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/spinlock.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/delay.h>
  16 #include <linux/errno.h>
  17 #include <linux/err.h>
  18 #include <linux/clk.h>
  19 #include <linux/device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/gpio.h>
  22 #include <linux/io.h>
  23 #include <linux/slab.h>
  24
  25 #include <linux/spi/spi.h>
  26 #include <linux/spi/spi_bitbang.h>
  27
  28 #include <linux/platform_data/spi-nuc900.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 SLEEP           (0x0f << 12)
  41 #define TXNUM           (0x03 << 8)
  42 #define TXBITLEN        (0x1f << 3)
  43 #define TXNEG           (0x01 << 2)
  44 #define RXNEG           (0x01 << 1)
  45 #define LSB             (0x01 << 10)
  46 #define SELECTLEV       (0x01 << 2)
  47 #define SELECTPOL       (0x01 << 31)
  48 #define SELECTSLAVE     0x01
  49 #define GOBUSY          0x01
  50
  51 struct nuc900_spi {
  52         struct spi_bitbang       bitbang;
  53         struct completion        done;
  54         void __iomem            *regs;
  55         int                      irq;
  56         int                      len;
  57         int                      count;
  58         const unsigned char     *tx;
  59         unsigned char           *rx;
  60         struct clk              *clk;
  61         struct spi_master       *master;
  62         struct nuc900_spi_info *pdata;
  63         spinlock_t              lock;
  64 };
  65
  66 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
  67 {
  68         return spi_master_get_devdata(sdev->master);
  69 }
  70
  71 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
  72 {
  73         struct nuc900_spi *hw = to_hw(spi);
  74         unsigned int val;
  75         unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
  76         unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
  77         unsigned long flags;
  78
  79         spin_lock_irqsave(&hw->lock, flags);
  80
  81         val = __raw_readl(hw->regs + USI_SSR);
  82
  83         if (!cs)
  84                 val &= ~SELECTLEV;
  85         else
  86                 val |= SELECTLEV;
  87
  88         if (!ssr)
  89                 val &= ~SELECTSLAVE;
  90         else
  91                 val |= SELECTSLAVE;
  92
  93         __raw_writel(val, hw->regs + USI_SSR);
  94
  95         val = __raw_readl(hw->regs + USI_CNT);
  96
  97         if (!cpol)
  98                 val &= ~SELECTPOL;
  99         else
 100                 val |= SELECTPOL;
 101
 102         __raw_writel(val, hw->regs + USI_CNT);
 103
 104         spin_unlock_irqrestore(&hw->lock, flags);
 105 }
 106
 107 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
 108 {
 109         switch (value) {
 110         case BITBANG_CS_INACTIVE:
 111                 nuc900_slave_select(spi, 0);
 112                 break;
 113
 114         case BITBANG_CS_ACTIVE:
 115                 nuc900_slave_select(spi, 1);
 116                 break;
 117         }
 118 }
 119
 120 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
 121 {
 122         unsigned int val;
 123         unsigned long flags;
 124
 125         spin_lock_irqsave(&hw->lock, flags);
 126
 127         val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;
 128
 129         if (txnum)
 130                 val |= txnum << 0x08;
 131
 132         __raw_writel(val, hw->regs + USI_CNT);
 133
 134         spin_unlock_irqrestore(&hw->lock, flags);
 135
 136 }
 137
 138 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
 139                                                         unsigned int txbitlen)
 140 {
 141         unsigned int val;
 142         unsigned long flags;
 143
 144         spin_lock_irqsave(&hw->lock, flags);
 145
 146         val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;
 147
 148         val |= (txbitlen << 0x03);
 149
 150         __raw_writel(val, hw->regs + USI_CNT);
 151
 152         spin_unlock_irqrestore(&hw->lock, flags);
 153 }
 154
 155 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
 156 {
 157         unsigned int val;
 158         unsigned long flags;
 159
 160         spin_lock_irqsave(&hw->lock, flags);
 161
