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