[PATCH v2 2/4] iio: light: vl6180: Avoid readback of integration time register

From: Stefan BrÃns
Date: Sat Sep 23 2017 - 18:59:17 EST


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

Signed-off-by: Stefan BrÃns <stefan.bruens@xxxxxxxxxxxxxx>
---
drivers/iio/light/vl6180.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index 68b9babfd298..e6466cc81766 100644
--- 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 = 0;
+ *val2 = data->als_it_ms * 1000;

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);
@@ -472,6 +474,7 @@ 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;
--
2.14.1