On Sun, 2019-08-18 at 20:22 +0100, Jonathan Cameron wrote: > On Tue, 13 Aug 2019 17:43:15 +0300 > Andy Shevchenko wrote: > > > On Sat, Jun 22, 2019 at 10:06:42AM +0100, Jonathan Cameron wrote: > > > On Wed, 19 Jun 2019 17:07:02 +0300 > > > Andy Shevchenko wrote: > > > > > > > Instead of linear approach to calculate power of 10, use > > > > generic int_pow() > > > > which does it better. > > > > */ > > > > u64 int_pow(u64 base, unsigned int exp) > > > > { > > > > u64 result = 1; > > > > > > > > while (exp) { > > > > if (exp & 1) > > > > result *= base; > > > > exp >>= 1; > > > > base *= base; > > > > } > > > > > > > > return result; > > > > } > > > > Signed-off-by: Andy Shevchenko < > > > > andriy.shevchenko@linux.intel.com> > > > Hi Jonathan, > > > Hi Andy, > > > > > > Looks good to me, but I would like Srinivas to take a look and > > > preferably test this a bit just to check we aren't all missing > > > something > > > subtle! > > > > > > +CC Srinivas > > > > Srinivas, do you have any comments on this? > > I think Srinivas got dropped from your CC list for some reason. > > Anyhow, it's been a while so let's conclude Srinivas is busy and > rely on it being as obviously correct as it seems to be ;) Looks correct to me. I will be LPC, so hope to see you if you are there. Thanks, Srinivas > > Applied to the togreg branch of iio.git and pushed out as testing for > the autobuilders to play with it. > > Thanks, > > Jonathan > > > > > > > > > Thanks, > > > > > > Jonathan > > > > --- > > > > .../hid-sensors/hid-sensor-attributes.c | 53 ++++++++--- > > > > -------- > > > > 1 file changed, 22 insertions(+), 31 deletions(-) > > > > > > > > diff --git a/drivers/iio/common/hid-sensors/hid-sensor- > > > > attributes.c b/drivers/iio/common/hid-sensors/hid-sensor- > > > > attributes.c > > > > index a8a3fe428d8d..b9dd19b34267 100644 > > > > --- a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c > > > > +++ b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c > > > > @@ -8,6 +8,7 @@ > > > > #include > > > > #include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > #include > > > > @@ -68,16 +69,6 @@ static struct { > > > > {HID_USAGE_SENSOR_HUMIDITY, 0, 1000, 0}, > > > > }; > > > > > > > > -static int pow_10(unsigned power) > > > > -{ > > > > - int i; > > > > - int ret = 1; > > > > - for (i = 0; i < power; ++i) > > > > - ret = ret * 10; > > > > - > > > > - return ret; > > > > -} > > > > - > > > > static void simple_div(int dividend, int divisor, int *whole, > > > > int *micro_frac) > > > > { > > > > @@ -96,14 +87,14 @@ static void simple_div(int dividend, int > > > > divisor, int *whole, > > > > rem *= 10; > > > > exp++; > > > > } > > > > - *micro_frac = (rem / divisor) * pow_10(6-exp); > > > > + *micro_frac = (rem / divisor) * int_pow(10, 6 - > > > > exp); > > > > } > > > > } > > > > > > > > static void split_micro_fraction(unsigned int no, int exp, int > > > > *val1, int *val2) > > > > { > > > > - *val1 = no/pow_10(exp); > > > > - *val2 = no%pow_10(exp) * pow_10(6-exp); > > > > + *val1 = no / int_pow(10, exp); > > > > + *val2 = no % int_pow(10, exp) * int_pow(10, 6 - exp); > > > > } > > > > > > > > /* > > > > @@ -125,7 +116,7 @@ static void convert_from_vtf_format(u32 > > > > value, int size, int exp, > > > > } > > > > exp = hid_sensor_convert_exponent(exp); > > > > if (exp >= 0) { > > > > - *val1 = sign * value * pow_10(exp); > > > > + *val1 = sign * value * int_pow(10, exp); > > > > *val2 = 0; > > > > } else { > > > > split_micro_fraction(value, -exp, val1, val2); > > > > @@ -145,10 +136,10 @@ static u32 convert_to_vtf_format(int > > > > size, int exp, int val1, int val2) > > > > sign = -1; > > > > exp = hid_sensor_convert_exponent(exp); > > > > if (exp < 0) { > > > > - value = abs(val1) * pow_10(-exp); > > > > - value += abs(val2) / pow_10(6+exp); > > > > + value = abs(val1) * int_pow(10, -exp); > > > > + value += abs(val2) / int_pow(10, 6 + exp); > > > > } else > > > > - value = abs(val1) / pow_10(exp); > > > > + value = abs(val1) / int_pow(10, exp); > > > > if (sign < 0) > > > > value = ((1LL << (size * 8)) - value); > > > > > > > > @@ -211,12 +202,12 @@ int > > > > hid_sensor_write_samp_freq_value(struct hid_sensor_common *st, > > > > if (val1 < 0 || val2 < 0) > > > > return -EINVAL; > > > > > > > > - value = val1 * pow_10(6) + val2; > > > > + value = val1 * int_pow(10, 6) + val2; > > > > if (value) { > > > > if (st->poll.units == > > > > HID_USAGE_SENSOR_UNITS_MILLISECOND) > > > > - value = pow_10(9)/value; > > > > + value = int_pow(10, 9) / value; > > > > else if (st->poll.units == > > > > HID_USAGE_SENSOR_UNITS_SECOND) > > > > - value = pow_10(6)/value; > > > > + value = int_pow(10, 6) / value; > > > > else > > > > value = 0; > > > > } > > > > @@ -311,34 +302,34 @@ static void adjust_exponent_nano(int > > > > *val0, int *val1, int scale0, > > > > int rem; > > > > > > > > if (exp > 0) { > > > > - *val0 = scale0 * pow_10(exp); > > > > + *val0 = scale0 * int_pow(10, exp); > > > > res = 0; > > > > if (exp > 9) { > > > > *val1 = 0; > > > > return; > > > > } > > > > for (i = 0; i < exp; ++i) { > > > > - x = scale1 / pow_10(8 - i); > > > > - res += (pow_10(exp - 1 - i) * x); > > > > - scale1 = scale1 % pow_10(8 - i); > > > > + x = scale1 / int_pow(10, 8 - i); > > > > + res += int_pow(10, exp - 1 - i) * x; > > > > + scale1 = scale1 % int_pow(10, 8 - i); > > > > } > > > > *val0 += res; > > > > - *val1 = scale1 * pow_10(exp); > > > > + *val1 = scale1 * int_pow(10, exp); > > > > } else if (exp < 0) { > > > > exp = abs(exp); > > > > if (exp > 9) { > > > > *val0 = *val1 = 0; > > > > return; > > > > } > > > > - *val0 = scale0 / pow_10(exp); > > > > - rem = scale0 % pow_10(exp); > > > > + *val0 = scale0 / int_pow(10, exp); > > > > + rem = scale0 % int_pow(10, exp); > > > > res = 0; > > > > for (i = 0; i < (9 - exp); ++i) { > > > > - x = scale1 / pow_10(8 - i); > > > > - res += (pow_10(8 - exp - i) * x); > > > > - scale1 = scale1 % pow_10(8 - i); > > > > + x = scale1 / int_pow(10, 8 - i); > > > > + res += int_pow(10, 8 - exp - i) * x; > > > > + scale1 = scale1 % int_pow(10, 8 - i); > > > > } > > > > - *val1 = rem * pow_10(9 - exp) + res; > > > > + *val1 = rem * int_pow(10, 9 - exp) + res; > > > > } else { > > > > *val0 = scale0; > > > > *val1 = scale1; > > > > > > > >