iio: imu: add support to lsm6dsx driver

Add support to STM LSM6DS3-LSM6DSM 6-axis (acc + gyro) Mems sensor

http://www.st.com/resource/en/datasheet/lsm6ds3.pdf
http://www.st.com/resource/en/datasheet/lsm6dsm.pdf

- continuous mode support
- i2c support
- spi support
- sw fifo mode support
- supported devices: lsm6ds3, lsm6dsm
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/imu/Kconfig

@@ -39,6 +39,7 @@ config KMX61
 	  be called kmx61.
 
 source "drivers/iio/imu/inv_mpu6050/Kconfig"
+source "drivers/iio/imu/st_lsm6dsx/Kconfig"
 
 endmenu
 

drivers/iio/imu/Makefile

@@ -17,3 +17,5 @@ obj-y += bmi160/
 obj-y += inv_mpu6050/
 
 obj-$(CONFIG_KMX61) += kmx61.o
+
+obj-y += st_lsm6dsx/

drivers/iio/imu/st_lsm6dsx/Kconfig

+
+config IIO_ST_LSM6DSX
+	tristate "ST_LSM6DSx driver for STM 6-axis IMU MEMS sensors"
+	depends on (I2C || SPI)
+	select IIO_BUFFER
+	select IIO_KFIFO_BUF
+	select IIO_ST_LSM6DSX_I2C if (I2C)
+	select IIO_ST_LSM6DSX_SPI if (SPI_MASTER)
+	help
+	  Say yes here to build support for STMicroelectronics LSM6DSx imu
+	  sensor. Supported devices: lsm6ds3, lsm6dsm
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called st_lsm6dsx.
+
+config IIO_ST_LSM6DSX_I2C
+	tristate
+	depends on IIO_ST_LSM6DSX
+
+config IIO_ST_LSM6DSX_SPI
+	tristate
+	depends on IIO_ST_LSM6DSX

drivers/iio/imu/st_lsm6dsx/Makefile

+st_lsm6dsx-y := st_lsm6dsx_core.o st_lsm6dsx_buffer.o
+
+obj-$(CONFIG_IIO_ST_LSM6DSX) += st_lsm6dsx.o
+obj-$(CONFIG_IIO_ST_LSM6DSX_I2C) += st_lsm6dsx_i2c.o
+obj-$(CONFIG_IIO_ST_LSM6DSX_SPI) += st_lsm6dsx_spi.o

