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1// SPDX-License-Identifier: GPL-2.0+2/*3 * vz89x.c - Support for SGX Sensortech MiCS VZ89X VOC sensors4 *5 * Copyright (C) 2015-20186 * Author: Matt Ranostay <matt.ranostay@konsulko.com>7 */8 9#include <linux/module.h>10#include <linux/mutex.h>11#include <linux/init.h>12#include <linux/i2c.h>13#include <linux/mod_devicetable.h>14 15#include <linux/iio/iio.h>16#include <linux/iio/sysfs.h>17 18#define VZ89X_REG_MEASUREMENT 0x0919#define VZ89X_REG_MEASUREMENT_RD_SIZE 620#define VZ89X_REG_MEASUREMENT_WR_SIZE 321 22#define VZ89X_VOC_CO2_IDX 023#define VZ89X_VOC_SHORT_IDX 124#define VZ89X_VOC_TVOC_IDX 225#define VZ89X_VOC_RESISTANCE_IDX 326 27#define VZ89TE_REG_MEASUREMENT 0x0c28#define VZ89TE_REG_MEASUREMENT_RD_SIZE 729#define VZ89TE_REG_MEASUREMENT_WR_SIZE 630 31#define VZ89TE_VOC_TVOC_IDX 032#define VZ89TE_VOC_CO2_IDX 133#define VZ89TE_VOC_RESISTANCE_IDX 234 35enum {36 VZ89X,37 VZ89TE,38};39 40struct vz89x_chip_data;41 42struct vz89x_data {43 struct i2c_client *client;44 const struct vz89x_chip_data *chip;45 struct mutex lock;46 int (*xfer)(struct vz89x_data *data, u8 cmd);47 48 bool is_valid;49 unsigned long last_update;50 u8 buffer[VZ89TE_REG_MEASUREMENT_RD_SIZE];51};52 53struct vz89x_chip_data {54 bool (*valid)(struct vz89x_data *data);55 const struct iio_chan_spec *channels;56 u8 num_channels;57 58 u8 cmd;59 u8 read_size;60 u8 write_size;61};62 63static const struct iio_chan_spec vz89x_channels[] = {64 {65 .type = IIO_CONCENTRATION,66 .channel2 = IIO_MOD_CO2,67 .modified = 1,68 .info_mask_separate =69 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),70 .address = VZ89X_VOC_CO2_IDX,71 },72 {73 .type = IIO_CONCENTRATION,74 .channel2 = IIO_MOD_VOC,75 .modified = 1,76 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),77 .address = VZ89X_VOC_SHORT_IDX,78 .extend_name = "short",79 },80 {81 .type = IIO_CONCENTRATION,82 .channel2 = IIO_MOD_VOC,83 .modified = 1,84 .info_mask_separate =85 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),86 .address = VZ89X_VOC_TVOC_IDX,87 },88 {89 .type = IIO_RESISTANCE,90 .info_mask_separate =91 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),92 .address = VZ89X_VOC_RESISTANCE_IDX,93 .scan_index = -1,94 .scan_type = {95 .endianness = IIO_LE,96 },97 },98};99 100static const struct iio_chan_spec vz89te_channels[] = {101 {102 .type = IIO_CONCENTRATION,103 .channel2 = IIO_MOD_VOC,104 .modified = 1,105 .info_mask_separate =106 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),107 .address = VZ89TE_VOC_TVOC_IDX,108 },109 110 {111 .type = IIO_CONCENTRATION,112 .channel2 = IIO_MOD_CO2,113 .modified = 1,114 .info_mask_separate =115 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),116 .address = VZ89TE_VOC_CO2_IDX,117 },118 {119 .type = IIO_RESISTANCE,120 .info_mask_separate =121 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),122 .address = VZ89TE_VOC_RESISTANCE_IDX,123 .scan_index = -1,124 .scan_type = {125 .endianness = IIO_BE,126 },127 },128};129 130static IIO_CONST_ATTR(in_concentration_co2_scale, "0.00000698689");131static IIO_CONST_ATTR(in_concentration_voc_scale, "0.00000000436681223");132 133static struct attribute *vz89x_attributes[] = {134 &iio_const_attr_in_concentration_co2_scale.dev_attr.attr,135 &iio_const_attr_in_concentration_voc_scale.dev_attr.attr,136 