 162         val = __raw_readl(hw->regs + USI_CNT);
 163
 164         val |= GOBUSY;
 165
 166         __raw_writel(val, hw->regs + USI_CNT);
 167
 168         spin_unlock_irqrestore(&hw->lock, flags);
 169 }
 170
 171 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
 172 {
 173         return hw->tx ? hw->tx[count] : 0;
 174 }
 175
 176 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 177 {
 178         struct nuc900_spi *hw = to_hw(spi);
 179
 180         hw->tx = t->tx_buf;
 181         hw->rx = t->rx_buf;
 182         hw->len = t->len;
 183         hw->count = 0;
 184
 185         __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
 186
 187         nuc900_spi_gobusy(hw);
 188
 189         wait_for_completion(&hw->done);
 190
 191         return hw->count;
 192 }
 193
 194 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
 195 {
 196         struct nuc900_spi *hw = dev;
 197         unsigned int status;
 198         unsigned int count = hw->count;
 199
 200         status = __raw_readl(hw->regs + USI_CNT);
 201         __raw_writel(status, hw->regs + USI_CNT);
 202
 203         if (status & ENFLG) {
 204                 hw->count++;
 205
 206                 if (hw->rx)
 207                         hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
 208                 count++;
 209
 210                 if (count < hw->len) {
 211                         __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
 212                         nuc900_spi_gobusy(hw);
 213                 } else {
 214                         complete(&hw->done);
 215                 }
 216
 217                 return IRQ_HANDLED;
 218         }
 219
 220         complete(&hw->done);
 221         return IRQ_HANDLED;
 222 }
 223
 224 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
 225 {
 226         unsigned int val;
 227         unsigned long flags;
 228
 229         spin_lock_irqsave(&hw->lock, flags);
 230
 231         val = __raw_readl(hw->regs + USI_CNT);
 232
 233         if (edge)
 234                 val |= TXNEG;
 235         else
 236                 val &= ~TXNEG;
 237         __raw_writel(val, hw->regs + USI_CNT);
 238
 239         spin_unlock_irqrestore(&hw->lock, flags);
 240 }
 241
 242 static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
 243 {
 244         unsigned int val;
 245         unsigned long flags;
 246
 247         spin_lock_irqsave(&hw->lock, flags);
 248
 249         val = __raw_readl(hw->regs + USI_CNT);
 250
 251         if (edge)
 252                 val |= RXNEG;
 253         else
 254                 val &= ~RXNEG;
 255         __raw_writel(val, hw->regs + USI_CNT);
 256
 257         spin_unlock_irqrestore(&hw->lock, flags);
 258 }
 259
 260 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
 261 {
 262         unsigned int val;
 263         unsigned long flags;
 264
 265         spin_lock_irqsave(&hw->lock, flags);
 266
 267         val = __raw_readl(hw->regs + USI_CNT);
 268
 269         if (lsb)
 270                 val |= LSB;
 271         else
 272                 val &= ~LSB;
 273         __raw_writel(val, hw->regs + USI_CNT);
 274
 275         spin_unlock_irqrestore(&hw->lock, flags);
 276 }
 277
 278 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
 279 {
 280         unsigned int val;
 281         unsigned long flags;
 282
 283         spin_lock_irqsave(&hw->lock, flags);
 284
 285         val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;
 286
 287         if (sleep)
 288                 val |= (sleep << 12);
 289
 290         __raw_writel(val, hw->regs + USI_CNT);
 291
 292         spin_unlock_irqrestore(&hw->lock, flags);
 293 }
 294
 295 static void nuc900_enable_int(struct nuc900_spi *hw)
 296 {
 297         unsigned int val;
 298         unsigned long flags;
 299
 300         spin_lock_irqsave(&hw->lock, flags);
 301
 302         val = __raw_readl(hw->regs + USI_CNT);
 303
 304         val |= ENINT;
 305
 306         __raw_writel(val, hw->regs + USI_CNT);
 307
 308         spin_unlock_irqrestore(&hw->lock, flags);
 309 }
 310
 311 static void nuc900_set_divider(struct nuc900_spi *hw)
 312 {
 313         __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
 314 }
 315
 316 static void nuc900_init_spi(struct nuc900_spi *hw)
