diff options
Diffstat (limited to 'drivers/iio/chemical/vz89x.c')
| -rw-r--r-- | drivers/iio/chemical/vz89x.c | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/drivers/iio/chemical/vz89x.c b/drivers/iio/chemical/vz89x.c new file mode 100644 index 000000000..415b39339 --- /dev/null +++ b/drivers/iio/chemical/vz89x.c @@ -0,0 +1,415 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * vz89x.c - Support for SGX Sensortech MiCS VZ89X VOC sensors + * + * Copyright (C) 2015-2018 + * Author: Matt Ranostay <matt.ranostay@konsulko.com> + */ + +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/init.h> +#include <linux/i2c.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define VZ89X_REG_MEASUREMENT 0x09 +#define VZ89X_REG_MEASUREMENT_RD_SIZE 6 +#define VZ89X_REG_MEASUREMENT_WR_SIZE 3 + +#define VZ89X_VOC_CO2_IDX 0 +#define VZ89X_VOC_SHORT_IDX 1 +#define VZ89X_VOC_TVOC_IDX 2 +#define VZ89X_VOC_RESISTANCE_IDX 3 + +#define VZ89TE_REG_MEASUREMENT 0x0c +#define VZ89TE_REG_MEASUREMENT_RD_SIZE 7 +#define VZ89TE_REG_MEASUREMENT_WR_SIZE 6 + +#define VZ89TE_VOC_TVOC_IDX 0 +#define VZ89TE_VOC_CO2_IDX 1 +#define VZ89TE_VOC_RESISTANCE_IDX 2 + +enum { + VZ89X, + VZ89TE, +}; + +struct vz89x_chip_data; + +struct vz89x_data { + struct i2c_client *client; + const struct vz89x_chip_data *chip; + struct mutex lock; + int (*xfer)(struct vz89x_data *data, u8 cmd); + + bool is_valid; + unsigned long last_update; + u8 buffer[VZ89TE_REG_MEASUREMENT_RD_SIZE]; +}; + +struct vz89x_chip_data { + bool (*valid)(struct vz89x_data *data); + const struct iio_chan_spec *channels; + u8 num_channels; + + u8 cmd; + u8 read_size; + u8 write_size; +}; + +static const struct iio_chan_spec vz89x_channels[] = { + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_CO2, + .modified = 1, + .info_mask_separate = + BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW), + .address = VZ89X_VOC_CO2_IDX, + }, + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_VOC, + .modified = 1, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .address = VZ89X_VOC_SHORT_IDX, + .extend_name = "short", + }, + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_VOC, + .modified = 1, + .info_mask_separate = + BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW), + .address = VZ89X_VOC_TVOC_IDX, + }, + { + .type = IIO_RESISTANCE, + .info_mask_separate = + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .address = VZ89X_VOC_RESISTANCE_IDX, + .scan_index = -1, + .scan_type = { + .endianness = IIO_LE, + }, + }, +}; + +static const struct iio_chan_spec vz89te_channels[] = { + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_VOC, + .modified = 1, + .info_mask_separate = + BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW), + .address = VZ89TE_VOC_TVOC_IDX, + }, + + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_CO2, + .modified = 1, + .info_mask_separate = + BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW), + .address = VZ89TE_VOC_CO2_IDX, + }, + { + .type = IIO_RESISTANCE, + .info_mask_separate = + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .address = VZ89TE_VOC_RESISTANCE_IDX, + .scan_index = -1, + .scan_type = { + .endianness = IIO_BE, + }, + }, +}; + +static IIO_CONST_ATTR(in_concentration_co2_scale, "0.00000698689"); +static IIO_CONST_ATTR(in_concentration_voc_scale, "0.00000000436681223"); + +static struct attribute *vz89x_attributes[] = { + &iio_const_attr_in_concentration_co2_scale.dev_attr.attr, + &iio_const_attr_in_concentration_voc_scale.dev_attr.attr, + NULL, +}; + +static const struct attribute_group vz89x_attrs_group = { + .attrs = vz89x_attributes, +}; + +/* + * Chipset sometime updates in the middle of a reading causing it to reset the + * data pointer, and causing invalid reading of previous data. + * We can check for this by reading MSB of the resistance reading that is + * always zero, and by also confirming the VOC_short isn't zero. + */ + +static bool vz89x_measurement_is_valid(struct vz89x_data *data) +{ + if (data->buffer[VZ89X_VOC_SHORT_IDX] == 0) + return true; + + return !!(data->buffer[data->chip->read_size - 1] > 0); +} + +/* VZ89TE device has a modified CRC-8 two complement check */ +static bool vz89te_measurement_is_valid(struct vz89x_data *data) +{ + u8 crc = 0; + int i, sum = 0; + + for (i = 0; i < (data->chip->read_size - 1); i++) { + sum = crc + data->buffer[i]; + crc = sum; + crc += sum / 256; + } + + return !((0xff - crc) == data->buffer[data->chip->read_size - 1]); +} + +static int vz89x_i2c_xfer(struct vz89x_data *data, u8 cmd) +{ + const struct vz89x_chip_data *chip = data->chip; + struct i2c_client *client = data->client; + struct i2c_msg msg[2]; + int ret; + u8 buf[6] = { cmd, 0, 0, 0, 0, 0xf3 }; + + msg[0].addr = client->addr; + msg[0].flags = client->flags; + msg[0].len = chip->write_size; + msg[0].buf = (char *) &buf; + + msg[1].addr = client->addr; + msg[1].flags = client->flags | I2C_M_RD; + msg[1].len = chip->read_size; + msg[1].buf = (char *) &data->buffer; + + ret = i2c_transfer(client->adapter, msg, 2); + + return (ret == 2) ? 