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iio: accel: adxl355: Add triggered buffer support
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Provide a way for continuous data capture by setting up buffer support. The
data ready signal exposed at the DRDY pin of the ADXL355 is exploited as
a hardware interrupt which triggers to fill the buffer.

Signed-off-by: Puranjay Mohan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>
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@puranjaymohan @jic23
puranjaymohan authored and jic23 committed Sep 14, 2021
1 parent 86ff6cb commit 327a0ea
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Showing 2 changed files with 158 additions and 1 deletion.
4 changes: 4 additions & 0 deletions drivers/iio/accel/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,8 @@ config ADXL355_I2C
depends on I2C
select ADXL355
select REGMAP_I2C
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
Say Y here if you want to build i2c support for the Analog Devices
ADXL355 3-axis digital accelerometer.
Expand All @@ -111,6 +113,8 @@ config ADXL355_SPI
depends on SPI
select ADXL355
select REGMAP_SPI
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
Say Y here if you want to build spi support for the Analog Devices
ADXL355 3-axis digital accelerometer.
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155 changes: 154 additions & 1 deletion drivers/iio/accel/adxl355_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,11 +9,16 @@

#include <linux/bits.h>
#include <linux/bitfield.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/limits.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of_irq.h>
#include <linux/regmap.h>
#include <asm/unaligned.h>

Expand Down Expand Up @@ -46,6 +51,7 @@
#define ADXL355_RANGE_REG 0x2C
#define ADXL355_POWER_CTL_REG 0x2D
#define ADXL355_POWER_CTL_MODE_MSK GENMASK(1, 0)
#define ADXL355_POWER_CTL_DRDY_MSK BIT(2)
#define ADXL355_SELF_TEST_REG 0x2E
#define ADXL355_RESET_REG 0x2F

Expand Down Expand Up @@ -165,7 +171,14 @@ struct adxl355_data {
enum adxl355_hpf_3db hpf_3db;
int calibbias[3];
int adxl355_hpf_3db_table[7][2];
u8 transf_buf[3] ____cacheline_aligned;
struct iio_trigger *dready_trig;
union {
u8 transf_buf[3];
struct {
u8 buf[14];
s64 ts;
} buffer;
} ____cacheline_aligned;
};

static int adxl355_set_op_mode(struct adxl355_data *data,
Expand All @@ -186,6 +199,23 @@ static int adxl355_set_op_mode(struct adxl355_data *data,
return ret;
}

static int adxl355_data_rdy_trigger_set_state(struct iio_trigger *trig,
bool state)
{
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
struct adxl355_data *data = iio_priv(indio_dev);
int ret;

mutex_lock(&data->lock);
ret = regmap_update_bits(data->regmap, ADXL355_POWER_CTL_REG,
ADXL355_POWER_CTL_DRDY_MSK,
FIELD_PREP(ADXL355_POWER_CTL_DRDY_MSK,
state ? 0 : 1));
mutex_unlock(&data->lock);

return ret;
}

static void adxl355_fill_3db_frequency_table(struct adxl355_data *data)
{
u32 multiplier;
Expand Down Expand Up @@ -246,6 +276,12 @@ static int adxl355_setup(struct adxl355_data *data)
if (ret)
return ret;

ret = regmap_update_bits(data->regmap, ADXL355_POWER_CTL_REG,
ADXL355_POWER_CTL_DRDY_MSK,
FIELD_PREP(ADXL355_POWER_CTL_DRDY_MSK, 1));
if (ret)
return ret;

adxl355_fill_3db_frequency_table(data);

return adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
Expand Down Expand Up @@ -527,12 +563,74 @@ static int adxl355_read_avail(struct iio_dev *indio_dev,
}
}

static const unsigned long adxl355_avail_scan_masks[] = {
GENMASK(3, 0),
0
};

static const struct iio_info adxl355_info = {
.read_raw = adxl355_read_raw,
.write_raw = adxl355_write_raw,
.read_avail = &adxl355_read_avail,
};

static const struct iio_trigger_ops adxl355_trigger_ops = {
.set_trigger_state = &adxl355_data_rdy_trigger_set_state,
.validate_device = &iio_trigger_validate_own_device,
};

static irqreturn_t adxl355_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct adxl355_data *data = iio_priv(indio_dev);
int ret;

mutex_lock(&data->lock);

