linux-kernel - [PATCH 2/2] iio: chemical: sgpxx: triggered buffer support

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Date:   Tue, 21 Nov 2017 17:11:29 +0100
From:   Andreas Brauchli <a.brauchli@...mentarea.net>
To:     Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] iio: chemical: sgpxx: triggered buffer support

Support triggered buffer for use with e.g. hrtimer for automated
polling to ensure that the sensor's internal baseline is correctly
updated independently of the use-case.

Triggered buffer support is only enabled when IIO_BUFFER is set.

Signed-off-by: Andreas Brauchli <andreas.brauchli@...sirion.com>
---
 drivers/iio/chemical/Kconfig |  3 +++
 drivers/iio/chemical/sgpxx.c | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 4574dd687513..6710fbfc6451 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -42,12 +42,15 @@ config SENSIRION_SGPXX
 	tristate "Sensirion SGPxx gas sensors"
 	depends on I2C
 	select CRC8
+	select IIO_TRIGGERED_BUFFER if (IIO_BUFFER)
 	help
 	  Say Y here to build I2C interface support for the following
 	  Sensirion SGP gas sensors:
 	    * SGP30 gas sensor
 	    * SGPC3 gas sensor
 
+	  Also select IIO_BUFFER to enable triggered buffers.
+
 	  To compile this driver as module, choose M here: the
 	  module will be called sgpxx.
 
diff --git a/drivers/iio/chemical/sgpxx.c b/drivers/iio/chemical/sgpxx.c
index aea55e41d4cc..025206448f73 100644
--- a/drivers/iio/chemical/sgpxx.c
+++ b/drivers/iio/chemical/sgpxx.c
@@ -27,6 +27,10 @@
 #include <linux/of_device.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
+#ifdef CONFIG_IIO_BUFFER
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#endif /* CONFIG_IIO_BUFFER */
 #include <linux/iio/sysfs.h>
 
 #define SGP_WORD_LEN			2
@@ -789,6 +793,26 @@ static const struct of_device_id sgp_dt_ids[] = {
 	{ }
 };
 
+#ifdef CONFIG_IIO_BUFFER
+static irqreturn_t sgp_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct sgp_data *data = iio_priv(indio_dev);
+	int ret;
+
+	ret = sgp_get_measurement(data, data->measure_iaq_cmd,
+				  SGP_MEASURE_MODE_IAQ);
+	if (!ret)
+		iio_push_to_buffers_with_timestamp(indio_dev,
+						   &data->buffer.start,
+						   pf->timestamp);
+
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+#endif /* CONFIG_IIO_BUFFER */
+
 static int sgp_probe(struct i2c_client *client,
 		     const struct i2c_device_id *id)
 {
@@ -846,6 +870,17 @@ static int sgp_probe(struct i2c_client *client,
 	indio_dev->channels = chip->channels;
 	indio_dev->num_channels = chip->num_channels;
 
+#ifdef CONFIG_IIO_BUFFER
+	ret = iio_triggered_buffer_setup(indio_dev,
+					 iio_pollfunc_store_time,
+					 sgp_trigger_handler,
+					 NULL);
+	if (ret) {
+		dev_err(&client->dev, "failed to setup iio triggered buffer\n");
+		goto fail_free;
+	}
+#endif /* CONFIG_IIO_BUFFER */
+
 	ret = devm_iio_device_register(&client->dev, indio_dev);
 	if (!ret)
 		return ret;
@@ -863,6 +898,9 @@ static int sgp_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 
+#ifdef CONFIG_IIO_BUFFER
+	iio_triggered_buffer_cleanup(indio_dev);
+#endif /* CONFIG_IIO_BUFFER */
 	devm_iio_device_unregister(&client->dev, indio_dev);
 	return 0;
 }
-- 
2.14.1