drivers/spi/mpc52xx_spi.c

   1 /*
   2  * (C) Copyright 2009
   3  * Frank Bodammer <frank.bodammer@gcd-solutions.de>
   4  * (C) Copyright 2009 Semihalf, Grzegorz Bernacki
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <asm/io.h>
  11 #include <malloc.h>
  12 #include <spi.h>
  13 #include <mpc5xxx.h>
  14
  15 void spi_init(void)
  16 {
  17         struct mpc5xxx_spi *spi = (struct mpc5xxx_spi *)MPC5XXX_SPI;
  18         /*
  19          * Its important to use the correct order when initializing the
  20          * registers
  21          */
  22         out_8(&spi->ddr, 0x0F); /* set all SPI pins as output */
  23         out_8(&spi->pdr, 0x00); /* set SS low */
  24         /* SPI is master, SS is general purpose output */
  25         out_8(&spi->cr1, SPI_CR_MSTR | SPI_CR_SPE);
  26         out_8(&spi->cr2, 0x00); /* normal operation */
  27         out_8(&spi->brr, 0x77); /* baud rate: IPB clock / 2048 */
  28 }
  29
  30 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  31                                   unsigned int max_hz, unsigned int mode)
  32 {
  33         struct spi_slave *slave;
  34
  35         slave = spi_alloc_slave_base(bus, cs);
  36         if (!slave)
  37                 return NULL;
  38
  39         return slave;
  40 }
  41
  42 void spi_free_slave(struct spi_slave *slave)
  43 {
  44         free(slave);
  45 }
  46
  47 int spi_claim_bus(struct spi_slave *slave)
  48 {
  49         return 0;
  50 }
  51
  52 void spi_release_bus(struct spi_slave *slave)
  53 {
  54         return;
  55 }
  56
  57 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
  58              void *din, unsigned long flags)
  59 {
  60         struct mpc5xxx_spi *spi = (struct mpc5xxx_spi *)MPC5XXX_SPI;
  61         int i, iter = bitlen >> 3;
  62         const uchar *txp = dout;
  63         uchar *rxp = din;
  64
  65         debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
  66               slave->bus, slave->cs, *(uint *) dout, *(uint *) din, bitlen);
  67
  68         if (flags & SPI_XFER_BEGIN)
  69                 setbits_8(&spi->pdr, SPI_PDR_SS);
  70
  71         for (i = 0; i < iter; i++) {
  72                 udelay(1000);
  73                 debug("spi_xfer: sending %x\n", txp[i]);
  74                 out_8(&spi->dr, txp[i]);
  75                 while (!(in_8(&spi->sr) & SPI_SR_SPIF)) {
  76                         udelay(1000);
  77                         if (in_8(&spi->sr) & SPI_SR_WCOL) {
  78                                 rxp[i] = in_8(&spi->dr);
  79                                 puts("spi_xfer: write collision\n");
  80                                 return -1;
  81                         }
  82                 }
  83                 rxp[i] = in_8(&spi->dr);
  84                 debug("spi_xfer: received %x\n", rxp[i]);
  85         }
  86         if (flags & SPI_XFER_END)
  87                 clrbits_8(&spi->pdr, SPI_PDR_SS);
  88
  89         return 0;
  90 }