iio: humidity: add support to hts221 rh/temp combo device

Add support to STM HTS221 humidity + temperature sensor

http://www.st.com/resource/en/datasheet/hts221.pdf

- continuous mode support
- i2c support
- spi support
- trigger mode support

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 169 insertions, 0 deletions

diff --git a/drivers/iio/humidity/hts221_buffer.c b/drivers/iio/humidity/hts221_buffer.c
new file mode 100644
index 000000000000..76b2e8130b6f
--- /dev/null
+++ b/drivers/iio/humidity/hts221_buffer.c
@@ -0,0 +1,169 @@
+/*
+ * STMicroelectronics hts221 sensor driver
+ *
+ * Copyright 2016 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+#include <linux/interrupt.h>
+#include <linux/iio/events.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/buffer.h>
+
+#include "hts221.h"
+
+#define HTS221_REG_STATUS_ADDR		0x27
+#define HTS221_RH_DRDY_MASK		BIT(1)
+#define HTS221_TEMP_DRDY_MASK		BIT(0)
+
+static int hts221_trig_set_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *iio_dev = iio_trigger_get_drvdata(trig);
+	struct hts221_hw *hw = iio_priv(iio_dev);
+
+	return hts221_config_drdy(hw, state);
+}
+
+static const struct iio_trigger_ops hts221_trigger_ops = {
+	.owner = THIS_MODULE,
+	.set_trigger_state = hts221_trig_set_state,
+};
+
+static irqreturn_t hts221_trigger_handler_thread(int irq, void *private)
+{
+	struct hts221_hw *hw = (struct hts221_hw *)private;
+	u8 status;
+	int err;
+
+	err = hw->tf->read(hw->dev, HTS221_REG_STATUS_ADDR, sizeof(status),
+			   &status);
+	if (err < 0)
+		return IRQ_HANDLED;
+
+	/* 
+	 * H_DA bit (humidity data available) is routed to DRDY line.
+	 * Humidity sample is computed after temperature one.
+	 * Here we can assume data channels are both available if H_DA bit
+	 * is set in status register
+	 */
+	if (!(status & HTS221_RH_DRDY_MASK))
+		return IRQ_NONE;
+
+	iio_trigger_poll_chained(hw->trig);
+
+	return IRQ_HANDLED;
+}
+
+int hts221_allocate_trigger(struct hts221_hw *hw)
+{
+	struct iio_dev *iio_dev = iio_priv_to_dev(hw);
+	unsigned long irq_type;
+	int err;
+
+	irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
+
+	switch (irq_type) {
+	case IRQF_TRIGGER_HIGH:
+	case IRQF_TRIGGER_RISING:
+		break;
+	default:
+		dev_info(hw->dev,
+			 "mode %lx unsupported, using IRQF_TRIGGER_RISING\n",
+			 irq_type);
+		irq_type = IRQF_TRIGGER_RISING;
+		break;
+	}
+
+	err = devm_request_threaded_irq(hw->dev, hw->irq, NULL,
+					hts221_trigger_handler_thread,
+					irq_type | IRQF_ONESHOT,
+					hw->name, hw);
+	if (err) {
+		dev_err(hw->dev, "failed to request trigger irq %d\n",
+			hw->irq);
+		return err;
+	}
+
+	hw->trig = devm_iio_trigger_alloc(hw->dev, "%s-trigger",
+					  iio_dev->name);
+	if (!hw->trig)
+		return -ENOMEM;
+
+	iio_trigger_set_drvdata(hw->trig, iio_dev);
+	hw->trig->ops = &hts221_trigger_ops;
+	hw->trig->dev.parent = hw->dev;
+	iio_dev->trig = iio_trigger_get(hw->trig);
+
+	return devm_iio_trigger_register(hw->dev, hw->trig);
+}
+
+static int hts221_buffer_preenable(struct iio_dev *iio_dev)
+{
+	return hts221_power_on(iio_priv(iio_dev));
+}
+
+static int hts221_buffer_postdisable(struct iio_dev *iio_dev)
+{
+	return hts221_power_off(iio_priv(iio_dev));
+}
+
+static const struct iio_buffer_setup_ops hts221_buffer_ops = {
+	.preenable = hts221_buffer_preenable,
+	.postenable = iio_triggered_buffer_postenable,
+	.predisable = iio_triggered_buffer_predisable,
+	.postdisable = hts221_buffer_postdisable,
+};
+
+static irqreturn_t hts221_buffer_handler_thread(int irq, void *p)
+{
+	u8 buffer[ALIGN(2 * HTS221_DATA_SIZE, sizeof(s64)) + sizeof(s64)];
+	struct iio_poll_func *pf = p;
+	struct iio_dev *iio_dev = pf->indio_dev;
+	struct hts221_hw *hw = iio_priv(iio_dev);
+	struct iio_chan_spec const *ch;
+	int err;
+
+	/* humidity data */
+	ch = &iio_dev->channels[HTS221_SENSOR_H];
+	err = hw->tf->read(hw->dev, ch->address, HTS221_DATA_SIZE,
+			   buffer);
+	if (err < 0)
+		goto out;
+
+	/* temperature data */
+	ch = &iio_dev->channels[HTS221_SENSOR_T];
+	err = hw->tf->read(hw->dev, ch->address, HTS221_DATA_SIZE,
+			   buffer + HTS221_DATA_SIZE);
+	if (err < 0)
+		goto out;
+
+	iio_push_to_buffers_with_timestamp(iio_dev, buffer,
+					   iio_get_time_ns(iio_dev));
+
+out:
+	iio_trigger_notify_done(hw->trig);
+
+	return IRQ_HANDLED;
+}
+
+int hts221_allocate_buffers(struct hts221_hw *hw)
+{
+	return devm_iio_triggered_buffer_setup(hw->dev, iio_priv_to_dev(hw),
+					NULL, hts221_buffer_handler_thread,
+					&hts221_buffer_ops);
+}
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics hts221 buffer driver");
+MODULE_LICENSE("GPL v2");