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 */ 26 struct 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 */ 39 static 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 48 ret = iio_read_channel_processed(&state->channels[sattr->index], 49 &result); 50 if (ret < 0) 51 return ret; 52 53 return sprintf(buf, "%d\n", result); 54 } 55 56 static int iio_hwmon_probe(struct platform_device *pdev) 57 { 58 struct device *dev = &pdev->dev; 59 struct iio_hwmon_state *st; 60 struct sensor_device_attribute *a; 61 int ret, i; 62 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1; 63 enum iio_chan_type type; 64 struct iio_channel *channels; 65 struct device *hwmon_dev; 66 char *sname; 67 68 channels = devm_iio_channel_get_all(dev); 69 if (IS_ERR(channels)) { 70 if (PTR_ERR(channels) == -ENODEV) 71 return -EPROBE_DEFER; 72 return PTR_ERR(channels); 73 } 74 75 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 76 if (st == NULL) 77 return -ENOMEM; 78 79 st->channels = channels; 80 81 /* count how many attributes we have */ 82 while (st->channels[st->num_channels].indio_dev) 83 st->num_channels++; 84 85 st->attrs = devm_kcalloc(dev, 86 st->num_channels + 1, sizeof(*st->attrs), 87 GFP_KERNEL); 88 if (st->attrs == NULL) 89 return -ENOMEM; 90 91 for (i = 0; i < st->num_channels; i++) { 92 const char *prefix; 93 int n; 94 95 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 96 if (a == NULL) 97 return -ENOMEM; 98 99 sysfs_attr_init(&a->dev_attr.attr); 100 ret = iio_get_channel_type(&st->channels[i], &type); 101 if (ret < 0) 102 return ret; 103 104 switch (type) { 105 case IIO_VOLTAGE: 106 n = in_i++; 107 prefix = "in"; 108 break; 109 case IIO_TEMP: 110 n = temp_i++; 111 prefix = "temp"; 112 break; 113 case IIO_CURRENT: 114 n = curr_i++; 115 prefix = "curr"; 116 break; 117 case IIO_HUMIDITYRELATIVE: 118 n = humidity_i++; 119 prefix = "humidity"; 120 break; 121 default: 122 return -EINVAL; 123 } 124 125 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 126 "%s%d_input", 127 prefix, n); 128 if (a->dev_attr.attr.name == NULL) 129 return -ENOMEM; 130 131 a->dev_attr.show = iio_hwmon_read_val; 132 a->dev_attr.attr.mode = 0444; 133 a->index = i; 134 st->attrs[i] = &a->dev_attr.attr; 135 } 136 137 st->attr_group.attrs = st->attrs; 138 st->groups[0] = &st->attr_group; 139 140 if (dev->of_node) { 141 sname = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node); 142 if (!sname) 143 return -ENOMEM; 144 strreplace(sname, '-', '_'); 145 } else { 146 sname = "iio_hwmon"; 147 } 148 149 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st, 150 st->groups); 151 return PTR_ERR_OR_ZERO(hwmon_dev); 152 } 153 154 static const struct of_device_id iio_hwmon_of_match[] = { 155 { .compatible = "iio-hwmon", }, 156 { } 157 }; 158 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 159 160 static struct platform_driver __refdata iio_hwmon_driver = { 161 .driver = { 162 .name = "iio_hwmon", 163 .of_match_table = iio_hwmon_of_match, 164 }, 165 .probe = iio_hwmon_probe, 166 }; 167 168 module_platform_driver(iio_hwmon_driver); 169 170 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 171 MODULE_DESCRIPTION("IIO to hwmon driver"); 172 MODULE_LICENSE("GPL v2"); 173