On Wed, 19 Jun 2019 17:07:02 +0300 Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > Instead of linear approach to calculate power of 10, use generic int_pow() > which does it better. > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> 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 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 <linux/module.h> > #include <linux/interrupt.h> > #include <linux/irq.h> > +#include <linux/kernel.h> > #include <linux/slab.h> > #include <linux/hid-sensor-hub.h> > #include <linux/iio/iio.h> > @@ -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;