diff options
Diffstat (limited to 'drivers/staging/iio/light/tsl2583.c')
| -rw-r--r-- | drivers/staging/iio/light/tsl2583.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/drivers/staging/iio/light/tsl2583.c b/drivers/staging/iio/light/tsl2583.c index 80f77cf8e9c2..5b6455a238d8 100644 --- a/drivers/staging/iio/light/tsl2583.c +++ b/drivers/staging/iio/light/tsl2583.c @@ -194,6 +194,7 @@ static int taos_get_lux(struct iio_dev *indio_dev) { u16 ch0, ch1; /* separated ch0/ch1 data from device */ u32 lux; /* raw lux calculated from device data */ + u64 lux64; u32 ratio; u8 buf[5]; struct taos_lux *p; @@ -297,9 +298,19 @@ static int taos_get_lux(struct iio_dev *indio_dev) lux = (lux + (chip->als_time_scale >> 1)) / chip->als_time_scale; - /* adjust for active gain scale */ - lux >>= 13; /* tables have factor of 8192 builtin for accuracy */ - lux = (lux * chip->taos_settings.als_gain_trim + 500) / 1000; + /* Adjust for active gain scale. + * The taos_device_lux tables above have a factor of 8192 built in, + * so we need to shift right. + * User-specified gain provides a multiplier. + * Apply user-specified gain before shifting right to retain precision. + * Use 64 bits to avoid overflow on multiplication. + * Then go back to 32 bits before division to avoid using div_u64(). + */ + lux64 = lux; + lux64 = lux64 * chip->taos_settings.als_gain_trim; + lux64 >>= 13; + lux = lux64; + lux = (lux + 500) / 1000; if (lux > TSL258X_LUX_CALC_OVER_FLOW) { /* check for overflow */ return_max: lux = TSL258X_LUX_CALC_OVER_FLOW; @@ -933,19 +944,7 @@ static struct i2c_driver taos_driver = { .probe = taos_probe, .remove = __devexit_p(taos_remove), }; - -static int __init taos_init(void) -{ - return i2c_add_driver(&taos_driver); -} - -static void __exit taos_exit(void) -{ - i2c_del_driver(&taos_driver); -} - -module_init(taos_init); -module_exit(taos_exit); +module_i2c_driver(taos_driver); MODULE_AUTHOR("J. August Brenner<jbrenner@taosinc.com>"); MODULE_DESCRIPTION("TAOS tsl2583 ambient light sensor driver"); |