diff options
Diffstat (limited to 'drivers/staging/iio/iio_hwmon.c')
| -rw-r--r-- | drivers/staging/iio/iio_hwmon.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/staging/iio/iio_hwmon.c b/drivers/staging/iio/iio_hwmon.c new file mode 100644 index 0000000..a603a5f --- /dev/null +++ b/drivers/staging/iio/iio_hwmon.c @@ -0,0 +1,232 @@ +/* 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/hwmon-sysfs.h> +#include "consumer.h" +#include "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) +{ + long result; + int val, ret, scaleint, scalepart; + struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); + struct iio_hwmon_state *state = dev_get_drvdata(dev); + + /* + * No locking between this pair, so theoretically possible + * the scale has changed. + */ + ret = iio_st_read_channel_raw(&state->channels[sattr->index], + &val); + if (ret < 0) + return ret; + + ret = iio_st_read_channel_scale(&state->channels[sattr->index], + &scaleint, &scalepart); + if (ret < 0) + return ret; + switch (ret) { + case IIO_VAL_INT: + result = val * scaleint; + break; + case IIO_VAL_INT_PLUS_MICRO: + result = (s64)val * (s64)scaleint + + div_s64((s64)val * (s64)scalepart, 1000000LL); + break; + case IIO_VAL_INT_PLUS_NANO: + result = (s64)val * (s64)scaleint + + div_s64((s64)val * (s64)scalepart, 1000000000LL); + break; + default: + return -EINVAL; + } + return sprintf(buf, "%ld\n", result); +} + +static void iio_hwmon_free_attrs(struct iio_hwmon_state *st) +{ + int i; + struct sensor_device_attribute *a; + for (i = 0; i < st->num_channels; i++) + if (st->attrs[i]) { + a = to_sensor_dev_attr( + container_of(st->attrs[i], + struct device_attribute, + attr)); + kfree(a); + } +} + +static int __devinit iio_hwmon_probe(struct platform_device *pdev) +{ + 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; + + st = kzalloc(sizeof(*st), GFP_KERNEL); + if (st == NULL) { + ret = -ENOMEM; + goto error_ret; + } + + st->channels = iio_st_channel_get_all(dev_name(&pdev->dev)); + if (IS_ERR(st->channels)) { + ret = PTR_ERR(st->channels); + goto error_free_state; + } + + /* count how many attributes we have */ + while (st->channels[st->num_channels].indio_dev) + st->num_channels++; + + st->attrs = kzalloc(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 = kzalloc(sizeof(*a), GFP_KERNEL); + if (a == NULL) { + ret = -ENOMEM; + goto error_free_attrs; + } + + sysfs_attr_init(&a->dev_attr.attr); + ret = iio_st_get_channel_type(&st->channels[i], &type); + if (ret < 0) { + kfree(a); + goto error_free_attrs; + } + 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; + kfree(a); + goto error_free_attrs; + } + if (a->dev_attr.attr.name == NULL) { + kfree(a); + ret = -ENOMEM; + goto error_free_attrs; + } + 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; + platform_set_drvdata(pdev, st); + ret = sysfs_create_group(&pdev->dev.kobj, &st->attr_group); + if (ret < 0) + goto error_free_attrs; + + st->hwmon_dev = hwmon_device_register(&pdev->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(&pdev->dev.kobj, &st->attr_group); +error_free_attrs: + iio_hwmon_free_attrs(st); + kfree(st->attrs); +error_release_channels: + iio_st_channel_release_all(st->channels); +error_free_state: + kfree(st); +error_ret: + return ret; +} + +static int __devexit 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_hwmon_free_attrs(st); + kfree(st->attrs); + iio_st_channel_release_all(st->channels); + + return 0; +} + +static struct platform_driver __refdata iio_hwmon_driver = { + .driver = { + .name = "iio_hwmon", + .owner = THIS_MODULE, + }, + .probe = iio_hwmon_probe, + .remove = __devexit_p(iio_hwmon_remove), +}; + +static int iio_inkern_init(void) +{ + return platform_driver_register(&iio_hwmon_driver); +} +module_init(iio_inkern_init); + +static void iio_inkern_exit(void) +{ + platform_driver_unregister(&iio_hwmon_driver); +} +module_exit(iio_inkern_exit); + +MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>"); +MODULE_DESCRIPTION("IIO to hwmon driver"); +MODULE_LICENSE("GPL v2"); |
