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path: root/drivers/iio/chemical/ccs811.c
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Diffstat (limited to 'drivers/iio/chemical/ccs811.c')
-rw-r--r--drivers/iio/chemical/ccs811.c578
1 files changed, 578 insertions, 0 deletions
diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
new file mode 100644
index 0000000000..87741f155c
--- /dev/null
+++ b/drivers/iio/chemical/ccs811.c
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ccs811.c - Support for AMS CCS811 VOC Sensor
+ *
+ * Copyright (C) 2017 Narcisa Vasile <narcisaanamaria12@gmail.com>
+ *
+ * Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
+ *
+ * IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
+ *
+ * TODO:
+ * 1. Make the drive mode selectable form userspace
+ * 2. Add support for interrupts
+ * 3. Adjust time to wait for data to be ready based on selected operation mode
+ * 4. Read error register and put the information in logs
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/module.h>
+
+#define CCS811_STATUS 0x00
+#define CCS811_MEAS_MODE 0x01
+#define CCS811_ALG_RESULT_DATA 0x02
+#define CCS811_RAW_DATA 0x03
+#define CCS811_HW_ID 0x20
+#define CCS811_HW_ID_VALUE 0x81
+#define CCS811_HW_VERSION 0x21
+#define CCS811_HW_VERSION_VALUE 0x10
+#define CCS811_HW_VERSION_MASK 0xF0
+#define CCS811_ERR 0xE0
+/* Used to transition from boot to application mode */
+#define CCS811_APP_START 0xF4
+#define CCS811_SW_RESET 0xFF
+
+/* Status register flags */
+#define CCS811_STATUS_ERROR BIT(0)
+#define CCS811_STATUS_DATA_READY BIT(3)
+#define CCS811_STATUS_APP_VALID_MASK BIT(4)
+#define CCS811_STATUS_APP_VALID_LOADED BIT(4)
+/*
+ * Value of FW_MODE bit of STATUS register describes the sensor's state:
+ * 0: Firmware is in boot mode, this allows new firmware to be loaded
+ * 1: Firmware is in application mode. CCS811 is ready to take ADC measurements
+ */
+#define CCS811_STATUS_FW_MODE_MASK BIT(7)
+#define CCS811_STATUS_FW_MODE_APPLICATION BIT(7)
+
+/* Measurement modes */
+#define CCS811_MODE_IDLE 0x00
+#define CCS811_MODE_IAQ_1SEC 0x10
+#define CCS811_MODE_IAQ_10SEC 0x20
+#define CCS811_MODE_IAQ_60SEC 0x30
+#define CCS811_MODE_RAW_DATA 0x40
+
+#define CCS811_MEAS_MODE_INTERRUPT BIT(3)
+
+#define CCS811_VOLTAGE_MASK 0x3FF
+
+struct ccs811_reading {
+ __be16 co2;
+ __be16 voc;
+ u8 status;
+ u8 error;
+ __be16 raw_data;
+} __attribute__((__packed__));
+
+struct ccs811_data {
+ struct i2c_client *client;
+ struct mutex lock; /* Protect readings */
+ struct ccs811_reading buffer;
+ struct iio_trigger *drdy_trig;
+ struct gpio_desc *wakeup_gpio;
+ bool drdy_trig_on;
+ /* Ensures correct alignment of timestamp if present */
+ struct {
+ s16 channels[2];
+ s64 ts __aligned(8);
+ } scan;
+};
+
+static const struct iio_chan_spec ccs811_channels[] = {
+ {
+ .type = IIO_CURRENT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .scan_index = -1,
+ }, {
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .scan_index = -1,
+ }, {
+ .type = IIO_CONCENTRATION,
+ .channel2 = IIO_MOD_CO2,
+ .modified = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .scan_index = 0,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_BE,
+ },
+ }, {
+ .type = IIO_CONCENTRATION,
+ .channel2 = IIO_MOD_VOC,
+ .modified = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .scan_index = 1,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_BE,
+ },
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(2),
+};
+
+/*
+ * The CCS811 powers-up in boot mode. A setup write to CCS811_APP_START will
+ * transition the sensor to application mode.
