diff options
Diffstat (limited to 'drivers/iio/chemical/scd30_core.c')
-rw-r--r-- | drivers/iio/chemical/scd30_core.c | 754 |
1 files changed, 754 insertions, 0 deletions
diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c new file mode 100644 index 0000000000..7be5a45cf7 --- /dev/null +++ b/drivers/iio/chemical/scd30_core.c @@ -0,0 +1,754 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sensirion SCD30 carbon dioxide sensor core driver + * + * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com> + */ +#include <linux/bits.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/iio/buffer.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/types.h> +#include <linux/interrupt.h> +#include <linux/irqreturn.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/regulator/consumer.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include <linux/types.h> +#include <asm/byteorder.h> + +#include "scd30.h" + +#define SCD30_PRESSURE_COMP_MIN_MBAR 700 +#define SCD30_PRESSURE_COMP_MAX_MBAR 1400 +#define SCD30_PRESSURE_COMP_DEFAULT 1013 +#define SCD30_MEAS_INTERVAL_MIN_S 2 +#define SCD30_MEAS_INTERVAL_MAX_S 1800 +#define SCD30_MEAS_INTERVAL_DEFAULT SCD30_MEAS_INTERVAL_MIN_S +#define SCD30_FRC_MIN_PPM 400 +#define SCD30_FRC_MAX_PPM 2000 +#define SCD30_TEMP_OFFSET_MAX 655360 +#define SCD30_EXTRA_TIMEOUT_PER_S 250 + +enum { + SCD30_CONC, + SCD30_TEMP, + SCD30_HR, +}; + +static int scd30_command_write(struct scd30_state *state, enum scd30_cmd cmd, u16 arg) +{ + return state->command(state, cmd, arg, NULL, 0); +} + +static int scd30_command_read(struct scd30_state *state, enum scd30_cmd cmd, u16 *val) +{ + __be16 tmp; + int ret; + + ret = state->command(state, cmd, 0, &tmp, sizeof(tmp)); + *val = be16_to_cpup(&tmp); + + return ret; +} + +static int scd30_reset(struct scd30_state *state) +{ + int ret; + u16 val; + + ret = scd30_command_write(state, CMD_RESET, 0); + if (ret) + return ret; + + /* sensor boots up within 2 secs */ + msleep(2000); + /* + * Power-on-reset causes sensor to produce some glitch on i2c bus and + * some controllers end up in error state. Try to recover by placing + * any data on the bus. + */ + scd30_command_read(state, CMD_MEAS_READY, &val); + + return 0; +} + +/* simplified float to fixed point conversion with a scaling factor of 0.01 */ +static int scd30_float_to_fp(int float32) +{ + int fraction, shift, + mantissa = float32 & GENMASK(22, 0), + sign = (float32 & BIT(31)) ? -1 : 1, + exp = (float32 & ~BIT(31)) >> 23; + + /* special case 0 */ + if (!exp && !mantissa) + return 0; + + exp -= 127; + if (exp < 0) { + exp = -exp; + /* return values ranging from 1 to 99 */ + return sign * ((((BIT(23) + mantissa) * 100) >> 23) >> exp); + } + + /* return values starting at 100 */ + shift = 23 - exp; + float32 = BIT(exp) + (mantissa >> shift); + fraction = mantissa & GENMASK(shift - 1, 0); + + return sign * (float32 * 100 + ((fraction * 100) >> shift)); +} + +static int scd30_read_meas(struct scd30_state *state) +{ + int i, ret; + + ret = state->command(state, CMD_READ_MEAS, 0, state->meas, sizeof(state->meas)); + if (ret) + return ret; + + be32_to_cpu_array(state->meas, (__be32 *)state->meas, ARRAY_SIZE(state->meas)); + + for (i = 0; i < ARRAY_SIZE(state->meas); i++) + state->meas[i] = scd30_float_to_fp(state->meas[i]); + + /* + * co2 is left unprocessed while temperature and humidity are scaled + * to milli deg C and milli percent respectively. + */ + state->meas[SCD30_TEMP] *= 10; + state->meas[SCD30_HR] *= 10; + + return 0; +} + +static int