diff options
author | Stefan Brüns <stefan.bruens@rwth-aachen.de> | 2017-09-24 23:59:19 +0200 |
---|---|---|
committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2017-10-09 20:50:15 +0100 |
commit | e794bf6751a0376a459ae1659a1646652b198cad (patch) | |
tree | adb2e7706adae36b19e01896a472452a25705e11 /drivers | |
parent | df698c0402eaa2c949344c45f42a7d85e9506533 (diff) |
iio: light: vl6180: Cleanup als_gain lookup, avoid register readback
Instead of manually iterating the array of allowed gain values, use
find_closest. Storing the current gain setting avoids accessing the
hardware on each query.
Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/iio/light/vl6180.c | 85 |
1 files changed, 44 insertions, 41 deletions
diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c index d2a57596f448..561a993a2723 100644 --- a/drivers/iio/light/vl6180.c +++ b/drivers/iio/light/vl6180.c @@ -24,6 +24,7 @@ #include <linux/err.h> #include <linux/of.h> #include <linux/delay.h> +#include <linux/util_macros.h> #include <linux/iio/iio.h> #include <linux/iio/sysfs.h> @@ -86,6 +87,7 @@ struct vl6180_data { struct i2c_client *client; struct mutex lock; + unsigned int als_gain_milli; unsigned int als_it_ms; }; @@ -276,19 +278,17 @@ static const struct iio_chan_spec vl6180_channels[] = { }; /* - * Columns 3 & 4 represent the same value in decimal and hex notations. - * Kept in order to avoid the datatype conversion while reading the - * hardware_gain. + * Available Ambient Light Sensor gain settings, 1/1000th, and + * corresponding setting for the VL6180_ALS_GAIN register */ -static const int vl6180_als_gain[8][4] = { - { 1, 0, 70, VL6180_ALS_GAIN_1 }, - { 1, 250000, 69, VL6180_ALS_GAIN_1_25 }, - { 1, 670000, 68, VL6180_ALS_GAIN_1_67 }, - { 2, 500000, 67, VL6180_ALS_GAIN_2_5 }, - { 5, 0, 66, VL6180_ALS_GAIN_5 }, - { 10, 0, 65, VL6180_ALS_GAIN_10 }, - { 20, 0, 64, VL6180_ALS_GAIN_20 }, - { 40, 0, 71, VL6180_ALS_GAIN_40 } +static const int vl6180_als_gain_tab[8] = { + 1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000 +}; +static const u8 vl6180_als_gain_tab_bits[8] = { + VL6180_ALS_GAIN_1, VL6180_ALS_GAIN_1_25, + VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5, + VL6180_ALS_GAIN_5, VL6180_ALS_GAIN_10, + VL6180_ALS_GAIN_20, VL6180_ALS_GAIN_40 }; static int vl6180_read_raw(struct iio_dev *indio_dev, @@ -296,7 +296,7 @@ static int vl6180_read_raw(struct iio_dev *indio_dev, int *val, int *val2, long mask) { struct vl6180_data *data = iio_priv(indio_dev); - int ret, i; + int ret; switch (mask) { case IIO_CHAN_INFO_RAW: @@ -328,17 +328,11 @@ static int vl6180_read_raw(struct iio_dev *indio_dev, return IIO_VAL_INT_PLUS_MICRO; case IIO_CHAN_INFO_HARDWAREGAIN: - ret = vl6180_read_byte(data->client, VL6180_ALS_GAIN); - if (ret < 0) - return -EINVAL; - for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) { - if (ret == vl6180_als_gain[i][2]) { - *val = vl6180_als_gain[i][0]; - *val2 = vl6180_als_gain[i][1]; - } - } + *val = data->als_gain_milli; + *val2 = 1000; + + return IIO_VAL_FRACTIONAL; - return IIO_VAL_INT_PLUS_MICRO; default: return -EINVAL; } @@ -364,25 +358,33 @@ static int vl6180_hold(struct vl6180_data *data, bool hold) static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2) { - int i, ret; - - for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) { - if (val == vl6180_als_gain[i][0] && - val2 == vl6180_als_gain[i][1]) { - mutex_lock(&data->lock); - ret = vl6180_hold(data, true); - if (ret < 0) - goto fail; - ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN, - vl6180_als_gain[i][3]); -fail: - vl6180_hold(data, false); - mutex_unlock(&data->lock); - return ret; - } - } + int i, ret, gain; + + if (val < 1 || val > 40) + return -EINVAL; - return -EINVAL; + gain = (val * 1000000 + val2) / 1000; + if (gain < 1 || gain > 40000) + return -EINVAL; + + i = find_closest(gain, vl6180_als_gain_tab, + ARRAY_SIZE(vl6180_als_gain_tab)); + + mutex_lock(&data->lock); + ret = vl6180_hold(data, true); + if (ret < 0) + goto fail; + + ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN, + vl6180_als_gain_tab_bits[i]); + + if (ret >= 0) + data->als_gain_milli = vl6180_als_gain_tab[i]; + +fail: + vl6180_hold(data, false); + mutex_unlock(&data->lock); + return ret; } static int vl6180_set_it(struct vl6180_data *data, int val, int val2) @@ -478,6 +480,7 @@ static int vl6180_init(struct vl6180_data *data) return ret; /* ALS gain: 1 */ + data->als_gain_milli = 1000; ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1); if (ret < 0) return ret; |