Matt Ranostay | cd8d9777 | 2015-09-13 20:26:14 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * vz89x.c - Support for SGX Sensortech MiCS VZ89X VOC sensors |
| 3 | * |
| 4 | * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/mutex.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/i2c.h> |
| 22 | |
| 23 | #include <linux/iio/iio.h> |
| 24 | #include <linux/iio/sysfs.h> |
| 25 | |
| 26 | #define VZ89X_REG_MEASUREMENT 0x09 |
| 27 | #define VZ89X_REG_MEASUREMENT_SIZE 6 |
| 28 | |
| 29 | #define VZ89X_VOC_CO2_IDX 0 |
| 30 | #define VZ89X_VOC_SHORT_IDX 1 |
| 31 | #define VZ89X_VOC_TVOC_IDX 2 |
| 32 | #define VZ89X_VOC_RESISTANCE_IDX 3 |
| 33 | |
| 34 | struct vz89x_data { |
| 35 | struct i2c_client *client; |
| 36 | struct mutex lock; |
| 37 | unsigned long last_update; |
| 38 | |
| 39 | u8 buffer[VZ89X_REG_MEASUREMENT_SIZE]; |
| 40 | }; |
| 41 | |
| 42 | static const struct iio_chan_spec vz89x_channels[] = { |
| 43 | { |
| 44 | .type = IIO_CONCENTRATION, |
| 45 | .channel2 = IIO_MOD_CO2, |
| 46 | .modified = 1, |
| 47 | .info_mask_separate = |
| 48 | BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW), |
| 49 | .address = VZ89X_VOC_CO2_IDX, |
| 50 | }, |
| 51 | { |
| 52 | .type = IIO_CONCENTRATION, |
| 53 | .channel2 = IIO_MOD_VOC, |
| 54 | .modified = 1, |
| 55 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
| 56 | .address = VZ89X_VOC_SHORT_IDX, |
| 57 | .extend_name = "short", |
| 58 | }, |
| 59 | { |
| 60 | .type = IIO_CONCENTRATION, |
| 61 | .channel2 = IIO_MOD_VOC, |
| 62 | .modified = 1, |
| 63 | .info_mask_separate = |
| 64 | BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW), |
| 65 | .address = VZ89X_VOC_TVOC_IDX, |
| 66 | }, |
| 67 | { |
| 68 | .type = IIO_RESISTANCE, |
| 69 | .info_mask_separate = |
| 70 | BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), |
| 71 | .address = VZ89X_VOC_RESISTANCE_IDX, |
| 72 | }, |
| 73 | }; |
| 74 | |
| 75 | static IIO_CONST_ATTR(in_concentration_co2_scale, "0.00000698689"); |
| 76 | static IIO_CONST_ATTR(in_concentration_voc_scale, "0.00000000436681223"); |
| 77 | |
| 78 | static struct attribute *vz89x_attributes[] = { |
| 79 | &iio_const_attr_in_concentration_co2_scale.dev_attr.attr, |
| 80 | &iio_const_attr_in_concentration_voc_scale.dev_attr.attr, |
| 81 | NULL, |
| 82 | }; |
| 83 | |
| 84 | static const struct attribute_group vz89x_attrs_group = { |
| 85 | .attrs = vz89x_attributes, |
| 86 | }; |
| 87 | |
| 88 | static int vz89x_get_measurement(struct vz89x_data *data) |
| 89 | { |
| 90 | int ret; |
| 91 | int i; |
| 92 | |
| 93 | /* sensor can only be polled once a second max per datasheet */ |
| 94 | if (!time_after(jiffies, data->last_update + HZ)) |
| 95 | return 0; |
| 96 | |
| 97 | ret = i2c_smbus_write_word_data(data->client, |
| 98 | VZ89X_REG_MEASUREMENT, 0); |
| 99 | if (ret < 0) |
| 100 | return ret; |
| 101 | |
| 102 | for (i = 0; i < VZ89X_REG_MEASUREMENT_SIZE; i++) { |
| 103 | ret = i2c_smbus_read_byte(data->client); |
| 104 | if (ret < 0) |
| 105 | return ret; |
| 106 | data->buffer[i] = ret; |
| 107 | } |
| 108 | |
| 109 | data->last_update = jiffies; |
| 110 | |
| 111 | return 0; |
| 112 | } |
| 113 | |
| 114 | static int vz89x_get_resistance_reading(struct vz89x_data *data) |
| 115 | { |
| 116 | u8 *buf = &data->buffer[VZ89X_VOC_TVOC_IDX]; |
| 117 | |
| 118 | return buf[0] | (buf[1] << 8) | (buf[2] << 16); |
| 119 | } |
| 120 | |
| 121 | static int vz89x_read_raw(struct iio_dev *indio_dev, |
| 122 | struct iio_chan_spec const *chan, int *val, |
| 123 | int *val2, long mask) |
