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>

Author: mstahl-iis

drivers/iio/gyro/Kconfig

@@ -70,4 +70,12 @@ config IIO_ST_GYRO_SPI_3AXIS
 	depends on IIO_ST_GYRO_3AXIS
 	depends on IIO_ST_SENSORS_SPI
 
+config ITG3200
+	tristate "InvenSense ITG3200 Digital 3-Axis Gyroscope I2C driver"
+	depends on I2C
+	select IIO_TRIGGERED_BUFFER if IIO_BUFFER
+	help
+	  Say yes here to add support for the InvenSense ITG3200 digital
+	  3-axis gyroscope sensor.
+
 endmenu

drivers/iio/gyro/Makefile

@@ -8,6 +8,10 @@ obj-$(CONFIG_ADXRS450) += adxrs450.o
 
 obj-$(CONFIG_HID_SENSOR_GYRO_3D) += hid-sensor-gyro-3d.o
 
+itg3200-y               := itg3200_core.o
+itg3200-$(CONFIG_IIO_BUFFER) += itg3200_buffer.o
+obj-$(CONFIG_ITG3200)   += itg3200.o
+
 obj-$(CONFIG_IIO_ST_GYRO_3AXIS) += st_gyro.o
 st_gyro-y := st_gyro_core.o
 st_gyro-$(CONFIG_IIO_BUFFER) += st_gyro_buffer.o

drivers/iio/gyro/itg3200_buffer.c

@@ -0,0 +1,156 @@
+/*
+ * itg3200_buffer.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.
+ */
+
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/gyro/itg3200.h>
+
+
+static int itg3200_read_all_channels(struct i2c_client *i2c, __be16 *buf)
+{
+	u8 tx = 0x80 | ITG3200_REG_TEMP_OUT_H;
+	struct i2c_msg msg[2] = {
+		{
+			.addr = i2c->addr,
+			.flags = i2c->flags,
+			.len = 1,
+			.buf = &tx,
+		},
+		{
+			.addr = i2c->addr,
+			.flags = i2c->flags | I2C_M_RD,
+			.len = ITG3200_SCAN_ELEMENTS * sizeof(s16),
+			.buf = (char *)&buf,
+		},
+	};
+
+	return i2c_transfer(i2c->adapter, msg, 2);
+}
+
+static irqreturn_t itg3200_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct itg3200 *st = iio_priv(indio_dev);
+	__be16 buf[ITG3200_SCAN_ELEMENTS + sizeof(s64)/sizeof(u16)];
+
+	int ret = itg3200_read_all_channels(st->i2c, buf);
+	if (ret < 0)
+		goto error_ret;
+
+	if (indio_dev->scan_timestamp)
+		memcpy(buf + indio_dev->scan_bytes - sizeof(s64),
+				&pf->timestamp, sizeof(pf->timestamp));
+
+	iio_push_to_buffers(indio_dev, (u8 *)buf);
+	iio_trigger_notify_done(indio_dev->trig);
+
+error_ret:
+	return IRQ_HANDLED;
+}
+
+int itg3200_buffer_configure(struct iio_dev *indio_dev)
+{
+	return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+		itg3200_trigger_handler, NULL);
+}
+
+void itg3200_buffer_unconfigure(struct iio_dev *indio_dev)
+{
+	iio_triggered_buffer_cleanup(indio_dev);
+}
+
+
+static int itg3200_data_rdy_trigger_set_state(struct iio_trigger *trig,
+		bool state)
+{
+	struct iio_dev *indio_dev = trig->private_data;
+	int ret;
+	u8 msc;
+
+	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_IRQ_CONFIG, &msc);
+	if (ret)
+		goto error_ret;
+
+	if (state)
+		msc |= ITG3200_IRQ_DATA_RDY_ENABLE;
+	else
+		msc &= ~ITG3200_IRQ_DATA_RDY_ENABLE;
+
+	ret = itg3200_write_reg_8(indio_dev, ITG3200_REG_IRQ_CONFIG, msc);
+	if (ret)
+		goto error_ret;
+
+error_ret:
+	return ret;
+
+}
+
+static const struct iio_trigger_ops itg3200_trigger_ops = {
+	.owner = THIS_MODULE,
+	.set_trigger_state = &itg3200_data_rdy_trigger_set_state,
+};
+
+int itg3200_probe_trigger(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct itg3200 *st = iio_priv(indio_dev);
+
+	st->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
+				     indio_dev->id);
+	if (!st->trig)
+		return -ENOMEM;
+
+	ret = request_irq(st->i2c->irq,
+			  &iio_trigger_generic_data_rdy_poll,
+			  IRQF_TRIGGER_RISING,
+			  "itg3200_data_rdy",
+			  st->trig);
+	if (ret)
+		goto error_free_trig;
+
+
+	st->trig->dev.parent = &st->i2c->dev;
+	st->trig->ops = &itg3200_trigger_ops;
+	st->trig->private_data = indio_dev;
+	ret = iio_trigger_register(st->trig);
+	if (ret)
+		goto error_free_irq;
+
+	/* select default trigger */
+	indio_dev->trig = st->trig;
+
+	return 0;
+
+error_free_irq:
+	free_irq(st->i2c->irq, st->trig);
+error_free_trig:
+	iio_trigger_free(st->trig);
+	return ret;
+}
+
+void itg3200_remove_trigger(struct iio_dev *indio_dev)
+{
+	struct itg3200 *st = iio_priv(indio_dev);
+
+	iio_trigger_unregister(st->trig);
+	free_irq(st->i2c->irq, st->trig);
+	iio_trigger_free(st->trig);
+}