[PATCH v2 2/2] iio: accel: adxl355: Add triggered buffer support
From: Puranjay Mohan
Date: Fri Sep 03 2021 - 14:43:39 EST
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 <puranjay12@xxxxxxxxx>
---
drivers/iio/accel/Kconfig | 4 +
drivers/iio/accel/adxl355_core.c | 153 ++++++++++++++++++++++++++++++-
2 files changed, 156 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index d0c45c809..9c16c1841 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -69,6 +69,8 @@ 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.
@@ -82,6 +84,8 @@ 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.
diff --git a/drivers/iio/accel/adxl355_core.c b/drivers/iio/accel/adxl355_core.c
index 0b9996c17..4c561315f 100644
--- a/drivers/iio/accel/adxl355_core.c
+++ b/drivers/iio/accel/adxl355_core.c
@@ -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>
@@ -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
@@ -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,
@@ -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));
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
static void adxl355_fill_3db_frequency_table(struct adxl355_data *data)
{
u32 multiplier;
@@ -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);
@@ -499,12 +535,74 @@ 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, \
@@ -518,6 +616,7 @@ 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, \
@@ -537,6 +636,7 @@ 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,
@@ -544,14 +644,48 @@ static const struct iio_chan_spec adxl355_channels[] = {
.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,
+ indio_dev->id);
+ 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)
@@ -568,6 +702,7 @@ 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) {
@@ -575,6 +710,22 @@ int adxl355_core_probe(struct device *dev, struct regmap *regmap,
return ret;
}
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+ &iio_pollfunc_store_time,
+ &adxl355_trigger_handler, NULL);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "iio triggered buffer setup failed\n");
+
+ /*
+ * 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);
--
2.30.1