![Greg Kroah-Hartman](/assets/img/avatar_default.png)
We want the IIO and staging driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
485 lines
12 KiB
C
485 lines
12 KiB
C
/*
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* ccs811.c - Support for AMS CCS811 VOC Sensor
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*
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* Copyright (C) 2017 Narcisa Vasile <narcisaanamaria12@gmail.com>
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*
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* Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
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*
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* TODO:
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* 1. Make the drive mode selectable form userspace
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* 2. Add support for interrupts
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* 3. Adjust time to wait for data to be ready based on selected operation mode
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* 4. Read error register and put the information in logs
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*/
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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/trigger.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/module.h>
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#define CCS811_STATUS 0x00
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#define CCS811_MEAS_MODE 0x01
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#define CCS811_ALG_RESULT_DATA 0x02
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#define CCS811_RAW_DATA 0x03
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#define CCS811_HW_ID 0x20
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#define CCS811_HW_ID_VALUE 0x81
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#define CCS811_HW_VERSION 0x21
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#define CCS811_HW_VERSION_VALUE 0x10
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#define CCS811_HW_VERSION_MASK 0xF0
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#define CCS811_ERR 0xE0
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/* Used to transition from boot to application mode */
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#define CCS811_APP_START 0xF4
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/* Status register flags */
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#define CCS811_STATUS_ERROR BIT(0)
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#define CCS811_STATUS_DATA_READY BIT(3)
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#define CCS811_STATUS_APP_VALID_MASK BIT(4)
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#define CCS811_STATUS_APP_VALID_LOADED BIT(4)
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/*
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* Value of FW_MODE bit of STATUS register describes the sensor's state:
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* 0: Firmware is in boot mode, this allows new firmware to be loaded
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* 1: Firmware is in application mode. CCS811 is ready to take ADC measurements
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*/
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#define CCS811_STATUS_FW_MODE_MASK BIT(7)
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#define CCS811_STATUS_FW_MODE_APPLICATION BIT(7)
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/* Measurement modes */
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#define CCS811_MODE_IDLE 0x00
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#define CCS811_MODE_IAQ_1SEC 0x10
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#define CCS811_MODE_IAQ_10SEC 0x20
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#define CCS811_MODE_IAQ_60SEC 0x30
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#define CCS811_MODE_RAW_DATA 0x40
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#define CCS811_MEAS_MODE_INTERRUPT BIT(3)
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#define CCS811_VOLTAGE_MASK 0x3FF
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struct ccs811_reading {
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__be16 co2;
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__be16 voc;
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u8 status;
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u8 error;
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__be16 raw_data;
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} __attribute__((__packed__));
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struct ccs811_data {
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struct i2c_client *client;
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struct mutex lock; /* Protect readings */
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struct ccs811_reading buffer;
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struct iio_trigger *drdy_trig;
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bool drdy_trig_on;
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};
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static const struct iio_chan_spec ccs811_channels[] = {
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{
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.type = IIO_CURRENT,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = -1,
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}, {
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.type = IIO_VOLTAGE,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = -1,
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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 = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = 0,
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.scan_type = {
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.sign = 'u',
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.realbits = 16,
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.storagebits = 16,
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.endianness = IIO_BE,
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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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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = 1,
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.scan_type = {
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.sign = 'u',
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.realbits = 16,
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.storagebits = 16,
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.endianness = IIO_BE,
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},
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},
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IIO_CHAN_SOFT_TIMESTAMP(2),
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};
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/*
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* The CCS811 powers-up in boot mode. A setup write to CCS811_APP_START will
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* transition the sensor to application mode.
