drivers/spi/sh_spi.c

   1 /*
   2  * SH SPI driver
   3  *
   4  * Copyright (C) 2011 Renesas Solutions Corp.
   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 as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18  *
  19  */
  20
  21 #include <common.h>
  22 #include <malloc.h>
  23 #include <spi.h>
  24 #include <asm/io.h>
  25 #include "sh_spi.h"
  26
  27 static void sh_spi_write(unsigned long data, unsigned long *reg)
  28 {
  29         writel(data, reg);
  30 }
  31
  32 static unsigned long sh_spi_read(unsigned long *reg)
  33 {
  34         return readl(reg);
  35 }
  36
  37 static void sh_spi_set_bit(unsigned long val, unsigned long *reg)
  38 {
  39         unsigned long tmp;
  40
  41         tmp = sh_spi_read(reg);
  42         tmp |= val;
  43         sh_spi_write(tmp, reg);
  44 }
  45
  46 static void sh_spi_clear_bit(unsigned long val, unsigned long *reg)
  47 {
  48         unsigned long tmp;
  49
  50         tmp = sh_spi_read(reg);
  51         tmp &= ~val;
  52         sh_spi_write(tmp, reg);
  53 }
  54
  55 static void clear_fifo(struct sh_spi *ss)
  56 {
  57         sh_spi_set_bit(SH_SPI_RSTF, &ss->regs->cr2);
  58         sh_spi_clear_bit(SH_SPI_RSTF, &ss->regs->cr2);
  59 }
  60
  61 static int recvbuf_wait(struct sh_spi *ss)
  62 {
  63         while (sh_spi_read(&ss->regs->cr1) & SH_SPI_RBE) {
  64                 if (ctrlc())
  65                         return 1;
  66                 udelay(10);
  67         }
  68         return 0;
  69 }
  70
  71 static int write_fifo_empty_wait(struct sh_spi *ss)
  72 {
  73         while (!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBE)) {
  74                 if (ctrlc())
  75                         return 1;
  76                 udelay(10);
  77         }
  78         return 0;
  79 }
  80
  81 void spi_init(void)
  82 {
  83 }
  84
  85 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  86                 unsigned int max_hz, unsigned int mode)
  87 {
  88         struct sh_spi *ss;
  89
  90         if (!spi_cs_is_valid(bus, cs))
  91                 return NULL;
  92
  93         ss = malloc(sizeof(struct spi_slave));
  94         if (!ss)
  95                 return NULL;
  96
  97         ss->slave.bus = bus;
  98         ss->slave.cs = cs;
  99         ss->regs = (struct sh_spi_regs *)CONFIG_SH_SPI_BASE;
 100
 101         /* SPI sycle stop */
 102         sh_spi_write(0xfe, &ss->regs->cr1);
 103         /* CR1 init */
 104         sh_spi_write(0x00, &ss->regs->cr1);
 105         /* CR3 init */
 106         sh_spi_write(0x00, &ss->regs->cr3);
 107
 108         clear_fifo(ss);
 109
 110         /* 1/8 clock */
 111         sh_spi_write(sh_spi_read(&ss->regs->cr2) | 0x07, &ss->regs->cr2);
 112         udelay(10);
 113
 114         return &ss->slave;
 115 }
 116
 117 void spi_free_slave(struct spi_slave *slave)
 118 {
 119         struct sh_spi *spi = to_sh_spi(slave);
 120
 121         free(spi);
 122 }
 123
 124 int spi_claim_bus(struct spi_slave *slave)
 125 {
 126         return 0;
 127 }
 128
 129 void spi_release_bus(struct spi_slave *slave)
 130 {
 131         struct sh_spi *ss = to_sh_spi(slave);
 132
 133         sh_spi_write(sh_spi_read(&ss->regs->cr1) &
 134                 ~(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD), &ss->regs->cr1);
 135 }
 136
 137 static int sh_spi_send(struct sh_spi *ss, const unsigned char *tx_data,
 138                         unsigned int len, unsigned long flags)
 139 {
 140         int i, cur_len, ret = 0;
 141         int remain = (int)len;
 142         unsigned long tmp;
 143
 144         if (len >= SH_SPI_FIFO_SIZE)
 145                 sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
 146
 147         while (remain > 0) {
 148                 cur_len = (remain < SH_SPI_FIFO_SIZE) ?
