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 * @groups: null terminated array of attribute groups 28 * @attrs: null terminated array of attribute pointers. 29 */ 30 struct iio_hwmon_state { 31 struct iio_channel *channels; 32 int num_channels; 33 struct device *hwmon_dev; 34 struct attribute_group attr_group; 35 const struct attribute_group *groups[2]; 36 struct attribute **attrs; 37 }; 38 39 /* 40 * Assumes that IIO and hwmon operate in the same base units. 41 * This is supposed to be true, but needs verification for 42 * new channel types. 43 */ 44 static ssize_t iio_hwmon_read_val(struct device *dev, 45 struct device_attribute *attr, 46 char *buf) 47 { 48 int result; 49 int ret; 50 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); 51 struct iio_hwmon_state *state = dev_get_drvdata(dev); 52 53 ret = iio_read_channel_processed(&state->channels[sattr->index], 54 &result); 55 if (ret < 0) 56 return ret; 57 58 return sprintf(buf, "%d\n", result); 59 } 60 61 static int iio_hwmon_probe(struct platform_device *pdev) 62 { 63 struct device *dev = &pdev->dev; 64 struct iio_hwmon_state *st; 65 struct sensor_device_attribute *a; 66 int ret, i; 67 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1; 68 enum iio_chan_type type; 69 struct iio_channel *channels; 70 const char *name = "iio_hwmon"; 71 char *sname; 72 73 if (dev->of_node && dev->of_node->name) 74 name = dev->of_node->name; 75 76 channels = iio_channel_get_all(dev); 77 if (IS_ERR(channels)) { 78 if (PTR_ERR(channels) == -ENODEV) 79 return -EPROBE_DEFER; 80 return PTR_ERR(channels); 81 } 82 83 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 84 if (st == NULL) { 85 ret = -ENOMEM; 86 goto error_release_channels; 87 } 88 89 st->channels = channels; 90 91 /* count how many attributes we have */ 92 while (st->channels[st->num_channels].indio_dev) 93 st->num_channels++; 94 95 st->attrs = devm_kcalloc(dev, 96 st->num_channels + 1, sizeof(*st->attrs), 97 GFP_KERNEL); 98 if (st->attrs == NULL) { 99 ret = -ENOMEM; 100 goto error_release_channels; 101 } 102 103 for (i = 0; i < st->num_channels; i++) { 104 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 105 if (a == NULL) { 106 ret = -ENOMEM; 107 goto error_release_channels; 108 } 109 110 sysfs_attr_init(&a->dev_attr.attr); 111 ret = iio_get_channel_type(&st->channels[i], &type); 112 if (ret < 0) 113 goto error_release_channels; 114 115 switch (type) { 116 case IIO_VOLTAGE: 117 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 118 "in%d_input", 119 in_i++); 120 break; 121 case IIO_TEMP: 122 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 123 "temp%d_input", 124 temp_i++); 125 break; 126 case IIO_CURRENT: 127 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 128 "curr%d_input", 129 curr_i++); 130 break; 131 case IIO_HUMIDITYRELATIVE: 132 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, 133 "humidity%d_input", 134 humidity_i++); 135 break; 136 default: 137 ret = -EINVAL; 138 goto error_release_channels; 139 } 140 if (a->dev_attr.attr.name == NULL) { 141 ret = -ENOMEM; 142 goto error_release_channels; 143 } 144 a->dev_attr.show = iio_hwmon_read_val; 145 a->dev_attr.attr.mode = S_IRUGO; 146 a->index = i; 147 st->attrs[i] = &a->dev_attr.attr; 148 } 149 150 st->attr_group.attrs = st->attrs; 151 st->groups[0] = &st->attr_group; 152 153 sname = devm_kstrdup(dev, name, GFP_KERNEL); 154 if (!sname) { 155 ret = -ENOMEM; 156 goto error_release_channels; 157 } 158 159 strreplace(sname, '-', '_'); 160 st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st, 161 st->groups); 162 if (IS_ERR(st->hwmon_dev)) { 163 ret = PTR_ERR(st->hwmon_dev); 164 goto error_release_channels; 165 } 166 platform_set_drvdata(pdev, st); 167 return 0; 168 169 error_release_channels: 170 iio_channel_release_all(channels); 171 return ret; 172 } 173 174 static int iio_hwmon_remove(struct platform_device *pdev) 175 { 176 struct iio_hwmon_state *st = platform_get_drvdata(pdev); 177 178 hwmon_device_unregister(st->hwmon_dev); 179 iio_channel_release_all(st->channels); 180 181 return 0; 182 } 183 184 static const struct of_device_id iio_hwmon_of_match[] = { 185 { .compatible = "iio-hwmon", }, 186 { } 187 }; 188 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match); 189 190 static struct platform_driver __refdata iio_hwmon_driver = { 191 .driver = { 192 .name = "iio_hwmon", 193 .of_match_table = iio_hwmon_of_match, 194 }, 195 .probe = iio_hwmon_probe, 196 .remove = iio_hwmon_remove, 197 }; 198 199 module_platform_driver(iio_hwmon_driver); 200 201 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 202 MODULE_DESCRIPTION("IIO to hwmon driver"); 203 MODULE_LICENSE("GPL v2"); 204