drivers/spi/spi-nuc900.c

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