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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>
This commit is contained in:
Stefan Brüns 2017-09-24 23:59:19 +02:00 committed by Jonathan Cameron
parent df698c0402
commit e794bf6751
1 changed files with 43 additions and 40 deletions
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67
drivers/iio/light/vl6180.c
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@ -24,6 +24,7 @@
#include <linux/err.h> #include <linux/err.h>
#include <linux/of.h> #include <linux/of.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/util_macros.h>
#include <linux/iio/iio.h> #include <linux/iio/iio.h>
#include <linux/iio/sysfs.h> #include <linux/iio/sysfs.h>
@ -86,6 +87,7 @@
struct vl6180_data { struct vl6180_data {
struct i2c_client *client; struct i2c_client *client;
struct mutex lock; struct mutex lock;
unsigned int als_gain_milli;
unsigned int als_it_ms; 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. * Available Ambient Light Sensor gain settings, 1/1000th, and
* Kept in order to avoid the datatype conversion while reading the * corresponding setting for the VL6180_ALS_GAIN register
* hardware_gain.
*/ */
static const int vl6180_als_gain[8][4] = { static const int vl6180_als_gain_tab[8] = {
{ 1, 0, 70, VL6180_ALS_GAIN_1 }, 1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000
{ 1, 250000, 69, VL6180_ALS_GAIN_1_25 }, };
{ 1, 670000, 68, VL6180_ALS_GAIN_1_67 }, static const u8 vl6180_als_gain_tab_bits[8] = {
{ 2, 500000, 67, VL6180_ALS_GAIN_2_5 }, VL6180_ALS_GAIN_1, VL6180_ALS_GAIN_1_25,
{ 5, 0, 66, VL6180_ALS_GAIN_5 }, VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5,
{ 10, 0, 65, VL6180_ALS_GAIN_10 }, VL6180_ALS_GAIN_5, VL6180_ALS_GAIN_10,
{ 20, 0, 64, VL6180_ALS_GAIN_20 }, VL6180_ALS_GAIN_20, VL6180_ALS_GAIN_40
{ 40, 0, 71, VL6180_ALS_GAIN_40 }
}; };
static int vl6180_read_raw(struct iio_dev *indio_dev, 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) int *val, int *val2, long mask)
{ {
struct vl6180_data *data = iio_priv(indio_dev); struct vl6180_data *data = iio_priv(indio_dev);
int ret, i; int ret;
switch (mask) { switch (mask) {
case IIO_CHAN_INFO_RAW: 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; return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_HARDWAREGAIN: case IIO_CHAN_INFO_HARDWAREGAIN:
ret = vl6180_read_byte(data->client, VL6180_ALS_GAIN); *val = data->als_gain_milli;
if (ret < 0) *val2 = 1000;
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) { return IIO_VAL_FRACTIONAL;
if (ret == vl6180_als_gain[i][2]) {
*val = vl6180_als_gain[i][0];
*val2 = vl6180_als_gain[i][1];
}
}
return IIO_VAL_INT_PLUS_MICRO;
default: default:
return -EINVAL; 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) static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2)
{ {
int i, ret; int i, ret, gain;
if (val < 1 || val > 40)
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));
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); mutex_lock(&data->lock);
ret = vl6180_hold(data, true); ret = vl6180_hold(data, true);
if (ret < 0) if (ret < 0)
goto fail; goto fail;
ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN, ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN,
vl6180_als_gain[i][3]); vl6180_als_gain_tab_bits[i]);
if (ret >= 0)
data->als_gain_milli = vl6180_als_gain_tab[i];
fail: fail:
vl6180_hold(data, false); vl6180_hold(data, false);
mutex_unlock(&data->lock); mutex_unlock(&data->lock);
return ret; return ret;
}
}
return -EINVAL;
} }
static int vl6180_set_it(struct vl6180_data *data, int val, int val2) 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; return ret;
/* ALS gain: 1 */ /* ALS gain: 1 */
data->als_gain_milli = 1000;
ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1); ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1);
if (ret < 0) if (ret < 0)
return ret; return ret;