diff options
Diffstat (limited to 'drivers/spi/spi-tegra20-slink.c')
| -rw-r--r-- | drivers/spi/spi-tegra20-slink.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/spi/spi-tegra20-slink.c b/drivers/spi/spi-tegra20-slink.c index 1427f343b39a..6d4679126213 100644 --- a/drivers/spi/spi-tegra20-slink.c +++ b/drivers/spi/spi-tegra20-slink.c @@ -717,9 +717,6 @@ static int tegra_slink_start_transfer_one(struct spi_device *spi, command2 = tspi->command2_reg; command2 &= ~(SLINK_RXEN | SLINK_TXEN); - tegra_slink_writel(tspi, command, SLINK_COMMAND); - tspi->command_reg = command; - tspi->cur_direction = 0; if (t->rx_buf) { command2 |= SLINK_RXEN; @@ -729,9 +726,18 @@ static int tegra_slink_start_transfer_one(struct spi_device *spi, command2 |= SLINK_TXEN; tspi->cur_direction |= DATA_DIR_TX; } + + /* + * Writing to the command2 register bevore the command register prevents + * a spike in chip_select line 0. This selects the chip_select line + * before changing the chip_select value. + */ tegra_slink_writel(tspi, command2, SLINK_COMMAND2); tspi->command2_reg = command2; + tegra_slink_writel(tspi, command, SLINK_COMMAND); + tspi->command_reg = command; + if (total_fifo_words > SLINK_FIFO_DEPTH) ret = tegra_slink_start_dma_based_transfer(tspi, t); else |