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 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 ssize_t show_name(struct device *dev, struct device_attribute *attr, 60 char *buf) 61 { 62 const char *name = "iio_hwmon"; 63 64 if (dev->of_node && dev->of_node->name) 65 name = dev->of_node->name; 66 67 return sprintf(buf, "%s\n", name); 68 } 69 70 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 71 72 static int iio_hwmon_probe(struct platform_device *pdev) 73 { 74 struct device *dev = &pdev->dev; 75 struct iio_hwmon_state *st; 76 struct sensor_device_attribute *a; 77 int ret, i; 78 int in_i = 1, temp_i = 1, curr_i = 1; 79 enum iio_chan_type type; 80 struct iio_channel *channels; 81 82 channels = iio_channel_get_all(dev); 83 if (IS_ERR(channels)) 84 return PTR_ERR(channels); 85 86 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); 87 if (st == NULL) 88 return -ENOMEM; 89 90 st->channels = channels; 91 92 /* count how many attributes we have */ 93 while (st->channels[st->num_channels].indio_dev) 94 st->num_channels++; 95 96 st->attrs = devm_kzalloc(dev, 97 sizeof(*st->attrs) * (st->num_channels + 2), 98 GFP_KERNEL); 99 if (st->attrs == NULL) { 100 ret = -ENOMEM; 101 goto error_release_channels; 102 } 103 104 for (i = 0; i < st->num_channels; i++) { 105 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); 106 if (a == NULL) { 107 ret = -ENOMEM; 108 goto error_release_channels; 109 } 110 111 sysfs_attr_init(&a->dev_attr.attr); 112 ret = iio_get_channel_type(&st->channels[i], &type); 113 if (ret < 0) 114 goto error_release_channels; 115 116 switch (type) { 117 case IIO_VOLTAGE: 118 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 119 "in%d_input", 120 in_i++); 121 break; 122 case IIO_TEMP: 123 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 124 "temp%d_input", 125 temp_i++); 126 break; 127 case IIO_CURRENT: 128 a->dev_attr.attr.name = kasprintf(GFP_KERNEL, 129 "curr%d_input", 130 curr_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 st->attrs[st->num_channels] = &dev_attr_name.attr; 146 st->attr_group.attrs = st->attrs; 147 platform_set_drvdata(pdev, st); 148 ret = sysfs_create_group(&dev->kobj, &st->attr_group); 149 if (ret < 0) 150 goto error_release_channels; 151 152 st->hwmon_dev = hwmon_device_register(dev); 153 if (IS_ERR(st->hwmon_dev)) { 154 ret = PTR_ERR(st->hwmon_dev); 155 goto error_remove_group; 156 } 157 return 0; 158 159 error_remove_group: 160 sysfs_remove_group(&dev->kobj, &st->attr_group); 161 error_release_channels: 162 iio_channel_release_all(st->channels); 163 return ret; 164 } 165 166 static int iio_hwmon_remove(struct platform_device *pdev) 167 { 168 struct iio_hwmon_state *st = platform_get_drvdata(pdev); 169 170 hwmon_device_unregister(st->hwmon_dev); 171 sysfs_remove_group(&pdev->dev.kobj, &st->attr_group); 172 iio_channel_release_all(st->channels); 173 174 return 0; 175 } 176 177 static struct of_device_id iio_hwmon_of_match[] = { 178 { .compatible = "iio-hwmon", }, 179 { } 180 }; 181 182 static struct platform_driver __refdata iio_hwmon_driver = { 183 .driver = { 184 .name = "iio_hwmon", 185 .owner = THIS_MODULE, 186 .of_match_table = iio_hwmon_of_match, 187 }, 188 .probe = iio_hwmon_probe, 189 .remove = iio_hwmon_remove, 190 }; 191 192 module_platform_driver(iio_hwmon_driver); 193 194 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 195 MODULE_DESCRIPTION("IIO to hwmon driver"); 196 MODULE_LICENSE("GPL v2"); 197