scd30_wait_meas_irq(struct scd30_state *state) +{ + int ret, timeout; + + reinit_completion(&state->meas_ready); + enable_irq(state->irq); + timeout = msecs_to_jiffies(state->meas_interval * (1000 + SCD30_EXTRA_TIMEOUT_PER_S)); + ret = wait_for_completion_interruptible_timeout(&state->meas_ready, timeout); + if (ret > 0) + ret = 0; + else if (!ret) + ret = -ETIMEDOUT; + + disable_irq(state->irq); + + return ret; +} + +static int scd30_wait_meas_poll(struct scd30_state *state) +{ + int timeout = state->meas_interval * SCD30_EXTRA_TIMEOUT_PER_S, tries = 5; + + do { + int ret; + u16 val; + + ret = scd30_command_read(state, CMD_MEAS_READY, &val); + if (ret) + return -EIO; + + /* new measurement available */ + if (val) + break; + + msleep_interruptible(timeout); + } while (--tries); + + return tries ? 0 : -ETIMEDOUT; +} + +static int scd30_read_poll(struct scd30_state *state) +{ + int ret; + + ret = scd30_wait_meas_poll(state); + if (ret) + return ret; + + return scd30_read_meas(state); +} + +static int scd30_read(struct scd30_state *state) +{ + if (state->irq > 0) + return scd30_wait_meas_irq(state); + + return scd30_read_poll(state); +} + +static int scd30_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct scd30_state *state = iio_priv(indio_dev); + int ret = -EINVAL; + u16 tmp; + + mutex_lock(&state->lock); + switch (mask) { + case IIO_CHAN_INFO_RAW: + case IIO_CHAN_INFO_PROCESSED: + if (chan->output) { + *val = state->pressure_comp; + ret = IIO_VAL_INT; + break; + } + + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + break; + + ret = scd30_read(state); + if (ret) { + iio_device_release_direct_mode(indio_dev); + break; + } + + *val = state->meas[chan->address]; + iio_device_release_direct_mode(indio_dev); + ret = IIO_VAL_INT; + break; + case IIO_CHAN_INFO_SCALE: + *val = 0; + *val2 = 1; + ret = IIO_VAL_INT_PLUS_MICRO; + break; + case IIO_CHAN_INFO_SAMP_FREQ: + ret = scd30_command_read(state, CMD_MEAS_INTERVAL, &tmp); + if (ret) + break; + + *val = 0; + *val2 = 1000000000 / tmp; + ret = IIO_VAL_INT_PLUS_NANO; + break; + case IIO_CHAN_INFO_CALIBBIAS: + ret = scd30_command_read(state, CMD_TEMP_OFFSET, &tmp); + if (ret) + break; + + *val = tmp; + ret = IIO_VAL_INT; + break; + } + mutex_unlock(&state->lock); + + return ret; +} + +static int scd30_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct scd30_state *state = iio_priv(indio_dev); + int ret = -EINVAL; + + mutex_lock(&state->lock); + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + if (val) + break; + + val = 1000000000 / val2; + if (val < SCD30_MEAS_INTERVAL_MIN_S || val > SCD30_MEAS_INTERVAL_MAX_S) + break; + + ret = scd30_command_write(state, CMD_MEAS_INTERVAL, val); + if (ret) + break; + + state->meas_interval = val; + break; + case IIO_CHAN_INFO_RAW: + switch (chan->type) { + case IIO_PRESSURE: + if (val < SCD30_PRESSURE_COMP_MIN_MBAR || + val > SCD30_PRESSURE_COMP_MAX_MBAR) + break; + + ret = scd30_command_write(state, CMD_START_MEAS, val); + if (ret) + break; + + state->pressure_comp = val; + break; + default: + break; + } + break; + case IIO_CHAN_INFO_CALIBBIAS: + if (val < 0 || val > SCD30_TEMP_OFFSET_MAX) + break; + /* + * Manufacturer does not explicitly specify min/max sensible + * values hence check is omitted for simplicity. + */ + ret = scd30_command_write(state, CMD_TEMP_OFFSET / 10, val); + } + mutex_unlock(&state->lock); + + return ret; +} + +static int scd30_write_raw_get_fmt(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + return IIO_VAL_INT_PLUS_NANO; + case IIO_CHAN_INFO_RAW: + case