| Message ID | 20210607144718.1724413-8-liambeguin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | iio: afe: add temperature rescaling support | expand |
Hi! On 2021-06-07 16:47, Liam Beguin wrote: > From: Liam Beguin <lvb@xiphos.com> > > Add support for linear temperature sensors. This is meant to work with > different kinds of analog front ends such as RTDs (resistance > thermometers), voltage IC sensors (like the LTC2997), and current IC > sensors (see AD590). > > Signed-off-by: Liam Beguin <lvb@xiphos.com> > --- > drivers/iio/afe/iio-rescale.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c > index 3d445c76dbb2..9e3c7e2b47cd 100644 > --- a/drivers/iio/afe/iio-rescale.c > +++ b/drivers/iio/afe/iio-rescale.c > @@ -272,10 +272,29 @@ static int rescale_voltage_divider_props(struct device *dev, > return 0; > } > > +static int rescale_temp_sense_amplifier_props(struct device *dev, > + struct rescale *rescale) > +{ > + s32 gain_mult = 1; > + s32 gain_div = 1; > + s32 offset = 0; > + > + device_property_read_u32(dev, "sense-gain-mult", &gain_mult); > + device_property_read_u32(dev, "sense-gain-div", &gain_div); > + device_property_read_u32(dev, "sense-offset-millicelsius", &offset); > + > + rescale->numerator = gain_mult; > + rescale->denominator = gain_div; > + rescale->offset = offset * gain_div / gain_mult; This should be done with 64-bit math, no? After all, An offset of approximately 300000 is not unexpected, and that's quite big to scale with 32-bit math. Cheers, Peter > + > + return 0; > +} > + > enum rescale_variant { > CURRENT_SENSE_AMPLIFIER, > CURRENT_SENSE_SHUNT, > VOLTAGE_DIVIDER, > + TEMP_SENSE_AMPLIFIER, > }; > > static const struct rescale_cfg rescale_cfg[] = { > @@ -291,6 +310,10 @@ static const struct rescale_cfg rescale_cfg[] = { > .type = IIO_VOLTAGE, > .props = rescale_voltage_divider_props, > }, > + [TEMP_SENSE_AMPLIFIER] = { > + .type = IIO_TEMP, > + .props = rescale_temp_sense_amplifier_props, > + }, > }; > > static const struct of_device_id rescale_match[] = { > @@ -300,6 +323,8 @@ static const struct of_device_id rescale_match[] = { > .data = &rescale_cfg[CURRENT_SENSE_SHUNT], }, > { .compatible = "voltage-divider", > .data = &rescale_cfg[VOLTAGE_DIVIDER], }, > + { .compatible = "temperature-sense-amplifier", > + .data = &rescale_cfg[TEMP_SENSE_AMPLIFIER], }, > { /* sentinel */ } > }; > MODULE_DEVICE_TABLE(of, rescale_match); >
diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 3d445c76dbb2..9e3c7e2b47cd 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -272,10 +272,29 @@ static int rescale_voltage_divider_props(struct device *dev, return 0; } +static int rescale_temp_sense_amplifier_props(struct device *dev, + struct rescale *rescale) +{ + s32 gain_mult = 1; + s32 gain_div = 1; + s32 offset = 0; + + device_property_read_u32(dev, "sense-gain-mult", &gain_mult); + device_property_read_u32(dev, "sense-gain-div", &gain_div); + device_property_read_u32(dev, "sense-offset-millicelsius", &offset); + + rescale->numerator = gain_mult; + rescale->denominator = gain_div; + rescale->offset = offset * gain_div / gain_mult; + + return 0; +} + enum rescale_variant { CURRENT_SENSE_AMPLIFIER, CURRENT_SENSE_SHUNT, VOLTAGE_DIVIDER, + TEMP_SENSE_AMPLIFIER, }; static const struct rescale_cfg rescale_cfg[] = { @@ -291,6 +310,10 @@ static const struct rescale_cfg rescale_cfg[] = { .type = IIO_VOLTAGE, .props = rescale_voltage_divider_props, }, + [TEMP_SENSE_AMPLIFIER] = { + .type = IIO_TEMP, + .props = rescale_temp_sense_amplifier_props, + }, }; static const struct of_device_id rescale_match[] = { @@ -300,6 +323,8 @@ static const struct of_device_id rescale_match[] = { .data = &rescale_cfg[CURRENT_SENSE_SHUNT], }, { .compatible = "voltage-divider", .data = &rescale_cfg[VOLTAGE_DIVIDER], }, + { .compatible = "temperature-sense-amplifier", + .data = &rescale_cfg[TEMP_SENSE_AMPLIFIER], }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, rescale_match);