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, 73 insertions, 0 deletions

diff --git a/drivers/iio/humidity/hts221.h b/drivers/iio/humidity/hts221.h
new file mode 100644
index 000000000000..c7154665512e
--- /dev/null
+++ b/drivers/iio/humidity/hts221.h
@@ -0,0 +1,73 @@
+/*
+ * STMicroelectronics hts221 sensor driver
+ *
+ * Copyright 2016 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef HTS221_H
+#define HTS221_H
+
+#define HTS221_DEV_NAME		"hts221"
+
+#include <linux/iio/iio.h>
+
+#define HTS221_RX_MAX_LENGTH	8
+#define HTS221_TX_MAX_LENGTH	8
+
+#define HTS221_DATA_SIZE	2
+
+struct hts221_transfer_buffer {
+	u8 rx_buf[HTS221_RX_MAX_LENGTH];
+	u8 tx_buf[HTS221_TX_MAX_LENGTH] ____cacheline_aligned;
+};
+
+struct hts221_transfer_function {
+	int (*read)(struct device *dev, u8 addr, int len, u8 *data);
+	int (*write)(struct device *dev, u8 addr, int len, u8 *data);
+};
+
+#define HTS221_AVG_DEPTH	8
+struct hts221_avg_avl {
+	u16 avg;
+	u8 val;
+};
+
+enum hts221_sensor_type {
+	HTS221_SENSOR_H,
+	HTS221_SENSOR_T,
+	HTS221_SENSOR_MAX,
+};
+
+struct hts221_sensor {
+	u8 cur_avg_idx;
+	int slope, b_gen;
+};
+
+struct hts221_hw {
+	const char *name;
+	struct device *dev;
+
+	struct mutex lock;
+	struct iio_trigger *trig;
+	int irq;
+
+	struct hts221_sensor sensors[HTS221_SENSOR_MAX];
+
+	u8 odr;
+
+	const struct hts221_transfer_function *tf;
+	struct hts221_transfer_buffer tb;
+};
+
+int hts221_config_drdy(struct hts221_hw *hw, bool enable);
+int hts221_probe(struct iio_dev *iio_dev);
+int hts221_power_on(struct hts221_hw *hw);
+int hts221_power_off(struct hts221_hw *hw);
+int hts221_allocate_buffers(struct hts221_hw *hw);
+int hts221_allocate_trigger(struct hts221_hw *hw);
+
+#endif /* HTS221_H */