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 if (PTR_ERR(channels) == -ENODEV) 78 return -EPROBE_DEFER; 79 return PTR_ERR(channels); 80 } 81 82 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 83 if (st == NULL) { 84 ret = -ENOMEM; 85 goto error_release_channels; 86 } 87 88 st->channels = channels; 89 90 /* count how many attributes we have */ 91 while (st->channels[st->num_channels].indio_dev) 92 st->num_channels++; 93 94 st->attrs = devm_kzalloc(dev, 95 sizeof(*st->attrs) * (st->num_channels + 1), 96 GFP_KERNEL); 97 if (st->attrs == NULL) { 98 ret = -ENOMEM; 99 goto error_release_channels; 100 } 101 102 for (i = 0; i < st->num_channels; i++) { 103 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 104 if (a == NULL) { 105 ret = -ENOMEM; 106 goto error_release_channels; 107 } 108 109 sysfs_attr_init(&a->dev_attr.attr); 110 ret = iio_get_channel_type(&st->channels[i], &type); 111 if (ret < 0) 112 goto error_release_channels; 113 114 switch (type) { 115 case IIO_VOLTAGE: 116 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 117 "in%d_input", 118 in_i++); 119 break; 120 case IIO_TEMP: 121 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 122 "temp%d_input", 123 temp_i++); 124 break; 125 case IIO_CURRENT: 126 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 127 "curr%d_input", 128 curr_i++); 129 break; 130 case IIO_HUMIDITYRELATIVE: 131 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 132 "humidity%d_input", 133 humidity_i++); 134 break; 135 default: 136 ret = -EINVAL; 137 goto error_release_channels; 138 } 139 if (a->dev_attr.attr.name == NULL) { 140 ret = -ENOMEM; 141 goto error_release_channels; 142 } 143 a->dev_attr.show = iio_hwmon_read_val; 144 a->dev_attr.attr.mode = S_IRUGO; 145 a->index = i; 146 st->attrs[i] = &a->dev_attr.attr; 147 } 148 149 st->attr_group.attrs = st->attrs; 150 st->groups[0] = &st->attr_group; 151 152 sname = devm_kstrdup(dev, name, GFP_KERNEL); 153 if (!sname) { 154 ret = -ENOMEM; 155 goto error_release_channels; 156 } 157 158 strreplace(sname, '-', '_'); 159 st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st, 160 st->groups); 161 if (IS_ERR(st->hwmon_dev)) { 162 ret = PTR_ERR(st->hwmon_dev); 163 goto error_release_channels; 164 } 165 platform_set_drvdata(pdev, st); 166 return 0; 167 168 error_release_channels: 169 iio_channel_release_all(channels); 170 return ret; 171 } 172 173 static int iio_hwmon_remove(struct platform_device *pdev) 174 { 175 struct iio_hwmon_state *st = platform_get_drvdata(pdev); 176 177 hwmon_device_unregister(st->hwmon_dev); 178 iio_channel_release_all(st->channels); 179 180 return 0; 181 } 182 183 static const struct of_device_id iio_hwmon_of_match[] = { 184 { .compatible = "iio-hwmon", }, 185 { } 186 }; 187 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 188 189 static struct platform_driver __refdata iio_hwmon_driver = { 190 .driver = { 191 .name = "iio_hwmon", 192 .of_match_table = iio_hwmon_of_match, 193 }, 194 .probe = iio_hwmon_probe, 195 .remove = iio_hwmon_remove, 196 }; 197 198 module_platform_driver(iio_hwmon_driver); 199 200 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 201 MODULE_DESCRIPTION("IIO to hwmon driver"); 202 MODULE_LICENSE("GPL v2"); 203