diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/mxc_spi.c | 149 |
1 files changed, 111 insertions, 38 deletions
diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c index c6c8f60c3..d558137c9 100644 --- a/drivers/spi/mxc_spi.c +++ b/drivers/spi/mxc_spi.c @@ -62,6 +62,7 @@ #define MXC_CSPICTRL_MAXBITS 0x1f #define MXC_CSPIPERIOD_32KHZ (1 << 15) +#define MAX_SPI_BYTES 4 static unsigned long spi_bases[] = { 0x43fa4000, @@ -95,6 +96,7 @@ static unsigned long spi_bases[] = { #define MXC_CSPICTRL_RXOVF (1 << 6) #define MXC_CSPIPERIOD_32KHZ (1 << 15) +#define MAX_SPI_BYTES 32 /* Bit position inside CTRL register to be associated with SS */ #define MXC_CSPICTRL_CHAN 18 @@ -252,13 +254,15 @@ static s32 spi_cfg(struct mxc_spi_slave *mxcs, unsigned int cs, } #endif -static u32 spi_xchg_single(struct spi_slave *slave, u32 data, int bitlen, - unsigned long flags) +int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen, + const u8 *dout, u8 *din, unsigned long flags) { struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave); + int nbytes = (bitlen + 7) / 8; + u32 data, cnt, i; - if (flags & SPI_XFER_BEGIN) - spi_cs_activate(slave); + debug("%s: bitlen %d dout 0x%x din 0x%x\n", + __func__, bitlen, (u32)dout, (u32)din); mxcs->ctrl_reg = (mxcs->ctrl_reg & ~MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS)) | @@ -273,8 +277,46 @@ static u32 spi_xchg_single(struct spi_slave *slave, u32 data, int bitlen, reg_write(mxcs->base + MXC_CSPISTAT, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF); - debug("Sending SPI 0x%x\n", data); - reg_write(mxcs->base + MXC_CSPITXDATA, data); + /* + * The SPI controller works only with words, + * check if less than a word is sent. + * Access to the FIFO is only 32 bit + */ + if (bitlen % 32) { + data = 0; + cnt = (bitlen % 32) / 8; + if (dout) { + for (i = 0; i < cnt; i++) { + data = (data << 8) | (*dout++ & 0xFF); + } + } + debug("Sending SPI 0x%x\n", data); + + reg_write(mxcs->base + MXC_CSPITXDATA, data); + nbytes -= cnt; + } + + data = 0; + + while (nbytes > 0) { + data = 0; + if (dout) { + /* Buffer is not 32-bit aligned */ + if ((unsigned long)dout & 0x03) { + data = 0; + for (i = 0; i < 4; i++, data <<= 8) { + data = (data << 8) | (*dout++ & 0xFF); + } + } else { + data = *(u32 *)dout; + data = cpu_to_be32(data); + } + dout += 4; + } + debug("Sending SPI 0x%x\n", data); + reg_write(mxcs->base + MXC_CSPITXDATA, data); + nbytes -= 4; + } /* FIFO is written, now starts the transfer setting the XCH bit */ reg_write(mxcs->base + MXC_CSPICTRL, mxcs->ctrl_reg | @@ -288,49 +330,78 @@ static u32 spi_xchg_single(struct spi_slave *slave, u32 data, int bitlen, reg_write(mxcs->base + MXC_CSPISTAT, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF); - data = reg_read(mxcs->base + MXC_CSPIRXDATA); - debug("SPI Rx: 0x%x\n", data); + nbytes = (bitlen + 7) / 8; - if (flags & SPI_XFER_END) - spi_cs_deactivate(slave); + cnt = nbytes % 32; - return data; + if (bitlen % 32) { + data = reg_read(mxcs->base + MXC_CSPIRXDATA); + cnt = (bitlen % 32) / 8; + debug("SPI Rx unaligned: 0x%x\n", data); + if (din) { + for (i = 0; i < cnt; i++, data >>= 8) { + *din++ = data & 0xFF; + } + } + nbytes -= cnt; + } + + while (nbytes > 0) { + u32 tmp; + tmp = reg_read(mxcs->base + MXC_CSPIRXDATA); + data = cpu_to_be32(tmp); + debug("SPI Rx: 0x%x 0x%x\n", tmp, data); + cnt = min(nbytes, sizeof(data)); + if (din) { + memcpy(din, &data, cnt); + din += cnt; + } + nbytes -= cnt; + } + + return 0; } + int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, void *din, unsigned long flags) { - int n_blks = (bitlen + 31) / 32; - u32 *out_l, *in_l; - int i; + int n_bytes = (bitlen + 7) / 8; + int n_bits; + int ret; + u32 blk_size; + u8 *p_outbuf = (u8 *)dout; + u8 *p_inbuf = (u8 *)din; - if ((int)dout & 3 || (int)din & 3) { - printf("Error: unaligned buffers in: %p, out: %p\n", din, dout); - return 1; - } + if (!slave) + return -1; - /* This driver is currently partly broken, alert the user */ - if (bitlen > 16 && (bitlen % 32)) { - printf("Error: SPI transfer with bitlen=%d is broken.\n", - bitlen); - return 1; + if (flags & SPI_XFER_BEGIN) + spi_cs_activate(slave); + + while (n_bytes > 0) { + + if (n_bytes < MAX_SPI_BYTES) + blk_size = n_bytes; + else + blk_size = MAX_SPI_BYTES; + + n_bits = blk_size * 8; + + ret = spi_xchg_single(slave, n_bits, p_outbuf, p_inbuf, 0); + + if (ret) + return ret; + if (dout) + p_outbuf += blk_size; + if (din) + p_inbuf += blk_size; + n_bytes -= blk_size; } - for (i = 0, in_l = (u32 *)din, out_l = (u32 *)dout; - i < n_blks; - i++, in_l++, out_l++, bitlen -= 32) { - u32 data = spi_xchg_single(slave, *out_l, bitlen, flags); - - /* Check if we're only transfering 8 or 16 bits */ - if (!i) { - if (bitlen < 9) - *(u8 *)din = data; - else if (bitlen < 17) - *(u16 *)din = data; - else - *in_l = data; - } + if (flags & SPI_XFER_END) { + spi_cs_deactivate(slave); } return 0; @@ -378,8 +449,10 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, return NULL; mxcs = malloc(sizeof(struct mxc_spi_slave)); - if (!mxcs) + if (!mxcs) { + puts("mxc_spi: SPI Slave not allocated !\n"); return NULL; + } ret = decode_cs(mxcs, cs); if (ret < 0) { |