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 * @hwmon_dev: associated hwmon device 26 * @attr_group: the group of attributes 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 device *hwmon_dev; 33 struct attribute_group attr_group; 34 const struct attribute_group *groups[2]; 35 struct attribute **attrs; 36 }; 37 38 /* 39 * Assumes that IIO and hwmon operate in the same base units. 40 * This is supposed to be true, but needs verification for 41 * new channel types. 42 */ 43 static ssize_t iio_hwmon_read_val(struct device *dev, 44 struct device_attribute *attr, 45 char *buf) 46 { 47 int result; 48 int ret; 49 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); 50 struct iio_hwmon_state *state = dev_get_drvdata(dev); 51 52 ret = iio_read_channel_processed(&state->channels[sattr->index], 53 &result); 54 if (ret < 0) 55 return ret; 56 57 return sprintf(buf, "%d\n", result); 58 } 59 60 static int iio_hwmon_probe(struct platform_device *pdev) 61 { 62 struct device *dev = &pdev->dev; 63 struct iio_hwmon_state *st; 64 struct sensor_device_attribute *a; 65 int ret, i; 66 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1; 67 enum iio_chan_type type; 68 struct iio_channel *channels; 69 const char *name = "iio_hwmon"; 70 char *sname; 71 72 if (dev->of_node && dev->of_node->name) 73 name = dev->of_node->name; 74 75 channels = iio_channel_get_all(dev); 76 if (IS_ERR(channels)) 77 return PTR_ERR(channels); 78 79 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 80 if (st == NULL) { 81 ret = -ENOMEM; 82 goto error_release_channels; 83 } 84 85 st->channels = channels; 86 87 /* count how many attributes we have */ 88 while (st->channels[st->num_channels].indio_dev) 89 st->num_channels++; 90 91 st->attrs = devm_kzalloc(dev, 92 sizeof(*st->attrs) * (st->num_channels + 1), 93 GFP_KERNEL); 94 if (st->attrs == NULL) { 95 ret = -ENOMEM; 96 goto error_release_channels; 97 } 98 99 for (i = 0; i < st->num_channels; i++) { 100 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 101 if (a == NULL) { 102 ret = -ENOMEM; 103 goto error_release_channels; 104 } 105 106 sysfs_attr_init(&a->dev_attr.attr); 107 ret = iio_get_channel_type(&st->channels[i], &type); 108 if (ret < 0) 109 goto error_release_channels; 110 111 switch (type) { 112 case IIO_VOLTAGE: 113 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 114 "in%d_input", 115 in_i++); 116 break; 117 case IIO_TEMP: 118 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 119 "temp%d_input", 120 temp_i++); 121 break; 122 case IIO_CURRENT: 123 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 124 "curr%d_input", 125 curr_i++); 126 break; 127 case IIO_HUMIDITYRELATIVE: 128 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 129 "humidity%d_input", 130 humidity_i++); 131 break; 132 default: 133 ret = -EINVAL; 134 goto error_release_channels; 135 } 136 if (a->dev_attr.attr.name == NULL) { 137 ret = -ENOMEM; 138 goto error_release_channels; 139 } 140 a->dev_attr.show = iio_hwmon_read_val; 141 a->dev_attr.attr.mode = S_IRUGO; 142 a->index = i; 143 st->attrs[i] = &a->dev_attr.attr; 144 } 145 146 st->attr_group.attrs = st->attrs; 147 st->groups[0] = &st->attr_group; 148 149 sname = devm_kstrdup(dev, name, GFP_KERNEL); 150 if (!sname) { 151 ret = -ENOMEM; 152 goto error_release_channels; 153 } 154 155 strreplace(sname, '-', '_'); 156 st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st, 157 st->groups); 158 if (IS_ERR(st->hwmon_dev)) { 159 ret = PTR_ERR(st->hwmon_dev); 160 goto error_release_channels; 161 } 162 platform_set_drvdata(pdev, st); 163 return 0; 164 165 error_release_channels: 166 iio_channel_release_all(channels); 167 return ret; 168 } 169 170 static int iio_hwmon_remove(struct platform_device *pdev) 171 { 172 struct iio_hwmon_state *st = platform_get_drvdata(pdev); 173 174 hwmon_device_unregister(st->hwmon_dev); 175 iio_channel_release_all(st->channels); 176 177 return 0; 178 } 179 180 static const struct of_device_id iio_hwmon_of_match[] = { 181 { .compatible = "iio-hwmon", }, 182 { } 183 }; 184 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 185 186 static struct platform_driver __refdata iio_hwmon_driver = { 187 .driver = { 188 .name = "iio_hwmon", 189 .of_match_table = iio_hwmon_of_match, 190 }, 191 .probe = iio_hwmon_probe, 192 .remove = iio_hwmon_remove, 193 }; 194 195 module_platform_driver(iio_hwmon_driver); 196 197 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 198 MODULE_DESCRIPTION("IIO to hwmon driver"); 199 MODULE_LICENSE("GPL v2"); 200