[v7,PATCH 1/2] dt-bindings: iio: Add MCP9600 thermocouple EMF converter

[v7,PATCH 1/2] dt-bindings: iio: Add MCP9600 thermocouple EMF converter

[Andrew Hepp]

Add support for the MCP9600 thermocouple electromotive force converter. The sensor has  integrated cold junction compensation and a typical accuracy of 0.5 degrees Celsius. The driver supports a resolution of 0.0625 degrees Celsius.

Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP960X-Data-Sheet-20005426.pdf
Signed-off-by: Andrew Hepp <andrew.hepp@ahepp.dev>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
Changes for v7:
- none
Changes for v6:
- none
Changes for v5:
- remove "bindings" from subject
- change unevaluatedProperties to additionalProperties
Changes for v4:
- use descriptive names for open/short circuit interrupts
- remove vdd regulator description
- remove unused import
- use generic sensor name in example
- don't use literal style for doc description
Changes for v3:
- Added dt-bindings
---
 .../iio/temperature/microchip,mcp9600.yaml    | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml

diff --git a/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml b/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
new file mode 100644
index 000000000000..d2cafa38a544
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/temperature/microchip,mcp9600.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip MCP9600 thermocouple EMF converter
+
+maintainers:
+  - Andrew Hepp <andrew.hepp@ahepp.dev>
+
+description:
+  https://ww1.microchip.com/downloads/en/DeviceDoc/MCP960X-Data-Sheet-20005426.pdf
+
+properties:
+  compatible:
+    const: microchip,mcp9600
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 6
+
+  interrupt-names:
+    minItems: 1
+    maxItems: 6
+    items:
+      enum:
+        - open-circuit
+        - short-circuit
+        - alert1
+        - alert2
+        - alert3
+        - alert4
+
+  thermocouple-type:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Type of thermocouple (THERMOCOUPLE_TYPE_K if omitted).
+      Use defines in dt-bindings/iio/temperature/thermocouple.h.
+      Supported types are B, E, J, K, N, R, S, T.
+
+  vdd-supply: true
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/iio/temperature/thermocouple.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        temperature-sensor@60 {
+            compatible = "microchip,mcp9600";
+            reg = <0x60>;
+            interrupt-parent = <&gpio>;
+            interrupts = <25 IRQ_TYPE_EDGE_RISING>;
+            interrupt-names = "open-circuit";
+            thermocouple-type = <THERMOCOUPLE_TYPE_K>;
+            vdd-supply = <&vdd>;
+        };
+    };
-- 
2.34.1

[v7,PATCH 2/2] iio: temperature: Add MCP9600 thermocouple EMF converter

[Andrew Hepp]

Add support for the MCP9600 thermocouple electromotive force converter. The sensor has  integrated cold junction compensation and a typical accuracy of 0.5 degrees Celsius. The driver supports a resolution of 0.0625 degrees Celsius.

Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP960X-Data-Sheet-20005426.pdf
Signed-off-by: Andrew Hepp <andrew.hepp@ahepp.dev>
---
Changes for v7:
- remove unused buffer 
- remove unnecessary mutex
- remove unusable timestamps
- add error message if driver fails to read DEVICE_ID register
- update probe callback
Changes for v6:
- read_word_swapped instead of block_data
Changes for v5:
- remove "driver" from subject
Changes for v4:
- none
Changes for v3:
- none
Changes for v2:
- remove unused sysfs include
- remove unused scan fields from channel
- warn rather than fail when probing unknown device
- register device through devm
- clean up style and prints
---
 drivers/iio/temperature/Kconfig   |  10 +++
 drivers/iio/temperature/Makefile  |   1 +
 drivers/iio/temperature/mcp9600.c | 139 ++++++++++++++++++++++++++++++
 3 files changed, 150 insertions(+)
 create mode 100644 drivers/iio/temperature/mcp9600.c

diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index ed384f33e0c7..ea2ce364b2e9 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -158,4 +158,14 @@ config MAX31865
 	  This driver can also be build as a module. If so, the module
 	  will be called max31865.
 
