iio: light: vl6180: Avoid readback of integration time register

Instead of reading the value from the register on each query, store the
set value.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index 3294839..d2a5759 100644 (file)
--- a/drivers/iio/light/vl6180.c
+++ b/drivers/iio/light/vl6180.c
@@ -86,6 +86,7 @@
 struct vl6180_data {
        struct i2c_client *client;
        struct mutex lock;
+       unsigned int als_it_ms;
 };
 
 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
@@ -306,13 +307,11 @@ static int vl6180_read_raw(struct iio_dev *indio_dev,
 
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_INT_TIME:
-               ret = vl6180_read_word(data->client, VL6180_ALS_IT);
-               if (ret < 0)
-                       return ret;
-               *val = 0; /* 1 count = 1ms (0 = 1ms) */
-               *val2 = (ret + 1) * 1000; /* convert to seconds */
+               *val = data->als_it_ms;
+               *val2 = 1000;
+
+               return IIO_VAL_FRACTIONAL;
 
-               return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_LIGHT:
@@ -401,6 +400,9 @@ static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
 
        ret = vl6180_write_word(data->client, VL6180_ALS_IT, it_ms - 1);
 
+       if (ret >= 0)
+               data->als_it_ms = it_ms;
+
 fail:
        vl6180_hold(data, false);
        mutex_unlock(&data->lock);
@@ -470,6 +472,7 @@ static int vl6180_init(struct vl6180_data *data)
                return ret;
 
        /* ALS integration time: 100ms */
+       data->als_it_ms = 100;
        ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
        if (ret < 0)
                return ret;