diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/atmel_spi.c | 29 | ||||
| -rw-r--r-- | drivers/spi/spi_bfin5xx.c | 7 | ||||
| -rw-r--r-- | drivers/spi/spi_s3c24xx.c | 6 |
3 files changed, 28 insertions, 14 deletions
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c index 02c8e305b14f..e81d59d78910 100644 --- a/drivers/spi/atmel_spi.c +++ b/drivers/spi/atmel_spi.c @@ -497,7 +497,7 @@ static int atmel_spi_setup(struct spi_device *spi) struct atmel_spi *as; u32 scbr, csr; unsigned int bits = spi->bits_per_word; - unsigned long bus_hz, sck_hz; + unsigned long bus_hz; unsigned int npcs_pin; int ret; @@ -536,14 +536,25 @@ static int atmel_spi_setup(struct spi_device *spi) return -EINVAL; } - /* speed zero convention is used by some upper layers */ + /* + * Pre-new_1 chips start out at half the peripheral + * bus speed. + */ bus_hz = clk_get_rate(as->clk); + if (!as->new_1) + bus_hz /= 2; + if (spi->max_speed_hz) { - /* assume div32/fdiv/mbz == 0 */ - if (!as->new_1) - bus_hz /= 2; - scbr = ((bus_hz + spi->max_speed_hz - 1) - / spi->max_speed_hz); + /* + * Calculate the lowest divider that satisfies the + * constraint, assuming div32/fdiv/mbz == 0. + */ + scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz); + + /* + * If the resulting divider doesn't fit into the + * register bitfield, we can't satisfy the constraint. + */ if (scbr >= (1 << SPI_SCBR_SIZE)) { dev_dbg(&spi->dev, "setup: %d Hz too slow, scbr %u; min %ld Hz\n", @@ -551,8 +562,8 @@ static int atmel_spi_setup(struct spi_device *spi) return -EINVAL; } } else + /* speed zero means "as slow as possible" */ scbr = 0xff; - sck_hz = bus_hz / scbr; csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8); if (spi->mode & SPI_CPOL) @@ -589,7 +600,7 @@ static int atmel_spi_setup(struct spi_device *spi) dev_dbg(&spi->dev, "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n", - sck_hz, bits, spi->mode, spi->chip_select, csr); + bus_hz / scbr, bits, spi->mode, spi->chip_select, csr); spi_writel(as, CSR0 + 4 * spi->chip_select, csr); diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c index a9ac1fdb3094..7fea3cf4588a 100644 --- a/drivers/spi/spi_bfin5xx.c +++ b/drivers/spi/spi_bfin5xx.c @@ -608,6 +608,7 @@ static void pump_transfers(unsigned long data) u8 width; u16 cr, dma_width, dma_config; u32 tranf_success = 1; + u8 full_duplex = 0; /* Get current state information */ message = drv_data->cur_msg; @@ -658,6 +659,7 @@ static void pump_transfers(unsigned long data) } if (transfer->rx_buf != NULL) { + full_duplex = transfer->tx_buf != NULL; drv_data->rx = transfer->rx_buf; drv_data->rx_end = drv_data->rx + transfer->len; dev_dbg(&drv_data->pdev->dev, "rx_buf is %p, rx_end is %p\n", @@ -740,7 +742,8 @@ static void pump_transfers(unsigned long data) * successful use different way to r/w according to * drv_data->cur_chip->enable_dma */ - if (drv_data->cur_chip->enable_dma && drv_data->len > 6) { + if (!full_duplex && drv_data->cur_chip->enable_dma + && drv_data->len > 6) { disable_dma(drv_data->dma_channel); clear_dma_irqstat(drv_data->dma_channel); @@ -828,7 +831,7 @@ static void pump_transfers(unsigned long data) /* IO mode write then read */ dev_dbg(&drv_data->pdev->dev, "doing IO transfer\n"); - if (drv_data->tx != NULL && drv_data->rx != NULL) { + if (full_duplex) { /* full duplex mode */ BUG_ON((drv_data->tx_end - drv_data->tx) != (drv_data->rx_end - drv_data->rx)); diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c index 34bfb7dd7764..0885cc357a37 100644 --- a/drivers/spi/spi_s3c24xx.c +++ b/drivers/spi/spi_s3c24xx.c @@ -125,10 +125,10 @@ static int s3c24xx_spi_setupxfer(struct spi_device *spi, /* is clk = pclk / (2 * (pre+1)), or is it * clk = (pclk * 2) / ( pre + 1) */ - div = (div / 2) - 1; + div /= 2; - if (div < 0) - div = 1; + if (div > 0) + div -= 1; if (div > 255) div = 255; |