On 01/06/16 17:22, Lars-Peter Clausen wrote: > On 06/01/2016 05:55 PM, Luis de Bethencourt wrote: >> Correctly handle the settling time cycles value. The else branch was an >> impossible condition (> 1022 in the else branch of > 511) and the handling >> of the values was dividing by 2 and 4, with a left shift, instead of >> multiplying. >> >> Based on the Table 13 at the bottom of Page 25 of the Data Sheet: >> http://www.analog.com/media/en/technical-documentation/data-sheets/AD5933.pdf >> >> Signed-off-by: Luis de Bethencourt <luisbg@xxxxxxxxxxxxxxx> >> --- >> >> Hi, >> >> I decided to use the hexadecimal values instead of (1 << 10) and (1 << 9), for >> briefness, I could resend using those instead if it is prefered. >> >> I also decided to use multiplications instead of right-shifts for readability. >> I could use change that as well. >> >> Thanks, >> Luis >> >> drivers/staging/iio/impedance-analyzer/ad5933.c | 11 +++++++---- >> 1 file changed, 7 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c >> index 9f43976..3a2cf8f3 100644 >> --- a/drivers/staging/iio/impedance-analyzer/ad5933.c >> +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c >> @@ -444,10 +444,13 @@ static ssize_t ad5933_store(struct device *dev, >> st->settling_cycles = val; >> >> /* 2x, 4x handling, see datasheet */ >> - if (val > 511) >> - val = (val >> 1) | (1 << 9); >> - else if (val > 1022) >> - val = (val >> 2) | (3 << 9); >> + if (val & 0x400 && val & 0x200) { >> + val &= 0x1ff; >> + val *= 4; >> + } else if (val & 0x200) { >> + val &= 0x1ff; >> + val *= 2; >> + } > > This does not look correct. D10 and D9 select an additional multiplier of > either 1, 2 or 4. So dividing the value before writing it to the register is > the right approach in that case. Just flipping the order in which the > conditions are evaluated should be sufficient. > >> >> dat = cpu_to_be16(val); >> ret = ad5933_i2c_write(st->client, >> > I misunderstood the register being read instead of being written. Looking at it now, I have no idea why. Sorry. Will resend a patch flipping the order of conditions. Thanks for the review, Luis -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