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*/
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static int ccs811_start_sensor_application(struct i2c_client *client)
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{
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int ret;
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ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
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if (ret < 0)
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return ret;
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if ((ret & CCS811_STATUS_FW_MODE_APPLICATION))
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return 0;
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if ((ret & CCS811_STATUS_APP_VALID_MASK) !=
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CCS811_STATUS_APP_VALID_LOADED)
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return -EIO;
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ret = i2c_smbus_write_byte(client, CCS811_APP_START);
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if (ret < 0)
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return ret;
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ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
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if (ret < 0)
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return ret;
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if ((ret & CCS811_STATUS_FW_MODE_MASK) !=
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CCS811_STATUS_FW_MODE_APPLICATION) {
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dev_err(&client->dev, "Application failed to start. Sensor is still in boot mode.\n");
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return -EIO;
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}
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return 0;
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}
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static int ccs811_setup(struct i2c_client *client)
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{
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int ret;
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ret = ccs811_start_sensor_application(client);
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if (ret < 0)
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return ret;
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return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
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CCS811_MODE_IAQ_1SEC);
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}
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static int ccs811_get_measurement(struct ccs811_data *data)
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{
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int ret, tries = 11;
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/* Maximum waiting time: 1s, as measurements are made every second */
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while (tries-- > 0) {
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ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
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if (ret < 0)
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return ret;
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if ((ret & CCS811_STATUS_DATA_READY) || tries == 0)
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break;
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msleep(100);
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}
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if (!(ret & CCS811_STATUS_DATA_READY))
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return -EIO;
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return i2c_smbus_read_i2c_block_data(data->client,
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CCS811_ALG_RESULT_DATA, 8,
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(char *)&data->buffer);
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}
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static int ccs811_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct ccs811_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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ret = iio_device_claim_direct_mode(indio_dev);
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if (ret)
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return ret;
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mutex_lock(&data->lock);
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ret = ccs811_get_measurement(data);
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if (ret < 0) {
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mutex_unlock(&data->lock);
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iio_device_release_direct_mode(indio_dev);
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return ret;
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}
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switch (chan->type) {
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case IIO_VOLTAGE:
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*val = be16_to_cpu(data->buffer.raw_data) &
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CCS811_VOLTAGE_MASK;
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ret = IIO_VAL_INT;
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break;
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case IIO_CURRENT:
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*val = be16_to_cpu(data->buffer.raw_data) >> 10;
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ret = IIO_VAL_INT;
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break;
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case IIO_CONCENTRATION:
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switch (chan->channel2) {
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case IIO_MOD_CO2:
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*val = be16_to_cpu(data->buffer.co2);
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ret = IIO_VAL_INT;
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break;
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case IIO_MOD_VOC:
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*val = be16_to_cpu(data->buffer.voc);
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ret = IIO_VAL_INT;
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break;
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default:
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ret = -EINVAL;
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}
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break;
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default:
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ret = -EINVAL;
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}
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mutex_unlock(&data->lock);
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iio_device_release_direct_mode(indio_dev);
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return ret;
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case IIO_CHAN_INFO_SCALE:
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switch (chan->type) {
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case IIO_VOLTAGE:
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*val = 1;
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*val2 = 612903;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_CURRENT:
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*val = 0;
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*val2 = 1000;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_CONCENTRATION:
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switch (chan->channel2) {
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case IIO_MOD_CO2:
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*val = 0;
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*val2 = 100;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_MOD_VOC:
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*val = 0;
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*val2 = 100;
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return IIO_VAL_INT_PLUS_NANO;
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default:
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return -EINVAL;
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}
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default:
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return -EINVAL;
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}
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info ccs811_info = {
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.read_raw = ccs811_read_raw,
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};
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static int ccs811_set_trigger_state(struct iio_trigger *trig,
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bool state)
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{
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struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
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struct ccs811_data *data = iio_priv(indio_dev);
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int ret;
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ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
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if (ret < 0)
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return ret;
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if (state)
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ret |= CCS811_MEAS_MODE_INTERRUPT;
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else
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ret &= ~CCS811_MEAS_MODE_INTERRUPT;
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data->drdy_trig_on = state;
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return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
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}
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static const struct iio_trigger_ops ccs811_trigger_ops = {
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.set_trigger_state = ccs811_set_trigger_state,