+config MCP9600
+	tristate "MCP9600 thermocouple EMF converter"
+	depends on I2C
+	help
+	  If you say yes here you get support for MCP9600
+	  thermocouple EMF converter connected via I2C.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called mcp9600.
+
 endmenu
diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
index dfec8c6d3019..9330d4a39598 100644
--- a/drivers/iio/temperature/Makefile
+++ b/drivers/iio/temperature/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o
 obj-$(CONFIG_MAX30208) += max30208.o
 obj-$(CONFIG_MAX31856) += max31856.o
 obj-$(CONFIG_MAX31865) += max31865.o
+obj-$(CONFIG_MCP9600) += mcp9600.o
 obj-$(CONFIG_MLX90614) += mlx90614.o
 obj-$(CONFIG_MLX90632) += mlx90632.o
 obj-$(CONFIG_TMP006) += tmp006.o
diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
new file mode 100644
index 000000000000..46845804292b
--- /dev/null
+++ b/drivers/iio/temperature/mcp9600.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * mcp9600.c - Support for Microchip MCP9600 thermocouple EMF converter
+ *
+ * Copyright (c) 2022 Andrew Hepp
+ * Author: <andrew.hepp@ahepp.dev>
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+
+/* MCP9600 registers */
+#define MCP9600_HOT_JUNCTION 0x0
+#define MCP9600_COLD_JUNCTION 0x2
+#define MCP9600_DEVICE_ID 0x20
+
+/* MCP9600 device id value */
+#define MCP9600_DEVICE_ID_MCP9600 0x40
+
+static const struct iio_chan_spec mcp9600_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.address = MCP9600_HOT_JUNCTION,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+	},
+	{
+		.type = IIO_TEMP,
+		.address = MCP9600_COLD_JUNCTION,
+		.channel2 = IIO_MOD_TEMP_AMBIENT,
+		.modified = 1,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+struct mcp9600_data {
+	struct i2c_client *client;
+};
+
+static int mcp9600_read(struct mcp9600_data *data,
+			struct iio_chan_spec const *chan, int *val)
+{
+	int ret;
+
+	ret = i2c_smbus_read_word_swapped(data->client, chan->address);
+
+	if (ret < 0)
+		return ret;
+	*val = ret;
+
+	return 0;
+}
+
+static int mcp9600_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct mcp9600_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = mcp9600_read(data, chan, val);
+		if (ret)
+			return ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 62;
+		*val2 = 500000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info mcp9600_info = {
+	.read_raw = mcp9600_read_raw,
+};
+
+static int mcp9600_probe(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev;
+	struct mcp9600_data *data;
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret, "Failed to read device ID\n");
+	if (ret != MCP9600_DEVICE_ID_MCP9600)
+		dev_warn(&client->dev, "Expected ID %x, got %x\n",
+				MCP9600_DEVICE_ID_MCP9600, ret);
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+
+	indio_dev->info = &mcp9600_info;
+	indio_dev->name = "mcp9600";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = mcp9600_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mcp9600_channels);
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id mcp9600_id[] = {
+	{ "mcp9600" },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, mcp9600_id);
+
+static const struct of_device_id mcp9600_of_match[] = {
+	{ .compatible = "microchip,mcp9600" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mcp9600_of_match);
+
+static struct i2c_driver mcp9600_driver = {
+	.driver = {
+		.name = "mcp9600",
+		.of_match_table = mcp9600_of_match,
+	},
+	.probe = mcp9600_probe,
+	.id_table = mcp9600_id
+};
+module_i2c_driver(mcp9600_driver);
+
+MODULE_AUTHOR("Andrew Hepp <andrew.hepp@ahepp.dev>");
+MODULE_DESCRIPTION("Microchip MCP9600 thermocouple EMF converter driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1

Re: [v7,PATCH 1/2] dt-bindings: iio: Add MCP9600 thermocouple EMF converter

[Jonathan Cameron]

On Wed, 25 Oct 2023 16:31:52 -0700
Andrew Hepp <andrew.hepp@ahepp.dev> wrote:

> Add support for the MCP9600 thermocouple electromotive force converter. The sensor has  integrated cold junction compensation and a typical accuracy of 0.5 degrees Celsius. The driver supports a resolution of 0.0625 degrees Celsius.
> 
> Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP960X-Data-Sheet-20005426.pdf
> Signed-off-by: Andrew Hepp <andrew.hepp@ahepp.dev>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Hi Andrew,

Series applied to the togreg branch of iio.git.
I will be rebasing that tree once rc1 is out in a few weeks time
so in the meantime I will only push this out as testing for 0-day to take
a look at it and see if we missed anything,

Thanks,

Jonathan

> ---
> Changes for v7:
> - none
> Changes for v6:
> - none
> Changes for v5:
> - remove "bindings" from subject
> - change unevaluatedProperties to additionalProperties
> Changes for v4:
> - use descriptive names for open/short circuit interrupts
> - remove vdd regulator description
> - remove unused import
> - use generic sensor name in example
> - don't use literal style for doc description
> Changes for v3:
> - Added dt-bindings
> ---
>  .../iio/temperature/microchip,mcp9600.yaml    | 70 +++++++++++++++++++
>  1 file changed, 70 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml b/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
> new file mode 100644
> index 000000000000..d2cafa38a544
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
> @@ -0,0 +1,70 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/temperature/microchip,mcp9600.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip MCP9600 thermocouple EMF converter
> +
> +maintainers:
> +  - Andrew Hepp <andrew.hepp@ahepp.dev>
> +
> +description:
> +  https://ww1.microchip.com/downloads/en/DeviceDoc/MCP960X-Data-Sheet-20005426.pdf
> +
> +properties:
> +  compatible:
> +    const: microchip,mcp9600
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    maxItems: 6
> +
> +  interrupt-names:
> +    minItems: 1
> +    maxItems: 6
> +    items:
> +      enum:
> +        - open-circuit
> +        - short-circuit
> +        - alert1
> +        - alert2
> +        - alert3
> +        - alert4
> +
> +  thermocouple-type:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Type of thermocouple (THERMOCOUPLE_TYPE_K if omitted).
> +      Use defines in dt-bindings/iio/temperature/thermocouple.h.
> +      Supported types are B, E, J, K, N, R, S, T.
> +
> +  vdd-supply: true
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/iio/temperature/thermocouple.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        temperature-sensor@60 {
> +            compatible = "microchip,mcp9600";
> +            reg = <0x60>;
> +            interrupt-parent = <&gpio>;
> +            interrupts = <25 IRQ_TYPE_EDGE_RISING>;
> +            interrupt-names = "open-circuit";
> +            thermocouple-type = <THERMOCOUPLE_TYPE_K>;
> +            vdd-supply = <&vdd>;
> +        };
> +    };