drivers/spi/kirkwood_spi.c

   1 /*
   2  * (C) Copyright 2009
   3  * Marvell Semiconductor <www.marvell.com>
   4  * Written-by: Prafulla Wadaskar <prafulla@marvell.com>
   5  *
   6  * Derived from drivers/spi/mpc8xxx_spi.c
   7  *
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  24  * MA 02110-1301 USA
  25  */
  26
  27 #include <common.h>
  28 #include <malloc.h>
  29 #include <spi.h>
  30 #include <asm/io.h>
  31 #include <asm/arch/kirkwood.h>
  32 #include <asm/arch/spi.h>
  33 #include <asm/arch/mpp.h>
  34
  35 static struct kwspi_registers *spireg = (struct kwspi_registers *)KW_SPI_BASE;
  36
  37 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  38                                 unsigned int max_hz, unsigned int mode)
  39 {
  40         struct spi_slave *slave;
  41         u32 data;
  42         u32 kwspi_mpp_config[] = {
  43                 MPP0_GPIO,
  44                 MPP7_SPI_SCn,
  45                 0
  46         };
  47
  48         if (!spi_cs_is_valid(bus, cs))
  49                 return NULL;
  50
  51         slave = malloc(sizeof(struct spi_slave));
  52         if (!slave)
  53                 return NULL;
  54
  55         slave->bus = bus;
  56         slave->cs = cs;
  57
  58         writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
  59
  60         /* calculate spi clock prescaller using max_hz */
  61         data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
  62         data |= 0x10;
  63
  64         /* program spi clock prescaller using max_hz */
  65         writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
  66         debug("data = 0x%08x \n", data);
  67
  68         writel(KWSPI_SMEMRDIRQ, &spireg->irq_cause);
  69         writel(KWSPI_IRQMASK, &spireg->irq_mask);
  70
  71         /* program mpp registers to select  SPI_CSn */
  72         if (cs) {
  73                 kwspi_mpp_config[0] = MPP0_GPIO;
  74                 kwspi_mpp_config[1] = MPP7_SPI_SCn;
  75         } else {
  76                 kwspi_mpp_config[0] = MPP0_SPI_SCn;
  77                 kwspi_mpp_config[1] = MPP7_GPO;
  78         }
  79         kirkwood_mpp_conf(kwspi_mpp_config);
  80
  81         return slave;
  82 }
  83
  84 void spi_free_slave(struct spi_slave *slave)
  85 {
  86         free(slave);
  87 }
  88
  89 int spi_claim_bus(struct spi_slave *slave)
  90 {
  91         return 0;
  92 }
  93
  94 void spi_release_bus(struct spi_slave *slave)
  95 {
  96 }
  97
  98 #ifndef CONFIG_SPI_CS_IS_VALID
  99 /*
 100  * you can define this function board specific
 101  * define above CONFIG in board specific config file and
 102  * provide the function in board specific src file
 103  */
 104 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 105 {
 106         return (bus == 0 && (cs == 0 || cs == 1));
 107 }
 108 #endif
 109
 110 void spi_init(void)
 111 {
 112 }
 113
 114 void spi_cs_activate(struct spi_slave *slave)
 115 {
 116         writel(readl(&spireg->ctrl) | KWSPI_IRQUNMASK, &spireg->ctrl);
 117 }
 118
 119 void spi_cs_deactivate(struct spi_slave *slave)
 120 {
 121         writel(readl(&spireg->ctrl) & KWSPI_IRQMASK, &spireg->ctrl);
 122 }
 123
 124 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 125              void *din, unsigned long flags)
 126 {
 127         unsigned int tmpdout, tmpdin;
 128         int tm, isread = 0;
 129
 130         debug("spi_xfer: slave %u:%u dout %p din %p bitlen %u\n",
 131               slave->bus, slave->cs, dout, din, bitlen);
 132
 133         if (flags & SPI_XFER_BEGIN)
 134                 spi_cs_activate(slave);
 135
 136         /*
 137          * handle data in 8-bit chunks
 138          * TBD: 2byte xfer mode to be enabled
 139          */
 140         writel(((readl(&spireg->cfg) & ~KWSPI_XFERLEN_MASK) |
 141                 KWSPI_XFERLEN_1BYTE), &spireg->cfg);
 142
 143         while (bitlen > 4) {
 144                 debug("loopstart bitlen %d\n", bitlen);
 145                 tmpdout = 0;
 146
 147                 /* Shift data so it's msb-justified */
 148                 if (dout)
 149                         tmpdout = *(u32 *) dout & 0x0ff;
 150
 151                 writel(~KWSPI_SMEMRDIRQ, &spireg->irq_cause);
 152                 writel(tmpdout, &spireg->dout); /* Write the data out */
 153                 debug("*** spi_xfer: ... %08x written, bitlen %d\n",
 154                       tmpdout, bitlen);
 155
 156                 /*
 157                  * Wait for SPI transmit to get out
 158                  * or time out (1 second = 1000 ms)
 159                  * The NE event must be read and cleared first
 160                  */
 161                 for (tm = 0, isread = 0; tm < KWSPI_TIMEOUT; ++tm) {
 162                         if (readl(&spireg->irq_cause) & KWSPI_SMEMRDIRQ) {
 163                                 isread = 1;
 164                                 tmpdin = readl(&spireg->din);
 165                                 debug
 166                                         ("spi_xfer: din %p..%08x read\n",
 167                                         din, tmpdin);
 168
 169                                 if (din) {
 170                                         *((u8 *) din) = (u8) tmpdin;
 171                                         din += 1;
 172                                 }
 173                                 if (dout)
 174                                         dout += 1;
 175                                 bitlen -= 8;
 176                         }
 177                         if (isread)
 178                                 break;
 179                 }
 180                 if (tm >= KWSPI_TIMEOUT)
 181                         printf("*** spi_xfer: Time out during SPI transfer\n");
 182
 183                 debug("loopend bitlen %d\n", bitlen);
 184         }
 185
 186         if (flags & SPI_XFER_END)
 187                 spi_cs_deactivate(slave);
 188
 189         return 0;
 190 }