diff options
Diffstat (limited to 'drivers/hwmon/iio_hwmon.c')
| -rw-r--r-- | drivers/hwmon/iio_hwmon.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c new file mode 100644 index 0000000000..4c8a808478 --- /dev/null +++ b/drivers/hwmon/iio_hwmon.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Hwmon client for industrial I/O devices + * + * Copyright (c) 2011 Jonathan Cameron + */ + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/property.h> + +#include <linux/hwmon.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) + * @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 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); + struct iio_channel *chan = &state->channels[sattr->index]; + enum iio_chan_type type; + + ret = iio_read_channel_processed(chan, &result); + if (ret < 0) + return ret; + + ret = iio_get_channel_type(chan, &type); + if (ret < 0) + return ret; + + if (type == IIO_POWER) + result *= 1000; /* mili-Watts to micro-Watts conversion */ + + 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, power_i = 1; + enum iio_chan_type type; + struct iio_channel *channels; + struct device *hwmon_dev; + char *sname; + + channels = devm_iio_channel_get_all(dev); + if (IS_ERR(channels)) { + ret = PTR_ERR(channels); + if (ret == -ENODEV) + ret = -EPROBE_DEFER; + return dev_err_probe(dev, ret, + "Failed to get channels\n"); + } + + 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_kcalloc(dev, + st->num_channels + 1, sizeof(*st->attrs), + GFP_KERNEL); + if (st->attrs == NULL) + return -ENOMEM; + + for (i = 0; i < st->num_channels; i++) { + const char *prefix; + int n; + + a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); + if (a == NULL) + return -ENOMEM; + + sysfs_attr_init(&a->dev_attr.attr); + ret = iio_get_channel_type(&st->channels[i], &type); + if (ret < 0) + return ret; + + switch (type) { + case IIO_VOLTAGE: + n = in_i++; + prefix = "in"; + break; + case IIO_TEMP: + n = temp_i++; + prefix = "temp"; + break; + case IIO_CURRENT: + n = curr_i++; + prefix = "curr"; + break; + case IIO_POWER: + n = power_i++; + prefix = "power"; + break; + case IIO_HUMIDITYRELATIVE: + n = humidity_i++; + prefix = "humidity"; + break; + default: + return -EINVAL; + } + + a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, + "%s%d_input", + prefix, n); + if (a->dev_attr.attr.name == NULL) + return -ENOMEM; + + a->dev_attr.show = iio_hwmon_read_val; + a->dev_attr.attr.mode = 0444; + a->index = i; + st->attrs[i] = &a->dev_attr.attr; + } + + st->attr_group.attrs = st->attrs; + st->groups[0] = &st->attr_group; + + if (dev_fwnode(dev)) { + sname = devm_kasprintf(dev, GFP_KERNEL, "%pfwP", dev_fwnode(dev)); + if (!sname) + return -ENOMEM; + strreplace(sname, '-', '_'); + } else { + sname = "iio_hwmon"; + } + + hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st, + st->groups); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +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 iio_hwmon_driver = { + .driver = { + .name = "iio_hwmon", + .of_match_table = iio_hwmon_of_match, + }, + .probe = iio_hwmon_probe, +}; + +module_platform_driver(iio_hwmon_driver); + +MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); +MODULE_DESCRIPTION("IIO to hwmon driver"); +MODULE_LICENSE("GPL v2"); |