package/uboot-ar71xx/files/drivers/spi/ar71xx_spi.c

   1 /*
   2  * (C) Copyright 2010
   3  * Michael Kurz <michi.kurz@googlemail.com>
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #include <common.h>
  25 #include <malloc.h>
  26 #include <spi.h>
  27
  28 #include <asm/addrspace.h>
  29 #include <asm/types.h>
  30 #include <asm/ar71xx.h>
  31
  32 /*-----------------------------------------------------------------------
  33  * Definitions
  34  */
  35
  36 #ifdef DEBUG_SPI
  37 #define PRINTD(fmt,args...)     printf (fmt ,##args)
  38 #else
  39 #define PRINTD(fmt,args...)
  40 #endif
  41
  42 struct ar71xx_spi_slave {
  43         struct spi_slave slave;
  44         unsigned int mode;
  45 };
  46
  47 static inline struct ar71xx_spi_slave *to_ar71xx_spi(struct spi_slave *slave)
  48 {
  49         return container_of(slave, struct ar71xx_spi_slave, slave);
  50 }
  51
  52 /*=====================================================================*/
  53 /*                         Public Functions                            */
  54 /*=====================================================================*/
  55
  56 /*-----------------------------------------------------------------------
  57  * Initialization
  58  */
  59
  60 void spi_init()
  61 {
  62         PRINTD("ar71xx_spi: spi_init");
  63
  64         // Init SPI Hardware, disable remap, set clock
  65         __raw_writel(0x43, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_CTRL));
  66
  67         PRINTD(" ---> out\n");
  68 }
  69
  70 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  71                 unsigned int max_hz, unsigned int mode)
  72 {
  73         struct ar71xx_spi_slave *ss;
  74
  75         PRINTD("ar71xx_spi: spi_setup_slave");
  76
  77         if ((bus != 0) || (cs > 2))
  78                 return NULL;
  79
  80         ss = malloc(sizeof(struct ar71xx_spi_slave));
  81         if (!ss)
  82                 return NULL;
  83
  84         ss->slave.bus = bus;
  85         ss->slave.cs = cs;
  86         ss->mode = mode;
  87
  88         /* TODO: Use max_hz to limit the SCK rate */
  89
  90         PRINTD(" ---> out\n");
  91
  92         return &ss->slave;
  93 }
  94
  95 void spi_free_slave(struct spi_slave *slave)
  96 {
  97         struct ar71xx_spi_slave *ss = to_ar71xx_spi(slave);
  98
  99         free(ss);
 100 }
 101
 102 int spi_claim_bus(struct spi_slave *slave)
 103 {
 104
 105         return 0;
 106 }
 107
 108 void spi_release_bus(struct spi_slave *slave)
 109 {
 110
 111 }
 112
 113 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 114                 void *din, unsigned long flags)
 115 {
 116         struct ar71xx_spi_slave *ss = to_ar71xx_spi(slave);
 117         uint8_t *rx = din;
 118         const uint8_t *tx = dout;
 119         uint8_t curbyte, curbitlen, restbits;
 120         uint32_t bytes = bitlen / 8;
 121         uint32_t out;
 122         uint32_t in;
 123
 124         PRINTD("ar71xx_spi: spi_xfer: slave:%p bitlen:%08x dout:%p din:%p flags:%08x\n", slave, bitlen, dout, din, flags);
 125
 126         if (flags & SPI_XFER_BEGIN) {
 127                 __raw_writel(SPI_FS_GPIO, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_FS));
 128                 __raw_writel(SPI_IOC_CS_ALL, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_IOC));
 129         }
 130
 131         restbits = (bitlen % 8);
 132         if (restbits != 0)
 133                 bytes++;
 134
 135         // enable chip select
 136         out = SPI_IOC_CS_ALL & ~(SPI_IOC_CS(slave->cs));
 137
 138         while (bytes--) {
 139
 140                 curbyte = 0;
 141                 if (tx) {
 142                         curbyte = *tx++;
 143                 }
 144
 145                 if (restbits != 0) {
 146                         curbitlen = restbits;
 147                         curbyte <<= 8 - restbits;
 148                 } else {
 149                         curbitlen = 8;
 150                 }
 151
 152                 PRINTD("ar71xx_spi: sending: data:%02x length:%d\n", curbyte, curbitlen);
 153
 154                 /* clock starts at inactive polarity */
 155                 for (curbyte <<= (8 - curbitlen); curbitlen; curbitlen--) {
 156
 157                         if (curbyte & (1 << 7))
 158                                 out |= SPI_IOC_DO;
 159                         else
 160                                 out &= ~(SPI_IOC_DO);
 161
 162                         /* setup MSB (to slave) on trailing edge */
 163                         __raw_writel(out, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_IOC));
 164
 165                         __raw_writel(out | SPI_IOC_CLK, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_IOC));
 166
 167                         curbyte <<= 1;
 168                 }
 169
 170                 in = __raw_readl(KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_RDS));
 171                 PRINTD("ar71xx_spi: received:%02x\n", in);
 172
 173                 if (rx) {
 174                         if (restbits == 0) {
 175                                 *rx++ = in;
 176                         } else {
 177                                 *rx++ = (in << (8 - restbits));
 178                         }
 179                 }
 180         }
 181
 182         if (flags & SPI_XFER_END) {
 183                 __raw_writel(SPI_IOC_CS(slave->cs), KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_IOC));
 184                 __raw_writel(SPI_IOC_CS_ALL, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_IOC));
 185                 __raw_writel(0, KSEG1ADDR(AR71XX_SPI_BASE + SPI_REG_FS));
 186         }
 187
 188         PRINTD(" ---> out\n");
 189
 190         return 0;
 191 }