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h

+/*
+ * STMicroelectronics st_lsm6dsx sensor driver
+ *
+ * Copyright 2016 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi@st.com>
+ * Denis Ciocca <denis.ciocca@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef ST_LSM6DSX_H
+#define ST_LSM6DSX_H
+
+#include <linux/device.h>
+
+#define ST_LSM6DS3_DEV_NAME	"lsm6ds3"
+#define ST_LSM6DSM_DEV_NAME	"lsm6dsm"
+
+enum st_lsm6dsx_hw_id {
+	ST_LSM6DS3_ID,
+	ST_LSM6DSM_ID,
+};
+
+#define ST_LSM6DSX_CHAN_SIZE		2
+#define ST_LSM6DSX_SAMPLE_SIZE		6
+#define ST_LSM6DSX_SAMPLE_DEPTH		(ST_LSM6DSX_SAMPLE_SIZE / \
+					 ST_LSM6DSX_CHAN_SIZE)
+
+#if defined(CONFIG_SPI_MASTER)
+#define ST_LSM6DSX_RX_MAX_LENGTH	256
+#define ST_LSM6DSX_TX_MAX_LENGTH	8
+
+struct st_lsm6dsx_transfer_buffer {
+	u8 rx_buf[ST_LSM6DSX_RX_MAX_LENGTH];
+	u8 tx_buf[ST_LSM6DSX_TX_MAX_LENGTH] ____cacheline_aligned;
+};
+#endif /* CONFIG_SPI_MASTER */
+
+struct st_lsm6dsx_transfer_function {
+	int (*read)(struct device *dev, u8 addr, int len, u8 *data);
+	int (*write)(struct device *dev, u8 addr, int len, u8 *data);
+};
+
+struct st_lsm6dsx_reg {
+	u8 addr;
+	u8 mask;
+};
+
+struct st_lsm6dsx_settings {
+	u8 wai;
+	u16 max_fifo_size;
+	enum st_lsm6dsx_hw_id id;
+};
+
+enum st_lsm6dsx_sensor_id {
+	ST_LSM6DSX_ID_ACC,
+	ST_LSM6DSX_ID_GYRO,
+	ST_LSM6DSX_ID_MAX,
+};
+
+enum st_lsm6dsx_fifo_mode {
+	ST_LSM6DSX_FIFO_BYPASS = 0x0,
+	ST_LSM6DSX_FIFO_CONT = 0x6,
+};
+
+/**
+ * struct st_lsm6dsx_sensor - ST IMU sensor instance
+ * @id: Sensor identifier.
+ * @hw: Pointer to instance of struct st_lsm6dsx_hw.
+ * @gain: Configured sensor sensitivity.
+ * @odr: Output data rate of the sensor [Hz].
+ * @watermark: Sensor watermark level.
+ * @sip: Number of samples in a given pattern.
+ * @decimator: FIFO decimation factor.
+ * @decimator_mask: Sensor mask for decimation register.
+ * @delta_ts: Delta time between two consecutive interrupts.
+ * @ts: Latest timestamp from the interrupt handler.
+ */
+struct st_lsm6dsx_sensor {
+	enum st_lsm6dsx_sensor_id id;
+	struct st_lsm6dsx_hw *hw;
+
+	u32 gain;
+	u16 odr;
+
+	u16 watermark;
+	u8 sip;
+	u8 decimator;
+	u8 decimator_mask;
+
+	s64 delta_ts;
+	s64 ts;
+};
+
+/**
+ * struct st_lsm6dsx_hw - ST IMU MEMS hw instance
+ * @dev: Pointer to instance of struct device (I2C or SPI).
+ * @irq: Device interrupt line (I2C or SPI).
+ * @lock: Mutex to protect read and write operations.
+ * @fifo_lock: Mutex to prevent concurrent access to the hw FIFO.
+ * @fifo_mode: FIFO operating mode supported by the device.
+ * @enable_mask: Enabled sensor bitmask.
+ * @sip: Total number of samples (acc/gyro) in a given pattern.
+ * @iio_devs: Pointers to acc/gyro iio_dev instances.
+ * @settings: Pointer to the specific sensor settings in use.
+ * @tf: Transfer function structure used by I/O operations.
+ * @tb: Transfer buffers used by SPI I/O operations.
+ */
+struct st_lsm6dsx_hw {
+	struct device *dev;
+	int irq;
+
+	struct mutex lock;
+	struct mutex fifo_lock;
+
+	enum st_lsm6dsx_fifo_mode fifo_mode;
+	u8 enable_mask;
+	u8 sip;
+
+	struct iio_dev *iio_devs[ST_LSM6DSX_ID_MAX];
+
+	const struct st_lsm6dsx_settings *settings;
+
+	const struct st_lsm6dsx_transfer_function *tf;
+#if defined(CONFIG_SPI_MASTER)
+	struct st_lsm6dsx_transfer_buffer tb;
+#endif /* CONFIG_SPI_MASTER */
+};
+
+int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id,
+		     const struct st_lsm6dsx_transfer_function *tf_ops);
+int st_lsm6dsx_sensor_enable(struct st_lsm6dsx_sensor *sensor);
+int st_lsm6dsx_sensor_disable(struct st_lsm6dsx_sensor *sensor);
+int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw);
+int st_lsm6dsx_write_with_mask(struct st_lsm6dsx_hw *hw, u8 addr, u8 mask,
+			       u8 val);
+int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor,
+				u16 watermark);
+
+#endif /* ST_LSM6DSX_H */

