| Message ID | 20191120144756.28424-2-andrea.merello@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: max31856: provide more configuration options | expand |
On Wed, 20 Nov 2019 15:47:48 +0100 Andrea Merello <andrea.merello@gmail.com> wrote: > This sensor has an embedded notch filter for reducing interferences caused > by the power mains. This filter can be tuned to reject either 50Hz or 60Hz > (and harmonics). > > Currently the said setting is left alone (the sensor defaults to 60Hz). > This patch introduces a IIO attribute that allows the user to set the said > filter to the desired frequency. > > NOTE: this has been intentionally not tied to any DT property to allow > the configuration of this setting from userspace, e.g. with a GUI or by > reading a configuration file, or maybe reading a GPIO tied to a physical > switch or accessing some device that can autodetect the line frequency. > > Cc: Hartmut Knaack <knaack.h@gmx.de> > Cc: Lars-Peter Clausen <lars@metafoo.de> > Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net> > Cc: Colin Ian King <colin.king@canonical.com> > Cc: Patrick Havelange <patrick.havelange@essensium.com> > Cc: Matt Weber <matthew.weber@rockwellcollins.com> > Cc: Matt Ranostay <matt.ranostay@konsulko.com> > Cc: Chuhong Yuan <hslester96@gmail.com> > Cc: Daniel Gomez <dagmcr@gmail.com> > Cc: linux-iio@vger.kernel.org > Signed-off-by: Andrea Merello <andrea.merello@gmail.com> > Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com> Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > drivers/iio/temperature/max31856.c | 50 ++++++++++++++++++++++++++++++ > 1 file changed, 50 insertions(+) > > diff --git a/drivers/iio/temperature/max31856.c b/drivers/iio/temperature/max31856.c > index 73ed550e3fc9..d97ba9ee1598 100644 > --- a/drivers/iio/temperature/max31856.c > +++ b/drivers/iio/temperature/max31856.c > @@ -23,6 +23,7 @@ > #define MAX31856_CR0_1SHOT BIT(6) > #define MAX31856_CR0_OCFAULT BIT(4) > #define MAX31856_CR0_OCFAULT_MASK GENMASK(5, 4) > +#define MAX31856_CR0_FILTER_50HZ BIT(0) > #define MAX31856_TC_TYPE_MASK GENMASK(3, 0) > #define MAX31856_FAULT_OVUV BIT(1) > #define MAX31856_FAULT_OPEN BIT(0) > @@ -63,6 +64,7 @@ static const struct iio_chan_spec max31856_channels[] = { > struct max31856_data { > struct spi_device *spi; > u32 thermocouple_type; > + bool filter_50hz; > }; > > static int max31856_read(struct max31856_data *data, u8 reg, > @@ -123,6 +125,11 @@ static int max31856_init(struct max31856_data *data) > reg_cr0_val &= ~MAX31856_CR0_1SHOT; > reg_cr0_val |= MAX31856_CR0_AUTOCONVERT; > > + if (data->filter_50hz) > + reg_cr0_val |= MAX31856_CR0_FILTER_50HZ; > + else > + reg_cr0_val &= ~MAX31856_CR0_FILTER_50HZ; > + > return max31856_write(data, MAX31856_CR0_REG, reg_cr0_val); > } > > @@ -249,12 +256,54 @@ static ssize_t show_fault_oc(struct device *dev, > return show_fault(dev, MAX31856_FAULT_OPEN, buf); > } > > +static ssize_t show_filter(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct iio_dev *indio_dev = dev_to_iio_dev(dev); > + struct max31856_data *data = iio_priv(indio_dev); > + > + return sprintf(buf, "%d\n", data->filter_50hz ? 