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Subject[PATCH v2 3/5] iio: srf08: add triggered buffer support
Add support for triggered buffers.

Data format is quite simple:
distance 16 Bit
alignment 48 Bit
timestamp 64 Bit

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
---
drivers/iio/proximity/srf08.c | 59 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 56 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/proximity/srf08.c b/drivers/iio/proximity/srf08.c
index 3f19536f215f..8018bb90b7b2 100644
--- a/drivers/iio/proximity/srf08.c
+++ b/drivers/iio/proximity/srf08.c
@@ -18,6 +18,9 @@
#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>

/* registers of SRF08 device */
#define SRF08_WRITE_COMMAND 0x00 /* Command Register */
@@ -35,9 +38,22 @@

struct srf08_data {
struct i2c_client *client;
- int sensitivity; /* Gain */
- int range_mm; /* max. Range in mm */
+
+ /*
+ * Gain in the datasheet is called sensitivity here to distinct it
+ * from the gain used with amplifiers of adc's
+ */
+ int sensitivity;
+
+ /* max. Range in mm */
+ int range_mm;
struct mutex lock;
+
+ /*
+ * triggered buffer
+ * 1x16-bit channel + 3x16 padding + 4x16 timestamp
+ */
+ s16 buffer[8];
};

/*
@@ -110,6 +126,28 @@ static int srf08_read_ranging(struct srf08_data *data)
return ret;
}

+static irqreturn_t srf08_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct srf08_data *data = iio_priv(indio_dev);
+ s16 sensor_data;
+
+ sensor_data = srf08_read_ranging(data);
+ if (sensor_data < 0)
+ goto err;
+
+ mutex_lock(&data->lock);
+ data->buffer[0] = sensor_data;
+ mutex_unlock(&data->lock);
+
+ iio_push_to_buffers_with_timestamp(indio_dev,
+ data->buffer, pf->timestamp);
+err:
+ iio_trigger_notify_done(indio_dev->trig);
+ return IRQ_HANDLED;
+}
+
static int srf08_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
@@ -323,7 +361,15 @@ static const struct iio_chan_spec srf08_channels[] = {
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
+ .scan_index = 0,
+ .scan_type = {
+ .sign = 's',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_CPU,
+ },
},
+ IIO_CHAN_SOFT_TIMESTAMP(1),
};

static const struct iio_info srf08_info = {
@@ -362,6 +408,13 @@ static int srf08_probe(struct i2c_client *client,

mutex_init(&data->lock);

+ ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
+ iio_pollfunc_store_time, srf08_trigger_handler, NULL);
+ if (ret < 0) {
+ dev_err(&client->dev, "setup of iio triggered buffer failed\n");
+ return ret;
+ }
+
/*
* set default values of device here
* these register values cannot be read from the hardware
@@ -402,5 +455,5 @@ static struct i2c_driver srf08_driver = {
module_i2c_driver(srf08_driver);

MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
-MODULE_DESCRIPTION("Devantech SRF08 ultrasonic ranger driver");
+MODULE_DESCRIPTION("Devantech SRF08/SRF10 ultrasonic ranger driver");
MODULE_LICENSE("GPL");
--
2.1.4

--

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