iio: ltr501: Add integration time support

Added support to modify and read ALS integration time.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index e2f73547fdc52c16253afc39e2992dffc5118180..809260402a53c3342f92cad11ec558f30add62f3 100644 (file)
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -28,6 +28,7 @@
 
 #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
 #define LTR501_PS_CONTR 0x81 /* PS operation mode */
+#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
 #define LTR501_PART_ID 0x86
 #define LTR501_MANUFAC_ID 0x87
 #define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
@@ -49,11 +50,17 @@
 
 #define LTR501_REGMAP_NAME "ltr501_regmap"
 
+static const int int_time_mapping[] = {100000, 50000, 200000, 400000};
+
+static const struct reg_field reg_field_it =
+                               REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
+
 struct ltr501_data {
        struct i2c_client *client;
        struct mutex lock_als, lock_ps;
        u8 als_contr, ps_contr;
        struct regmap *regmap;
+       struct regmap_field *reg_it;
 };
 
 static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
@@ -74,6 +81,58 @@ static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
        return -EIO;
 }
 
+static int ltr501_set_it_time(struct ltr501_data *data, int it)
+{
+       int ret, i, index = -1, status;
+
+       for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
+               if (int_time_mapping[i] == it) {
+                       index = i;
+                       break;
+               }
+       }
+       /* Make sure integ time index is valid */
+       if (index < 0)
+               return -EINVAL;
+
+       ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
+       if (ret < 0)
+               return ret;
+
+       if (status & LTR501_CONTR_ALS_GAIN_MASK) {
+               /*
+                * 200 ms and 400 ms integ time can only be
+                * used in dynamic range 1
+                */
+               if (index > 1)
+                       return -EINVAL;
+       } else
+               /* 50 ms integ time can only be used in dynamic range 2 */
+               if (index == 1)
+                       return -EINVAL;
+
+       return regmap_field_write(data->reg_it, index);
+}
+
+/* read int time in micro seconds */
+static int ltr501_read_it_time(struct ltr501_data *data, int *val, int *val2)
+{
+       int ret, index;
+
+       ret = regmap_field_read(data->reg_it, &index);
+       if (ret < 0)
+               return ret;
+
+       /* Make sure integ time index is valid */
+       if (index < 0 || index >= ARRAY_SIZE(int_time_mapping))
+               return -EINVAL;
+
+       *val2 = int_time_mapping[index];
+       *val = 0;
+
+       return IIO_VAL_INT_PLUS_MICRO;
+}
+
 static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
 {
        int ret;
@@ -121,7 +180,8 @@ static int ltr501_read_ps(struct ltr501_data *data)
 static const struct iio_chan_spec ltr501_channels[] = {
        LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
        LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
-                                BIT(IIO_CHAN_INFO_SCALE)),
+                                BIT(IIO_CHAN_INFO_SCALE) |
+                                BIT(IIO_CHAN_INFO_INT_TIME)),
        {
                .type = IIO_PROXIMITY,
                .address = LTR501_PS_DATA,
@@ -196,6 +256,13 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
                default:
                        return -EINVAL;
                }
+       case IIO_CHAN_INFO_INT_TIME:
+               switch (chan->type) {
+               case IIO_INTENSITY:
+                       return ltr501_read_it_time(data, val, val2);
+               default:
+                       return -EINVAL;
+               }
        }
        return -EINVAL;
 }
@@ -246,16 +313,30 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
                default:
                        return -EINVAL;
                }
+       case IIO_CHAN_INFO_INT_TIME:
+               switch (chan->type) {
+               case IIO_INTENSITY:
+                       if (val != 0)
+                               return -EINVAL;
+                       mutex_lock(&data->lock_als);
+                       i = ltr501_set_it_time(data, val2);
+                       mutex_unlock(&data->lock_als);
+                       return i;
+               default:
+                       return -EINVAL;
+               }
        }
        return -EINVAL;
 }
 
 static IIO_CONST_ATTR(in_proximity_scale_available, "1 0.25 0.125 0.0625");
 static IIO_CONST_ATTR(in_intensity_scale_available, "1 0.005");
+static IIO_CONST_ATTR_INT_TIME_AVAIL("0.05 0.1 0.2 0.4");
 
 static struct attribute *ltr501_attributes[] = {
        &iio_const_attr_in_proximity_scale_available.dev_attr.attr,
        &iio_const_attr_in_intensity_scale_available.dev_attr.attr,
+       &iio_const_attr_integration_time_available.dev_attr.attr,
        NULL
 };
 
@@ -404,6 +485,13 @@ static int ltr501_probe(struct i2c_client *client,
        mutex_init(&data->lock_als);
        mutex_init(&data->lock_ps);
 
+       data->reg_it = devm_regmap_field_alloc(&client->dev, regmap,
+                                              reg_field_it);
+       if (IS_ERR(data->reg_it)) {
+               dev_err(&client->dev, "Integ time reg field init failed.\n");
+               return PTR_ERR(data->reg_it);
+       }
+
        ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
        if (ret < 0)
                return ret;