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, 110 insertions, 0 deletions

diff --git a/drivers/iio/humidity/hts221_i2c.c b/drivers/iio/humidity/hts221_i2c.c
new file mode 100644
index 000000000000..367ecd509f31
--- /dev/null
+++ b/drivers/iio/humidity/hts221_i2c.c
@@ -0,0 +1,110 @@
+/*
+ * STMicroelectronics hts221 i2c 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/i2c.h>
+#include <linux/slab.h>
+#include "hts221.h"
+
+#define I2C_AUTO_INCREMENT	0x80
+
+static int hts221_i2c_read(struct device *dev, u8 addr, int len, u8 *data)
+{
+	struct i2c_msg msg[2];
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (len > 1)
+		addr |= I2C_AUTO_INCREMENT;
+
+	msg[0].addr = client->addr;
+	msg[0].flags = client->flags;
+	msg[0].len = 1;
+	msg[0].buf = &addr;
+
+	msg[1].addr = client->addr;
+	msg[1].flags = client->flags | I2C_M_RD;
+	msg[1].len = len;
+	msg[1].buf = data;
+
+	return i2c_transfer(client->adapter, msg, 2);
+}
+
+static int hts221_i2c_write(struct device *dev, u8 addr, int len, u8 *data)
+{
+	u8 send[len + 1];
+	struct i2c_msg msg;
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (len > 1)
+		addr |= I2C_AUTO_INCREMENT;
+
+	send[0] = addr;
+	memcpy(&send[1], data, len * sizeof(u8));
+
+	msg.addr = client->addr;
+	msg.flags = client->flags;
+	msg.len = len + 1;
+	msg.buf = send;
+
+	return i2c_transfer(client->adapter, &msg, 1);
+}
+
+static const struct hts221_transfer_function hts221_transfer_fn = {
+	.read = hts221_i2c_read,
+	.write = hts221_i2c_write,
+};
+
+static int hts221_i2c_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct hts221_hw *hw;
+	struct iio_dev *iio_dev;
+
+	iio_dev = devm_iio_device_alloc(&client->dev, sizeof(*hw));
+	if (!iio_dev)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, iio_dev);
+
+	hw = iio_priv(iio_dev);
+	hw->name = client->name;
+	hw->dev = &client->dev;
+	hw->irq = client->irq;
+	hw->tf = &hts221_transfer_fn;
+
+	return hts221_probe(iio_dev);
+}
+
+static const struct of_device_id hts221_i2c_of_match[] = {
+	{ .compatible = "st,hts221", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, hts221_i2c_of_match);
+
+static const struct i2c_device_id hts221_i2c_id_table[] = {
+	{ HTS221_DEV_NAME },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, hts221_i2c_id_table);
+
+static struct i2c_driver hts221_driver = {
+	.driver = {
+		.name = "hts221_i2c",
+		.of_match_table = of_match_ptr(hts221_i2c_of_match),
+	},
+	.probe = hts221_i2c_probe,
+	.id_table = hts221_i2c_id_table,
+};
+module_i2c_driver(hts221_driver);
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics hts221 i2c driver");
+MODULE_LICENSE("GPL v2");