iio: gyro: Add itg3200

This patch adds support for the InvenSense itg3200.
The itg3200 is a three-axis gyro with 16-bit ADC and
I2C interface.

Signed-off-by: Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 401 insertions, 0 deletions

diff --git a/drivers/iio/gyro/itg3200_core.c b/drivers/iio/gyro/itg3200_core.c
new file mode 100644
index 000000000000..df2e6aa5d73b
--- /dev/null
+++ b/drivers/iio/gyro/itg3200_core.c
@@ -0,0 +1,401 @@
+/*
+ * itg3200_core.c -- support InvenSense ITG3200
+ *                   Digital 3-Axis Gyroscope driver
+ *
+ * Copyright (c) 2011 Christian Strobel <christian.strobel@iis.fraunhofer.de>
+ * Copyright (c) 2011 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
+ * Copyright (c) 2012 Thorsten Nowak <thorsten.nowak@iis.fraunhofer.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * TODO:
+ * - Support digital low pass filter
+ * - Support power management
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+#include <linux/iio/buffer.h>
+
+#include <linux/iio/gyro/itg3200.h>
+
+
+int itg3200_write_reg_8(struct iio_dev *indio_dev,
+		u8 reg_address, u8 val)
+{
+	struct itg3200 *st = iio_priv(indio_dev);
+
+	return i2c_smbus_write_byte_data(st->i2c, 0x80 | reg_address, val);
+}
+
+int itg3200_read_reg_8(struct iio_dev *indio_dev,
+		u8 reg_address, u8 *val)
+{
+	struct itg3200 *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(st->i2c, reg_address);
+	if (ret < 0)
+		return ret;
+	*val = ret;
+	return 0;
+}
+
+static int itg3200_read_reg_s16(struct iio_dev *indio_dev, u8 lower_reg_address,
+		int *val)
+{
+	struct itg3200 *st = iio_priv(indio_dev);
+	struct i2c_client *client = st->i2c;
+	int ret;
+	s16 out;
+
+	struct i2c_msg msg[2] = {
+		{
+			.addr = client->addr,
+			.flags = client->flags,
+			.len = 1,
+			.buf = (char *)&lower_reg_address,
+		},
+		{
+			.addr = client->addr,
+			.flags = client->flags | I2C_M_RD,
+			.len = 2,
+			.buf = (char *)&out,
+		},
+	};
+
+	lower_reg_address |= 0x80;
+	ret = i2c_transfer(client->adapter, msg, 2);
+	be16_to_cpus(&out);
+	*val = out;
+
+	return (ret == 2) ? 0 : ret;
+}
+
+static int itg3200_read_raw(struct iio_dev *indio_dev,
+		const struct iio_chan_spec *chan,
+		int *val, int *val2, long info)
+{
+	int ret = 0;
+	u8 reg;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		reg = (u8)chan->address;
+		ret = itg3200_read_reg_s16(indio_dev, reg, val);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		if (chan->type == IIO_TEMP)
+			*val2 = 1000000000/280;
+		else
+			*val2 = 1214142; /* (1 / 14,375) * (PI / 180) */
+		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_OFFSET:
+		/* Only the temperature channel has an offset */
+		*val = 23000;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static ssize_t itg3200_read_frequency(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	int ret, sps;
+	u8 val;
+
+	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
+	if (ret)
+		return ret;
+
+	sps = (val & ITG3200_DLPF_CFG_MASK) ? 1000 : 8000;
+
+	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_SAMPLE_RATE_DIV, &val);
+	if (ret)
+		return ret;
+
+	sps /= val + 1;
+
+	return sprintf(buf, "%d\n", sps);
+}
+
+static ssize_t itg3200_write_frequency(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	unsigned val;
+	int ret;
+	u8 t;
+
+	ret = kstrtouint(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+
+	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &t);
+	if (ret)
+		goto err_ret;
+
+	if (val == 0) {
+		ret = -EINVAL;
+		goto err_ret;
+	}
+	t = ((t & ITG3200_DLPF_CFG_MASK) ? 1000u : 8000u) / val - 1;
+
+	ret = itg3200_write_reg_8(indio_dev, ITG3200_REG_SAMPLE_RATE_DIV, t);
+
+err_ret:
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+
+/*
+ * Reset device and internal registers to the power-up-default settings
+ * Use the gyro clock as reference, as suggested by the datasheet
+ */
+static int itg3200_reset(struct iio_dev *indio_dev)
+{
+	struct itg3200 *st = iio_priv(indio_dev);
+	int ret;
+
+	dev_dbg(&st->i2c->dev, "reset device");
+
+	ret = itg3200_write_reg_8(indio_dev,
+			ITG3200_REG_POWER_MANAGEMENT,
+			ITG3200_RESET);
+	if (ret) {
+		dev_err(&st->i2c->dev, "error resetting device");
+		goto error_ret;
+	}
+
+	/* Wait for PLL (1ms according to datasheet) */
+	udelay(1500);
+
+	ret = itg3200_write_reg_8(indio_dev,
+			ITG3200_REG_IRQ_CONFIG,
+			ITG3200_IRQ_ACTIVE_HIGH |
+			ITG3200_IRQ_PUSH_PULL |
+			ITG3200_IRQ_LATCH_50US_PULSE |
+			ITG3200_IRQ_LATCH_CLEAR_ANY);
+
+	if (ret)
+		dev_err(&st->i2c->dev, "error init device");
+
+error_ret:
+	return ret;
