Commit f50f9831 authored by Hans de Goede's avatar Hans de Goede Committed by Jonathan Cameron
Browse files

iio: light: cm32181: Use units of 1/100000th for calibscale and lux_per_bit 



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.

Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 7574cb1d

drivers/iio/light/cm32181.c

+11 −11
Original line number Original line Diff line number Diff line
@@ -46,11 +46,11 @@ 
#define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)

#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_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)





#define CM32181_MLUX_PER_BIT		5	/* ALS_SM=01 IT=800ms */

#define CM32181_LUX_PER_BIT		500	/* ALS_SM=01 IT=800ms */

#define CM32181_MLUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */

#define CM32181_LUX_PER_BIT_RESOLUTION	100000

#define	CM32181_CALIBSCALE_DEFAULT	1000

#define CM32181_LUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */

#define CM32181_CALIBSCALE_RESOLUTION	1000

#define CM32181_CALIBSCALE_DEFAULT	100000

#define MLUX_PER_LUX			1000

#define CM32181_CALIBSCALE_RESOLUTION	100000





#define SMBUS_ALERT_RESPONSE_ADDRESS	0x0c

#define SMBUS_ALERT_RESPONSE_ADDRESS	0x0c
@@ -205,15 +205,15 @@ static int cm32181_get_lux(struct cm32181_chip *cm32181) 
	struct i2c_client *client = cm32181->client;

	struct i2c_client *client = cm32181->client;

	int ret;

	int ret;

	int als_it;

	int als_it;

	unsigned long lux;

	u64 lux;





	ret = cm32181_read_als_it(cm32181, &als_it);

	ret = cm32181_read_als_it(cm32181, &als_it);

	if (ret < 0)

	if (ret < 0)

		return -EINVAL;

		return -EINVAL;





	lux = CM32181_MLUX_PER_BIT;

	lux = CM32181_LUX_PER_BIT;

	lux *= CM32181_MLUX_PER_BIT_BASE_IT;

	lux *= CM32181_LUX_PER_BIT_BASE_IT;

	lux /= als_it;

	lux = div_u64(lux, als_it);





	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);

	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);

	if (ret < 0)

	if (ret < 0)
@@ -221,8 +221,8 @@ static int cm32181_get_lux(struct cm32181_chip *cm32181) 




	lux *= ret;

	lux *= ret;

	lux *= cm32181->calibscale;

	lux *= cm32181->calibscale;

	lux /= CM32181_CALIBSCALE_RESOLUTION;

	lux = div_u64(lux, CM32181_CALIBSCALE_RESOLUTION);

	lux /= MLUX_PER_LUX;

	lux = div_u64(lux, CM32181_LUX_PER_BIT_RESOLUTION);





	if (lux > 0xFFFF)

	if (lux > 0xFFFF)

		lux = 0xFFFF;

		lux = 0xFFFF;