| 124 | { |
| 125 | struct vz89x_data *data = iio_priv(indio_dev); |
| 126 | int ret = -EINVAL; |
| 127 | |
| 128 | switch (mask) { |
| 129 | case IIO_CHAN_INFO_RAW: |
| 130 | mutex_lock(&data->lock); |
| 131 | ret = vz89x_get_measurement(data); |
| 132 | mutex_unlock(&data->lock); |
| 133 | |
| 134 | if (ret) |
| 135 | return ret; |
| 136 | |
| 137 | switch (chan->address) { |
| 138 | case VZ89X_VOC_CO2_IDX: |
| 139 | case VZ89X_VOC_SHORT_IDX: |
| 140 | case VZ89X_VOC_TVOC_IDX: |
| 141 | *val = data->buffer[chan->address]; |
| 142 | return IIO_VAL_INT; |
| 143 | case VZ89X_VOC_RESISTANCE_IDX: |
| 144 | *val = vz89x_get_resistance_reading(data); |
| 145 | return IIO_VAL_INT; |
| 146 | default: |
| 147 | return -EINVAL; |
| 148 | } |
| 149 | break; |
| 150 | case IIO_CHAN_INFO_SCALE: |
| 151 | switch (chan->type) { |
| 152 | case IIO_RESISTANCE: |
| 153 | *val = 10; |
| 154 | return IIO_VAL_INT; |
| 155 | default: |
| 156 | return -EINVAL; |
| 157 | } |
| 158 | break; |
| 159 | case IIO_CHAN_INFO_OFFSET: |
| 160 | switch (chan->address) { |
| 161 | case VZ89X_VOC_CO2_IDX: |
| 162 | *val = 44; |
| 163 | *val2 = 250000; |
| 164 | return IIO_VAL_INT_PLUS_MICRO; |
| 165 | case VZ89X_VOC_TVOC_IDX: |
| 166 | *val = -13; |
| 167 | return IIO_VAL_INT; |
| 168 | default: |
| 169 | return -EINVAL; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | return ret; |
| 174 | } |
| 175 | |
| 176 | static const struct iio_info vz89x_info = { |
| 177 | .attrs = &vz89x_attrs_group, |
| 178 | .read_raw = vz89x_read_raw, |
| 179 | .driver_module = THIS_MODULE, |
| 180 | }; |
| 181 | |
| 182 | static int vz89x_probe(struct i2c_client *client, |
| 183 | const struct i2c_device_id *id) |
| 184 | { |
| 185 | struct iio_dev *indio_dev; |
| 186 | struct vz89x_data *data; |
| 187 | |
| 188 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA | |
| 189 | I2C_FUNC_SMBUS_BYTE)) |
| 190 | return -ENODEV; |
| 191 | |
| 192 | indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); |
| 193 | if (!indio_dev) |
| 194 | return -ENOMEM; |
| 195 | |
| 196 | data = iio_priv(indio_dev); |
| 197 | i2c_set_clientdata(client, indio_dev); |
| 198 | data->client = client; |
| 199 | data->last_update = jiffies - HZ; |
| 200 | mutex_init(&data->lock); |
| 201 | |
| 202 | indio_dev->dev.parent = &client->dev; |
| 203 | indio_dev->info = &vz89x_info, |
| 204 | indio_dev->name = dev_name(&client->dev); |
| 205 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 206 | |
| 207 | indio_dev->channels = vz89x_channels; |
| 208 | indio_dev->num_channels = ARRAY_SIZE(vz89x_channels); |
| 209 | |
| 210 | return devm_iio_device_register(&client->dev, indio_dev); |
| 211 | } |
| 212 | |
| 213 | static const struct i2c_device_id vz89x_id[] = { |
| 214 | { "vz89x", 0 }, |
| 215 | { } |
| 216 | }; |
| 217 | MODULE_DEVICE_TABLE(i2c, vz89x_id); |
| 218 | |
| 219 | static const struct of_device_id vz89x_dt_ids[] = { |
| 220 | { .compatible = "sgx,vz89x" }, |
| 221 | { } |
| 222 | }; |
| 223 | MODULE_DEVICE_TABLE(of, vz89x_dt_ids); |
| 224 | |
| 225 | static struct i2c_driver vz89x_driver = { |
| 226 | .driver = { |
| 227 | .name = "vz89x", |
| 228 | .of_match_table = of_match_ptr(vz89x_dt_ids), |
| 229 | }, |
| 230 | .probe = vz89x_probe, |
| 231 | .id_table = vz89x_id, |
| 232 | }; |
| 233 | module_i2c_driver(vz89x_driver); |
| 234 | |
| 235 | MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); |
| 236 | MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors"); |
| 237 | MODULE_LICENSE("GPL v2"); |