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