Added rate control support for ALS and proximity
threshold interrupts.Also, Added support to modify
and read ALS & proximity sensor sampling frequency.
LTR-501 supports interrupt rate control using persistence
register settings. Writing <n> to persistence register
would generate interrupt only if there are <n> consecutive
data values outside the threshold range.
Since we don't have any existing ABI's to directly
control the persistence register count, we have implemented
the rate control using IIO_EV_INFO_PERIOD. _period event
attribute represents the amount of time in seconds an
event should be true for the device to generate the
interrupt. So using _period value and device frequency,
persistence count is calculated in driver using following
logic.
count = period / measurement_rate
If the given period is not a multiple of measurement rate then
we round up the value to next multiple.
This patch also handles change to persistence count whenever
there is change in frequency.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
drivers/iio/light/ltr501.c | 413 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 406 insertions(+), 7 deletions(-)
diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index 593dbb1..d9b4536 100644
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -9,7 +9,7 @@
*
* 7-bit I2C slave address 0x23
*
- * TODO: measurement rate, IR LED characteristics
+ * TODO: IR LED characteristics
*/
#include <linux/module.h>
@@ -29,6 +29,7 @@
#define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
#define LTR501_PS_CONTR 0x81 /* PS operation mode */
+#define LTR501_PS_MEAS_RATE 0x84 /* measurement rate*/
#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
#define LTR501_PART_ID 0x86
#define LTR501_MANUFAC_ID 0x87
@@ -41,6 +42,7 @@
#define LTR501_PS_THRESH_LOW 0x92 /* 11 bit, ps lower threshold */
#define LTR501_ALS_THRESH_UP 0x97 /* 16 bit, ALS upper threshold */
#define LTR501_ALS_THRESH_LOW 0x99 /* 16 bit, ALS lower threshold */
+#define LTR501_INTR_PRST 0x9e /* ps thresh, als thresh */
#define LTR501_MAX_REG 0x9f
#define LTR501_ALS_CONTR_SW_RESET BIT(2)
@@ -58,6 +60,9 @@
#define LTR501_PS_THRESH_MASK 0x7ff
#define LTR501_ALS_THRESH_MASK 0xffff
+#define LTR501_ALS_DEF_PERIOD 500000
+#define LTR501_PS_DEF_PERIOD 100000
+
#define LTR501_REGMAP_NAME "ltr501_regmap"
static const int int_time_mapping[] = {100000, 50000, 200000, 400000};
@@ -68,17 +73,171 @@ static const struct reg_field reg_field_als_intr =
REG_FIELD(LTR501_INTR, 0, 0);
static const struct reg_field reg_field_ps_intr =
REG_FIELD(LTR501_INTR, 1, 1);
+static const struct reg_field reg_field_als_rate =
+ REG_FIELD(LTR501_ALS_MEAS_RATE, 0, 2);
+static const struct reg_field reg_field_ps_rate =
+ REG_FIELD(LTR501_PS_MEAS_RATE, 0, 3);
+static const struct reg_field reg_field_als_prst =
+ REG_FIELD(LTR501_INTR_PRST, 0, 3);
+static const struct reg_field reg_field_ps_prst =
+ REG_FIELD(LTR501_INTR_PRST, 4, 7);
+
+struct ltr501_samp_table {
+ int freq_val; /* repetition frequency in micro HZ*/
+ int time_val; /* repetition rate in micro seconds */
+};
struct ltr501_data {
struct i2c_client *client;
struct mutex lock_als, lock_ps;
u8 als_contr, ps_contr;
+ int als_period, ps_period; /* period in micro seconds */
struct regmap *regmap;
struct regmap_field *reg_it;
struct regmap_field *reg_als_intr;
struct regmap_field *reg_ps_intr;
+ struct regmap_field *reg_als_rate;
+ struct regmap_field *reg_ps_rate;
+ struct regmap_field *reg_als_prst;
+ struct regmap_field *reg_ps_prst;
+};
+
+static const struct ltr501_samp_table ltr501_als_samp_table[] = {
+ {20000000, 50000}, {10000000, 100000},