NULL,137};138 139static const struct attribute_group vz89x_attrs_group = {140 .attrs = vz89x_attributes,141};142 143/*144 * Chipset sometime updates in the middle of a reading causing it to reset the145 * data pointer, and causing invalid reading of previous data.146 * We can check for this by reading MSB of the resistance reading that is147 * always zero, and by also confirming the VOC_short isn't zero.148 */149 150static bool vz89x_measurement_is_valid(struct vz89x_data *data)151{152 if (data->buffer[VZ89X_VOC_SHORT_IDX] == 0)153 return true;154 155 return !!(data->buffer[data->chip->read_size - 1] > 0);156}157 158/* VZ89TE device has a modified CRC-8 two complement check */159static bool vz89te_measurement_is_valid(struct vz89x_data *data)160{161 u8 crc = 0;162 int i, sum = 0;163 164 for (i = 0; i < (data->chip->read_size - 1); i++) {165 sum = crc + data->buffer[i];166 crc = sum;167 crc += sum / 256;168 }169 170 return !((0xff - crc) == data->buffer[data->chip->read_size - 1]);171}172 173static int vz89x_i2c_xfer(struct vz89x_data *data, u8 cmd)174{175 const struct vz89x_chip_data *chip = data->chip;176 struct i2c_client *client = data->client;177 struct i2c_msg msg[2];178 int ret;179 u8 buf[6] = { cmd, 0, 0, 0, 0, 0xf3 };180 181 msg[0].addr = client->addr;182 msg[0].flags = client->flags;183 msg[0].len = chip->write_size;184 msg[0].buf = (char *) &buf;185 186 msg[1].addr = client->addr;187 msg[1].flags = client->flags | I2C_M_RD;188 msg[1].len = chip->read_size;189 msg[1].buf = (char *) &data->buffer;190 191 ret = i2c_transfer(client->adapter, msg, 2);192 193 return (ret == 2) ? 0 : ret;194}195 196static int vz89x_smbus_xfer(struct vz89x_data *data, u8 cmd)197{198 struct i2c_client *client = data->client;199 int ret;200 int i;201 202 ret = i2c_smbus_write_word_data(client, cmd, 0);203 if (ret < 0)204 return ret;205 206 for (i = 0; i < data->chip->read_size; i++) {207 ret = i2c_smbus_read_byte(client);208 if (ret < 0)209 return ret;210 data->buffer[i] = ret;211 }212 213 return 0;214}215 216static int vz89x_get_measurement(struct vz89x_data *data)217{218 const struct vz89x_chip_data *chip = data->chip;219 int ret;220 221 /* sensor can only be polled once a second max per datasheet */222 if (!time_after(jiffies, data->last_update + HZ))223 return data->is_valid ? 0 : -EAGAIN;224 225 data->is_valid = false;226 data->last_update = jiffies;227 228 ret = data->xfer(data, chip->cmd);229 if (ret < 0)230 return ret;231 232 ret = chip->valid(data);233 if (ret)234 return -EAGAIN;235 236 data->is_valid = true;237 238 return 0;239}240 241static int vz89x_get_resistance_reading(struct vz89x_data *data,242 struct iio_chan_spec const *chan,243 int *val)244{245 u8 *tmp = &data->buffer[chan->address];246 247 switch (chan->scan_type.endianness) {248 case IIO_LE:249 *val = le32_to_cpup((__le32 *) tmp) & GENMASK(23, 0);250 break;251 case IIO_BE:252 *val = be32_to_cpup((__be32 *) tmp) >> 8;253 break;254 default:255 return -EINVAL;256 }257 258 return 0;259}260 261static int vz89x_read_raw(struct iio_dev *indio_dev,262 struct iio_chan_spec const *chan, int *val,263 int *val2, long mask)264{265 struct vz89x_data *data = iio_priv(indio_dev);266 int ret = -EINVAL;267 268 switch (mask) {269 case IIO_CHAN_INFO_RAW:270 mutex_lock(&data->lock);271 ret = vz89x_get_measurement(data);272 