On Sun, 24 Sep 2017 23:59:19 +0200
Stefan Brüns <stefan.bru...@rwth-aachen.de> wrote:
> 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.bru...@rwth-aachen.de>
>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
Thanks,
Jonathan
> ---
>
> Changes in v3: None
> Changes in v2:
> - Add missing spaces
>
> drivers/iio/light/vl6180.c | 85
> ++++++++++++++++++++++++----------------------
> 1 file changed, 44 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
> index 9b056c83a90a..49e9f92cd116 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)
> @@ -479,6 +481,7 @@ 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;
