linux-kernel - Re: [PATCH v2] iio: chemical: sps30: add support for self cleaning

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Message-Id: <20181228144747.15730-1-andreas.brauchli@sensirion.com>
Date:   Fri, 28 Dec 2018 15:47:47 +0100
From:   Andreas Brauchli <a.brauchli@...mentarea.net>
To:     Jonathan Cameron <jic23@...nel.org>,
        Tomasz Duszynski <tduszyns@...il.com>
Cc:     andreas.brauchli@...sirion.com, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] iio: chemical: sps30: add support for self cleaning

On Sat, 22 Dec 2018 17:23:46 +0000
Jonathan Cameron <jic23@...nel.org> wrote:

> On Tue, 18 Dec 2018 21:28:09 +0100
> Tomasz Duszynski <tduszyns@...il.com> wrote:
> 
> > Self cleaning is especially useful in cases where sensor undergoes
> > frequent power on/off cycles. In such scenarios it is recommended to
> > turn self cleaning at least once per week in order to maintain reliable
> > measurements.
> > 
> > Self cleaning is activated by writing 1 to a dedicated attribute.
> > Internal fan accelerates to its maximum speed and keeps spinning
> > for about 10 seconds blowing out accumulated dust.
> > 
> > Signed-off-by: Tomasz Duszynski <tduszyns@...il.com>
> Applied to the togreg branch of iio.git.   I took this today rather than
> leaving it on the list for longer simply because I'm not sure I'll be
> very timely in applying patches.
> 
> If anyone has any comments, it'll only be out as testing so we can
> still modify if that make sense for at least the next couple of weeks.

I backported and tested the whole series on a 4.9.53 raspberry pi with an SPS30.

Tested-by: Andreas Brauchli <andreas.brauchli@...sirion.com>

Cheers,
Andreas

> 
> Thanks,
> 
> Jonathan
> 
> > ---
> > v2:
> >  * removed TODO item
> >  * sensor cleaning is not measurement related per se so drop in_ prefix
> > 
> >  Documentation/ABI/testing/sysfs-bus-iio-sps30 |  8 +++++
> >  drivers/iio/chemical/sps30.c                  | 35 ++++++++++++++++++-
> >  2 files changed, 42 insertions(+), 1 deletion(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-sps30
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-sps30
> b/Documentation/ABI/testing/sysfs-bus-iio-sps30
> > new file mode 100644
> > index 000000000000..e7ce2c57635e
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio-sps30
> > @@ -0,0 +1,8 @@
> > +What:		/sys/bus/iio/devices/iio:deviceX/start_cleaning
> > +Date:		December 2018
> > +KernelVersion:	4.22
> > +Contact:	linux-iio@...r.kernel.org
> > +Description:
> > +		Writing 1 starts sensor self cleaning. Internal fan accelerates
> > +		to its maximum speed and keeps spinning for about 10 seconds in
> > +		order to blow out accumulated dust.
> > diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c
> > index fa3cd409b90b..f3b4390c8f5c 100644
> > --- a/drivers/iio/chemical/sps30.c
> > +++ b/drivers/iio/chemical/sps30.c
> > @@ -7,7 +7,6 @@
> >   * I2C slave address: 0x69
> >   *
> >   * TODO:
> > - *  - support for turning on fan cleaning
> >   *  - support for reading/setting auto cleaning interval
> >   */
> > 
> > @@ -37,6 +36,7 @@
> >  #define SPS30_READ_DATA_READY_FLAG 0x0202
> >  #define SPS30_READ_DATA 0x0300
> >  #define SPS30_READ_SERIAL 0xd033
> > +#define SPS30_START_FAN_CLEANING 0x5607
> > 
> >  enum {
> >  	PM1,
> > @@ -104,6 +104,7 @@ static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int
> size)
> >  		break;
> >  	case SPS30_STOP_MEAS:
> >  	case SPS30_RESET:
> > +	case SPS30_START_FAN_CLEANING:
> >  		ret = sps30_write_then_read(state, buf, 2, NULL, 0);
> >  		break;
> >  	case SPS30_READ_DATA_READY_FLAG:
> > @@ -275,7 +276,39 @@ static int sps30_read_raw(struct iio_dev *indio_dev,
> >  	return -EINVAL;
> >  }
> > 
> > +static ssize_t start_cleaning_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 sps30_state *state = iio_priv(indio_dev);
> > +	int val, ret;
> > +
> > +	if (kstrtoint(buf, 0, &val) || val != 1)
> > +		return -EINVAL;
> > +
> > +	mutex_lock(&state->lock);
> > +	ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0);
> > +	mutex_unlock(&state->lock);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return len;
> > +}
> > +
> > +static IIO_DEVICE_ATTR_WO(start_cleaning, 0);
> > +
> > +static struct attribute *sps30_attrs[] = {
> > +	&iio_dev_attr_start_cleaning.dev_attr.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group sps30_attr_group = {
> > +	.attrs = sps30_attrs,
> > +};
> > +
> >  static const struct iio_info sps30_info = {
> > +	.attrs = &sps30_attr_group,
> >  	.read_raw = sps30_read_raw,
> >  };
> > 
> > --
> > 2.20.1
> >