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};
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static irqreturn_t ccs811_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct ccs811_data *data = iio_priv(indio_dev);
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struct i2c_client *client = data->client;
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s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */
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int ret;
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ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4,
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(u8 *)&buf);
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if (ret != 4) {
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dev_err(&client->dev, "cannot read sensor data\n");
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goto err;
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}
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iio_push_to_buffers_with_timestamp(indio_dev, buf,
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iio_get_time_ns(indio_dev));
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err:
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
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{
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struct iio_dev *indio_dev = private;
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struct ccs811_data *data = iio_priv(indio_dev);
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if (data->drdy_trig_on)
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iio_trigger_poll(data->drdy_trig);
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return IRQ_HANDLED;
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}
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static int ccs811_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct iio_dev *indio_dev;
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struct ccs811_data *data;
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int ret;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
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| I2C_FUNC_SMBUS_BYTE_DATA
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| I2C_FUNC_SMBUS_READ_I2C_BLOCK))
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return -EOPNOTSUPP;
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/* Check hardware id (should be 0x81 for this family of devices) */
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ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
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if (ret < 0)
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return ret;
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if (ret != CCS811_HW_ID_VALUE) {
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dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
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return -ENODEV;
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}
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ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
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if (ret < 0)
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return ret;
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if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
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dev_err(&client->dev, "no CCS811 sensor\n");
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return -ENODEV;
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}
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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ret = ccs811_setup(client);
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if (ret < 0)
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return ret;
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data = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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data->client = client;
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mutex_init(&data->lock);
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indio_dev->dev.parent = &client->dev;
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indio_dev->name = id->name;
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indio_dev->info = &ccs811_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = ccs811_channels;
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indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
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if (client->irq > 0) {
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ret = devm_request_threaded_irq(&client->dev, client->irq,
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ccs811_data_rdy_trigger_poll,
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NULL,
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IRQF_TRIGGER_FALLING |
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IRQF_ONESHOT,
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"ccs811_irq", indio_dev);
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if (ret) {
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dev_err(&client->dev, "irq request error %d\n", -ret);
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goto err_poweroff;
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}
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data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
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"%s-dev%d",
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indio_dev->name,
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indio_dev->id);
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if (!data->drdy_trig) {
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ret = -ENOMEM;
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goto err_poweroff;
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}
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data->drdy_trig->dev.parent = &client->dev;
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data->drdy_trig->ops = &ccs811_trigger_ops;
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iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
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indio_dev->trig = data->drdy_trig;
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iio_trigger_get(indio_dev->trig);
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ret = iio_trigger_register(data->drdy_trig);
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if (ret)
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goto err_poweroff;
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}
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ret = iio_triggered_buffer_setup(indio_dev, NULL,
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ccs811_trigger_handler, NULL);
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if (ret < 0) {
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dev_err(&client->dev, "triggered buffer setup failed\n");
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goto err_trigger_unregister;
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}
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ret = iio_device_register(indio_dev);
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if (ret < 0) {
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dev_err(&client->dev, "unable to register iio device\n");
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goto err_buffer_cleanup;
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}
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return 0;
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err_buffer_cleanup:
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iio_triggered_buffer_cleanup(indio_dev);
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err_trigger_unregister:
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if (data->drdy_trig)
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iio_trigger_unregister(data->drdy_trig);
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err_poweroff:
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i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
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return ret;
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}
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static int ccs811_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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struct ccs811_data *data = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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if (data->drdy_trig)
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iio_trigger_unregister(data->drdy_trig);
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return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
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CCS811_MODE_IDLE);
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}
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static const struct i2c_device_id ccs811_id[] = {
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{"ccs811", 0},
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ccs811_id);
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static struct i2c_driver ccs811_driver = {
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.driver = {
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.name = "ccs811",
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},
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.probe = ccs811_probe,
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.remove = ccs811_remove,
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.id_table = ccs811_id,
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};
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module_i2c_driver(ccs811_driver);
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MODULE_AUTHOR("Narcisa Vasile <narcisaanamaria12@gmail.com>");
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MODULE_DESCRIPTION("CCS811 volatile organic compounds sensor");
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MODULE_LICENSE("GPL v2");
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