+ {5000000, 200000}, {2000000, 500000},
+ {1000000, 1000000}, {500000, 2000000},
+ {500000, 2000000}, {500000, 2000000}
};
+static const struct ltr501_samp_table ltr501_ps_samp_table[] = {
+ {20000000, 50000}, {14285714, 70000},
+ {10000000, 100000}, {5000000, 200000},
+ {2000000, 500000}, {1000000, 1000000},
+ {500000, 2000000}, {500000, 2000000},
+ {500000, 2000000}
+};
+
+static unsigned int ltr501_match_samp_freq(const struct ltr501_samp_table *tab,
+ int len, int val, int val2)
+{
+ int i, freq;
+
+ freq = val * 1000000 + val2;
+
+ for (i = 0; i < len; i++) {
+ if (tab[i].freq_val == freq)
+ return i;
+ }
+
+ return -EINVAL;
+}
+
+static int ltr501_als_read_samp_freq(struct ltr501_data *data,
+ int *val, int *val2)
+{
+ int ret, i;
+
+ ret = regmap_field_read(data->reg_als_rate, &i);
+ if (ret < 0)
+ return ret;
+
+ if (i < 0 || i >= ARRAY_SIZE(ltr501_als_samp_table))
+ return -EINVAL;
+
+ *val = ltr501_als_samp_table[i].freq_val / 1000000;
+ *val2 = ltr501_als_samp_table[i].freq_val % 1000000;
+
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ltr501_ps_read_samp_freq(struct ltr501_data *data,
+ int *val, int *val2)
+{
+ int ret, i;
+
+ ret = regmap_field_read(data->reg_ps_rate, &i);
+ if (ret < 0)
+ return ret;
+
+ if (i < 0 || i >= ARRAY_SIZE(ltr501_ps_samp_table))
+ return -EINVAL;
+
+ *val = ltr501_ps_samp_table[i].freq_val / 1000000;
+ *val2 = ltr501_ps_samp_table[i].freq_val % 1000000;
+
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ltr501_als_write_samp_freq(struct ltr501_data *data,
+ int val, int val2)
+{
+ int i, ret;
+
+ i = ltr501_match_samp_freq(ltr501_als_samp_table,
+ ARRAY_SIZE(ltr501_als_samp_table),
+ val, val2);
+
+ if (i < 0)
+ return i;
+
+ mutex_lock(&data->lock_als);
+ ret = regmap_field_write(data->reg_als_rate, i);
+ mutex_unlock(&data->lock_als);
+
+ return ret;
+}
+
+static int ltr501_ps_write_samp_freq(struct ltr501_data *data,
+ int val, int val2)
+{
+ int i, ret;
+
+ i = ltr501_match_samp_freq(ltr501_ps_samp_table,
+ ARRAY_SIZE(ltr501_ps_samp_table),
+ val, val2);
+
+ if (i < 0)
+ return i;
+
+ mutex_lock(&data->lock_ps);
+ ret = regmap_field_write(data->reg_ps_rate, i);
+ mutex_unlock(&data->lock_ps);
+
+ return ret;
+}
+
+static int ltr501_als_read_samp_period(struct ltr501_data *data, int *val)
+{
+ int ret, i;
+
+ ret = regmap_field_read(data->reg_als_rate, &i);
+ if (ret < 0)
+ return ret;
+
+ if (i < 0 || i >= ARRAY_SIZE(ltr501_als_samp_table))
+ return -EINVAL;
+
+ *val = ltr501_als_samp_table[i].time_val;
+
+ return IIO_VAL_INT;
+}
+
+static int ltr501_ps_read_samp_period(struct ltr501_data *data, int *val)
+{
+ int ret, i;
+
+ ret = regmap_field_read(data->reg_ps_rate, &i);
+ if (ret < 0)
+ return ret;
+
+ if (i < 0 || i >= ARRAY_SIZE(ltr501_ps_samp_table))
+ return -EINVAL;
+
+ *val = ltr501_ps_samp_table[i].time_val;
+
+ return IIO_VAL_INT;
+}
+
static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
{
int tries = 100;
@@ -177,6 +336,104 @@ static int ltr501_read_ps(struct ltr501_data *data)
return status;
}
+static int ltr501_read_intr_prst(struct ltr501_data *data,
+ enum iio_chan_type type,
+ int *val2)
+{
+ int ret, samp_period, prst;
+
+ switch (type) {
+ case IIO_INTENSITY:
+ ret = regmap_field_read(data->reg_als_prst, &prst);
+ if (ret < 0)
+ return ret;
+
+ ret = ltr501_als_read_samp_period(data, &samp_period);
+
+ if (ret < 0)
+ return ret;
+ *val2 = samp_period * prst;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_PROXIMITY:
+ ret = regmap_field_read(data->reg_ps_prst, &prst);
+ if (ret < 0)
+ return ret;
+
+ ret = ltr501_ps_read_samp_period(data, &samp_period);
+