IIO_CHAN_INFO_CALIBBIAS: + return IIO_VAL_INT; + } + + return -EINVAL; +} + +static const int scd30_pressure_raw_available[] = { + SCD30_PRESSURE_COMP_MIN_MBAR, 1, SCD30_PRESSURE_COMP_MAX_MBAR, +}; + +static const int scd30_temp_calibbias_available[] = { + 0, 10, SCD30_TEMP_OFFSET_MAX, +}; + +static int scd30_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_RAW: + *vals = scd30_pressure_raw_available; + *type = IIO_VAL_INT; + + return IIO_AVAIL_RANGE; + case IIO_CHAN_INFO_CALIBBIAS: + *vals = scd30_temp_calibbias_available; + *type = IIO_VAL_INT; + + return IIO_AVAIL_RANGE; + } + + return -EINVAL; +} + +static ssize_t sampling_frequency_available_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + int i = SCD30_MEAS_INTERVAL_MIN_S; + ssize_t len = 0; + + do { + len += sysfs_emit_at(buf, len, "0.%09u ", 1000000000 / i); + /* + * Not all values fit PAGE_SIZE buffer hence print every 6th + * (each frequency differs by 6s in time domain from the + * adjacent). Unlisted but valid ones are still accepted. + */ + i += 6; + } while (i <= SCD30_MEAS_INTERVAL_MAX_S); + + buf[len - 1] = '\n'; + + return len; +} + +static ssize_t calibration_auto_enable_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct scd30_state *state = iio_priv(indio_dev); + int ret; + u16 val; + + mutex_lock(&state->lock); + ret = scd30_command_read(state, CMD_ASC, &val); + mutex_unlock(&state->lock); + + return ret ?: sysfs_emit(buf, "%d\n", val); +} + +static ssize_t calibration_auto_enable_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct scd30_state *state = iio_priv(indio_dev); + bool val; + int ret; + + ret = kstrtobool(buf, &val); + if (ret) + return ret; + + mutex_lock(&state->lock); + ret = scd30_command_write(state, CMD_ASC, val); + mutex_unlock(&state->lock); + + return ret ?: len; +} + +static ssize_t calibration_forced_value_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct scd30_state *state = iio_priv(indio_dev); + int ret; + u16 val; + + mutex_lock(&state->lock); + ret = scd30_command_read(state, CMD_FRC, &val); + mutex_unlock(&state->lock); + + return ret ?: sysfs_emit(buf, "%d\n", val); +} + +static ssize_t calibration_forced_value_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct scd30_state *state = iio_priv(indio_dev); + int ret; + u16 val; + + ret = kstrtou16(buf, 0, &val); + if (ret) + return ret; + + if (val < SCD30_FRC_MIN_PPM || val > SCD30_FRC_MAX_PPM) + return -EINVAL; + + mutex_lock(&state->lock); + ret = scd30_command_write(state, CMD_FRC, val); + mutex_unlock(&state->lock); + + return ret ?: len; +} + +static IIO_DEVICE_ATTR_RO(sampling_frequency_available, 0); +static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0); +static IIO_DEVICE_ATTR_RW(calibration_forced_value, 0); + +static struct attribute *scd30_attrs[] = { + &iio_dev_attr_sampling_frequency_available.dev_attr.attr, + &iio_dev_attr_calibration_auto_enable.dev_attr.attr, + &iio_dev_attr_calibration_forced_value.dev_attr.attr, + NULL +}; + +static const struct attribute_group scd30_attr_group = { + .attrs = scd30_attrs, +}; + +static const struct iio_info scd30_info = { + .attrs = &scd30_attr_group, + .read_raw = scd30_read_raw, + .write_raw = scd30_write_raw, + .write_raw_get_fmt = scd30_write_raw_get_fmt, + .read_avail = scd30_read_avail, +}; + +#define SCD30_CHAN_SCAN_TYPE(_sign, _realbits) .scan_type = { \ + .sign = _sign, \ + .realbits = _realbits, \ + .storagebits = 32, \ + .endianness = IIO_CPU, \ +} + +static const struct iio_chan_spec scd30_channels[] = { + { + /* + * this