Use units of 1/100000th for calibscale and lux_per_bit. The similar cm3232 driver already uses 1/100000th as unit for calibscale. This allows for higher-accuracy and makes it easier to add support for getting device-specific calibscale and lux_per_bit values from a device's ACPI tables, as the values in the ACPI tables also use 1/100000th units. This units change means that our intermediate values in cm32181_get_lux() may get quite big, change the type of the lux variable to a u64 to deal with this. Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> --- drivers/iio/light/cm32181.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c index e31c1005b03d..4fdf2f4a23ab 100644 --- a/drivers/iio/light/cm32181.c +++ b/drivers/iio/light/cm32181.c @@ -45,11 +45,11 @@ #define CM32181_CMD_ALS_SM_MASK (0x03 << CM32181_CMD_ALS_SM_SHIFT) #define CM32181_CMD_ALS_SM_DEFAULT (0x01 << CM32181_CMD_ALS_SM_SHIFT) -#define CM32181_MLUX_PER_BIT 5 /* ALS_SM=01 IT=800ms */ -#define CM32181_MLUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */ -#define CM32181_CALIBSCALE_DEFAULT 1000 -#define CM32181_CALIBSCALE_RESOLUTION 1000 -#define MLUX_PER_LUX 1000 +#define CM32181_LUX_PER_BIT 500 /* ALS_SM=01 IT=800ms */ +#define CM32181_LUX_PER_BIT_RESOLUTION 100000 +#define CM32181_LUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */ +#define CM32181_CALIBSCALE_DEFAULT 100000 +#define CM32181_CALIBSCALE_RESOLUTION 100000 #define SMBUS_ALERT_RESPONSE_ADDRESS 0x0c @@ -208,15 +208,15 @@ static int cm32181_get_lux(struct cm32181_chip *cm32181) struct i2c_client *client = cm32181->client; int ret; int als_it; - unsigned long lux; + u64 lux; ret = cm32181_read_als_it(cm32181, &als_it); if (ret < 0) return -EINVAL; - lux = CM32181_MLUX_PER_BIT; - lux *= CM32181_MLUX_PER_BIT_BASE_IT; - lux /= als_it; + lux = CM32181_LUX_PER_BIT; + lux *= CM32181_LUX_PER_BIT_BASE_IT; + lux = div_u64(lux, als_it); ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS); if (ret < 0) @@ -224,8 +224,8 @@ static int cm32181_get_lux(struct cm32181_chip *cm32181) lux *= ret; lux *= cm32181->calibscale; - lux /= CM32181_CALIBSCALE_RESOLUTION; - lux /= MLUX_PER_LUX; + lux = div_u64(lux, CM32181_CALIBSCALE_RESOLUTION); + lux = div_u64(lux, CM32181_LUX_PER_BIT_RESOLUTION); if (lux > 0xFFFF) lux = 0xFFFF; -- 2.26.0
