drivers/spi/omap3_spi.c

   1 /*
   2  * Copyright (C) 2010 Dirk Behme <[email protected]>
   3  *
   4  * Driver for McSPI controller on OMAP3. Based on davinci_spi.c
   5  * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
   6  *
   7  * Copyright (C) 2007 Atmel Corporation
   8  *
   9  * Parts taken from linux/drivers/spi/omap2_mcspi.c
  10  * Copyright (C) 2005, 2006 Nokia Corporation
  11  *
  12  * Modified by Ruslan Araslanov <[email protected]>
  13  *
  14  * See file CREDITS for list of people who contributed to this
  15  * project.
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License as
  19  * published by the Free Software Foundation; either version 2 of
  20  * the License, or (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  30  * MA 02111-1307 USA
  31  *
  32  */
  33
  34 #include <common.h>
  35 #include <spi.h>
  36 #include <malloc.h>
  37 #include <asm/io.h>
  38 #include "omap3_spi.h"
  39
  40 #define WORD_LEN        8
  41 #define SPI_WAIT_TIMEOUT 3000000;
  42
  43 static void spi_reset(struct omap3_spi_slave *ds)
  44 {
  45         unsigned int tmp;
  46
  47         writel(OMAP3_MCSPI_SYSCONFIG_SOFTRESET, &ds->regs->sysconfig);
  48         do {
  49                 tmp = readl(&ds->regs->sysstatus);
  50         } while (!(tmp & OMAP3_MCSPI_SYSSTATUS_RESETDONE));
  51
  52         writel(OMAP3_MCSPI_SYSCONFIG_AUTOIDLE |
  53                                  OMAP3_MCSPI_SYSCONFIG_ENAWAKEUP |
  54                                  OMAP3_MCSPI_SYSCONFIG_SMARTIDLE,
  55                                  &ds->regs->sysconfig);
  56
  57         writel(OMAP3_MCSPI_WAKEUPENABLE_WKEN, &ds->regs->wakeupenable);
  58 }
  59
  60 void spi_init()
  61 {
  62         /* do nothing */
  63 }
  64
  65 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  66                                   unsigned int max_hz, unsigned int mode)
  67 {
  68         struct omap3_spi_slave  *ds;
  69
  70         ds = malloc(sizeof(struct omap3_spi_slave));
  71         if (!ds) {
  72                 printf("SPI error: malloc of SPI structure failed\n");
  73                 return NULL;
  74         }
  75
  76         /*
  77          * OMAP3 McSPI (MultiChannel SPI) has 4 busses (modules)
  78          * with different number of chip selects (CS, channels):
  79          * McSPI1 has 4 CS (bus 0, cs 0 - 3)
  80          * McSPI2 has 2 CS (bus 1, cs 0 - 1)
  81          * McSPI3 has 2 CS (bus 2, cs 0 - 1)
  82          * McSPI4 has 1 CS (bus 3, cs 0)
  83          */
  84
  85         switch (bus) {
  86         case 0:
  87                 ds->regs = (struct mcspi *)OMAP3_MCSPI1_BASE;
  88                 break;
  89         case 1:
  90                 ds->regs = (struct mcspi *)OMAP3_MCSPI2_BASE;
  91                 break;
  92         case 2:
  93                 ds->regs = (struct mcspi *)OMAP3_MCSPI3_BASE;
  94                 break;
  95         case 3:
  96                 ds->regs = (struct mcspi *)OMAP3_MCSPI4_BASE;
  97                 break;
  98         default:
  99                 printf("SPI error: unsupported bus %i. \
 100                         Supported busses 0 - 3\n", bus);
 101                 return NULL;
 102         }
 103         ds->slave.bus = bus;
 104
 105         if (((bus == 0) && (cs > 3)) ||
 106                         ((bus == 1) && (cs > 1)) ||
 107                         ((bus == 2) && (cs > 1)) ||
 108                         ((bus == 3) && (cs > 0))) {
 109                 printf("SPI error: unsupported chip select %i \
 110                         on bus %i\n", cs, bus);
 111                 return NULL;
 112         }
 113         ds->slave.cs = cs;
 114
 115         if (max_hz > OMAP3_MCSPI_MAX_FREQ) {
 116                 printf("SPI error: unsupported frequency %i Hz. \
 117                         Max frequency is 48 Mhz\n", max_hz);
 118                 return NULL;
 119         }
 120         ds->freq = max_hz;
 121
 122         if (mode > SPI_MODE_3) {
 123                 printf("SPI error: unsupported SPI mode %i\n", mode);
 124                 return NULL;
 125         }
 126         ds->mode = mode;
 127
 128         return &ds->slave;
 129 }
 130
 131 void spi_free_slave(struct spi_slave *slave)
