 179         return 0;
 180 }
 181
 182 static int nuc900_spi_setup(struct spi_device *spi)
 183 {
 184         return 0;
 185 }
 186
 187 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
 188 {
 189         return hw->tx ? hw->tx[count] : 0;
 190 }
 191
 192 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 193 {
 194         struct nuc900_spi *hw = to_hw(spi);
 195
 196         hw->tx = t->tx_buf;
 197         hw->rx = t->rx_buf;
 198         hw->len = t->len;
 199         hw->count = 0;
 200
 201         __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
 202
 203         nuc900_spi_gobusy(hw);
 204
 205         wait_for_completion(&hw->done);
 206
 207         return hw->count;
 208 }
 209
 210 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
 211 {
 212         struct nuc900_spi *hw = dev;
 213         unsigned int status;
 214         unsigned int count = hw->count;
 215
 216         status = __raw_readl(hw->regs + USI_CNT);
 217         __raw_writel(status, hw->regs + USI_CNT);
 218
 219         if (status & ENFLG) {
 220                 hw->count++;
 221
 222                 if (hw->rx)
 223                         hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
 224                 count++;
 225
 226                 if (count < hw->len) {
 227                         __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
 228                         nuc900_spi_gobusy(hw);
 229                 } else {
 230                         complete(&hw->done);
 231                 }
 232
 233                 return IRQ_HANDLED;
 234         }
 235
 236         complete(&hw->done);
 237         return IRQ_HANDLED;
 238 }
 239
 240 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
 241 {
 242         unsigned int val;
 243         unsigned long flags;
 244
 245         spin_lock_irqsave(&hw->lock, flags);
 246
 247         val = __raw_readl(hw->regs + USI_CNT);
 248
 249         if (edge)
 250                 val |= TXNEG;
 251         else
 252                 val &= ~TXNEG;
 253         __raw_writel(val, hw->regs + USI_CNT);
 254
 255         spin_unlock_irqrestore(&hw->lock, flags);
 256 }
 257
 258 static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
 259 {
 260         unsigned int val;
 261         unsigned long flags;
 262
 263         spin_lock_irqsave(&hw->lock, flags);
 264
 265         val = __raw_readl(hw->regs + USI_CNT);
 266
 267         if (edge)
 268                 val |= RXNEG;
 269         else
 270                 val &= ~RXNEG;
 271         __raw_writel(val, hw->regs + USI_CNT);
 272
 273         spin_unlock_irqrestore(&hw->lock, flags);
 274 }
 275
 276 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
 277 {
 278         unsigned int val;
 279         unsigned long flags;
 280
 281         spin_lock_irqsave(&hw->lock, flags);
 282
 283         val = __raw_readl(hw->regs + USI_CNT);
 284
 285         if (lsb)
 286                 val |= LSB;
 287         else
 288                 val &= ~LSB;
 289         __raw_writel(val, hw->regs + USI_CNT);
 290
 291         spin_unlock_irqrestore(&hw->lock, flags);
 292 }
 293
 294 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
 295 {
 296         unsigned int val;
 297         unsigned long flags;
 298
 299         spin_lock_irqsave(&hw->lock, flags);
 300
 301         val = __raw_readl(hw->regs + USI_CNT);
 302
 303         if (sleep)
 304                 val |= (sleep << 12);
 305         else
 306                 val &= ~(0x0f << 12);
 307         __raw_writel(val, hw->regs + USI_CNT);
 308
 309         spin_unlock_irqrestore(&hw->lock, flags);
 310 }
 311
 312 static void nuc900_enable_int(struct nuc900_spi *hw)
 313 {
 314         unsigned int val;
 315         unsigned long flags;
 316
 317         spin_lock_irqsave(&hw->lock, flags);
 318
 319         val = __raw_readl(hw->regs + USI_CNT);
 320
 321         val |= ENINT;
 322
 323         __raw_writel(val, hw->regs + USI_CNT);
 324
 325         spin_unlock_irqrestore(&hw->lock, flags);
 326 }
 327
 328 static void nuc900_set_divider(struct nuc900_spi *hw)
 329 {
 330         __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
 331 }
 332
 333 static void nuc900_init_spi(struct nuc900_spi *hw)
 334 {
 335         clk_enable(hw->clk);
 336         spin_lock_init(&hw->lock);
 337
 338         nuc900_tx_edge(hw, hw->pdata->txneg);
 339         nuc900_rx_edge(hw, hw->pdata->rxneg);
 340         nuc900_send_first(hw, hw->pdata->lsb);
 341         nuc900_set_sleep(hw, hw->pdata->sleep);
 342         nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
 343         nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
 344         nuc900_set_divider(hw);
 345         nuc900_enable_int(hw);
 346 }
 347
 348 static int __devinit nuc900_spi_probe(struct platform_device *pdev)
 349 {
 350         struct nuc900_spi *hw;
 351         struct spi_master *master;
 352         int err = 0;
 353
 354         master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