0 : ret; +} + +static int vz89x_smbus_xfer(struct vz89x_data *data, u8 cmd) +{ + struct i2c_client *client = data->client; + int ret; + int i; + + ret = i2c_smbus_write_word_data(client, cmd, 0); + if (ret < 0) + return ret; + + for (i = 0; i < data->chip->read_size; i++) { + ret = i2c_smbus_read_byte(client); + if (ret < 0) + return ret; + data->buffer[i] = ret; + } + + return 0; +} + +static int vz89x_get_measurement(struct vz89x_data *data) +{ + const struct vz89x_chip_data *chip = data->chip; + int ret; + + /* sensor can only be polled once a second max per datasheet */ + if (!time_after(jiffies, data->last_update + HZ)) + return data->is_valid ? 0 : -EAGAIN; + + data->is_valid = false; + data->last_update = jiffies; + + ret = data->xfer(data, chip->cmd); + if (ret < 0) + return ret; + + ret = chip->valid(data); + if (ret) + return -EAGAIN; + + data->is_valid = true; + + return 0; +} + +static int vz89x_get_resistance_reading(struct vz89x_data *data, + struct iio_chan_spec const *chan, + int *val) +{ + u8 *tmp = (u8 *) &data->buffer[chan->address]; + + switch (chan->scan_type.endianness) { + case IIO_LE: + *val = le32_to_cpup((__le32 *) tmp) & GENMASK(23, 0); + break; + case IIO_BE: + *val = be32_to_cpup((__be32 *) tmp) >> 8; + break; + default: + return -EINVAL; + } + + return 0; +} + +static int vz89x_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + struct vz89x_data *data = iio_priv(indio_dev); + int ret = -EINVAL; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + ret = vz89x_get_measurement(data); + mutex_unlock(&data->lock); + + if (ret) + return ret; + + switch (chan->type) { + case IIO_CONCENTRATION: + *val = data->buffer[chan->address]; + return IIO_VAL_INT; + case IIO_RESISTANCE: + ret = vz89x_get_resistance_reading(data, chan, val); + if (!ret) + return IIO_VAL_INT; + break; + default: + return -EINVAL; + } + break; + case IIO_CHAN_INFO_SCALE: + switch (chan->type) { + case IIO_RESISTANCE: + *val = 10; + return IIO_VAL_INT; + default: + return -EINVAL; + } + break; + case IIO_CHAN_INFO_OFFSET: + switch (chan->channel2) { + case IIO_MOD_CO2: + *val = 44; + *val2 = 250000; + return IIO_VAL_INT_PLUS_MICRO; + case IIO_MOD_VOC: + *val = -13; + return IIO_VAL_INT; + default: + return -EINVAL; + } + } + + return ret; +} + +static const struct iio_info vz89x_info = { + .attrs = &vz89x_attrs_group, + .read_raw = vz89x_read_raw, +}; + +static const struct vz89x_chip_data vz89x_chips[] = { + { + .valid = vz89x_measurement_is_valid, + + .cmd = VZ89X_REG_MEASUREMENT, + .read_size = VZ89X_REG_MEASUREMENT_RD_SIZE, + .write_size = VZ89X_REG_MEASUREMENT_WR_SIZE, + + .channels = vz89x_channels, + .num_channels = ARRAY_SIZE(vz89x_channels), + }, + { + .valid = vz89te_measurement_is_valid, + + .cmd = VZ89TE_REG_MEASUREMENT, + .read_size = VZ89TE_REG_MEASUREMENT_RD_SIZE, + .write_size = VZ89TE_REG_MEASUREMENT_WR_SIZE, + + .channels = vz89te_channels, + .num_channels = ARRAY_SIZE(vz89te_channels), + }, +}; + +static const struct of_device_id vz89x_dt_ids[] = { + { .compatible = "sgx,vz89x", .data = (void *) VZ89X }, + { .compatible = "sgx,vz89te", .data = (void *) VZ89TE }, + { } +}; +MODULE_DEVICE_TABLE(of, vz89x_dt_ids); + +static int vz89x_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct iio_dev *indio_dev; + struct vz89x_data *data; + const struct of_device_id *of_id; + int chip_id; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + data = iio_priv(indio_dev); + + if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + data->xfer = vz89x_i2c_xfer; + else if (i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE)) + data->xfer = vz89x_smbus_xfer; + else + return -EOPNOTSUPP; + + of_id = of_match_device(vz89x_dt_ids, &client->dev); + if (!of_id) + chip_id = id->driver_data; + else + chip_id = (unsigned long)of_id->data; + + i2c_set_clientdata(client, indio_dev); + data->client = client; + data->chip = &vz89x_chips[chip_id]; + data->last_update = jiffies - HZ; + mutex_init(&data->lock); + + indio_dev->dev.parent = &client->dev; + indio_dev->info = &vz89x_info; + indio_dev->name = dev_name(&client->dev); + indio_dev->modes = INDIO_DIRECT_MODE; + + indio_dev->channels = data->chip->channels; + indio_dev->num_channels = data->chip->num_channels; + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static const struct i2c_device_id vz89x_id[] = { + { "vz89x", VZ89X }, + { "vz89te", VZ89TE }, + { } +}; +MODULE_DEVICE_TABLE(i2c, vz89x_id); + +static struct i2c_driver vz89x_driver = { + .driver = { + .name = "vz89x", + .of_match_table = of_match_ptr(vz89x_dt_ids), + }, + .probe = vz89x_probe, + .id_table = vz89x_id, +}; +module_i2c_driver(vz89x_driver); + +MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>"); +MODULE_DESCRIPTION("SGX Sensortech MiCS VZ89X VOC sensors"); +MODULE_LICENSE("GPL v2"); |