+}
+
+/* itg3200_enable_full_scale() - Disables the digital low pass filter */
+static int itg3200_enable_full_scale(struct iio_dev *indio_dev)
+{
+	u8 val;
+	int ret;
+
+	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
+	if (ret)
+		goto err_ret;
+
+	val |= ITG3200_DLPF_FS_SEL_2000;
+	return itg3200_write_reg_8(indio_dev, ITG3200_REG_DLPF, val);
+
+err_ret:
+	return ret;
+}
+
+static int itg3200_initial_setup(struct iio_dev *indio_dev)
+{
+	struct itg3200 *st = iio_priv(indio_dev);
+	int ret;
+	u8 val;
+
+	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_ADDRESS, &val);
+	if (ret)
+		goto err_ret;
+
+	if (((val >> 1) & 0x3f) != 0x34) {
+		dev_err(&st->i2c->dev, "invalid reg value 0x%02x", val);
+		ret = -ENXIO;
+		goto err_ret;
+	}
+
+	ret = itg3200_reset(indio_dev);
+	if (ret)
+		goto err_ret;
+
+	ret = itg3200_enable_full_scale(indio_dev);
+err_ret:
+	return ret;
+}
+
+#define ITG3200_TEMP_INFO_MASK	(IIO_CHAN_INFO_OFFSET_SHARED_BIT | \
+				 IIO_CHAN_INFO_SCALE_SHARED_BIT | \
+				 IIO_CHAN_INFO_RAW_SEPARATE_BIT)
+#define ITG3200_GYRO_INFO_MASK	(IIO_CHAN_INFO_SCALE_SHARED_BIT | \
+				 IIO_CHAN_INFO_RAW_SEPARATE_BIT)
+
+#define ITG3200_ST						\
+	{ .sign = 's', .realbits = 16, .storagebits = 16, .endianness = IIO_BE }
+
+#define ITG3200_GYRO_CHAN(_mod) { \
+	.type = IIO_ANGL_VEL, \
+	.modified = 1, \
+	.channel2 = IIO_MOD_ ## _mod, \
+	.info_mask = ITG3200_GYRO_INFO_MASK, \
+	.address = ITG3200_REG_GYRO_ ## _mod ## OUT_H, \
+	.scan_index = ITG3200_SCAN_GYRO_ ## _mod, \
+	.scan_type = ITG3200_ST, \
+}
+
+static const struct iio_chan_spec itg3200_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.channel2 = IIO_NO_MOD,
+		.info_mask = ITG3200_TEMP_INFO_MASK,
+		.address = ITG3200_REG_TEMP_OUT_H,
+		.scan_index = ITG3200_SCAN_TEMP,
+		.scan_type = ITG3200_ST,
+	},
+	ITG3200_GYRO_CHAN(X),
+	ITG3200_GYRO_CHAN(Y),
+	ITG3200_GYRO_CHAN(Z),
+	IIO_CHAN_SOFT_TIMESTAMP(ITG3200_SCAN_ELEMENTS),
+};
+
+/* IIO device attributes */
+static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO, itg3200_read_frequency,
+		itg3200_write_frequency);
+
+static struct attribute *itg3200_attributes[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group itg3200_attribute_group = {
+	.attrs = itg3200_attributes,
+};
+
+static const struct iio_info itg3200_info = {
+	.attrs = &itg3200_attribute_group,
+	.read_raw = &itg3200_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static const unsigned long itg3200_available_scan_masks[] = { 0xffffffff, 0x0 };
+
+static int itg3200_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	int ret;
+	struct itg3200 *st;
+	struct iio_dev *indio_dev;
+
+	dev_dbg(&client->dev, "probe I2C dev with IRQ %i", client->irq);
+
+	indio_dev = iio_device_alloc(sizeof(*st));
+	if (indio_dev == NULL) {
+		ret =  -ENOMEM;
+		goto error_ret;
+	}
+
+	st = iio_priv(indio_dev);
+
+	i2c_set_clientdata(client, indio_dev);
+	st->i2c = client;
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->name = client->dev.driver->name;
+	indio_dev->channels = itg3200_channels;
+	indio_dev->num_channels = ARRAY_SIZE(itg3200_channels);
+	indio_dev->available_scan_masks = itg3200_available_scan_masks;
+	indio_dev->info = &itg3200_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = itg3200_buffer_configure(indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	if (client->irq) {
+		ret = itg3200_probe_trigger(indio_dev);
+		if (ret)
+			goto error_unconfigure_buffer;
+	}
+
+	ret = itg3200_initial_setup(indio_dev);
+	if (ret)
+		goto error_remove_trigger;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_remove_trigger;
+
+	return 0;
+
+error_remove_trigger:
+	if (client->irq)
+		itg3200_remove_trigger(indio_dev);
+error_unconfigure_buffer:
+	itg3200_buffer_unconfigure(indio_dev);
+error_free_dev:
+	iio_device_free(indio_dev);
+error_ret:
+	return ret;
+}
+
+static int itg3200_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+
+	if (client->irq)
+		itg3200_remove_trigger(indio_dev);
+
+	itg3200_buffer_unconfigure(indio_dev);
+
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id itg3200_id[] = {
+	{ "itg3200", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, itg3200_id);
+
+static struct i2c_driver itg3200_driver = {
+	.driver = {
+		.owner  = THIS_MODULE,
+		.name	= "itg3200",
+	},
+	.id_table	= itg3200_id,
+	.probe		= itg3200_probe,
+	.remove		= itg3200_remove,
+};
+
+module_i2c_driver(itg3200_driver);
+
+MODULE_AUTHOR("Christian Strobel <christian.strobel@iis.fraunhofer.de>");
+MODULE_DESCRIPTION("ITG3200 Gyroscope I2C driver");
+MODULE_LICENSE("GPL v2");