diff options
Diffstat (limited to 'drivers/spi/spi-davinci.c')
| -rw-r--r-- | drivers/spi/spi-davinci.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c index 987afebea093..b4605c4158f4 100644 --- a/drivers/spi/spi-davinci.c +++ b/drivers/spi/spi-davinci.c @@ -255,7 +255,7 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) * This function calculates the prescale value that generates a clock rate * less than or equal to the specified maximum. * - * Returns: calculated prescale - 1 for easy programming into SPI registers + * Returns: calculated prescale value for easy programming into SPI registers * or negative error number if valid prescalar cannot be updated. */ static inline int davinci_spi_get_prescale(struct davinci_spi *dspi, @@ -263,12 +263,13 @@ static inline int davinci_spi_get_prescale(struct davinci_spi *dspi, { int ret; - ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz); + /* Subtract 1 to match what will be programmed into SPI register. */ + ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz) - 1; - if (ret < 1 || ret > 256) + if (ret < 0 || ret > 255) return -EINVAL; - return ret - 1; + return ret; } /** |