 317 {
 318         clk_enable(hw->clk);
 319         spin_lock_init(&hw->lock);
 320
 321         nuc900_tx_edge(hw, hw->pdata->txneg);
 322         nuc900_rx_edge(hw, hw->pdata->rxneg);
 323         nuc900_send_first(hw, hw->pdata->lsb);
 324         nuc900_set_sleep(hw, hw->pdata->sleep);
 325         nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
 326         nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
 327         nuc900_set_divider(hw);
 328         nuc900_enable_int(hw);
 329 }
 330
 331 static int nuc900_spi_probe(struct platform_device *pdev)
 332 {
 333         struct nuc900_spi *hw;
 334         struct spi_master *master;
 335         struct resource *res;
 336         int err = 0;
 337
 338         master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
 339         if (master == NULL) {
 340                 dev_err(&pdev->dev, "No memory for spi_master\n");
 341                 return -ENOMEM;
 342         }
 343
 344         hw = spi_master_get_devdata(master);
 345         hw->master = master;
 346         hw->pdata  = dev_get_platdata(&pdev->dev);
 347
 348         if (hw->pdata == NULL) {
 349                 dev_err(&pdev->dev, "No platform data supplied\n");
 350                 err = -ENOENT;
 351                 goto err_pdata;
 352         }
 353
 354         platform_set_drvdata(pdev, hw);
 355         init_completion(&hw->done);
 356
 357         master->mode_bits          = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 358         if (hw->pdata->lsb)
 359                 master->mode_bits |= SPI_LSB_FIRST;
 360         master->num_chipselect     = hw->pdata->num_cs;
 361         master->bus_num            = hw->pdata->bus_num;
 362         hw->bitbang.master         = hw->master;
 363         hw->bitbang.chipselect     = nuc900_spi_chipsel;
 364         hw->bitbang.txrx_bufs      = nuc900_spi_txrx;
 365
 366         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 367         hw->regs = devm_ioremap_resource(&pdev->dev, res);
 368         if (IS_ERR(hw->regs)) {
 369                 err = PTR_ERR(hw->regs);
 370                 goto err_pdata;
 371         }
 372
 373         hw->irq = platform_get_irq(pdev, 0);
 374         if (hw->irq < 0) {
 375                 dev_err(&pdev->dev, "No IRQ specified\n");
 376                 err = -ENOENT;
 377                 goto err_pdata;
 378         }
 379
 380         err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
 381                                 pdev->name, hw);
 382         if (err) {
 383                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
 384                 goto err_pdata;
 385         }
 386
 387         hw->clk = devm_clk_get(&pdev->dev, "spi");
 388         if (IS_ERR(hw->clk)) {
 389                 dev_err(&pdev->dev, "No clock for device\n");
 390                 err = PTR_ERR(hw->clk);
 391                 goto err_pdata;
 392         }
 393
 394         mfp_set_groupg(&pdev->dev, NULL);
 395         nuc900_init_spi(hw);
 396
 397         err = spi_bitbang_start(&hw->bitbang);
 398         if (err) {
 399                 dev_err(&pdev->dev, "Failed to register SPI master\n");
 400                 goto err_register;
 401         }
 402
 403         return 0;
 404
 405 err_register:
 406         clk_disable(hw->clk);
 407 err_pdata:
 408         spi_master_put(hw->master);
 409         return err;
 410 }
 411
 412 static int nuc900_spi_remove(struct platform_device *dev)
 413 {
 414         struct nuc900_spi *hw = platform_get_drvdata(dev);
 415
 416         spi_bitbang_stop(&hw->bitbang);
 417         clk_disable(hw->clk);
 418         spi_master_put(hw->master);
 419         return 0;
 420 }
 421
 422 static struct platform_driver nuc900_spi_driver = {
 423         .probe          = nuc900_spi_probe,
 424         .remove         = nuc900_spi_remove,
 425         .driver         = {
 426                 .name   = "nuc900-spi",
 427                 .owner  = THIS_MODULE,
 428         },
 429 };
 430 module_platform_driver(nuc900_spi_driver);
 431
 432 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
 433 MODULE_DESCRIPTION("nuc900 spi driver!");
 434 MODULE_LICENSE("GPL");
 435 MODULE_ALIAS("platform:nuc900-spi");