Initial import

1 files changed, 190 insertions, 0 deletions

diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c
new file mode 100644
index 000000000..17ae2eb26
--- /dev/null
+++ b/drivers/hwmon/iio_hwmon.c
@@ -0,0 +1,190 @@
+/* Hwmon client for industrial I/O devices
+ *
+ * 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/hwmon.h>
+#include <linux/of.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.h>
+
+/**
+ * struct iio_hwmon_state - device instance state
+ * @channels:		filled with array of channels from iio
+ * @num_channels:	number of channels in channels (saves counting twice)
+ * @hwmon_dev:		associated hwmon device
+ * @attr_group:	the group of attributes
+ * @attrs:		null terminated array of attribute pointers.
+ */
+struct iio_hwmon_state {
+	struct iio_channel *channels;
+	int num_channels;
+	struct device *hwmon_dev;
+	struct attribute_group attr_group;
+	const struct attribute_group *groups[2];
+	struct attribute **attrs;
+};
+
+/*
+ * Assumes that IIO and hwmon operate in the same base units.
+ * This is supposed to be true, but needs verification for
+ * new channel types.
+ */
+static ssize_t iio_hwmon_read_val(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	int result;
+	int ret;
+	struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
+	struct iio_hwmon_state *state = dev_get_drvdata(dev);
+
+	ret = iio_read_channel_processed(&state->channels[sattr->index],
+					&result);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", result);
+}
+
+static int iio_hwmon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct iio_hwmon_state *st;
+	struct sensor_device_attribute *a;
+	int ret, i;
+	int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1;
+	enum iio_chan_type type;
+	struct iio_channel *channels;
+	const char *name = "iio_hwmon";
+
+	if (dev->of_node && dev->of_node->name)
+		name = dev->of_node->name;
+
+	channels = iio_channel_get_all(dev);
+	if (IS_ERR(channels))
+		return PTR_ERR(channels);
+
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+	if (st == NULL) {
+		ret = -ENOMEM;
+		goto error_release_channels;
+	}
+
+	st->channels = channels;
+
+	/* count how many attributes we have */
+	while (st->channels[st->num_channels].indio_dev)
+		st->num_channels++;
+
+	st->attrs = devm_kzalloc(dev,
+				 sizeof(*st->attrs) * (st->num_channels + 1),
+				 GFP_KERNEL);
+	if (st->attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_release_channels;
+	}
+
+	for (i = 0; i < st->num_channels; i++) {
+		a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
+		if (a == NULL) {
+			ret = -ENOMEM;
+			goto error_release_channels;
+		}
+
+		sysfs_attr_init(&a->dev_attr.attr);
+		ret = iio_get_channel_type(&st->channels[i], &type);
+		if (ret < 0)
+			goto error_release_channels;
+
+		switch (type) {
+		case IIO_VOLTAGE:
+			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
+							  "in%d_input",
+							  in_i++);
+			break;
+		case IIO_TEMP:
+			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
+							  "temp%d_input",
+							  temp_i++);
+			break;
+		case IIO_CURRENT:
+			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
+							  "curr%d_input",
+							  curr_i++);
+			break;
+		case IIO_HUMIDITYRELATIVE:
+			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
+							  "humidity%d_input",
+							  humidity_i++);
+			break;
+		default:
+			ret = -EINVAL;
+			goto error_release_channels;
+		}
+		if (a->dev_attr.attr.name == NULL) {
+			ret = -ENOMEM;
+			goto error_release_channels;
+		}
+		a->dev_attr.show = iio_hwmon_read_val;
+		a->dev_attr.attr.mode = S_IRUGO;
+		a->index = i;
+		st->attrs[i] = &a->dev_attr.attr;
+	}
+
+	st->attr_group.attrs = st->attrs;
+	st->groups[0] = &st->attr_group;
+	st->hwmon_dev = hwmon_device_register_with_groups(dev, name, st,
+							  st->groups);
+	if (IS_ERR(st->hwmon_dev)) {
+		ret = PTR_ERR(st->hwmon_dev);
+		goto error_release_channels;
+	}
+	platform_set_drvdata(pdev, st);
+	return 0;
+
+error_release_channels:
+	iio_channel_release_all(channels);
+	return ret;
+}
+
+static int iio_hwmon_remove(struct platform_device *pdev)
+{
+	struct iio_hwmon_state *st = platform_get_drvdata(pdev);
+
+	hwmon_device_unregister(st->hwmon_dev);
+	iio_channel_release_all(st->channels);
+
+	return 0;
+}
+
+static const struct of_device_id iio_hwmon_of_match[] = {
+	{ .compatible = "iio-hwmon", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
+
+static struct platform_driver __refdata iio_hwmon_driver = {
+	.driver = {
+		.name = "iio_hwmon",
+		.of_match_table = iio_hwmon_of_match,
+	},
+	.probe = iio_hwmon_probe,
+	.remove = iio_hwmon_remove,
+};
+
+module_platform_driver(iio_hwmon_driver);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("IIO to hwmon driver");
+MODULE_LICENSE("GPL v2");