diff options
Diffstat (limited to 'drivers/spi/mxs_spi.c')
| -rw-r--r-- | drivers/spi/mxs_spi.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c index 7859536a6..a21b02b7f 100644 --- a/drivers/spi/mxs_spi.c +++ b/drivers/spi/mxs_spi.c @@ -146,21 +146,33 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave); struct mx28_ssp_regs *ssp_regs = mxs_slave->regs; int len = bitlen / 8; - const char *tx = dout; - char *rx = din; char dummy; + int write = 0; + char *data = NULL; if (bitlen == 0) { if (flags & SPI_XFER_END) { - rx = &dummy; + din = (void *)&dummy; len = 1; } else return 0; } - if (!rx && !tx) + /* Half-duplex only */ + if (din && dout) + return -EINVAL; + /* No data */ + if (!din && !dout) return 0; + if (dout) { + data = (char *)dout; + write = 1; + } else if (din) { + data = (char *)din; + write = 0; + } + if (flags & SPI_XFER_BEGIN) mxs_spi_start_xfer(ssp_regs); @@ -171,7 +183,7 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, if ((flags & SPI_XFER_END) && !len) mxs_spi_end_xfer(ssp_regs); - if (tx) + if (write) writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_clr); else writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_set); @@ -184,20 +196,20 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, return -ETIMEDOUT; } - if (tx) - writel(*tx++, &ssp_regs->hw_ssp_data); + if (write) + writel(*data++, &ssp_regs->hw_ssp_data); writel(SSP_CTRL0_DATA_XFER, &ssp_regs->hw_ssp_ctrl0_set); - if (rx) { + if (!write) { if (mx28_wait_mask_clr(&ssp_regs->hw_ssp_status_reg, SSP_STATUS_FIFO_EMPTY, MXS_SPI_MAX_TIMEOUT)) { printf("MXS SPI: Timeout waiting for data\n"); return -ETIMEDOUT; } - *rx = readl(&ssp_regs->hw_ssp_data); - rx++; + *data = readl(&ssp_regs->hw_ssp_data); + data++; } if (mx28_wait_mask_clr(&ssp_regs->hw_ssp_ctrl0_reg, |