From: Liam Beguin <liambeguin@gmail.com>
To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org,
lars@metafoo.de, pmeerw@pmeerw.net
Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
devicetree@vger.kernel.org, robh+dt@kernel.org
Subject: [PATCH v6 10/13] iio: afe: rescale: add RTD temperature sensor support
Date: Tue, 20 Jul 2021 23:06:10 -0400 [thread overview]
Message-ID: <20210721030613.3105327-11-liambeguin@gmail.com> (raw)
In-Reply-To: <20210721030613.3105327-1-liambeguin@gmail.com>
From: Liam Beguin <lvb@xiphos.com>
An RTD (Resistance Temperature Detector) is a kind of temperature
sensor used to get a linear voltage to temperature reading within a
give range (usually 0 to 100 degrees Celsius). Common types of RTDs
include PT100, PT500, and PT1000.
Signed-off-by: Liam Beguin <lvb@xiphos.com>
---
drivers/iio/afe/iio-rescale.c | 48 +++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index 47cd4a6d9aca..6a1ecaad2da4 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -351,10 +351,52 @@ static int rescale_voltage_divider_props(struct device *dev,
return 0;
}
+static int rescale_temp_sense_rtd_props(struct device *dev,
+ struct rescale *rescale)
+{
+ u32 factor;
+ u32 alpha;
+ u32 iexc;
+ u32 tmp;
+ int ret;
+ u32 r0;
+
+ ret = device_property_read_u32(dev, "excitation-current-microamp",
+ &iexc);
+ if (ret) {
+ dev_err(dev, "failed to read excitation-current-microamp: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = device_property_read_u32(dev, "alpha-ppm-per-celsius", &alpha);
+ if (ret) {
+ dev_err(dev, "failed to read alpha-ppm-per-celsius: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = device_property_read_u32(dev, "r-naught-ohms", &r0);
+ if (ret) {
+ dev_err(dev, "failed to read r-naught-ohms: %d\n", ret);
+ return ret;
+ }
+
+ tmp = r0 * iexc * alpha / 1000000;
+ factor = gcd(tmp, 1000000);
+ rescale->numerator = 1000000 / factor;
+ rescale->denominator = tmp / factor;
+
+ rescale->offset = -1 * ((r0 * iexc) / 1000);
+
+ return 0;
+}
+
enum rescale_variant {
CURRENT_SENSE_AMPLIFIER,
CURRENT_SENSE_SHUNT,
VOLTAGE_DIVIDER,
+ TEMP_SENSE_RTD,
};
static const struct rescale_cfg rescale_cfg[] = {
@@ -370,6 +412,10 @@ static const struct rescale_cfg rescale_cfg[] = {
.type = IIO_VOLTAGE,
.props = rescale_voltage_divider_props,
},
+ [TEMP_SENSE_RTD] = {
+ .type = IIO_TEMP,
+ .props = rescale_temp_sense_rtd_props,
+ },
};
static const struct of_device_id rescale_match[] = {
@@ -379,6 +425,8 @@ 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-rtd",
+ .data = &rescale_cfg[TEMP_SENSE_RTD], },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rescale_match);
--
2.30.1.489.g328c10930387
next prev parent reply other threads:[~2021-07-21 3:14 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 3:06 [PATCH v6 00/13] iio: afe: add temperature rescaling support Liam Beguin
2021-07-21 3:06 ` [PATCH v6 01/13] iio: inkern: apply consumer scale on IIO_VAL_INT cases Liam Beguin
2021-07-21 3:06 ` [PATCH v6 02/13] iio: inkern: apply consumer scale when no channel scale is available Liam Beguin
2021-07-21 3:06 ` [PATCH v6 03/13] iio: inkern: make a best effort on offset calculation Liam Beguin
2021-07-21 3:06 ` [PATCH v6 04/13] iio: afe: rescale: expose scale processing function Liam Beguin
2021-07-21 3:06 ` [PATCH v6 05/13] iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support Liam Beguin
2021-07-23 21:16 ` Peter Rosin
2021-07-28 0:21 ` Liam Beguin
2021-07-28 7:19 ` Peter Rosin
2021-07-29 15:56 ` Liam Beguin
2021-07-30 6:49 ` Peter Rosin
2021-07-30 7:01 ` Peter Rosin
2021-07-30 20:01 ` Liam Beguin
2021-07-30 19:57 ` Liam Beguin
2021-07-31 17:47 ` Jonathan Cameron
2021-07-21 3:06 ` [PATCH v6 06/13] iio: afe: rescale: add offset support Liam Beguin
2021-07-21 3:06 ` [PATCH v6 07/13] iio: test: add basic tests for the iio-rescale driver Liam Beguin
2021-07-24 8:40 ` kernel test robot
2021-07-21 3:06 ` [PATCH v6 08/13] iio: afe: rescale: reduce risk of integer overflow Liam Beguin
2021-07-23 21:17 ` Peter Rosin
2021-07-28 0:07 ` Liam Beguin
2021-07-28 7:47 ` Peter Rosin
2021-07-29 16:02 ` Liam Beguin
2021-07-21 3:06 ` [PATCH v6 09/13] iio: afe: rescale: fix precision on fractional log scale Liam Beguin
2021-07-23 21:20 ` Peter Rosin
2021-07-28 0:26 ` Liam Beguin
2021-07-28 7:58 ` Peter Rosin
2021-07-29 16:19 ` Liam Beguin
2021-07-21 3:06 ` Liam Beguin [this message]
2021-07-21 3:06 ` [PATCH v6 11/13] iio: afe: rescale: add temperature transducers Liam Beguin
2021-07-21 3:06 ` [PATCH v6 12/13] dt-bindings: iio: afe: add bindings for temperature-sense-rtd Liam Beguin
2021-07-21 3:06 ` [PATCH v6 13/13] dt-bindings: iio: afe: add bindings for temperature transducers Liam Beguin
2021-07-23 22:59 ` Rob Herring
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210721030613.3105327-11-liambeguin@gmail.com \
--to=liambeguin@gmail.com \
--cc=devicetree@vger.kernel.org \
--cc=jic23@kernel.org \
--cc=lars@metafoo.de \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=peda@axentia.se \
--cc=pmeerw@pmeerw.net \
--cc=robh+dt@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).