channel is special in a sense we are pretending that + * sensor is able to change measurement chamber pressure but in + * fact we're just setting pressure compensation value + */ + .type = IIO_PRESSURE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW), + .output = 1, + .scan_index = -1, + }, + { + .type = IIO_CONCENTRATION, + .channel2 = IIO_MOD_CO2, + .address = SCD30_CONC, + .scan_index = SCD30_CONC, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + .modified = 1, + + SCD30_CHAN_SCAN_TYPE('u', 20), + }, + { + .type = IIO_TEMP, + .address = SCD30_TEMP, + .scan_index = SCD30_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_CALIBBIAS), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBBIAS), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + + SCD30_CHAN_SCAN_TYPE('s', 18), + }, + { + .type = IIO_HUMIDITYRELATIVE, + .address = SCD30_HR, + .scan_index = SCD30_HR, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + + SCD30_CHAN_SCAN_TYPE('u', 17), + }, + IIO_CHAN_SOFT_TIMESTAMP(3), +}; + +static int scd30_suspend(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct scd30_state *state = iio_priv(indio_dev); + int ret; + + ret = scd30_command_write(state, CMD_STOP_MEAS, 0); + if (ret) + return ret; + + return regulator_disable(state->vdd); +} + +static int scd30_resume(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct scd30_state *state = iio_priv(indio_dev); + int ret; + + ret = regulator_enable(state->vdd); + if (ret) + return ret; + + return scd30_command_write(state, CMD_START_MEAS, state->pressure_comp); +} + +EXPORT_NS_SIMPLE_DEV_PM_OPS(scd30_pm_ops, scd30_suspend, scd30_resume, IIO_SCD30); + +static void scd30_stop_meas(void *data) +{ + struct scd30_state *state = data; + + scd30_command_write(state, CMD_STOP_MEAS, 0); +} + +static void scd30_disable_regulator(void *data) +{ + struct scd30_state *state = data; + + regulator_disable(state->vdd); +} + +static irqreturn_t scd30_irq_handler(int irq, void *priv) +{ + struct iio_dev *indio_dev = priv; + + if (iio_buffer_enabled(indio_dev)) { + iio_trigger_poll(indio_dev->trig); + + return IRQ_HANDLED; + } + + return IRQ_WAKE_THREAD; +} + +static irqreturn_t scd30_irq_thread_handler(int irq, void *priv) +{ + struct iio_dev *indio_dev = priv; + struct scd30_state *state = iio_priv(indio_dev); + int ret; + + ret = scd30_read_meas(state); + if (ret) + goto out; + + complete_all(&state->meas_ready); +out: + return IRQ_HANDLED; +} + +static irqreturn_t scd30_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct scd30_state *state = iio_priv(indio_dev); + struct { + int data[SCD30_MEAS_COUNT]; + s64 ts __aligned(8); + } scan; + int ret; + + mutex_lock(&state->lock); + if (!iio_trigger_using_own(indio_dev)) + ret = scd30_read_poll(state); + else + ret = scd30_read_meas(state); + memset(&scan, 0, sizeof(scan)); + memcpy(scan.data, state->meas, sizeof(state->meas)); + mutex_unlock(&state->lock); + if (ret) + goto out; + + iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev)); +out: + iio_trigger_notify_done(indio_dev->trig); + return IRQ_HANDLED; +} + +static int scd30_set_trigger_state(struct iio_trigger *trig, bool state) +{ + struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); + struct scd30_state *st = iio_priv(indio_dev); + + if (state) + enable_irq(st->irq); + else + disable_irq(st->irq); + + return 0; +} + +static const struct iio_trigger_ops scd30_trigger_ops = { + .set_trigger_state = scd30_set_trigger_state, + .validate_device = iio_trigger_validate_own_device, +}; + +static