iio_hwmon.c (4399B)
1// SPDX-License-Identifier: GPL-2.0-only 2/* Hwmon client for industrial I/O devices 3 * 4 * Copyright (c) 2011 Jonathan Cameron 5 */ 6 7#include <linux/kernel.h> 8#include <linux/slab.h> 9#include <linux/module.h> 10#include <linux/err.h> 11#include <linux/platform_device.h> 12#include <linux/hwmon.h> 13#include <linux/of.h> 14#include <linux/hwmon-sysfs.h> 15#include <linux/iio/consumer.h> 16#include <linux/iio/types.h> 17 18/** 19 * struct iio_hwmon_state - device instance state 20 * @channels: filled with array of channels from iio 21 * @num_channels: number of channels in channels (saves counting twice) 22 * @attr_group: the group of attributes 23 * @groups: null terminated array of attribute groups 24 * @attrs: null terminated array of attribute pointers. 25 */ 26struct iio_hwmon_state { 27 struct iio_channel *channels; 28 int num_channels; 29 struct attribute_group attr_group; 30 const struct attribute_group *groups[2]; 31 struct attribute **attrs; 32}; 33 34/* 35 * Assumes that IIO and hwmon operate in the same base units. 36 * This is supposed to be true, but needs verification for 37 * new channel types. 38 */ 39static ssize_t iio_hwmon_read_val(struct device *dev, 40 struct device_attribute *attr, 41 char *buf) 42{ 43 int result; 44 int ret; 45 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); 46 struct iio_hwmon_state *state = dev_get_drvdata(dev); 47 struct iio_channel *chan = &state->channels[sattr->index]; 48 enum iio_chan_type type; 49 50 ret = iio_read_channel_processed(chan, &result); 51 if (ret < 0) 52 return ret; 53 54 ret = iio_get_channel_type(chan, &type); 55 if (ret < 0) 56 return ret; 57 58 if (type == IIO_POWER) 59 result *= 1000; /* mili-Watts to micro-Watts conversion */ 60 61 return sprintf(buf, "%d\n", result); 62} 63 64static int iio_hwmon_probe(struct platform_device *pdev) 65{ 66 struct device *dev = &pdev->dev; 67 struct iio_hwmon_state *st; 68 struct sensor_device_attribute *a; 69 int ret, i; 70 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1, power_i = 1; 71 enum iio_chan_type type; 72 struct iio_channel *channels; 73 struct device *hwmon_dev; 74 char *sname; 75 76 channels = devm_iio_channel_get_all(dev); 77 if (IS_ERR(channels)) { 78 if (PTR_ERR(channels) == -ENODEV) 79 return -EPROBE_DEFER; 80 return PTR_ERR(channels); 81 } 82 83 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 84 if (st == NULL) 85 return -ENOMEM; 86 87 st->channels = channels; 88 89 /* count how many attributes we have */ 90 while (st->channels[st->num_channels].indio_dev) 91 st->num_channels++; 92 93 st->attrs = devm_kcalloc(dev, 94 st->num_channels + 1, sizeof(*st->attrs), 95 GFP_KERNEL); 96 if (st->attrs == NULL) 97 return -ENOMEM; 98 99 for (i = 0; i < st->num_channels; i++) { 100 const char *prefix; 101 int n; 102 103 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 104 if (a == NULL) 105 return -ENOMEM; 106 107 sysfs_attr_init(&a->dev_attr.attr); 108 ret = iio_get_channel_type(&st->channels[i], &type); 109 if (ret < 0) 110 return ret; 111 112 switch (type) { 113 case IIO_VOLTAGE: 114 n = in_i++; 115 prefix = "in"; 116 break; 117 case IIO_TEMP: 118 n = temp_i++; 119 prefix = "temp"; 120 break; 121 case IIO_CURRENT: 122 n = curr_i++; 123 prefix = "curr"; 124 break; 125 case IIO_POWER: 126 n = power_i++; 127 prefix = "power"; 128 break; 129 case IIO_HUMIDITYRELATIVE: 130 n = humidity_i++; 131 prefix = "humidity"; 132 break; 133 default: 134 return -EINVAL; 135 } 136 137 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 138 "%s%d_input", 139 prefix, n); 140 if (a->dev_attr.attr.name == NULL) 141 return -ENOMEM; 142 143 a->dev_attr.show = iio_hwmon_read_val; 144 a->dev_attr.attr.mode = 0444; 145 a->index = i; 146 st->attrs[i] = &a->dev_attr.attr; 147 } 148 149 st->attr_group.attrs = st->attrs; 150 st->groups[0] = &st->attr_group; 151 152 if (dev->of_node) { 153 sname = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node); 154 if (!sname) 155 return -ENOMEM; 156 strreplace(sname, '-', '_'); 157 } else { 158 sname = "iio_hwmon"; 159 } 160 161 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st, 162 st->groups); 163 return PTR_ERR_OR_ZERO(hwmon_dev); 164} 165 166static const struct of_device_id iio_hwmon_of_match[] = { 167 { .compatible = "iio-hwmon", }, 168 { } 169}; 170MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 171 172static struct platform_driver iio_hwmon_driver = { 173 .driver = { 174 .name = "iio_hwmon", 175 .of_match_table = iio_hwmon_of_match, 176 }, 177 .probe = iio_hwmon_probe, 178}; 179 180module_platform_driver(iio_hwmon_driver); 181 182MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 183MODULE_DESCRIPTION("IIO to hwmon driver"); 184MODULE_LICENSE("GPL v2");