50 : 60); > +} > + > +static ssize_t set_filter(struct device *dev, > + struct device_attribute *attr, > + const char *buf, > + size_t len) > +{ > + struct iio_dev *indio_dev = dev_to_iio_dev(dev); > + struct max31856_data *data = iio_priv(indio_dev); > + unsigned int freq; > + int ret; > + > + ret = kstrtouint(buf, 10, &freq); > + if (ret) > + return ret; > + > + switch (freq) { > + case 50: > + data->filter_50hz = true; > + break; > + case 60: > + data->filter_50hz = false; > + break; > + default: > + return -EINVAL; > + } > + > + max31856_init(data); > + return len; > +} > + > static IIO_DEVICE_ATTR(fault_ovuv, 0444, show_fault_ovuv, NULL, 0); > static IIO_DEVICE_ATTR(fault_oc, 0444, show_fault_oc, NULL, 0); > +static IIO_DEVICE_ATTR(in_temp_filter_notch_center_frequency, 0644, > + show_filter, set_filter, 0); > > static struct attribute *max31856_attributes[] = { > &iio_dev_attr_fault_ovuv.dev_attr.attr, > &iio_dev_attr_fault_oc.dev_attr.attr, > + &iio_dev_attr_in_temp_filter_notch_center_frequency.dev_attr.attr, > NULL, > }; > > @@ -280,6 +329,7 @@ static int max31856_probe(struct spi_device *spi) > > data = iio_priv(indio_dev); > data->spi = spi; > + data->filter_50hz = false; > > spi_set_drvdata(spi, indio_dev); >
diff --git a/drivers/iio/temperature/max31856.c b/drivers/iio/temperature/max31856.c index 73ed550e3fc9..d97ba9ee1598 100644 --- a/drivers/iio/temperature/max31856.c +++ b/drivers/iio/temperature/max31856.c @@ -23,6 +23,7 @@ #define MAX31856_CR0_1SHOT BIT(6) #define MAX31856_CR0_OCFAULT BIT(4) #define MAX31856_CR0_OCFAULT_MASK GENMASK(5, 4) +#define MAX31856_CR0_FILTER_50HZ BIT(0) #define MAX31856_TC_TYPE_MASK GENMASK(3, 0) #define MAX31856_FAULT_OVUV BIT(1) #define MAX31856_FAULT_OPEN BIT(0) @@ -63,6 +64,7 @@ static const struct iio_chan_spec max31856_channels[] = { struct max31856_data { struct spi_device *spi; u32 thermocouple_type; + bool filter_50hz; }; static int max31856_read(struct max31856_data *data, u8 reg, @@ -123,6 +125,11 @@ static int max31856_init(struct max31856_data *data) reg_cr0_val &= ~MAX31856_CR0_1SHOT; reg_cr0_val |= MAX31856_CR0_AUTOCONVERT; + if (data->filter_50hz) + reg_cr0_val |= MAX31856_CR0_FILTER_50HZ; + else + reg_cr0_val &= ~MAX31856_CR0_FILTER_50HZ; + return max31856_write(data, MAX31856_CR0_REG, reg_cr0_val); } @@ -249,12 +256,54 @@ static ssize_t show_fault_oc(struct device *dev, return show_fault(dev, MAX31856_FAULT_OPEN, buf); } +static ssize_t show_filter(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct max31856_data *data = iio_priv(indio_dev); + + return sprintf(buf, "%d\n", data->filter_50hz ? 50 : 60); +} + +static ssize_t set_filter(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct max31856_data *data = iio_priv(indio_dev); + unsigned int freq; + int ret; + + ret = kstrtouint(buf, 10, &freq); + if (ret) + return ret; + + switch (freq) { + case 50: + data->filter_50hz = true; + break; + case 60: + data->filter_50hz = false; + break; + default: + return -EINVAL; + } + + max31856_init(data); + return len; +} + static IIO_DEVICE_ATTR(fault_ovuv, 0444, show_fault_ovuv, NULL, 0); static IIO_DEVICE_ATTR(fault_oc, 0444, show_fault_oc, NULL, 0); +static IIO_DEVICE_ATTR(in_temp_filter_notch_center_frequency, 0644, + show_filter, set_filter, 0); static struct attribute *max31856_attributes[] = { &iio_dev_attr_fault_ovuv.dev_attr.attr, &iio_dev_attr_fault_oc.dev_attr.attr, + &iio_dev_attr_in_temp_filter_notch_center_frequency.dev_attr.attr, NULL, }; @@ -280,6 +329,7 @@ static int max31856_probe(struct spi_device *spi) data = iio_priv(indio_dev); data->spi = spi; + data->filter_50hz = false; spi_set_drvdata(spi, indio_dev);