mutex_unlock(&data->lock);273 274 if (ret)275 return ret;276 277 switch (chan->type) {278 case IIO_CONCENTRATION:279 *val = data->buffer[chan->address];280 return IIO_VAL_INT;281 case IIO_RESISTANCE:282 ret = vz89x_get_resistance_reading(data, chan, val);283 if (!ret)284 return IIO_VAL_INT;285 break;286 default:287 return -EINVAL;288 }289 break;290 case IIO_CHAN_INFO_SCALE:291 switch (chan->type) {292 case IIO_RESISTANCE:293 *val = 10;294 return IIO_VAL_INT;295 default:296 return -EINVAL;297 }298 break;299 case IIO_CHAN_INFO_OFFSET:300 switch (chan->channel2) {301 case IIO_MOD_CO2:302 *val = 44;303 *val2 = 250000;304 return IIO_VAL_INT_PLUS_MICRO;305 case IIO_MOD_VOC:306 *val = -13;307 return IIO_VAL_INT;308 default:309 return -EINVAL;310 }311 }312 313 return ret;314}315 316static const struct iio_info vz89x_info = {317 .attrs = &vz89x_attrs_group,318 .read_raw = vz89x_read_raw,319};320 321static const struct vz89x_chip_data vz89x_chips[] = {322 {323 .valid = vz89x_measurement_is_valid,324 325 .cmd = VZ89X_REG_MEASUREMENT,326 .read_size = VZ89X_REG_MEASUREMENT_RD_SIZE,327 .write_size = VZ89X_REG_MEASUREMENT_WR_SIZE,328 329 .channels = vz89x_channels,330 .num_channels = ARRAY_SIZE(vz89x_channels),331 },332 {333 .valid = vz89te_measurement_is_valid,334 335 .cmd = VZ89TE_REG_MEASUREMENT,336 .read_size = VZ89TE_REG_MEASUREMENT_RD_SIZE,337 .write_size = VZ89TE_REG_MEASUREMENT_WR_SIZE,338 339 .channels = vz89te_channels,340 .num_channels = ARRAY_SIZE(vz89te_channels),341 },342};343 344static const struct of_device_id vz89x_dt_ids[] = {345 { .compatible = "sgx,vz89x", .data = &vz89x_chips[VZ89X] },346 { .compatible = "sgx,vz89te", .data = &vz89x_chips[VZ89TE] },347 { }348};349MODULE_DEVICE_TABLE(of, vz89x_dt_ids);350 351static int vz89x_probe(struct i2c_client *client)352{353 struct device *dev = &client->dev;354 struct iio_dev *indio_dev;355 struct vz89x_data *data;356 357 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));358 if (!indio_dev)359 return -ENOMEM;360 data = iio_priv(indio_dev);361 362 if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))363 data->xfer = vz89x_i2c_xfer;364 else if (i2c_check_functionality(client->adapter,365 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))366 data->xfer = vz89x_smbus_xfer;367 else368 return -EOPNOTSUPP;369 370 data->chip = i2c_get_match_data(client);371 372 i2c_set_clientdata(client, indio_dev);373 data->client = client;374 data->last_update = jiffies - HZ;375 mutex_init(&data->lock);376 377 indio_dev->info = &vz89x_info;378 indio_dev->name = dev_name(dev);379 indio_dev->modes = INDIO_DIRECT_MODE;380 381 indio_dev->channels = data->chip->channels;382 indio_dev->num_channels = data->chip->num_channels;383 384 return devm_iio_device_register(dev, indio_dev);385}386 387static const struct i2c_device_id vz89x_id[] = {388 { "vz89x", (kernel_ulong_t)&vz89x_chips[VZ89X] },389 { "vz89te", (kernel_ulong_t)&vz89x_chips[VZ89TE] },390 { }391};392MODULE_DEVICE_TABLE(i2c, vz89x_id);393 394static struct i2c_driver vz89x_driver = {395 .driver = {396 .name = "vz89x",397 .of_match_table = vz89x_dt_ids,398 },399 .probe = vz89x_probe,400 .id_table = vz89x_id,401};402module_i2c_driver(vz89x_driver);403 404MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");405MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors");406MODULE_LICENSE("GPL v2");407