iio:common: Add STMicroelectronics common library

This patch add a generic library for STMicroelectronics 3-axis sensors.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 128 insertions, 0 deletions

diff --git a/drivers/iio/common/st_sensors/st_sensors_spi.c b/drivers/iio/common/st_sensors/st_sensors_spi.c
new file mode 100644
index 000000000000..f0aa2f105222
--- /dev/null
+++ b/drivers/iio/common/st_sensors/st_sensors_spi.c
@@ -0,0 +1,128 @@
+/*
+ * STMicroelectronics sensors spi library driver
+ *
+ * Copyright 2012-2013 STMicroelectronics Inc.
+ *
+ * Denis Ciocca <denis.ciocca@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/iio/iio.h>
+
+#include <linux/iio/common/st_sensors_spi.h>
+
+
+#define ST_SENSORS_SPI_MULTIREAD	0xc0
+#define ST_SENSORS_SPI_READ		0x80
+
+static unsigned int st_sensors_spi_get_irq(struct iio_dev *indio_dev)
+{
+	struct st_sensor_data *sdata = iio_priv(indio_dev);
+
+	return to_spi_device(sdata->dev)->irq;
+}
+
+static int st_sensors_spi_read(struct st_sensor_transfer_buffer *tb,
+	struct device *dev, u8 reg_addr, int len, u8 *data, bool multiread_bit)
+{
+	struct spi_message msg;
+	int err;
+
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = tb->tx_buf,
+			.bits_per_word = 8,
+			.len = 1,
+		},
+		{
+			.rx_buf = tb->rx_buf,
+			.bits_per_word = 8,
+			.len = len,
+		}
+	};
+
+	mutex_lock(&tb->buf_lock);
+	if ((multiread_bit) && (len > 1))
+		tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_MULTIREAD;
+	else
+		tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_READ;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfers[0], &msg);
+	spi_message_add_tail(&xfers[1], &msg);
+	err = spi_sync(to_spi_device(dev), &msg);
+	if (err)
+		goto acc_spi_read_error;
+
+	memcpy(data, tb->rx_buf, len*sizeof(u8));
+	mutex_unlock(&tb->buf_lock);
+	return len;
+
+acc_spi_read_error:
+	mutex_unlock(&tb->buf_lock);
+	return err;
+}
+
+static int st_sensors_spi_read_byte(struct st_sensor_transfer_buffer *tb,
+				struct device *dev, u8 reg_addr, u8 *res_byte)
+{
+	return st_sensors_spi_read(tb, dev, reg_addr, 1, res_byte, false);
+}
+
+static int st_sensors_spi_read_multiple_byte(
+	struct st_sensor_transfer_buffer *tb, struct device *dev,
+			u8 reg_addr, int len, u8 *data, bool multiread_bit)
+{
+	return st_sensors_spi_read(tb, dev, reg_addr, len, data, multiread_bit);
+}
+
+static int st_sensors_spi_write_byte(struct st_sensor_transfer_buffer *tb,
+				struct device *dev, u8 reg_addr, u8 data)
+{
+	struct spi_message msg;
+	int err;
+
+	struct spi_transfer xfers = {
+		.tx_buf = tb->tx_buf,
+		.bits_per_word = 8,
+		.len = 2,
+	};
+
+	mutex_lock(&tb->buf_lock);
+	tb->tx_buf[0] = reg_addr;
+	tb->tx_buf[1] = data;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfers, &msg);
+	err = spi_sync(to_spi_device(dev), &msg);
+	mutex_unlock(&tb->buf_lock);
+
+	return err;
+}
+
+static const struct st_sensor_transfer_function st_sensors_tf_spi = {
+	.read_byte = st_sensors_spi_read_byte,
+	.write_byte = st_sensors_spi_write_byte,
+	.read_multiple_byte = st_sensors_spi_read_multiple_byte,
+};
+
+void st_sensors_spi_configure(struct iio_dev *indio_dev,
+			struct spi_device *spi, struct st_sensor_data *sdata)
+{
+	spi_set_drvdata(spi, indio_dev);
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi->modalias;
+
+	sdata->tf = &st_sensors_tf_spi;
+	sdata->get_irq_data_ready = st_sensors_spi_get_irq;
+}
+EXPORT_SYMBOL(st_sensors_spi_configure);
+
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
+MODULE_LICENSE("GPL v2");