+ */
+static int ccs811_start_sensor_application(struct i2c_client *client)
+{
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
+ if (ret < 0)
+ return ret;
+
+ if ((ret & CCS811_STATUS_FW_MODE_APPLICATION))
+ return 0;
+
+ if ((ret & CCS811_STATUS_APP_VALID_MASK) !=
+ CCS811_STATUS_APP_VALID_LOADED)
+ return -EIO;
+
+ ret = i2c_smbus_write_byte(client, CCS811_APP_START);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
+ if (ret < 0)
+ return ret;
+
+ if ((ret & CCS811_STATUS_FW_MODE_MASK) !=
+ CCS811_STATUS_FW_MODE_APPLICATION) {
+ dev_err(&client->dev, "Application failed to start. Sensor is still in boot mode.\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ccs811_setup(struct i2c_client *client)
+{
+ int ret;
+
+ ret = ccs811_start_sensor_application(client);
+ if (ret < 0)
+ return ret;
+
+ return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
+ CCS811_MODE_IAQ_1SEC);
+}
+
+static void ccs811_set_wakeup(struct ccs811_data *data, bool enable)
+{
+ if (!data->wakeup_gpio)
+ return;
+
+ gpiod_set_value(data->wakeup_gpio, enable);
+
+ if (enable)
+ usleep_range(50, 60);
+ else
+ usleep_range(20, 30);
+}
+
+static int ccs811_get_measurement(struct ccs811_data *data)
+{
+ int ret, tries = 11;
+
+ ccs811_set_wakeup(data, true);
+
+ /* Maximum waiting time: 1s, as measurements are made every second */
+ while (tries-- > 0) {
+ ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
+ if (ret < 0)
+ return ret;
+
+ if ((ret & CCS811_STATUS_DATA_READY) || tries == 0)
+ break;
+ msleep(100);
+ }
+ if (!(ret & CCS811_STATUS_DATA_READY))
+ return -EIO;
+
+ ret = i2c_smbus_read_i2c_block_data(data->client,
+ CCS811_ALG_RESULT_DATA, 8,
+ (char *)&data->buffer);
+ ccs811_set_wakeup(data, false);
+
+ return ret;
+}
+
+static int ccs811_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ccs811_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
+ mutex_lock(&data->lock);
+ ret = ccs811_get_measurement(data);
+ if (ret < 0) {
+ mutex_unlock(&data->lock);
+ iio_device_release_direct_mode(indio_dev);
+ return ret;
+ }
+
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *val = be16_to_cpu(data->buffer.raw_data) &
+ CCS811_VOLTAGE_MASK;
+ ret = IIO_VAL_INT;
+ break;
+ case IIO_CURRENT:
+ *val = be16_to_cpu(data->buffer.raw_data) >> 10;
+ ret = IIO_VAL_INT;
+ break;
+ case IIO_CONCENTRATION:
+ switch (chan->channel2) {
+ case IIO_MOD_CO2:
+ *val = be16_to_cpu(data->buffer.co2);
+ ret = IIO_VAL_INT;
+ break;
+ case IIO_MOD_VOC:
+ *val = be16_to_cpu(data->buffer.voc);
+ ret = IIO_VAL_INT;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ mutex_unlock(&data->lock);
+ iio_device_release_direct_mode(indio_dev);
+
+ return ret;
+
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *val = 1;
+ *val2 = 612903;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CURRENT:
+ *val = 0;
+ *val2 = 1000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CONCENTRATION:
+ switch (chan->channel2) {
+ case IIO_MOD_CO2:
+ *val = 0;
+ *val2 = 100;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_MOD_VOC:
+ *val = 0;
+ *val2 = 100;
+ return IIO_VAL_INT_PLUS_NANO;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info ccs811_info = {
+ .read_raw = ccs811_read_raw,
+};
+
+static int ccs811_set_trigger_state(struct iio_trigger *trig,
+ bool state)
+{
+ struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+ struct ccs811_data *data = iio_priv(indio_dev);
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
+ if (ret < 0)
+ return ret;
+
+ if (state)
+ ret |= CCS811_MEAS_MODE_INTERRUPT;
+ else
+ ret &= ~CCS811_MEAS_MODE_INTERRUPT;
+
+ data->drdy_trig_on = state;
+
+ return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
+}
+
+static const struct iio_trigger_ops ccs811_trigger_ops = {
+ .set_trigger_state = ccs811_set_trigger_state,
+};
+
+static irqreturn_t ccs811_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct ccs811_data *data = iio_priv(indio_dev);
+ struct i2c_client *client = data->client;
+ int ret;
+
+ ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA,
+ sizeof(data->scan.channels),
+ (u8 *)data->scan.channels);
+ if (ret != 4) {
+ dev_err(&client->dev, "cannot read sensor data\n");
+ goto err;
+ }
+
+ iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
+ iio_get_time_ns(indio_dev));
+
+err:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
+{
+ struct iio_dev *indio_dev = private;
+ struct ccs811_data *data = iio_priv(indio_dev);
+
+ if (data->drdy_trig_on)
+ iio_trigger_poll(data->drdy_trig);
+
+ return IRQ_HANDLED;
+}
+
+static int ccs811_reset(struct i2c_client *client)
+{
+ struct gpio_desc *reset_gpio;
+ int ret;
+
+ reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(reset_gpio))
+ return PTR_ERR(reset_gpio);
+
+ /* Try to reset using nRESET pin if available else do SW reset */
+ if (reset_gpio) {
+ gpiod_set_value(reset_gpio, 1);
+ usleep_range(20, 30);
+ gpiod_set_value(reset_gpio, 0);
+ } else {
+ /*
+ * As per the datasheet, this sequence of values needs to be
+ * written to the SW_RESET register for triggering the soft
+ * reset in the device and placing it in boot mode.
