Off-by-one error, gave erroneous divisor value 16 if speed_hz is over zero but less than OMAP2_MCSPI_MAX_FREQ / (1 << 15), that is, [1..1463].
Also few overly complex bit shifts in divisor fixed. Also one dev_dgb line fixed, which indicated max speed exceeding transfer speed. Introducing a new function omap2_mcspi_calc_divisor() for getting the right divisor in omap2_mcspi_setup_transfer(). Signed-off-by: Phil Carmody <[email protected]> Signed-off-by: Hannu Heikkinen <[email protected]> --- drivers/spi/omap2_mcspi.c | 29 ++++++++++++++++++----------- 1 files changed, 18 insertions(+), 11 deletions(-) diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c index 36501ad..845248c 100644 --- a/drivers/spi/omap2_mcspi.c +++ b/drivers/spi/omap2_mcspi.c @@ -631,6 +631,17 @@ out: return count - c; } +static u32 omap2_mcspi_calc_divisor(u32 speed_hz) +{ + u32 div; + + for (div = 0; div < 15; div++) + if (speed_hz >= (OMAP2_MCSPI_MAX_FREQ >> div)) + return div; + + return 15; +} + /* called only when no transfer is active to this device */ static int omap2_mcspi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) @@ -653,12 +664,8 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi, if (t && t->speed_hz) speed_hz = t->speed_hz; - if (speed_hz) { - while (div <= 15 && (OMAP2_MCSPI_MAX_FREQ / (1 << div)) - > speed_hz) - div++; - } else - div = 15; + speed_hz = min(speed_hz, OMAP2_MCSPI_MAX_FREQ); + div = omap2_mcspi_calc_divisor(speed_hz); l = mcspi_cached_chconf0(spi); @@ -695,7 +702,7 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi, mcspi_write_chconf0(spi, l); dev_dbg(&spi->dev, "setup: speed %d, sample %s edge, clk %s\n", - OMAP2_MCSPI_MAX_FREQ / (1 << div), + OMAP2_MCSPI_MAX_FREQ >> div, (spi->mode & SPI_CPHA) ? "trailing" : "leading", (spi->mode & SPI_CPOL) ? "inverted" : "normal"); @@ -996,10 +1003,10 @@ static int omap2_mcspi_transfer(struct spi_device *spi, struct spi_message *m) t->bits_per_word); return -EINVAL; } - if (t->speed_hz && t->speed_hz < OMAP2_MCSPI_MAX_FREQ/(1<<16)) { - dev_dbg(&spi->dev, "%d Hz max exceeds %d\n", - t->speed_hz, - OMAP2_MCSPI_MAX_FREQ/(1<<16)); + if (t->speed_hz && t->speed_hz < (OMAP2_MCSPI_MAX_FREQ >> 15)) { + dev_dbg(&spi->dev, "speed_hz %d below minimum %d Hz\n", + t->speed_hz, + OMAP2_MCSPI_MAX_FREQ >> 15); return -EINVAL; } -- 1.7.3 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
