3 files changed, 206 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 89ac1cb26f24..effbd11ff5ec 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -499,6 +499,15 @@ config SENSORS_IBMPEX
           This driver can also be built as a module.  If so, the module
           will be called ibmpex.
 
+config SENSORS_IIO_HWMON
+        tristate "Hwmon driver that uses channels specified via iio maps"
+        depends on IIO
+        help
+          This is a platform driver that in combination with a suitable
+          map allows IIO devices to provide basic hwmon functionality
+          for those channels specified in the map.  This map can be provided
+          either via platform data or the device tree bindings.
+
 config SENSORS_IT87
         tristate "ITE IT87xx and compatibles"
         depends on !PPC
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 8d6d97ea7c1e..a87fdabddfff 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o
 obj-$(CONFIG_SENSORS_I5K_AMB)   += i5k_amb.o
 obj-$(CONFIG_SENSORS_IBMAEM)    += ibmaem.o
 obj-$(CONFIG_SENSORS_IBMPEX)    += ibmpex.o
+obj-$(CONFIG_SENSORS_IIO_HWMON) += iio_hwmon.o
 obj-$(CONFIG_SENSORS_INA209)    += ina209.o
 obj-$(CONFIG_SENSORS_INA2XX)    += ina2xx.o
 obj-$(CONFIG_SENSORS_IT87)      += it87.o
diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c
new file mode 100644
index 000000000000..aafa4531b961
--- /dev/null
+++ b/drivers/hwmon/iio_hwmon.c
@@ -0,0 +1,196 @@
+/* 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;
+        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 ssize_t show_name(struct device *dev, struct device_attribute *attr,
+                         char *buf)
+{
+        const char *name = "iio_hwmon";
+
+        if (dev->of_node && dev->of_node->name)
+                name = dev->of_node->name;
+
+        return sprintf(buf, "%s\n", name);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
+
+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;
+        enum iio_chan_type type;
+        struct iio_channel *channels;
+
+        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)
+                return -ENOMEM;
+
+        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 + 2),
+                                 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;
+                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->attrs[st->num_channels] = &dev_attr_name.attr;
+        st->attr_group.attrs = st->attrs;
+        platform_set_drvdata(pdev, st);
+        ret = sysfs_create_group(&dev->kobj, &st->attr_group);
+        if (ret < 0)
+                goto error_release_channels;
+
+        st->hwmon_dev = hwmon_device_register(dev);
+        if (IS_ERR(st->hwmon_dev)) {
+                ret = PTR_ERR(st->hwmon_dev);
+                goto error_remove_group;
+        }
+        return 0;
+
+error_remove_group:
+        sysfs_remove_group(&dev->kobj, &st->attr_group);
+error_release_channels:
+        iio_channel_release_all(st->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);
+        sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
+        iio_channel_release_all(st->channels);
+
+        return 0;
+}
+
+static struct of_device_id iio_hwmon_of_match[] = {
+        { .compatible = "iio-hwmon", },
+        { }
+};
+
+static struct platform_driver __refdata iio_hwmon_driver = {
+        .driver = {
+                .name = "iio_hwmon",
+                .owner = THIS_MODULE,
+                .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");