 355         if (master == NULL) {
 356                 dev_err(&pdev->dev, "No memory for spi_master\n");
 357                 err = -ENOMEM;
 358                 goto err_nomem;
 359         }
 360
 361         hw = spi_master_get_devdata(master);
 362         memset(hw, 0, sizeof(struct nuc900_spi));
 363
 364         hw->master = spi_master_get(master);
 365         hw->pdata  = pdev->dev.platform_data;
 366         hw->dev = &pdev->dev;
 367
 368         if (hw->pdata == NULL) {
 369                 dev_err(&pdev->dev, "No platform data supplied\n");
 370                 err = -ENOENT;
 371                 goto err_pdata;
 372         }
 373
 374         platform_set_drvdata(pdev, hw);
 375         init_completion(&hw->done);
 376
 377         master->mode_bits          = SPI_MODE_0;
 378         master->num_chipselect     = hw->pdata->num_cs;
 379         master->bus_num            = hw->pdata->bus_num;
 380         hw->bitbang.master         = hw->master;
 381         hw->bitbang.setup_transfer = nuc900_spi_setupxfer;
 382         hw->bitbang.chipselect     = nuc900_spi_chipsel;
 383         hw->bitbang.txrx_bufs      = nuc900_spi_txrx;
 384         hw->bitbang.master->setup  = nuc900_spi_setup;
 385
 386         hw->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 387         if (hw->res == NULL) {
 388                 dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
 389                 err = -ENOENT;
 390                 goto err_pdata;
 391         }
 392
 393         hw->ioarea = request_mem_region(hw->res->start,
 394                                         resource_size(hw->res), pdev->name);
 395
 396         if (hw->ioarea == NULL) {
 397                 dev_err(&pdev->dev, "Cannot reserve region\n");
 398                 err = -ENXIO;
 399                 goto err_pdata;
 400         }
 401
 402         hw->regs = ioremap(hw->res->start, resource_size(hw->res));
 403         if (hw->regs == NULL) {
 404                 dev_err(&pdev->dev, "Cannot map IO\n");
 405                 err = -ENXIO;
 406                 goto err_iomap;
 407         }
 408
 409         hw->irq = platform_get_irq(pdev, 0);
 410         if (hw->irq < 0) {
 411                 dev_err(&pdev->dev, "No IRQ specified\n");
 412                 err = -ENOENT;
 413                 goto err_irq;
 414         }
 415
 416         err = request_irq(hw->irq, nuc900_spi_irq, 0, pdev->name, hw);
 417         if (err) {
 418                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 419                 goto err_irq;
 420         }
 421
 422         hw->clk = clk_get(&pdev->dev, "spi");
 423         if (IS_ERR(hw->clk)) {
 424                 dev_err(&pdev->dev, "No clock for device\n");
 425                 err = PTR_ERR(hw->clk);
 426                 goto err_clk;
 427         }
 428
 429         mfp_set_groupg(&pdev->dev);
 430         nuc900_init_spi(hw);
 431
 432         err = spi_bitbang_start(&hw->bitbang);
 433         if (err) {
 434                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 435                 goto err_register;
 436         }
 437
 438         return 0;
 439
 440 err_register:
 441         clk_disable(hw->clk);
 442         clk_put(hw->clk);
 443 err_clk:
 444         free_irq(hw->irq, hw);
 445 err_irq:
 446         iounmap(hw->regs);
 447 err_iomap:
 448         release_mem_region(hw->res->start, resource_size(hw->res));
 449         kfree(hw->ioarea);
 450 err_pdata:
 451         spi_master_put(hw->master);;
 452
 453 err_nomem:
 454         return err;
 455 }
 456
 457 static int __devexit nuc900_spi_remove(struct platform_device *dev)
 458 {
 459         struct nuc900_spi *hw = platform_get_drvdata(dev);
 460
 461         free_irq(hw->irq, hw);
 462
 463         platform_set_drvdata(dev, NULL);
 464
 465         spi_unregister_master(hw->master);
 466
 467         clk_disable(hw->clk);
 468         clk_put(hw->clk);
 469
 470         iounmap(hw->regs);
 471
 472         release_mem_region(hw->res->start, resource_size(hw->res));
 473         kfree(hw->ioarea);
 474
 475         spi_master_put(hw->master);
 476         return 0;
 477 }
 478
 479 static struct platform_driver nuc900_spi_driver = {
 480         .probe          = nuc900_spi_probe,
 481         .remove         = __devexit_p(nuc900_spi_remove),
 482         .driver         = {
 483                 .name   = "nuc900-spi",
 484                 .owner  = THIS_MODULE,
 485         },
 486 };
 487
 488 static int __init nuc900_spi_init(void)
 489 {
 490         return platform_driver_register(&nuc900_spi_driver);
 491 }
 492
 493 static void __exit nuc900_spi_exit(void)
 494 {
 495         platform_driver_unregister(&nuc900_spi_driver);
 496 }
 497
 498 module_init(nuc900_spi_init);
 499 module_exit(nuc900_spi_exit);
 500
 501 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
 502 MODULE_DESCRIPTION("nuc900 spi driver!");
 503 MODULE_LICENSE("GPL");
 504 MODULE_ALIAS("platform:nuc900-spi");