linux-kernel - [PATCH v2 6/6] iio: pressure: Add triggered buffer support for BMP280 driver

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Message-Id: <20240313174007.1934983-7-vassilisamir@gmail.com>
Date: Wed, 13 Mar 2024 18:40:07 +0100
From: Vasileios Amoiridis <vassilisamir@...il.com>
To: jic23@...nel.org
Cc: lars@...afoo.de,
	andriy.shevchenko@...ux.intel.com,
	ang.iglesiasg@...il.com,
	mazziesaccount@...il.com,
	ak@...klinger.de,
	petre.rodan@...dimension.ro,
	linus.walleij@...aro.org,
	phil@...pberrypi.com,
	579lpy@...il.com,
	linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Vasileios Amoiridis <vassilisamir@...il.com>
Subject: [PATCH v2 6/6] iio: pressure: Add triggered buffer support for BMP280 driver

Add a buffer struct that will hold the values of the measurements
and will be pushed to userspace and a buffer_handler function to
read the data and push them.

Signed-off-by: Vasileios Amoiridis <vassilisamir@...il.com>
---
 drivers/iio/pressure/Kconfig       |  2 +
 drivers/iio/pressure/bmp280-core.c | 61 ++++++++++++++++++++++++++++++
 drivers/iio/pressure/bmp280.h      |  7 ++++
 3 files changed, 70 insertions(+)

diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
index 79adfd059c3a..5145b94b4679 100644
--- a/drivers/iio/pressure/Kconfig
+++ b/drivers/iio/pressure/Kconfig
@@ -31,6 +31,8 @@ config BMP280
 	select REGMAP
 	select BMP280_I2C if (I2C)
 	select BMP280_SPI if (SPI_MASTER)
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	  Say yes here to build support for Bosch Sensortec BMP180, BMP280, BMP380
 	  and BMP580 pressure and temperature sensors. Also supports the BME280 with
diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index f2cf9bef522c..7c889cda396a 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -40,7 +40,10 @@
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 
+#include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 
 #include <asm/unaligned.h>
 
@@ -2188,6 +2191,57 @@ static int bmp085_fetch_eoc_irq(struct device *dev,
 	return 0;
 }
 
+static irqreturn_t bmp280_buffer_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct bmp280_data *data = iio_priv(indio_dev);
+	int ret, temp;
+
+	/*
+	 * data->buf[3] is used to transfer data from the device. Whenever a
+	 * pressure or a humidity reading takes place, the data written in the
+	 * data->buf[3] overwrites the iio_buf.temperature value. Keep the
+	 * temperature value and apply it after the readings.
+	 */
+	mutex_lock(&data->lock);
+
+	if (test_bit(BMP280_TEMP, indio_dev->active_scan_mask)) {
+		ret = data->chip_info->read_temp(data);
+		if (ret < 0)
+			goto done;
+
+		temp = ret;
+	}
+
+	if (test_bit(BMP280_PRESS, indio_dev->active_scan_mask)) {
+		ret = data->chip_info->read_press(data);
+		if (ret < 0)
+			goto done;
+
+		data->iio_buf.pressure = ret;
+		data->iio_buf.temperature = temp;
+	}
+
+	if (test_bit(BME280_HUMID, indio_dev->active_scan_mask)) {
+		ret = data->chip_info->read_humid(data);
+		if (ret < 0)
+			goto done;
+
+		data->iio_buf.humidity = ret;
+		data->iio_buf.temperature = temp;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->iio_buf,
+					   iio_get_time_ns(indio_dev));
+
+done:
+	mutex_unlock(&data->lock);
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
 static void bmp280_pm_disable(void *data)
 {
 	struct device *dev = data;
@@ -2329,6 +2383,13 @@ int bmp280_common_probe(struct device *dev,
 			return ret;
 	}
 
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+					      iio_pollfunc_store_time,
+					      &bmp280_buffer_handler, NULL);
+	if (ret)
+		return dev_err_probe(data->dev, ret,
+				     "iio triggered buffer setup failed\n");
+
 	/* Enable runtime PM */
 	pm_runtime_get_noresume(dev);
 	pm_runtime_set_active(dev);
diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
index c8cb7c417dab..b5369dd496ba 100644
--- a/drivers/iio/pressure/bmp280.h
+++ b/drivers/iio/pressure/bmp280.h
@@ -407,6 +407,13 @@ struct bmp280_data {
 	union {
 		/* Sensor data buffer */
 		u8 buf[3];
+		/* Data buffer to push to userspace */
+		struct {
+			s32 temperature;
+			u32 pressure;
+			u32 humidity;
+			s64 timestamp __aligned(8);
+		} iio_buf;
 		/* Calibration data buffers */
 		__le16 bmp280_cal_buf[BMP280_CONTIGUOUS_CALIB_REGS / 2];
 		__be16 bmp180_cal_buf[BMP180_REG_CALIB_COUNT / 2];
-- 
2.25.1