> This patch adds support for dsm501 and ppd42ns particle sensors. quick comments below > Both sensors work on the same principle. Heater (resistor) heats up air > in sensor chamber which induces upward flow. Particles convect up through > a light beam provided by internal infra-red LED. Light scattered by > particles is picked by photodiode and internal electronics outputs PWM > signal. > > Measuring low time occupancy of the signal during 30s measurement period > particles number in cubic meter can be computed. > > Signed-off-by: Tomasz Duszynski <tduszyns@xxxxxxxxx> > --- > drivers/iio/chemical/Kconfig | 10 ++ > drivers/iio/chemical/Makefile | 1 + > drivers/iio/chemical/dsm501.c | 231 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 242 insertions(+) > create mode 100644 drivers/iio/chemical/dsm501.c > > diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig > index cea7f9857a1f..986d612aa77f 100644 > --- a/drivers/iio/chemical/Kconfig > +++ b/drivers/iio/chemical/Kconfig > @@ -21,6 +21,16 @@ config ATLAS_PH_SENSOR > To compile this driver as module, choose M here: the > module will be called atlas-ph-sensor. > > +config DSM501 > + tristate "Samyoung DSM501 particle sensor" > + depends on GPIOLIB > + help > + Say yes here to build support for the Samyoung DSM501 > + particle sensor. > + > + To compile this driver as a module, choose M here: the module > + will be called dsm501. > + > config IAQCORE > tristate "AMS iAQ-Core VOC sensors" > depends on I2C > diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile > index b02202b41289..76f50ff8ba7d 100644 > --- a/drivers/iio/chemical/Makefile > +++ b/drivers/iio/chemical/Makefile > @@ -4,5 +4,6 @@ > > # When adding new entries keep the list in alphabetical order > obj-$(CONFIG_ATLAS_PH_SENSOR) += atlas-ph-sensor.o > +obj-$(CONFIG_DSM501) += dsm501.o > obj-$(CONFIG_IAQCORE) += ams-iaq-core.o > obj-$(CONFIG_VZ89X) += vz89x.o > diff --git a/drivers/iio/chemical/dsm501.c b/drivers/iio/chemical/dsm501.c > new file mode 100644 > index 000000000000..013f6b3bfd48 > --- /dev/null > +++ b/drivers/iio/chemical/dsm501.c > @@ -0,0 +1,231 @@ > +/* > + * Samyoung DSM501 particle sensor driver > + * > + * Copyright (C) 2017 Tomasz Duszynski <tduszyns@xxxxxxxxx> > + * > + * Datasheets: > + * http://www.samyoungsnc.com/products/3-1%20Specification%20DSM501.pdf > + * http://wiki.timelab.org/images/f/f9/PPD42NS.pdf > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#include <linux/delay.h> > +#include <linux/gpio/consumer.h> > +#include <linux/iio/iio.h> > +#include <linux/init.h> > +#include <linux/interrupt.h> > +#include <linux/module.h> > +#include <linux/mutex.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/timekeeping.h> > + > +#define DSM501_DRV_NAME "dsm501" > +#define DSM501_IRQ_NAME "dsm501_irq" replace tab by space > + > +#define DSM501_DEFAULT_MEASUREMENT_TIME 30 /* seconds */ > + > +struct dsm501_data { > + ktime_t ts; > + ktime_t low_time; > + ktime_t meas_time; > + > + int irq; > + struct gpio_desc *gpio; > + > + struct mutex lock; > + > + int (*number_concentration)(struct dsm501_data *data); > +}; > + > +/* > + * Series of data points in Fig. 8-3 (Low Ratio vs Particle) > + * can be approximated by following polynomials: > + * > + * p(r) = 0 (undefined) for r < 4 > + * p(r) = 2353564.2r - 4373814.7 for 4 <= r < 20 > + * p(r) = 4788112.4r - 53581390 for r >= 20 > + * > + * Note: Result is in pcs/m3. To convert to pcs/0.01cf multiply > + * by 0.0002831685. is cf needed? > + */ > +static int dsm501_number_concentartion(struct dsm501_data *data) > +{ > + s64 retval = 0, r = div64_s64(ktime_to_ns(data->low_time) * 100, > + ktime_to_ns(data->meas_time)); > + > + if (r >= 4 && r < 20) > + retval = 23535642 * r - 43738147; > + else if (r >= 20) > + retval = 47881124 * r - 535813900; > + > + return div_s64(retval, 10); > +} > + > +/* > + * Series of data points in Fig. 2 (Lo Pulse Occupancy Time vs Concentration) > + * can be approximated by following polynomial: > + * > + * p(r) = 3844.2r^3 - 16201.3r^2 + 1848746.1r + 52497.2 > + * > + * Note: Result is in pcs/m3. To convert to pcs/0.01cf multiply > + * by 0.0002831685. > + */ > +static int ppd42ns_number_concentration(struct dsm501_data *data) > +{ > + s64 retval, r3, r2, r = div64_s64(ktime_to_ns(data->low_time) * 100, > + ktime_to_ns(data->meas_time)); > + > + r2 = r * r; > + r3 = r2 * r; > + > + retval = 38442 * r3; > + retval -= 162013 * r2; > + retval += 18487461 * r; > + retval += 524972; > + > + return div_s64(retval, 10); > +} > + > +static irqreturn_t dsm501_irq(int irq, void *dev_id) > +{ > + struct dsm501_data *data = iio_priv(dev_id); > + int val = gpiod_get_value(data->gpio); > + ktime_t dt, ts = ktime_get(); > + > + if (ktime_to_ns(data->ts) == 0) { > + data->ts = ts; > + data->low_time = ktime_set(0, 0); > + } > + > + if (val) { > + dt = ktime_sub(ts, data->ts); > + data->low_time = ktime_add(data->low_time, dt); > + } else { > + data->ts = ts; > + } {} needed? > + > + return IRQ_HANDLED; > +} > + > +static int dsm501_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, int *val, > + int *val2, long mask) > +{ > + struct dsm501_data *data = iio_priv(indio_dev); > + struct device *dev = indio_dev->dev.parent; > + unsigned long irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING; > + int ret; > + > + > + switch (mask) { > + case IIO_CHAN_INFO_PROCESSED: > + mutex_lock(&data->lock); > + data->ts = ktime_set(0, 0); > + > + ret = devm_request_irq(dev, data->irq, dsm501_irq, irqflags, > + DSM501_IRQ_NAME, indio_dev); why devm_()? if the irq is explicitly freed below? requesting the irq for every measurement seems weird even if it only happens every 30s > + if (ret) { > + dev_err(dev, "Failed to request interrupt %d\n", data->irq); > + mutex_unlock(&data->lock); > + return ret; > + } > + > + msleep_interruptible(ktime_to_ms(data->meas_time)); > + devm_free_irq(dev, data->irq, indio_dev); > + > + *val = data->number_concentration(data); > + mutex_unlock(&data->lock); > + > + return IIO_VAL_INT; > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info dsm501_info = { > + .driver_module = THIS_MODULE, > + .read_raw = dsm501_read_raw, > +}; > + > +static const struct iio_chan_spec dsm501_channels[] = { > + { > + .type = IIO_NUMBERCONCENTRATION, > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), > + }, > +}; > + > +static int dsm501_probe(struct platform_device *pdev) > +{ > + struct dsm501_data *data; > + struct iio_dev *indio_dev; > + struct device *dev = &pdev->dev; > + > + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*data)); > + if (!indio_dev) > + return -ENOMEM; > + > + data = iio_priv(indio_dev); > + platform_set_drvdata(pdev, indio_dev); > + > + data->gpio = devm_gpiod_get_index(dev, NULL, 0, GPIOD_IN); > + if (IS_ERR(data->gpio)) { > + dev_err(dev, "Failed to get GPIO\n"); > + return PTR_ERR(data->gpio); > + } > + > + data->irq = gpiod_to_irq(data->gpio); > + if (data->irq < 0) { > + dev_err(dev, "GPIO has no interrupt\n"); > + return data->irq; > + } > + > + data->meas_time = ktime_set(DSM501_DEFAULT_MEASUREMENT_TIME, 0); > + data->number_concentration = of_device_get_match_data(dev); > + mutex_init(&data->lock); > + > + indio_dev->name = DSM501_DRV_NAME; > + indio_dev->dev.parent = dev; > + indio_dev->info = &dsm501_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = dsm501_channels; > + indio_dev->num_channels = ARRAY_SIZE(dsm501_channels); > + > + return devm_iio_device_register(&pdev->dev, indio_dev); > +} > + > +static const struct of_device_id dsm501_id[] = { > + { > + .compatible = "samyoung,dsm501", > + .data = dsm501_number_concentartion, type: concentration > + }, > + { > + .compatible = "shinyei,ppd42ns", > + .data = ppd42ns_number_concentration, > + }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, dsm501_id); > + > +static struct platform_driver dsm501_driver = { > + .driver = { > + .name = DSM501_DRV_NAME, > + .of_match_table = of_match_ptr(dsm501_id) > + }, > + .probe = dsm501_probe > +}; > +module_platform_driver(dsm501_driver); > + > +MODULE_AUTHOR("Tomasz Duszynski <tduszyns@xxxxxxxxx>"); > +MODULE_DESCRIPTION("Samyoung DSM501 particle sensor driver"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald-Stadler +43-664-2444418 (mobile) -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
