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driver_si7210: add support for threshold and hysteresis
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@panantoni01
panantoni01 committed Jul 23, 2024
1 parent 5ae9ff2 commit 46994e5
Showing 1 changed file with 173 additions and 7 deletions.
180 changes: 173 additions & 7 deletions driver_si7210/si7210_driver.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,10 @@
#include <linux/regmap.h>
#include <linux/math64.h>
#include <linux/mutex.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/iio/events.h>
#include <linux/log2.h>

#define SI7210_REG_DSPSIGM 0xC1
#define SI7210_REG_DSPSIGL 0xC2
Expand All @@ -24,6 +28,12 @@
#define SI7210_REG_POWER_CTRL 0xC4
#define SI7210_MASK_ARAUTOINC BIT(0)
#define SI7210_REG_ARAUTOINC 0xC5
#define SI7210_MASK_LOW4FIELD BIT(7)
#define SI7210_MASK_OP GENMASK(6, 0)
#define SI7210_REG_THRESHOLD 0xC6
#define SI7210_MASK_HYST GENMASK(5, 0)
#define SI7210_REG_HYSTERESIS 0xC7

#define SI7210_REG_OTP_ADDR 0xE1
#define SI7210_REG_OTP_DATA 0xE2
#define SI7210_MASK_OTP_READ_EN BIT(1)
Expand All @@ -33,7 +43,7 @@
#define SI7210_OTPREG_TMP_GAIN 0x1E

static const struct regmap_range si7210_read_reg_ranges[] = {
regmap_reg_range(SI7210_REG_DSPSIGM, SI7210_REG_ARAUTOINC),
regmap_reg_range(SI7210_REG_DSPSIGM, SI7210_REG_HYSTERESIS),
regmap_reg_range(SI7210_REG_OTP_ADDR, SI7210_REG_OTP_CTRL),
};

Expand All @@ -43,7 +53,7 @@ static const struct regmap_access_table si7210_readable_regs = {
};

static const struct regmap_range si7210_write_reg_ranges[] = {
regmap_reg_range(SI7210_REG_DSPSIGSEL, SI7210_REG_ARAUTOINC),
regmap_reg_range(SI7210_REG_DSPSIGSEL, SI7210_REG_HYSTERESIS),
regmap_reg_range(SI7210_REG_OTP_ADDR, SI7210_REG_OTP_CTRL),
};

Expand Down Expand Up @@ -81,18 +91,146 @@ struct si7210_data {
struct mutex otp_lock;
};

static const struct iio_event_spec si7210_magn_event[] = {
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_RISING,
.mask_separate = BIT(IIO_EV_INFO_VALUE) |
BIT(IIO_EV_INFO_HYSTERESIS),
},
};

static const struct iio_chan_spec si7210_channels[] = {
{
.type = IIO_MAGN,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET)
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
.event_spec = si7210_magn_event,
.num_event_specs = ARRAY_SIZE(si7210_magn_event)
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED)
}
};

static inline int is_threshold_zero(int threshold) {
/* From the datasheet: "threshold = 0, when sw_op = 127" */
return ((threshold & SI7210_MASK_OP) == SI7210_MASK_OP);
}

static inline int is_hysteresis_zero(int hysteresis) {
/* "When sw_hyst = 63, the hysteresis is set to zero" */
return ((hysteresis & SI7210_MASK_HYST) == SI7210_MASK_HYST);
}

static int si7210_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)
{
struct si7210_data *data = iio_priv(indio_dev);
int ret, raw_thresh, raw_hyst, thresh, hyst;

ret = regmap_read(data->regmap, SI7210_REG_THRESHOLD, &raw_thresh);
if (ret < 0)
return ret;

if (info == IIO_EV_INFO_VALUE) {
if (is_threshold_zero(raw_thresh))
thresh = 0;
else
thresh = (16 + (raw_thresh & 0x0F)) *
(1 << ((raw_thresh & 0x70) >> 4)) * 5;

*val = thresh / 1000;
*val2 = 1000 * (thresh % 1000);
} else {
ret = regmap_read(data->regmap, SI7210_REG_HYSTERESIS, &raw_hyst);
if (ret < 0)
return ret;

if (is_hysteresis_zero(raw_hyst))
hyst = 0;
else
hyst = (8 + (raw_hyst & 0x7)) * (1 << ((raw_hyst & 0x38) >> 3)) * 5;

