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>
diff --git a/drivers/iio/humidity/hts221_spi.c b/drivers/iio/humidity/hts221_spi.c
new file mode 100644
index 0000000..70df5e7
--- /dev/null
+++ b/drivers/iio/humidity/hts221_spi.c
@@ -0,0 +1,125 @@
+/*
+ * STMicroelectronics hts221 spi 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/spi/spi.h>
+#include <linux/slab.h>
+#include "hts221.h"
+
+#define SENSORS_SPI_READ 0x80
+#define SPI_AUTO_INCREMENT 0x40
+
+static int hts221_spi_read(struct device *dev, u8 addr, int len, u8 *data)
+{
+ int err;
+ struct spi_device *spi = to_spi_device(dev);
+ struct iio_dev *iio_dev = spi_get_drvdata(spi);
+ struct hts221_hw *hw = iio_priv(iio_dev);
+
+ struct spi_transfer xfers[] = {
+ {
+ .tx_buf = hw->tb.tx_buf,
+ .bits_per_word = 8,
+ .len = 1,
+ },
+ {
+ .rx_buf = hw->tb.rx_buf,
+ .bits_per_word = 8,
+ .len = len,
+ }
+ };
+
+ if (len > 1)
+ addr |= SPI_AUTO_INCREMENT;
+ hw->tb.tx_buf[0] = addr | SENSORS_SPI_READ;
+
+ err = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
+ if (err < 0)
+ return err;
+
+ memcpy(data, hw->tb.rx_buf, len * sizeof(u8));
+
+ return len;
+}
+
+static int hts221_spi_write(struct device *dev, u8 addr, int len, u8 *data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct iio_dev *iio_dev = spi_get_drvdata(spi);
+ struct hts221_hw *hw = iio_priv(iio_dev);
+
+ struct spi_transfer xfers = {
+ .tx_buf = hw->tb.tx_buf,
+ .bits_per_word = 8,
+ .len = len + 1,
+ };
+
+ if (len >= HTS221_TX_MAX_LENGTH)
+ return -ENOMEM;
+
+ if (len > 1)
+ addr |= SPI_AUTO_INCREMENT;
+ hw->tb.tx_buf[0] = addr;
+ memcpy(&hw->tb.tx_buf[1], data, len);
+
+ return spi_sync_transfer(spi, &xfers, 1);
+}
+
+static const struct hts221_transfer_function hts221_transfer_fn = {
+ .read = hts221_spi_read,
+ .write = hts221_spi_write,
+};
+
+static int hts221_spi_probe(struct spi_device *spi)
+{
+ struct hts221_hw *hw;
+ struct iio_dev *iio_dev;
+
+ iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*hw));
+ if (!iio_dev)
+ return -ENOMEM;
+
+ spi_set_drvdata(spi, iio_dev);
+
+ hw = iio_priv(iio_dev);
+ hw->name = spi->modalias;
+ hw->dev = &spi->dev;
+ hw->irq = spi->irq;
+ hw->tf = &hts221_transfer_fn;
+
+ return hts221_probe(iio_dev);
+}
+
+static const struct of_device_id hts221_spi_of_match[] = {
+ { .compatible = "st,hts221", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, hts221_spi_of_match);
+
+static const struct spi_device_id hts221_spi_id_table[] = {
+ { HTS221_DEV_NAME },
+ {},
+};
+MODULE_DEVICE_TABLE(spi, hts221_spi_id_table);
+
+static struct spi_driver hts221_driver = {
+ .driver = {
+ .name = "hts221_spi",
+ .of_match_table = of_match_ptr(hts221_spi_of_match),
+ },
+ .probe = hts221_spi_probe,
+ .id_table = hts221_spi_id_table,
+};
+module_spi_driver(hts221_driver);
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics hts221 spi driver");
+MODULE_LICENSE("GPL v2");