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/mod_devicetable.h> 10 #include <linux/module.h> 11 #include <linux/err.h> 12 #include <linux/platform_device.h> 13 #include <linux/property.h> 14 15 #include <linux/hwmon.h> 16 #include <linux/hwmon-sysfs.h> 17 #include <linux/iio/consumer.h> 18 #include <linux/iio/types.h> 19 20 /** 21 * struct iio_hwmon_state - device instance state 22 * @channels: filled with array of channels from iio 23 * @num_channels: number of channels in channels (saves counting twice) 24 * @attr_group: the group of attributes 25 * @groups: null terminated array of attribute groups 26 * @attrs: null terminated array of attribute pointers. 27 */ 28 struct iio_hwmon_state { 29 struct iio_channel *channels; 30 int num_channels; 31 struct attribute_group attr_group; 32 const struct attribute_group *groups[2]; 33 struct attribute **attrs; 34 }; 35 36 /* 37 * Assumes that IIO and hwmon operate in the same base units. 38 * This is supposed to be true, but needs verification for 39 * new channel types. 40 */ 41 static ssize_t iio_hwmon_read_val(struct device *dev, 42 struct device_attribute *attr, 43 char *buf) 44 { 45 int result; 46 int ret; 47 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); 48 struct iio_hwmon_state *state = dev_get_drvdata(dev); 49 struct iio_channel *chan = &state->channels[sattr->index]; 50 enum iio_chan_type type; 51 52 ret = iio_read_channel_processed(chan, &result); 53 if (ret < 0) 54 return ret; 55 56 ret = iio_get_channel_type(chan, &type); 57 if (ret < 0) 58 return ret; 59 60 if (type == IIO_POWER) 61 result *= 1000; /* mili-Watts to micro-Watts conversion */ 62 63 return sprintf(buf, "%d\n", result); 64 } 65 66 static int iio_hwmon_probe(struct platform_device *pdev) 67 { 68 struct device *dev = &pdev->dev; 69 struct iio_hwmon_state *st; 70 struct sensor_device_attribute *a; 71 int ret, i; 72 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1, power_i = 1; 73 enum iio_chan_type type; 74 struct iio_channel *channels; 75 struct device *hwmon_dev; 76 char *sname; 77 78 channels = devm_iio_channel_get_all(dev); 79 if (IS_ERR(channels)) { 80 if (PTR_ERR(channels) == -ENODEV) 81 return -EPROBE_DEFER; 82 return PTR_ERR(channels); 83 } 84 85 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 86 if (st == NULL) 87 return -ENOMEM; 88 89 st->channels = channels; 90 91 /* count how many attributes we have */ 92 while (st->channels[st->num_channels].indio_dev) 93 st->num_channels++; 94 95 st->attrs = devm_kcalloc(dev, 96 st->num_channels + 1, sizeof(*st->attrs), 97 GFP_KERNEL); 98 if (st->attrs == NULL) 99 return -ENOMEM; 100 101 for (i = 0; i < st->num_channels; i++) { 102 const char *prefix; 103 int n; 104 105 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 106 if (a == NULL) 107 return -ENOMEM; 108 109 sysfs_attr_init(&a->dev_attr.attr); 110 ret = iio_get_channel_type(&st->channels[i], &type); 111 if (ret < 0) 112 return ret; 113 114 switch (type) { 115 case IIO_VOLTAGE: 116 n = in_i++; 117 prefix = "in"; 118 break; 119 case IIO_TEMP: 120 n = temp_i++; 121 prefix = "temp"; 122 break; 123 case IIO_CURRENT: 124 n = curr_i++; 125 prefix = "curr"; 126 break; 127 case IIO_POWER: 128 n = power_i++; 129 prefix = "power"; 130 break; 131 case IIO_HUMIDITYRELATIVE: 132 n = humidity_i++; 133 prefix = "humidity"; 134 break; 135 default: 136 return -EINVAL; 137 } 138 139 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 140 "%s%d_input", 141 prefix, n); 142 if (a->dev_attr.attr.name == NULL) 143 return -ENOMEM; 144 145 a->dev_attr.show = iio_hwmon_read_val; 146 a->dev_attr.attr.mode = 0444; 147 a->index = i; 148 st->attrs[i] = &a->dev_attr.attr; 149 } 150 151 st->attr_group.attrs = st->attrs; 152 st->groups[0] = &st->attr_group; 153 154 if (dev_fwnode(dev)) { 155 sname = devm_kasprintf(dev, GFP_KERNEL, "%pfwP", dev_fwnode(dev)); 156 if (!sname) 157 return -ENOMEM; 158 strreplace(sname, '-', '_'); 159 } else { 160 sname = "iio_hwmon"; 161 } 162 163 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st, 164 st->groups); 165 return PTR_ERR_OR_ZERO(hwmon_dev); 166 } 167 168 static const struct of_device_id iio_hwmon_of_match[] = { 169 { .compatible = "iio-hwmon", }, 170 { } 171 }; 172 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 173 174 static struct platform_driver iio_hwmon_driver = { 175 .driver = { 176 .name = "iio_hwmon", 177 .of_match_table = iio_hwmon_of_match, 178 }, 179 .probe = iio_hwmon_probe, 180 }; 181 182 module_platform_driver(iio_hwmon_driver); 183 184 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 185 MODULE_DESCRIPTION("IIO to hwmon driver"); 186 MODULE_LICENSE("GPL v2"); 187