+ */
+ static const u8 reset_seq[] = {
+ 0x11, 0xE5, 0x72, 0x8A,
+ };
+
+ ret = i2c_smbus_write_i2c_block_data(client, CCS811_SW_RESET,
+ sizeof(reset_seq), reset_seq);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failed to reset sensor\n");
+ return ret;
+ }
+ }
+
+ /* tSTART delay required after reset */
+ usleep_range(1000, 2000);
+
+ return 0;
+}
+
+static int ccs811_probe(struct i2c_client *client)
+{
+ const struct i2c_device_id *id = i2c_client_get_device_id(client);
+ struct iio_dev *indio_dev;
+ struct ccs811_data *data;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
+ | I2C_FUNC_SMBUS_BYTE_DATA
+ | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+ return -EOPNOTSUPP;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(data->wakeup_gpio))
+ return PTR_ERR(data->wakeup_gpio);
+
+ ccs811_set_wakeup(data, true);
+
+ ret = ccs811_reset(client);
+ if (ret) {
+ ccs811_set_wakeup(data, false);
+ return ret;
+ }
+
+ /* Check hardware id (should be 0x81 for this family of devices) */
+ ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
+ if (ret < 0) {
+ ccs811_set_wakeup(data, false);
+ return ret;
+ }
+
+ if (ret != CCS811_HW_ID_VALUE) {
+ dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
+ ccs811_set_wakeup(data, false);
+ return -ENODEV;
+ }
+
+ ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
+ if (ret < 0) {
+ ccs811_set_wakeup(data, false);
+ return ret;
+ }
+
+ if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
+ dev_err(&client->dev, "no CCS811 sensor\n");
+ ccs811_set_wakeup(data, false);
+ return -ENODEV;
+ }
+
+ ret = ccs811_setup(client);
+ if (ret < 0) {
+ ccs811_set_wakeup(data, false);
+ return ret;
+ }
+
+ ccs811_set_wakeup(data, false);
+
+ mutex_init(&data->lock);
+
+ indio_dev->name = id->name;
+ indio_dev->info = &ccs811_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ indio_dev->channels = ccs811_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
+
+ if (client->irq > 0) {
+ ret = devm_request_threaded_irq(&client->dev, client->irq,
+ ccs811_data_rdy_trigger_poll,
+ NULL,
+ IRQF_TRIGGER_FALLING |
+ IRQF_ONESHOT,
+ "ccs811_irq", indio_dev);
+ if (ret) {
+ dev_err(&client->dev, "irq request error %d\n", -ret);
+ goto err_poweroff;
+ }
+
+ data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
+ "%s-dev%d",
+ indio_dev->name,
+ iio_device_id(indio_dev));
+ if (!data->drdy_trig) {
+ ret = -ENOMEM;
+ goto err_poweroff;
+ }
+
+ data->drdy_trig->ops = &ccs811_trigger_ops;
+ iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
+ ret = iio_trigger_register(data->drdy_trig);
+ if (ret)
+ goto err_poweroff;
+
+ indio_dev->trig = iio_trigger_get(data->drdy_trig);
+ }
+
+ ret = iio_triggered_buffer_setup(indio_dev, NULL,
+ ccs811_trigger_handler, NULL);
+
+ if (ret < 0) {
+ dev_err(&client->dev, "triggered buffer setup failed\n");
+ goto err_trigger_unregister;
+ }
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(&client->dev, "unable to register iio device\n");
+ goto err_buffer_cleanup;
+ }
+ return 0;
+
+err_buffer_cleanup:
+ iio_triggered_buffer_cleanup(indio_dev);
+err_trigger_unregister:
+ if (data->drdy_trig)
+ iio_trigger_unregister(data->drdy_trig);
+err_poweroff:
+ i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
+
+ return ret;
+}
+
+static void ccs811_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ccs811_data *data = iio_priv(indio_dev);
+ int ret;
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+ if (data->drdy_trig)
+ iio_trigger_unregister(data->drdy_trig);
+
+ ret = i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
+ CCS811_MODE_IDLE);
+ if (ret)
+ dev_warn(&client->dev, "Failed to power down device (%pe)\n",
+ ERR_PTR(ret));
+}
+
+static const struct i2c_device_id ccs811_id[] = {
+ {"ccs811", 0},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ccs811_id);
+
+static const struct of_device_id ccs811_dt_ids[] = {
+ { .compatible = "ams,ccs811" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ccs811_dt_ids);
+
+static struct i2c_driver ccs811_driver = {
+ .driver = {
+ .name = "ccs811",
+ .of_match_table = ccs811_dt_ids,
+ },
+ .probe = ccs811_probe,
+ .remove = ccs811_remove,
+ .id_table = ccs811_id,
+};
+module_i2c_driver(ccs811_driver);
+
+MODULE_AUTHOR("Narcisa Vasile <narcisaanamaria12@gmail.com>");
+MODULE_DESCRIPTION("CCS811 volatile organic compounds sensor");
+MODULE_LICENSE("GPL v2");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 18:02:43 +0000