/* 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 * @groups: null terminated array of attribute groups * @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"; char *sname; if (dev->of_node && dev->of_node->name) name = dev->of_node->name; channels = iio_channel_get_all(dev); if (IS_ERR(channels)) { if (PTR_ERR(channels) == -ENODEV) return -EPROBE_DEFER; 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 = devm_kasprintf(dev, GFP_KERNEL, "in%d_input", in_i++); break; case IIO_TEMP: a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, "temp%d_input", temp_i++); break; case IIO_CURRENT: a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, "curr%d_input", curr_i++); break; case IIO_HUMIDITYRELATIVE: a->dev_attr.attr.name = devm_kasprintf(dev, 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; sname = devm_kstrdup(dev, name, GFP_KERNEL); if (!sname) { ret = -ENOMEM; goto error_release_channels; } strreplace(sname, '-', '_'); st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, 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");