 149                                 remain : SH_SPI_FIFO_SIZE;
 150                 for (i = 0; i < cur_len &&
 151                         !(sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) &&
 152                         !(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBF);
 153                                 i++)
 154                         sh_spi_write(tx_data[i], &ss->regs->tbr_rbr);
 155
 156                 cur_len = i;
 157
 158                 if (sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) {
 159                         /* Abort the transaction */
 160                         flags |= SPI_XFER_END;
 161                         sh_spi_set_bit(SH_SPI_WPABRT, &ss->regs->cr4);
 162                         ret = 1;
 163                         break;
 164                 }
 165
 166                 remain -= cur_len;
 167                 tx_data += cur_len;
 168
 169                 if (remain > 0)
 170                         write_fifo_empty_wait(ss);
 171         }
 172
 173         if (flags & SPI_XFER_END) {
 174                 tmp = sh_spi_read(&ss->regs->cr1);
 175                 tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB);
 176                 sh_spi_write(tmp, &ss->regs->cr1);
 177                 sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
 178                 udelay(100);
 179                 write_fifo_empty_wait(ss);
 180         }
 181
 182         return ret;
 183 }
 184
 185 static int sh_spi_receive(struct sh_spi *ss, unsigned char *rx_data,
 186                           unsigned int len, unsigned long flags)
 187 {
 188         int i;
 189         unsigned long tmp;
 190
 191         if (len > SH_SPI_MAX_BYTE)
 192                 sh_spi_write(SH_SPI_MAX_BYTE, &ss->regs->cr3);
 193         else
 194                 sh_spi_write(len, &ss->regs->cr3);
 195
 196         tmp = sh_spi_read(&ss->regs->cr1);
 197         tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB);
 198         sh_spi_write(tmp, &ss->regs->cr1);
 199         sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
 200
 201         for (i = 0; i < len; i++) {
 202                 if (recvbuf_wait(ss))
 203                         return 0;
 204
 205                 rx_data[i] = (unsigned char)sh_spi_read(&ss->regs->tbr_rbr);
 206         }
 207         sh_spi_write(0, &ss->regs->cr3);
 208
 209         return 0;
 210 }
 211
 212 int  spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 213                 void *din, unsigned long flags)
 214 {
 215         struct sh_spi *ss = to_sh_spi(slave);
 216         const unsigned char *tx_data = dout;
 217         unsigned char *rx_data = din;
 218         unsigned int len = bitlen / 8;
 219         int ret = 0;
 220
 221         if (flags & SPI_XFER_BEGIN)
 222                 sh_spi_write(sh_spi_read(&ss->regs->cr1) & ~SH_SPI_SSA,
 223                                 &ss->regs->cr1);
 224
 225         if (tx_data)
 226                 ret = sh_spi_send(ss, tx_data, len, flags);
 227
 228         if (ret == 0 && rx_data)
 229                 ret = sh_spi_receive(ss, rx_data, len, flags);
 230
 231         if (flags & SPI_XFER_END) {
 232                 sh_spi_set_bit(SH_SPI_SSD, &ss->regs->cr1);
 233                 udelay(100);
 234
 235                 sh_spi_clear_bit(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD,
 236                                  &ss->regs->cr1);
 237                 clear_fifo(ss);
 238         }
 239
 240         return ret;
 241 }
 242
 243 int  spi_cs_is_valid(unsigned int bus, unsigned int cs)
 244 {
 245         /* This driver supports "bus = 0" and "cs = 0" only. */
 246         if (!bus && !cs)
 247                 return 1;
 248         else
 249                 return 0;
 250 }
 251
 252 void spi_cs_activate(struct spi_slave *slave)
 253 {
 254
 255 }
 256
 257 void spi_cs_deactivate(struct spi_slave *slave)
 258 {
 259
 260 }