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Message-ID: <20170205162434.GB2191@Arch.lan>
Date: Sun, 5 Feb 2017 17:24:36 +0100
From: Tomasz Duszynski <tduszyns@...il.com>
To: Peter Meerwald-Stadler <pmeerw@...erw.net>
Cc: Tomasz Duszynski <tduszyns@...il.com>,
linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
jic23@...nel.org, knaack.h@....de, lars@...afoo.de
Subject: Re: [PATCH 2/4] iio: chemical: add driver for dsm501/ppd42ns
particle sensors
Thanks for review!
On Sun, Feb 05, 2017 at 04:19:47PM +0100, Peter Meerwald-Stadler wrote:
>
> > This patch adds support for dsm501 and ppd42ns particle sensors.
>
> quick comments below
> G
> > 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@...il.com>
> > ---
> > 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@...il.com>
> > + *
> > + * 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
Ack.
>
> > +
> > +#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?
No. I've put that sidenote so that others looking at figures in
datahseets won't scratch their heads why units here are pcs/m3 and
pcs/0.01cf there. Anyway I am happy to drop that part.
>
> > + */
> > +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?
According to CodingStyle yes. {} could be dropped if there was single
statement under if (val) { ...
>
> > +
> > + 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
Ack.
>
> > + 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
Are you refering to function naming here? *_number_concentration was named
after returned physical quantity.
>
> > + },
> > + {
> > + .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@...il.com>");
> > +MODULE_DESCRIPTION("Samyoung DSM501 particle sensor driver");
> > +MODULE_LICENSE("GPL v2");
> >
>
> --
>
> Peter Meerwald-Stadler
> +43-664-2444418 (mobile)
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