int scd30_setup_trigger(struct iio_dev *indio_dev) +{ + struct scd30_state *state = iio_priv(indio_dev); + struct device *dev = indio_dev->dev.parent; + struct iio_trigger *trig; + int ret; + + trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name, + iio_device_id(indio_dev)); + if (!trig) + return dev_err_probe(dev, -ENOMEM, "failed to allocate trigger\n"); + + trig->ops = &scd30_trigger_ops; + iio_trigger_set_drvdata(trig, indio_dev); + + ret = devm_iio_trigger_register(dev, trig); + if (ret) + return ret; + + indio_dev->trig = iio_trigger_get(trig); + + /* + * Interrupt is enabled just before taking a fresh measurement + * and disabled afterwards. This means we need to ensure it is not + * enabled here to keep calls to enable/disable balanced. + */ + ret = devm_request_threaded_irq(dev, state->irq, scd30_irq_handler, + scd30_irq_thread_handler, + IRQF_TRIGGER_HIGH | IRQF_ONESHOT | + IRQF_NO_AUTOEN, + indio_dev->name, indio_dev); + if (ret) + return dev_err_probe(dev, ret, "failed to request irq\n"); + + return 0; +} + +int scd30_probe(struct device *dev, int irq, const char *name, void *priv, + scd30_command_t command) +{ + static const unsigned long scd30_scan_masks[] = { 0x07, 0x00 }; + struct scd30_state *state; + struct iio_dev *indio_dev; + int ret; + u16 val; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*state)); + if (!indio_dev) + return -ENOMEM; + + state = iio_priv(indio_dev); + state->dev = dev; + state->priv = priv; + state->irq = irq; + state->pressure_comp = SCD30_PRESSURE_COMP_DEFAULT; + state->meas_interval = SCD30_MEAS_INTERVAL_DEFAULT; + state->command = command; + mutex_init(&state->lock); + init_completion(&state->meas_ready); + + dev_set_drvdata(dev, indio_dev); + + indio_dev->info = &scd30_info; + indio_dev->name = name; + indio_dev->channels = scd30_channels; + indio_dev->num_channels = ARRAY_SIZE(scd30_channels); + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->available_scan_masks = scd30_scan_masks; + + state->vdd = devm_regulator_get(dev, "vdd"); + if (IS_ERR(state->vdd)) + return dev_err_probe(dev, PTR_ERR(state->vdd), "failed to get regulator\n"); + + ret = regulator_enable(state->vdd); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, scd30_disable_regulator, state); + if (ret) + return ret; + + ret = scd30_reset(state); + if (ret) + return dev_err_probe(dev, ret, "failed to reset device\n"); + + if (state->irq > 0) { + ret = scd30_setup_trigger(indio_dev); + if (ret) + return dev_err_probe(dev, ret, "failed to setup trigger\n"); + } + + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, scd30_trigger_handler, NULL); + if (ret) + return ret; + + ret = scd30_command_read(state, CMD_FW_VERSION, &val); + if (ret) + return dev_err_probe(dev, ret, "failed to read firmware version\n"); + dev_info(dev, "firmware version: %d.%d\n", val >> 8, (char)val); + + ret = scd30_command_write(state, CMD_MEAS_INTERVAL, state->meas_interval); + if (ret) + return dev_err_probe(dev, ret, "failed to set measurement interval\n"); + + ret = scd30_command_write(state, CMD_START_MEAS, state->pressure_comp); + if (ret) + return dev_err_probe(dev, ret, "failed to start measurement\n"); + + ret = devm_add_action_or_reset(dev, scd30_stop_meas, state); + if (ret) + return ret; + + return devm_iio_device_register(dev, indio_dev); +} +EXPORT_SYMBOL_NS(scd30_probe, IIO_SCD30); + +MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>"); +MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor core driver"); +MODULE_LICENSE("GPL v2"); |