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c

+/*
+ * STMicroelectronics st_lsm6dsx i2c driver
+ *
+ * Copyright 2016 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi@st.com>
+ * Denis Ciocca <denis.ciocca@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+
+#include "st_lsm6dsx.h"
+
+static int st_lsm6dsx_i2c_read(struct device *dev, u8 addr, int len, u8 *data)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_msg msg[2];
+
+	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 st_lsm6dsx_i2c_write(struct device *dev, u8 addr, int len, u8 *data)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_msg msg;
+	u8 send[len + 1];
+
+	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 st_lsm6dsx_transfer_function st_lsm6dsx_transfer_fn = {
+	.read = st_lsm6dsx_i2c_read,
+	.write = st_lsm6dsx_i2c_write,
+};
+
+static int st_lsm6dsx_i2c_probe(struct i2c_client *client,
+				const struct i2c_device_id *id)
+{
+	return st_lsm6dsx_probe(&client->dev, client->irq,
+				(int)id->driver_data,
+				&st_lsm6dsx_transfer_fn);
+}
+
+static const struct of_device_id st_lsm6dsx_i2c_of_match[] = {
+	{
+		.compatible = "st,lsm6ds3",
+		.data = (void *)ST_LSM6DS3_ID,
+	},
+	{
+		.compatible = "st,lsm6dsm",
+		.data = (void *)ST_LSM6DSM_ID,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, st_lsm6dsx_i2c_of_match);
+
+static const struct i2c_device_id st_lsm6dsx_i2c_id_table[] = {
+	{ ST_LSM6DS3_DEV_NAME, ST_LSM6DS3_ID },
+	{ ST_LSM6DSM_DEV_NAME, ST_LSM6DSM_ID },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, st_lsm6dsx_i2c_id_table);
+
+static struct i2c_driver st_lsm6dsx_driver = {
+	.driver = {
+		.name = "st_lsm6dsx_i2c",
+		.of_match_table = of_match_ptr(st_lsm6dsx_i2c_of_match),
+	},
+	.probe = st_lsm6dsx_i2c_probe,
+	.id_table = st_lsm6dsx_i2c_id_table,
+};
+module_i2c_driver(st_lsm6dsx_driver);
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics st_lsm6dsx i2c driver");
+MODULE_LICENSE("GPL v2");

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c

+/*
+ * STMicroelectronics st_lsm6dsx spi driver
+ *
+ * Copyright 2016 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi@st.com>
+ * Denis Ciocca <denis.ciocca@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 <linux/of.h>
+
+#include "st_lsm6dsx.h"
+
+#define SENSORS_SPI_READ	BIT(7)
+
+static int st_lsm6dsx_spi_read(struct device *dev, u8 addr, int len,
+			       u8 *data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct st_lsm6dsx_hw *hw = spi_get_drvdata(spi);
+	int err;
+
+	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,
+		}
+	};
+
+	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 st_lsm6dsx_spi_write(struct device *dev, u8 addr, int len,
+				u8 *data)
+{
+	struct st_lsm6dsx_hw *hw;
+	struct spi_device *spi;
+
+	if (len >= ST_LSM6DSX_TX_MAX_LENGTH)
+		return -ENOMEM;
+
+	spi = to_spi_device(dev);
+	hw = spi_get_drvdata(spi);
+
+	hw->tb.tx_buf[0] = addr;
+	memcpy(&hw->tb.tx_buf[1], data, len);
+
+	return spi_write(spi, hw->tb.tx_buf, len + 1);
+}
+
+static const struct st_lsm6dsx_transfer_function st_lsm6dsx_transfer_fn = {
+	.read = st_lsm6dsx_spi_read,
+	.write = st_lsm6dsx_spi_write,
+};
+
+static int st_lsm6dsx_spi_probe(struct spi_device *spi)
+{
+	const struct spi_device_id *id = spi_get_device_id(spi);
+
+	return st_lsm6dsx_probe(&spi->dev, spi->irq,
+				(int)id->driver_data,
+				&st_lsm6dsx_transfer_fn);
+}
+
+static const struct of_device_id st_lsm6dsx_spi_of_match[] = {
+	{
+		.compatible = "st,lsm6ds3",
+		.data = (void *)ST_LSM6DS3_ID,
+	},
+	{
+		.compatible = "st,lsm6dsm",
+		.data = (void *)ST_LSM6DSM_ID,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, st_lsm6dsx_spi_of_match);
+
+static const struct spi_device_id st_lsm6dsx_spi_id_table[] = {
+	{ ST_LSM6DS3_DEV_NAME, ST_LSM6DS3_ID },
+	{ ST_LSM6DSM_DEV_NAME, ST_LSM6DSM_ID },
+	{},
+};
+MODULE_DEVICE_TABLE(spi, st_lsm6dsx_spi_id_table);
+
+static struct spi_driver st_lsm6dsx_driver = {
+	.driver = {
+		.name = "st_lsm6dsx_spi",
+		.of_match_table = of_match_ptr(st_lsm6dsx_spi_of_match),
+	},
+	.probe = st_lsm6dsx_spi_probe,
+	.id_table = st_lsm6dsx_spi_id_table,
+};
+module_spi_driver(st_lsm6dsx_driver);
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics st_lsm6dsx spi driver");
+MODULE_LICENSE("GPL v2");