 132 {
 133         struct omap3_spi_slave *ds = to_omap3_spi(slave);
 134
 135         free(ds);
 136 }
 137
 138 int spi_claim_bus(struct spi_slave *slave)
 139 {
 140         struct omap3_spi_slave *ds = to_omap3_spi(slave);
 141         unsigned int conf, div = 0;
 142
 143         /* McSPI global module configuration */
 144
 145         /*
 146          * setup when switching from (reset default) slave mode
 147          * to single-channel master mode
 148          */
 149         spi_reset(ds);
 150         conf = readl(&ds->regs->modulctrl);
 151         conf &= ~(OMAP3_MCSPI_MODULCTRL_STEST | OMAP3_MCSPI_MODULCTRL_MS);
 152         conf |= OMAP3_MCSPI_MODULCTRL_SINGLE;
 153         writel(conf, &ds->regs->modulctrl);
 154
 155         /* McSPI individual channel configuration */
 156
 157         /* Calculate clock divisor. Valid range: 0x0 - 0xC ( /1 - /4096 ) */
 158         if (ds->freq) {
 159                 while (div <= 0xC && (OMAP3_MCSPI_MAX_FREQ / (1 << div))
 160                                          > ds->freq)
 161                         div++;
 162         } else
 163                 div = 0xC;
 164
 165         conf = readl(&ds->regs->channel[ds->slave.cs].chconf);
 166
 167         /* standard 4-wire master mode: SCK, MOSI/out, MISO/in, nCS
 168          * REVISIT: this controller could support SPI_3WIRE mode.
 169          */
 170         conf &= ~(OMAP3_MCSPI_CHCONF_IS|OMAP3_MCSPI_CHCONF_DPE1);
 171         conf |= OMAP3_MCSPI_CHCONF_DPE0;
 172
 173         /* wordlength */
 174         conf &= ~OMAP3_MCSPI_CHCONF_WL_MASK;
 175         conf |= (WORD_LEN - 1) << 7;
 176
 177         /* set chipselect polarity; manage with FORCE */
 178         if (!(ds->mode & SPI_CS_HIGH))
 179                 conf |= OMAP3_MCSPI_CHCONF_EPOL; /* active-low; normal */
 180         else
 181                 conf &= ~OMAP3_MCSPI_CHCONF_EPOL;
 182
 183         /* set clock divisor */
 184         conf &= ~OMAP3_MCSPI_CHCONF_CLKD_MASK;
 185         conf |= div << 2;
 186
 187         /* set SPI mode 0..3 */
 188         if (ds->mode & SPI_CPOL)
 189                 conf |= OMAP3_MCSPI_CHCONF_POL;
 190         else
 191                 conf &= ~OMAP3_MCSPI_CHCONF_POL;
 192         if (ds->mode & SPI_CPHA)
 193                 conf |= OMAP3_MCSPI_CHCONF_PHA;
 194         else
 195                 conf &= ~OMAP3_MCSPI_CHCONF_PHA;
 196
 197         /* Transmit & receive mode */
 198         conf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
 199
 200         writel(conf, &ds->regs->channel[ds->slave.cs].chconf);
 201
 202         return 0;
 203 }
 204
 205 void spi_release_bus(struct spi_slave *slave)
 206 {
 207         struct omap3_spi_slave *ds = to_omap3_spi(slave);
 208
 209         /* Reset the SPI hardware */
 210         spi_reset(ds);
 211 }
 212
 213 int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp,
 214                     unsigned long flags)
 215 {
 216         struct omap3_spi_slave *ds = to_omap3_spi(slave);
 217         int i;
 218         int timeout = SPI_WAIT_TIMEOUT;
 219         int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
 220
 221         if (flags & SPI_XFER_BEGIN)
 222                 writel(OMAP3_MCSPI_CHCTRL_EN,
 223                        &ds->regs->channel[ds->slave.cs].chctrl);
 224
 225         chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
 226         chconf |= OMAP3_MCSPI_CHCONF_TRM_TX_ONLY;
 227         chconf |= OMAP3_MCSPI_CHCONF_FORCE;
 228         writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
 229
 230         for (i = 0; i < len; i++) {
 231                 /* wait till TX register is empty (TXS == 1) */
 232                 while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) &
 233                          OMAP3_MCSPI_CHSTAT_TXS)) {
 234                         if (--timeout <= 0) {
 235                                 printf("SPI TXS timed out, status=0x%08x\n",
 236                                        readl(&ds->regs->channel[ds->slave.cs].chstat));
 237                                 return -1;
 238                         }
 239                 }
 240                 /* Write the data */
 241                 writel(txp[i], &ds->regs->channel[ds->slave.cs].tx);