/*
* data->buffer is used both for triggered buffer support
* and read/write_raw(), hence, it has to be zeroed here before usage.
*/
data->buffer.buf[0] = 0;

/*
* The acceleration data is 24 bits and big endian. It has to be saved
* in 32 bits, hence, it is saved in the 2nd byte of the 4 byte buffer.
* The buf array is 14 bytes as it includes 3x4=12 bytes for
* accelaration data of x, y, and z axis. It also includes 2 bytes for
* temperature data.
*/
ret = regmap_bulk_read(data->regmap, ADXL355_XDATA3_REG,
&data->buffer.buf[1], 3);
if (ret)
goto out_unlock_notify;

ret = regmap_bulk_read(data->regmap, ADXL355_YDATA3_REG,
&data->buffer.buf[5], 3);
if (ret)
goto out_unlock_notify;

ret = regmap_bulk_read(data->regmap, ADXL355_ZDATA3_REG,
&data->buffer.buf[9], 3);
if (ret)
goto out_unlock_notify;

ret = regmap_bulk_read(data->regmap, ADXL355_TEMP2_REG,
&data->buffer.buf[12], 2);
if (ret)
goto out_unlock_notify;

iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
pf->timestamp);

out_unlock_notify:
mutex_unlock(&data->lock);
iio_trigger_notify_done(indio_dev->trig);

return IRQ_HANDLED;
}

#define ADXL355_ACCEL_CHANNEL(index, reg, axis) { \
.type = IIO_ACCEL, \
.address = reg, \
Expand All @@ -546,6 +644,7 @@ static const struct iio_info adxl355_info = {
.info_mask_shared_by_type_available = \
BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY), \
.scan_index = index, \
.scan_type = { \
.sign = 's', \
.realbits = 20, \
Expand All @@ -565,21 +664,56 @@ static const struct iio_chan_spec adxl355_channels[] = {
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET),
.scan_index = 3,
.scan_type = {
.sign = 's',
.realbits = 12,
.storagebits = 16,
.endianness = IIO_BE,
},
},
IIO_CHAN_SOFT_TIMESTAMP(4),
};

static int adxl355_probe_trigger(struct iio_dev *indio_dev, int irq)
{
struct adxl355_data *data = iio_priv(indio_dev);
int ret;

data->dready_trig = devm_iio_trigger_alloc(data->dev, "%s-dev%d",
indio_dev->name,
iio_device_id(indio_dev));
if (!data->dready_trig)
return -ENOMEM;

data->dready_trig->ops = &adxl355_trigger_ops;
iio_trigger_set_drvdata(data->dready_trig, indio_dev);

ret = devm_request_irq(data->dev, irq,
&iio_trigger_generic_data_rdy_poll,
IRQF_ONESHOT, "adxl355_irq", data->dready_trig);
if (ret)
return dev_err_probe(data->dev, ret, "request irq %d failed\n",
irq);

ret = devm_iio_trigger_register(data->dev, data->dready_trig);
if (ret) {
dev_err(data->dev, "iio trigger register failed\n");
return ret;
}

indio_dev->trig = iio_trigger_get(data->dready_trig);

return 0;
}

int adxl355_core_probe(struct device *dev, struct regmap *regmap,
const char *name)
{
struct adxl355_data *data;
struct iio_dev *indio_dev;
int ret;
int irq;

indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
Expand All @@ -596,13 +730,32 @@ int adxl355_core_probe(struct device *dev, struct regmap *regmap,
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = adxl355_channels;
indio_dev->num_channels = ARRAY_SIZE(adxl355_channels);
indio_dev->available_scan_masks = adxl355_avail_scan_masks;

ret = adxl355_setup(data);
if (ret) {
dev_err(dev, "ADXL355 setup failed\n");
return ret;
}

ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
&iio_pollfunc_store_time,
&adxl355_trigger_handler, NULL);
if (ret) {
dev_err(dev, "iio triggered buffer setup failed\n");
return ret;
}

/*
* TODO: Would be good to move it to the generic version.
*/
irq = of_irq_get_byname(dev->of_node, "DRDY");
if (irq > 0) {
ret = adxl355_probe_trigger(indio_dev, irq);
if (ret)
return ret;
}

return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_GPL(adxl355_core_probe);
Expand Down

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