/* "If sw_op = 127, (...) the hysteresis is multiplied by 2" */
if (is_threshold_zero(raw_thresh))
hyst *= 2;

*val = hyst / 1000;
*val2 = 1000 * (hyst % 1000);
}

return IIO_VAL_INT_PLUS_MICRO;
}

static int si7210_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)
{
struct si7210_data *data = iio_priv(indio_dev);
int ret, raw_thresh;

if (val < 0)
return -EINVAL;

val = (val * 1000 + val2 / 1000) / 5;

if (info == IIO_EV_INFO_VALUE) {
if (val < 16)
/* "threshold = 0, when sw_op = 127" */
val = SI7210_MASK_OP;
else {
val = clamp_val(val, 16, 3840);
val = (ilog2(val / 16) << 4) | (val / (1 << ilog2(val / 16)) - 16);
}

ret = regmap_update_bits(data->regmap, SI7210_REG_THRESHOLD,
SI7210_MASK_OP, val);
if (ret < 0)
return ret;

} else { /* IIO_EV_INFO_HYSTERESIS */
ret = regmap_read(data->regmap, SI7210_REG_THRESHOLD, &raw_thresh);
if (ret < 0)
return ret;

if (is_threshold_zero(raw_thresh))
val /= 2;

if (val < 8)
/* "When sw_hyst = 63, the hysteresis is set to zero" */
val = SI7210_MASK_HYST;
else {
val = clamp_val(val, 8, 1792);
val = (ilog2(val / 8) << 3) | (val / (1 << ilog2(val / 8)) - 8);
}

ret = regmap_update_bits(data->regmap, SI7210_REG_HYSTERESIS,
SI7210_MASK_HYST, val);
if (ret < 0)
return ret;
}

return 0;
}

static irqreturn_t si7210_interrupt_handler(int irq, void *private)
{
struct iio_dev *indio_dev = private;

iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_MAGN, 0,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_RISING),
iio_get_time_ns(indio_dev));

return IRQ_HANDLED;
}

static int si7210_fetch_measurement(struct si7210_data* data,
struct iio_chan_spec const *chan,
void* buf)
Expand Down Expand Up @@ -227,22 +365,39 @@ static int si7210_device_init(struct si7210_data *data)
{
int ret;

si7210_device_wake(data);

ret = si7210_read_otpreg_val(data, SI7210_OTPREG_TMP_GAIN, &data->temp_gain);
if (ret < 0)
return 0;
return ret;
ret = si7210_read_otpreg_val(data, SI7210_OTPREG_TMP_OFF, &data->temp_offset);
if (ret < 0)
return 0;
return ret;

si7210_device_wake(data);
ret = regmap_update_bits(data->regmap, SI7210_REG_THRESHOLD,
SI7210_MASK_LOW4FIELD, ~SI7210_MASK_LOW4FIELD);
if (ret < 0)
return ret;

msleep(1);
/* "threshold = 0, when sw_op = 127" */
ret = regmap_update_bits(data->regmap, SI7210_REG_THRESHOLD,
SI7210_MASK_OP, SI7210_MASK_OP);
if (ret < 0)
return ret;

/* "When sw_hyst = 63, the hysteresis is set to zero" */
ret = regmap_update_bits(data->regmap, SI7210_REG_HYSTERESIS,
SI7210_MASK_HYST, SI7210_MASK_HYST);
if (ret < 0)
return ret;

return 0;
}

static const struct iio_info si7210_info = {
.read_raw = si7210_read_raw,
.read_event_value = si7210_read_event,
.write_event_value = si7210_write_event,
};

static int si7210_probe(struct i2c_client *client,
Expand Down Expand Up @@ -278,6 +433,17 @@ static int si7210_probe(struct i2c_client *client,
if (ret)
return dev_err_probe(&client->dev, ret, "device initialization failed\n");

if (client->irq) {
ret = devm_request_threaded_irq(&client->dev, client->irq,
NULL, si7210_interrupt_handler,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
indio_dev->name, indio_dev);
if (ret) {
dev_err_probe(&client->dev, ret, "irq request error\n");
return ret;
}
}

return devm_iio_device_register(&client->dev, indio_dev);
}

Expand Down

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