diff options
Diffstat (limited to 'drivers/hwmon/iio_hwmon.c')
| -rw-r--r-- | drivers/hwmon/iio_hwmon.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c new file mode 100644 index 00000000000..aafa4531b96 --- /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"); |