 242         }
 243
 244         if (flags & SPI_XFER_END) {
 245                 /* wait to finish of transfer */
 246                 while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) &
 247                          OMAP3_MCSPI_CHSTAT_EOT));
 248
 249                 chconf &= ~OMAP3_MCSPI_CHCONF_FORCE;
 250                 writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
 251
 252                 writel(0, &ds->regs->channel[ds->slave.cs].chctrl);
 253         }
 254         return 0;
 255 }
 256
 257 int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp,
 258                    unsigned long flags)
 259 {
 260         struct omap3_spi_slave *ds = to_omap3_spi(slave);
 261         int i;
 262         int timeout = SPI_WAIT_TIMEOUT;
 263         int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
 264
 265         if (flags & SPI_XFER_BEGIN)
 266                 writel(OMAP3_MCSPI_CHCTRL_EN,
 267                        &ds->regs->channel[ds->slave.cs].chctrl);
 268
 269         chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
 270         chconf |= OMAP3_MCSPI_CHCONF_TRM_RX_ONLY;
 271         chconf |= OMAP3_MCSPI_CHCONF_FORCE;
 272         writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
 273
 274         writel(0, &ds->regs->channel[ds->slave.cs].tx);
 275
 276         for (i = 0; i < len; i++) {
 277                 /* Wait till RX register contains data (RXS == 1) */
 278                 while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) &
 279                          OMAP3_MCSPI_CHSTAT_RXS)) {
 280                         if (--timeout <= 0) {
 281                                 printf("SPI RXS timed out, status=0x%08x\n",
 282                                        readl(&ds->regs->channel[ds->slave.cs].chstat));
 283                                 return -1;
 284                         }
 285                 }
 286                 /* Read the data */
 287                 rxp[i] = readl(&ds->regs->channel[ds->slave.cs].rx);
 288         }
 289
 290         if (flags & SPI_XFER_END) {
 291                 chconf &= ~OMAP3_MCSPI_CHCONF_FORCE;
 292                 writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
 293
 294                 writel(0, &ds->regs->channel[ds->slave.cs].chctrl);
 295         }
 296
 297         return 0;
 298 }
 299
 300 int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
 301              const void *dout, void *din, unsigned long flags)
 302 {
 303         struct omap3_spi_slave *ds = to_omap3_spi(slave);
 304         unsigned int    len;
 305         const u8        *txp = dout;
 306         u8              *rxp = din;
 307         int ret = -1;
 308
 309         if (bitlen % 8)
 310                 return -1;
 311
 312         len = bitlen / 8;
 313
 314         if (bitlen == 0) {       /* only change CS */
 315                 int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
 316
 317                 if (flags & SPI_XFER_BEGIN) {
 318                         writel(OMAP3_MCSPI_CHCTRL_EN,
 319                                &ds->regs->channel[ds->slave.cs].chctrl);
 320                         chconf |= OMAP3_MCSPI_CHCONF_FORCE;
 321                         writel(chconf,
 322                                &ds->regs->channel[ds->slave.cs].chconf);
 323                 }
 324                 if (flags & SPI_XFER_END) {
 325                         chconf &= ~OMAP3_MCSPI_CHCONF_FORCE;
 326                         writel(chconf,
 327                                &ds->regs->channel[ds->slave.cs].chconf);
 328                         writel(0, &ds->regs->channel[ds->slave.cs].chctrl);
 329                 }
 330                 ret = 0;
 331         } else {
 332                 if (dout != NULL)
 333                         ret = omap3_spi_write(slave, len, txp, flags);
 334
 335                 if (din != NULL)
 336                         ret = omap3_spi_read(slave, len, rxp, flags);
 337         }
 338         return ret;
 339 }
 340
 341 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 342 {
 343         return 1;
 344 }
 345
 346 void spi_cs_activate(struct spi_slave *slave)
 347 {
 348 }
 349
 350 void spi_cs_deactivate(struct spi_slave *slave)
 351 {
 352 }