+ if (ret < 0)
+ return ret;
+
+ *val2 = samp_period * prst;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static int ltr501_write_intr_prst(struct ltr501_data *data,
+ enum iio_chan_type type,
+ int val, int val2)
+{
+ int ret, samp_period, new_val;
+ unsigned long period;
+
+ if (val < 0 || val2 < 0)
+ return -EINVAL;
+
+ /* period in microseconds */
+ period = ((val * 1000000) + val2);
+
+ switch (type) {
+ case IIO_INTENSITY:
+ ret = ltr501_als_read_samp_period(data, &samp_period);
+ if (ret < 0)
+ return ret;
+
+ /* period should be atleast equal to sampling period */
+ if (period < samp_period)
+ return -EINVAL;
+
+ new_val = DIV_ROUND_UP(period, samp_period);
+ if (new_val < 0 || new_val > 0x0f)
+ return -EINVAL;
+
+ mutex_lock(&data->lock_als);
+ ret = regmap_field_write(data->reg_als_prst, new_val);
+ mutex_unlock(&data->lock_als);
+ if (ret >= 0)
+ data->als_period = period;
+
+ return ret;
+ case IIO_PROXIMITY:
+ ret = ltr501_ps_read_samp_period(data, &samp_period);
+ if (ret < 0)
+ return ret;
+
+ /* period should be atleast equal to rate */
+ if (period < samp_period)
+ return -EINVAL;
+
+ new_val = DIV_ROUND_UP(period, samp_period);
+ if (new_val < 0 || new_val > 0x0f)
+ return -EINVAL;
+
+ mutex_lock(&data->lock_ps);
+ ret = regmap_field_write(data->reg_ps_prst, new_val);
+ mutex_unlock(&data->lock_ps);
+ if (ret >= 0)
+ data->ps_period = period;
+
+ return ret;
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
static const struct iio_event_spec ltr501_als_event_spec[] = {
{
.type = IIO_EV_TYPE_THRESH,
@@ -189,7 +446,8 @@ static const struct iio_event_spec ltr501_als_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),
},
};
@@ -206,7 +464,8 @@ static const struct iio_event_spec ltr501_pxs_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),
},
};
@@ -235,7 +494,8 @@ static const struct iio_chan_spec ltr501_channels[] = {
ARRAY_SIZE(ltr501_als_event_spec)),
LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
BIT(IIO_CHAN_INFO_SCALE) |
- BIT(IIO_CHAN_INFO_INT_TIME),
+ BIT(IIO_CHAN_INFO_INT_TIME) |
+ BIT(IIO_CHAN_INFO_SAMP_FREQ),
NULL, 0),
{
.type = IIO_PROXIMITY,
@@ -320,6 +580,15 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
default:
return -EINVAL;
}
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ switch (chan->type) {
+ case IIO_INTENSITY:
+ return ltr501_als_read_samp_freq(data, val, val2);
+ case IIO_PROXIMITY:
+ return ltr501_ps_read_samp_freq(data, val, val2);
+ default:
+ return -EINVAL;
+ }
}
return -EINVAL;
}
@@ -340,7 +609,7 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
int val, int val2, long mask)
{
struct ltr501_data *data = iio_priv(indio_dev);
- int i;
+ int i, ret, freq_val, freq_val2;
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
@@ -382,6 +651,49 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
default:
return -EINVAL;
}
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ switch (chan->type) {
+ case IIO_INTENSITY:
+ ret = ltr501_als_read_samp_freq(data, &freq_val,
+ &freq_val2);
+ if (ret < 0)
+ return ret;
+
+ ret = ltr501_als_write_samp_freq(data, val, val2);
+ if (ret < 0)
+ return ret;
+
+ /* update persistence count when changing frequency */
+ ret = ltr501_write_intr_prst(data, chan->type,
+ 0, data->als_period);
+
+ if (ret < 0)
+ return ltr501_als_write_samp_freq(data,
+ freq_val,
+ freq_val2);
+ return ret;
+ case IIO_PROXIMITY:
+ ret = ltr501_ps_read_samp_freq(data, &freq_val,
+ &freq_val2);
+ if (ret < 0)
+ return ret;
+
+ ret = ltr501_ps_write_samp_freq(data, val, val2);
+ if (ret < 0)
+ return ret;
+
+ /* update persistence count when changing frequency */
