[PATCH v2 1/4] iio: light: ltr390: Added configurable sampling frequency support

Abhash Jha
2024-09-10T04:51:38Z

Provied configurable sampling frequency(Measurement rate) support.
Also exposed the available sampling frequency values using read_avail
callback.

Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com>
---
drivers/iio/light/ltr390.c | 68 ++++++++++++++++++++++++++++++++++++--
1 file changed, 66 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/light/ltr390.c b/drivers/iio/light/ltr390.c
index 7e58b50f3..73ef4a5a0 100644
--- a/drivers/iio/light/ltr390.c
+++ b/drivers/iio/light/ltr390.c
@@ -39,6 +39,7 @@

#define LTR390_PART_NUMBER_ID 0xb
#define LTR390_ALS_UVS_GAIN_MASK 0x07
+#define LTR390_ALS_UVS_MEAS_RATE_MASK 0x07
#define LTR390_ALS_UVS_INT_TIME_MASK 0x70
#define LTR390_ALS_UVS_INT_TIME(x) FIELD_PREP(LTR390_ALS_UVS_INT_TIME_MASK, (x))

@@ -87,6 +88,18 @@ static const struct regmap_config ltr390_regmap_config = {
.val_bits = 8,
};

+/* Sampling frequency is in mili Hz and mili Seconds */
+static const int ltr390_samp_freq_table[][2] = {
+ [0] = {40000, 25},
+ [1] = {20000, 50},
+ [2] = {10000, 100},
+ [3] = {5000, 200},
+ [4] = {2000, 500},
+ [5] = {1000, 1000},
+ [6] = {500, 2000},
+ [7] = {500, 2000}
+};
+
static int ltr390_register_read(struct ltr390_data *data, u8 register_address)
{
struct device *dev = &data->client->dev;
@@ -135,6 +148,18 @@ static int ltr390_counts_per_uvi(struct ltr390_data *data)
return DIV_ROUND_CLOSEST(23 * data->gain * data->int_time_us, 10 * orig_gain * orig_int_time);
}

+static int ltr390_get_samp_freq(struct ltr390_data *data)
+{
+ int ret, value;
+
+ ret = regmap_read(data->regmap, LTR390_ALS_UVS_MEAS_RATE, &value);
+ if (ret < 0)
+ return ret;
+ value &= LTR390_ALS_UVS_MEAS_RATE_MASK;
+
+ return ltr390_samp_freq_table[value][0];
+}
+
static int ltr390_read_raw(struct iio_dev *iio_device,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
@@ -191,6 +216,10 @@ static int ltr390_read_raw(struct iio_dev *iio_device,
*val = data->int_time_us;
return IIO_VAL_INT;

+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = ltr390_get_samp_freq(data);
+ return IIO_VAL_INT;
+
default:
return -EINVAL;
}
@@ -199,6 +228,7 @@ static int ltr390_read_raw(struct iio_dev *iio_device,
/* integration time in us */
static const int ltr390_int_time_map_us[] = { 400000, 200000, 100000, 50000, 25000, 12500 };
static const int ltr390_gain_map[] = { 1, 3, 6, 9, 18 };
+static const int ltr390_freq_map[] = { 40000, 20000, 10000, 5000, 2000, 1000, 500, 500 };

static const struct iio_chan_spec ltr390_channels[] = {
/* UV sensor */
@@ -206,16 +236,18 @@ static const struct iio_chan_spec ltr390_channels[] = {
.type = IIO_UVINDEX,
.scan_index = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
- .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) | BIT(IIO_CHAN_INFO_SCALE)
+ | BIT(IIO_CHAN_INFO_SAMP_FREQ)
},
/* ALS sensor */
{
.type = IIO_LIGHT,
.scan_index = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
- .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) | BIT(IIO_CHAN_INFO_SCALE)
+ | BIT(IIO_CHAN_INFO_SAMP_FREQ)
},
};

@@ -264,6 +296,27 @@ static int ltr390_set_int_time(struct ltr390_data *data, int val)
return -EINVAL;
}

+static int ltr390_set_samp_freq(struct ltr390_data *data, int val)
+{
+ int ret, idx;
+
+ for (idx = 0; idx < ARRAY_SIZE(ltr390_samp_freq_table); idx++) {
+ if (ltr390_samp_freq_table[idx][0] != val)
+ continue;
+
+ guard(mutex)(&data->lock);
+ ret = regmap_update_bits(data->regmap,
+ LTR390_ALS_UVS_MEAS_RATE,
+ LTR390_ALS_UVS_MEAS_RATE_MASK, idx);
+ if (ret)
+ return ret;
+
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
static int ltr390_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
const int **vals, int *type, int *length, long mask)
{
@@ -278,6 +331,11 @@ static int ltr390_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec con
*type = IIO_VAL_INT;
*vals = ltr390_int_time_map_us;
return IIO_AVAIL_LIST;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *length = ARRAY_SIZE(ltr390_freq_map);
+ *type = IIO_VAL_INT;
+ *vals = ltr390_freq_map;
+ return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
@@ -301,6 +359,12 @@ static int ltr390_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec cons

return ltr390_set_int_time(data, val);

+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (val2 != 0)
+ return -EINVAL;
+
+ return ltr390_set_samp_freq(data, val);
+
default:
return -EINVAL;
}
--
2.43.0