iio: light: ltr390: Add interrupt persistance support

Added support to configure the threshold interrupt persistance value by
providing IIO_EV_INFO_PERIOD attribute. The value written to the
attribute should be in miliseconds and should be greater than the
sampling rate of the sensor.

Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com>
Link: https://patch.msgid.link/20240914181246.504450-5-abhashkumarjha123@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/light/ltr390.c b/drivers/iio/light/ltr390.c
index 22c06a49ed0f0809b2936e196271f2f1d342672d..1d9f2149a62772e993e3b34f39540e2d4d2326c6 100644 (file)
--- a/drivers/iio/light/ltr390.c
+++ b/drivers/iio/light/ltr390.c
@@ -41,6 +41,7 @@
 #define LTR390_ALS_DATA                        0x0D
 #define LTR390_UVS_DATA                        0x10
 #define LTR390_INT_CFG                 0x19
+#define LTR390_INT_PST                 0x1A
 #define LTR390_THRESH_UP               0x21
 #define LTR390_THRESH_LOW              0x24
 
@@ -49,6 +50,8 @@
 #define LTR390_ALS_UVS_MEAS_RATE_MASK  GENMASK(2, 0)
 #define LTR390_ALS_UVS_INT_TIME_MASK   0x70
 #define LTR390_ALS_UVS_INT_TIME(x)     FIELD_PREP(LTR390_ALS_UVS_INT_TIME_MASK, (x))
+#define LTR390_INT_PST_MASK            GENMASK(7, 4)
+#define LTR390_INT_PST_VAL(x)          FIELD_PREP(LTR390_INT_PST_MASK, (x))
 
 #define LTR390_SW_RESET              BIT(4)
 #define LTR390_UVS_MODE              BIT(3)
@@ -80,6 +83,11 @@ enum ltr390_mode {
        LTR390_SET_UVS_MODE,
 };
 
+enum ltr390_meas_rate {
+       LTR390_GET_FREQ,
+       LTR390_GET_PERIOD,
+};
+
 struct ltr390_data {
        struct regmap *regmap;
        struct i2c_client *client;
@@ -157,7 +165,8 @@ 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)
+static int ltr390_get_samp_freq_or_period(struct ltr390_data *data,
+                                       enum ltr390_meas_rate option)
 {
        int ret, value;
 
@@ -166,7 +175,7 @@ static int ltr390_get_samp_freq(struct ltr390_data *data)
                return ret;
        value = FIELD_GET(LTR390_ALS_UVS_MEAS_RATE_MASK, value);
 
-       return ltr390_samp_freq_table[value][0];
+       return ltr390_samp_freq_table[value][option];
 }
 
 static int ltr390_read_raw(struct iio_dev *iio_device,
@@ -226,7 +235,7 @@ static int ltr390_read_raw(struct iio_dev *iio_device,
                return IIO_VAL_INT;
 
        case IIO_CHAN_INFO_SAMP_FREQ:
-               *val = ltr390_get_samp_freq(data);
+               *val = ltr390_get_samp_freq_or_period(data, LTR390_GET_FREQ);
                return IIO_VAL_INT;
 
        default:
@@ -251,7 +260,8 @@ static const struct iio_event_spec ltr390_event_spec[] = {
        }, {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_EITHER,
-               .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+               .mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+                               BIT(IIO_EV_INFO_PERIOD),
        }
 };
 
@@ -397,6 +407,44 @@ static int ltr390_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec cons
        }
 }
 
+static int ltr390_read_intr_prst(struct ltr390_data *data, int *val)
+{
+       int ret, prst, samp_period;
+
+       samp_period = ltr390_get_samp_freq_or_period(data, LTR390_GET_PERIOD);
+       ret = regmap_read(data->regmap, LTR390_INT_PST, &prst);
+       if (ret < 0)
+               return ret;
+       *val = prst * samp_period;
+
+       return IIO_VAL_INT;
+}
+
+static int ltr390_write_intr_prst(struct ltr390_data *data, int val)
+{
+       int ret, samp_period, new_val;
+
+       samp_period = ltr390_get_samp_freq_or_period(data, LTR390_GET_PERIOD);
+
+       /* persist period should be greater than or equal to samp period */
+       if (val < samp_period)
+               return -EINVAL;
+
+       new_val = DIV_ROUND_UP(val, samp_period);
+       if (new_val < 0 || new_val > 0x0f)
+               return -EINVAL;
+
+       guard(mutex)(&data->lock);
+       ret = regmap_update_bits(data->regmap,
+                               LTR390_INT_PST,
+                               LTR390_INT_PST_MASK,
+                               LTR390_INT_PST_VAL(new_val));
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
 static int ltr390_read_threshold(struct iio_dev *indio_dev,
                                enum iio_event_direction dir,
                                int *val, int *val2)
@@ -453,6 +501,9 @@ static int ltr390_read_event_value(struct iio_dev *indio_dev,
        case IIO_EV_INFO_VALUE:
                return ltr390_read_threshold(indio_dev, dir, val, val2);
 
+       case IIO_EV_INFO_PERIOD:
+               return ltr390_read_intr_prst(iio_priv(indio_dev), val);
+
        default:
                return -EINVAL;
        }
@@ -472,6 +523,12 @@ static int ltr390_write_event_value(struct iio_dev *indio_dev,
 
                return ltr390_write_threshold(indio_dev, dir, val, val2);
 
+       case IIO_EV_INFO_PERIOD:
+               if (val2 != 0)
+                       return -EINVAL;
+
+               return ltr390_write_intr_prst(iio_priv(indio_dev), val);
+
        default:
                return -EINVAL;
        }