+ ret = ltr501_write_intr_prst(data, chan->type,
+ 0, data->ps_period);
+
+ if (ret < 0)
+ return ltr501_ps_write_samp_freq(data,
+ freq_val,
+ freq_val2);
+ return ret;
+ default:
+ return -EINVAL;
+ }
}
return -EINVAL;
}
@@ -509,6 +821,55 @@ static int ltr501_write_thresh(struct iio_dev *indio_dev,
return -EINVAL;
}
+static int ltr501_read_event(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int *val, int *val2)
+{
+ int ret;
+
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ return ltr501_read_thresh(indio_dev, chan, type, dir,
+ info, val, val2);
+ case IIO_EV_INFO_PERIOD:
+ ret = ltr501_read_intr_prst(iio_priv(indio_dev),
+ chan->type, val2);
+ *val = *val2 / 1000000;
+ *val2 = *val2 % 1000000;
+ return ret;
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static int ltr501_write_event(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int val, int val2)
+{
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ if (val2 != 0)
+ return -EINVAL;
+ return ltr501_write_thresh(indio_dev, chan, type, dir,
+ info, val, val2);
+ case IIO_EV_INFO_PERIOD:
+ return ltr501_write_intr_prst(iio_priv(indio_dev), chan->type,
+ val, val2);
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
static int ltr501_read_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
@@ -568,11 +929,13 @@ static int ltr501_write_event_config(struct iio_dev *indio_dev,
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 IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");
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,
+ &iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL
};
@@ -591,8 +954,8 @@ static const struct iio_info ltr501_info = {
.read_raw = ltr501_read_raw,
.write_raw = ltr501_write_raw,
.attrs = <r501_attribute_group,
- .read_event_value = <r501_read_thresh,
- .write_event_value = <r501_write_thresh,
+ .read_event_value = <r501_read_event,
+ .write_event_value = <r501_write_event,
.read_event_config = <r501_read_event_config,
.write_event_config = <r501_write_event_config,
.driver_module = THIS_MODULE,
@@ -706,6 +1069,14 @@ static int ltr501_init(struct ltr501_data *data)
data->ps_contr = status | LTR501_CONTR_ACTIVE;
+ ret = ltr501_read_intr_prst(data, IIO_INTENSITY, &data->als_period);
+ if (ret < 0)
+ return ret;
+
+ ret = ltr501_read_intr_prst(data, IIO_PROXIMITY, &data->ps_period);
+ if (ret < 0)
+ return ret;
+
return ltr501_write_contr(data, data->als_contr, data->ps_contr);
}
@@ -783,6 +1154,34 @@ static int ltr501_probe(struct i2c_client *client,
return PTR_ERR(data->reg_ps_intr);
}
+ data->reg_als_rate = devm_regmap_field_alloc(&client->dev, regmap,
+ reg_field_als_rate);
+ if (IS_ERR(data->reg_als_rate)) {
+ dev_err(&client->dev, "ALS samp rate field init failed.\n");
+ return PTR_ERR(data->reg_als_rate);
+ }
+
+ data->reg_ps_rate = devm_regmap_field_alloc(&client->dev, regmap,
+ reg_field_ps_rate);
+ if (IS_ERR(data->reg_ps_rate)) {
+ dev_err(&client->dev, "PS samp rate field init failed.\n");
+ return PTR_ERR(data->reg_ps_rate);
+ }
+
+ data->reg_als_prst = devm_regmap_field_alloc(&client->dev, regmap,
+ reg_field_als_prst);
+ if (IS_ERR(data->reg_als_prst)) {
+ dev_err(&client->dev, "ALS prst reg field init failed\n");
+ return PTR_ERR(data->reg_als_prst);
+ }
+
+ data->reg_ps_prst = devm_regmap_field_alloc(&client->dev, regmap,
+ reg_field_ps_prst);
+ if (IS_ERR(data->reg_ps_prst)) {
+ dev_err(&client->dev, "PS prst reg field init failed.\n");
+ return PTR_ERR(data->reg_ps_prst);
+ }
+
ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
if (ret < 0)
return ret;
--
1.9.1
--
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