413 lines
9.2 KiB
C
413 lines
9.2 KiB
C
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// 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 <matt.ranostay@konsulko.com>
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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 = &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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{
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const struct i2c_device_id *id = i2c_client_get_device_id(client);
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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;
|
||
|
|
else
|
||
|
|
return -EOPNOTSUPP;
|
||
|
|
|
||
|
|
if (!dev_fwnode(dev))
|
||
|
|
chip_id = id->driver_data;
|
||
|
|
else
|
||
|
|
chip_id = (unsigned long)device_get_match_data(dev);
|
||
|
|
|
||
|
|
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->info = &vz89x_info;
|
||
|
|
indio_dev->name = dev_name(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(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 = vz89x_dt_ids,
|
||
|
|
},
|
||
|
|
.probe_new = 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");
|