On Sat, 23 Nov 2019 12:40:19 +0000
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On Wed, 20 Nov 2019 15:47:54 +0100
> Andrea Merello <andrea.merello@xxxxxxxxx> wrote:
>
> > The sensor support various thermocouple types (e.g. J, K, N, ...). The
> > driver allows to configure this parameter using a DT property.
> >
> > This is useful when i.e. the thermocouple is physically tied to the sensor
> > and it is usually not removed, or when it is at least known in advance
> > which sensor will be connected to the circuit.
> >
> > However, if the user can randomly connect any kind of thermocouples (i.e.
> > the device exposes a connector, and the user is free to connect its own
> > sensors), it would be more appropriate to provide a mechanism to
> > dynamically switch from one thermocouple type to another. This can be i.e.
> > handled in userspace by a GUI, a configuration file or a program that
> > detects the thermocouple type by reading a GPIO, or a eeprom on the probe,
> > or whatever.
> >
> > This patch adds a IIO attribute that can be used to override, at run-time,
> > the DT-provided setting (which serves as default).
> >
> > Cc: Hartmut Knaack <knaack.h@xxxxxx>
> > Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
> > Cc: Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx>
> > Cc: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > Cc: Patrick Havelange <patrick.havelange@xxxxxxxxxxxxx>
> > Cc: Matt Weber <matthew.weber@xxxxxxxxxxxxxxxxxxx>
> > Cc: Matt Ranostay <matt.ranostay@xxxxxxxxxxxx>
> > Cc: Chuhong Yuan <hslester96@xxxxxxxxx>
> > Cc: Daniel Gomez <dagmcr@xxxxxxxxx>
> > Cc: linux-iio@xxxxxxxxxxxxxxx
> > Signed-off-by: Andrea Merello <andrea.merello@xxxxxxxxx>
> Applied to the togreg branch of iio.git and pushed out as testing for
> the autobuilders to play with it.
>
One immediate tweak from my own build tests. Missing static on the
types array. I've fixed up.
Jonathan
> thanks,
>
> Jonathan
>
> > ---
> > drivers/iio/temperature/max31856.c | 41 +++++++++++++++++++++++++++++-
> > 1 file changed, 40 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/temperature/max31856.c b/drivers/iio/temperature/max31856.c
> > index 8457ca9ae326..4952e89c00bb 100644
> > --- a/drivers/iio/temperature/max31856.c
> > +++ b/drivers/iio/temperature/max31856.c
> > @@ -6,6 +6,7 @@
> > * Copyright (C) 2018-2019 Rockwell Collins
> > */
> >
> > +#include <linux/ctype.h>
> > #include <linux/module.h>
> > #include <linux/init.h>
> > #include <linux/err.h>
> > @@ -53,7 +54,8 @@ static const struct iio_chan_spec max31856_channels[] = {
> > { /* Thermocouple Temperature */
> > .type = IIO_TEMP,
> > .info_mask_separate =
> > - BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> > + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) |
> > + BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE),
> > .info_mask_shared_by_type =
> > BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO)
> > },
> > @@ -75,6 +77,10 @@ struct max31856_data {
> > int averaging;
> > };
> >
> > +const char max31856_tc_types[] = {
> > + 'B', 'E', 'J', 'K', 'N', 'R', 'S', 'T'
> > +};
> > +
> > static int max31856_read(struct max31856_data *data, u8 reg,
> > u8 val[], unsigned int read_size)
> > {
> > @@ -232,6 +238,9 @@ static int max31856_read_raw(struct iio_dev *indio_dev,
> > case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> > *val = 1 << data->averaging;
> > return IIO_VAL_INT;
> > + case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
> > + *val = max31856_tc_types[data->thermocouple_type];
> > + return IIO_VAL_CHAR;
> > default:
> > ret = -EINVAL;
> > break;
> > @@ -240,6 +249,18 @@ static int max31856_read_raw(struct iio_dev *indio_dev,
> > return ret;
> > }
> >
> > +static int max31856_write_raw_get_fmt(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + long mask)
> > +{
> > + switch (mask) {
> > + case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
> > + return IIO_VAL_CHAR;
> > + default:
> > + return IIO_VAL_INT;
> > + }
> > +}
> > +
> > static int max31856_write_raw(struct iio_dev *indio_dev,
> > struct iio_chan_spec const *chan,
> > int val, int val2, long mask)
> > @@ -259,7 +280,24 @@ static int max31856_write_raw(struct iio_dev *indio_dev,
> > data->averaging = msb;
> > max31856_init(data);
> > break;
> > + case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
> > + {
> > + int tc_type = -1;
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(max31856_tc_types); i++) {
> > + if (max31856_tc_types[i] == toupper(val)) {
> > + tc_type = i;
> > + break;
> > + }
> > + }
> > + if (tc_type < 0)
> > + return -EINVAL;
> >
> > + data->thermocouple_type = tc_type;
> > + max31856_init(data);
> > + break;
> > + }
> > default:
> > return -EINVAL;
> > }
> > @@ -356,6 +394,7 @@ static const struct attribute_group max31856_group = {
> > static const struct iio_info max31856_info = {
> > .read_raw = max31856_read_raw,
> > .write_raw = max31856_write_raw,
> > + .write_raw_get_fmt = max31856_write_raw_get_fmt,
> > .attrs = &max31856_group,
> > };
> >
>
