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 ret = PTR_ERR(channels); 81 if (ret == -ENODEV) 82 ret = -EPROBE_DEFER; 83 return dev_err_probe(dev, ret, 84 "Failed to get channels\n"); 85 } 86 87 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 88 if (st == NULL) 89 return -ENOMEM; 90 91 st->channels = channels; 92 93 /* count how many attributes we have */ 94 while (st->channels[st->num_channels].indio_dev) 95 st->num_channels++; 96 97 st->attrs = devm_kcalloc(dev, 98 st->num_channels + 1, sizeof(*st->attrs), 99 GFP_KERNEL); 100 if (st->attrs == NULL) 101 return -ENOMEM; 102 103 for (i = 0; i < st->num_channels; i++) { 104 const char *prefix; 105 int n; 106 107 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 108 if (a == NULL) 109 return -ENOMEM; 110 111 sysfs_attr_init(&a->dev_attr.attr); 112 ret = iio_get_channel_type(&st->channels[i], &type); 113 if (ret < 0) 114 return ret; 115 116 switch (type) { 117 case IIO_VOLTAGE: 118 n = in_i++; 119 prefix = "in"; 120 break; 121 case IIO_TEMP: 122 n = temp_i++; 123 prefix = "temp"; 124 break; 125 case IIO_CURRENT: 126 n = curr_i++; 127 prefix = "curr"; 128 break; 129 case IIO_POWER: 130 n = power_i++; 131 prefix = "power"; 132 break; 133 case IIO_HUMIDITYRELATIVE: 134 n = humidity_i++; 135 prefix = "humidity"; 136 break; 137 default: 138 return -EINVAL; 139 } 140 141 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 142 "%s%d_input", 143 prefix, n); 144 if (a->dev_attr.attr.name == NULL) 145 return -ENOMEM; 146 147 a->dev_attr.show = iio_hwmon_read_val; 148 a->dev_attr.attr.mode = 0444; 149 a->index = i; 150 st->attrs[i] = &a->dev_attr.attr; 151 } 152 153 st->attr_group.attrs = st->attrs; 154 st->groups[0] = &st->attr_group; 155 156 if (dev_fwnode(dev)) { 157 sname = devm_kasprintf(dev, GFP_KERNEL, "%pfwP", dev_fwnode(dev)); 158 if (!sname) 159 return -ENOMEM; 160 strreplace(sname, '-', '_'); 161 } else { 162 sname = "iio_hwmon"; 163 } 164 165 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st, 166 st->groups); 167 return PTR_ERR_OR_ZERO(hwmon_dev); 168 } 169 170 static const struct of_device_id iio_hwmon_of_match[] = { 171 { .compatible = "iio-hwmon", }, 172 { } 173 }; 174 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 175 176 static struct platform_driver iio_hwmon_driver = { 177 .driver = { 178 .name = "iio_hwmon", 179 .of_match_table = iio_hwmon_of_match, 180 }, 181 .probe = iio_hwmon_probe, 182 }; 183 184 module_platform_driver(iio_hwmon_driver); 185 186 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 187 MODULE_DESCRIPTION("IIO to hwmon driver"); 188 MODULE_LICENSE("GPL v2"); 189