[PATCH 4/4] staging:iio: Proof of concept input driver.

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <jic23@cam.ac.uk>

This is no where near ready to merge.  Lots of stuff missing.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/staging/iio/Kconfig     |   11 +++
 drivers/staging/iio/Makefile    |    1 +
 drivers/staging/iio/iio_input.c |  176 +++++++++++++++++++++++++++++++++++++++
 drivers/staging/iio/iio_input.h |   23 +++++
 4 files changed, 211 insertions(+)

diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
index 04cd6ec..022463e 100644
--- a/drivers/staging/iio/Kconfig
+++ b/drivers/staging/iio/Kconfig
@@ -4,6 +4,17 @@
 menu "IIO staging drivers"
 	depends on IIO
 
+config IIO_ST_INPUT
+	tristate "Input driver that uses channels specified via iio maps"
+	depends on INPUT
+	depends on IIO_BUFFER
+	select IIO_BUFFER_CB
+	help
+	  Client driver for IIO via the push interfaces.  Used to provide
+	  and input interface for IIO devices that can feed a buffer on
+	  a trigger interrupt.  Note that all channels must come from a
+	  single IIO supported device.
+
 config IIO_ST_HWMON
 	tristate "Hwmon driver that uses channels specified via iio maps"
 	depends on HWMON
diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
index fa6937d..9e71498 100644
--- a/drivers/staging/iio/Makefile
+++ b/drivers/staging/iio/Makefile
@@ -12,6 +12,7 @@ iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_BUFFER) += iio_simple_dummy_buffer.o
 obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o
 
 obj-$(CONFIG_IIO_ST_HWMON) += iio_hwmon.o
+obj-$(CONFIG_IIO_ST_INPUT) += iio_input.o
 
 obj-y += accel/
 obj-y += adc/
diff --git a/drivers/staging/iio/iio_input.c b/drivers/staging/iio/iio_input.c
new file mode 100644
index 0000000..42f4cfb
--- /dev/null
+++ b/drivers/staging/iio/iio_input.c
@@ -0,0 +1,176 @@
+/*
+ * The industrial I/O input client driver
+ *
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * 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/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/consumer.h>
+#include "iio_input.h"
+
+struct iio_input_state {
+	struct iio_cb_buffer *buff;
+	struct input_dev *idev;
+};
+
+static int iio_channel_value(u8 *data,
+			     const struct iio_chan_spec *chan,
+			     int *val)
+{
+	int value;
+
+	if (chan->scan_type.sign == 's') {
+		switch (chan->scan_type.storagebits) {
+		case 8:
+			value = *(s8 *)(data);
+			break;
+		case 16:
+			value = *(s16 *)(data);
+			break;
+		case 32:
+			value = *(s32 *)(data);
+			break;
+		default:
+			return -EINVAL;
+		}
+		value >>= chan->scan_type.shift;
+		value &= (1 << chan->scan_type.realbits) - 1;
+		value = (value << (sizeof(value)*8 - chan->scan_type.realbits))
+			>> (sizeof(value)*8 - chan->scan_type.realbits);
+	} else {
+		switch (chan->scan_type.storagebits) {
+		case 8:
+			value = *(u8 *)(data);
+			break;
+		case 16:
+			value = *(u16 *)(data);
+			break;
+		case 32:
+			value = *(u32 *)(data);
+			break;
+		default:
+			return -EINVAL;
+		}
+		value >>= chan->scan_type.shift;
+		value &= (1 << chan->scan_type.realbits) - 1;
+	}
+	*val = value;
+
+	return 0;
+}
+
+static int iio_input_store_to(u8 *data, void *private)
+{
+	struct iio_input_state *st = private;
+	struct iio_channel *channel;
+	struct iio_input_channel_data *input_data;
+	int offset = 0;
+	int value, ret;
+
+	channel = iio_channel_cb_get_channels(st->buff);
+	while (channel->indio_dev) {
+		input_data = channel->data;
+		offset = ALIGN(offset,
+			       channel->channel->scan_type.storagebits/8);
+		offset += channel->channel->scan_type.storagebits/8;
+		ret = iio_channel_value(&data[offset],
+					channel->channel,
+					&value);
+		if (ret < 0)
+			return ret;
+		input_report_abs(st->idev, input_data->code, value);
+	}
+	input_sync(st->idev);
+
+	return 0;
+}
+
+static int __devinit iio_input_probe(struct platform_device *pdev)
+{
+	struct iio_input_state *st;
+	int ret;
+	struct iio_channel *channel;
+	struct iio_input_channel_data *input_data;
+
+	st = kzalloc(sizeof(*st), GFP_KERNEL);
+	if (st == NULL)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, st);
+	st->buff = iio_channel_get_all_cb(dev_name(&pdev->dev),
+					  &iio_input_store_to,
+					  st);
+	if (IS_ERR(st->buff)) {
+		ret = PTR_ERR(st->buff);
+		goto error_free_state;
+	}
+
+	st->idev = input_allocate_device();
+	if (!st->idev) {
+		ret = -ENOMEM;
+		goto error_channels_release_all;
+	}
+
+	__set_bit(EV_ABS, st->idev->evbit);
+	channel = iio_channel_cb_get_channels(st->buff);
+	while (channel->indio_dev) {
+		input_data = channel->data;
+		input_set_abs_params(st->idev, input_data->code,
+				     input_data->min,
+				     input_data->max,
+				     input_data->fuzz,
+				     input_data->flat);
+	}
+
+	ret = input_register_device(st->idev);
+	if (ret < 0)
+		goto error_free_idev;
+
+	/* NORMALLY IN THE OPEN */
+	iio_channel_start_all_cb(st->buff);
+
+	return 0;
+error_free_idev:
+	input_free_device(st->idev);
+error_channels_release_all:
+	iio_channel_release_all_cb(st->buff);
+error_free_state:
+	kfree(st);
+	return ret;
+}
+
+static int __devexit iio_input_remove(struct platform_device *pdev)
+{
+	struct iio_input_state *st = platform_get_drvdata(pdev);
+	/* NORMALLY IN THE CLOSE */
+	iio_channel_stop_all_cb(st->buff);
+	input_unregister_device(st->idev);
+	iio_channel_release_all_cb(st->buff);
+
+	kfree(st);
+	return 0;
+}
+
+static struct platform_driver iio_input_driver = {
+	.driver = {
+		.name = "iio_snoop",
+		.owner = THIS_MODULE,
+	},
+	.probe = iio_input_probe,
+	.remove = __devexit_p(iio_input_remove),
+};
+
+module_platform_driver(iio_input_driver);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
+MODULE_DESCRIPTION("IIO input buffer driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/iio/iio_input.h b/drivers/staging/iio/iio_input.h
new file mode 100644
index 0000000..cfd1d34
--- /dev/null
+++ b/drivers/staging/iio/iio_input.h
@@ -0,0 +1,23 @@
+/*
+ * The industrial I/O input client driver
+ *
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * 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.
+ */
+
+/**
+ * iio_input_channel_data - description of the channel for input subsystem
+ * @code:	Absolute axis.
+ * @min:	Minimum value.
+ * @max:	Maximum value.
+ * @fuzz:	Used to filter noise from the event stream.
+ * @flat:	Values within this value will be discarded by joydev
+ *		and reported as 0 instead.
+ */
+struct iio_input_channel_data {
+	unsigned int code;
+	int min, max, fuzz, flat;
+};
-- 
1.7.10.2