[PATCH v4 0/5] iio: mcp9600: Features and improvements

[PATCH v4 0/5] iio: mcp9600: Features and improvements

[Ben Collins]

ChangeLog:
v3 -> v4:
  - Based on feedback from David Lechner <dlechner@baylibre.com>
    * Allow fallback compatible in dt-bindings for mcp9601.
  - Based on feedback from Jonathan Cameron <jic23@kernel.org>
    * Be explicit in patch description for fixed width changes.
    * Check chip_info for NULL to quiet warnings from kernel-test-robot
    * Remove "and similar" for long description of MCP9600.
  - Based on lots of feedback, use frequency values for IIR, and use
    filter_type[none, ema] to enable or disable.
  - Set default 3 for thermocouple in dt-binding
  - Rework open/short circuit in dt-bindings

v2 -> v3:
  - Improve changelogs in each patch
  - Based on feedback from Andy Shevchenko <andy.shevchenko@gmail.com>
    * Set register offsets to fixed width
    * Fix typos
    * Future-proof Kconfig changes
    * Convert to using chip_info paradigm
    * Verbiage: dt -> firmware description
    * Use proper specifiers and drop castings
    * Fix register offset to be fixed-width
    * u8 for cfg var
    * Fix % type for u32 to be %u
    * Make blank lines consistent between case statements
    * FIELD_PREP -> FIELD_MODIFY
    * Remove explicit setting of 0 value in filter_level
  - Based on feedback from David Lechner <dlechner@baylibre.com>
    * Rework IIR values exposed to sysfs. Using the ratios, there was no
      way to represent "disabled" (i.e. infinity). Based on the bmp280
      driver I went with using the power coefficients (e.g. 1, 2, 4, 8,
      ...) where 1 is disabled (n=0).

v1 -> v2:
  - Break into individual patches

v1:
  - Initial patch to enable IIR and thermocouple-type
  - Recognize mcp9601

Ben Collins (5):
  dt-bindings: iio: mcp9600: Add compatible for microchip,mcp9601
  iio: mcp9600: White space and fixed width cleanup
  iio: mcp9600: Recognize chip id for mcp9601
  iio: mcp9600: Add support for thermocouple-type
  iio: mcp9600: Add support for IIR filter

 .../iio/temperature/microchip,mcp9600.yaml    |  25 +-
 drivers/iio/temperature/Kconfig               |   8 +-
 drivers/iio/temperature/mcp9600.c             | 220 ++++++++++++++++--
 3 files changed, 231 insertions(+), 22 deletions(-)

-- 
2.39.5

[PATCH v4 1/5] dt-bindings: iio: mcp9600: Add microchip,mcp9601 and add constraints

[Ben Collins]

The mcp9600 driver supports the mcp9601 chip, but complains about not
recognizing the device id on probe. A separate patch...

	iio: mcp9600: Recognize chip id for mcp9601

...addresses this. This patch updates the dt-bindings for this chip to
reflect the change to allow explicitly setting microchip,mcp9601 as
the expected chip type.

The mcp9601 also supports features not found on the mcp9600, so this
will also allow the driver to differentiate the support of these
features.

In addition, the thermocouple-type needs a default of 3 (k-type). The
driver doesn't support this, yet. A later patch in this series adds it:

	iio: mcp9600: Add support for thermocouple-type

Lastly, the open/short circuit functionality is dependent on mcp9601
chipsset. Add constraints for this and a new property, microchip,vsense,
enables this feature since it depends on the chip being wired
properly.

Passed dt_binding_check.

Signed-off-by: Ben Collins <bcollins@watter.com>
---
 .../iio/temperature/microchip,mcp9600.yaml    | 69 +++++++++++++++----
 1 file changed, 56 insertions(+), 13 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml b/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
index d2cafa38a5442..1caeb6526fd20 100644
--- a/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
+++ b/Documentation/devicetree/bindings/iio/temperature/microchip,mcp9600.yaml
@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/iio/temperature/microchip,mcp9600.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Microchip MCP9600 thermocouple EMF converter
+title: Microchip MCP9600 and similar thermocouple EMF converters
 
 maintainers:
   - Andrew Hepp <andrew.hepp@ahepp.dev>
@@ -14,29 +14,30 @@ description:
 
 properties:
   compatible:
-    const: microchip,mcp9600
+    oneOf:
+      - const: microchip,mcp9600
+      - items:
+          - const: microchip,mcp9600
+          - const: microchip,mcp9601
 
   reg:
     maxItems: 1
 
   interrupts:
     minItems: 1
-    maxItems: 6
+    maxItems: 4
 
   interrupt-names:
     minItems: 1
-    maxItems: 6
     items:
-      enum:
-        - open-circuit
-        - short-circuit
-        - alert1
-        - alert2
-        - alert3
-        - alert4
+      - const: alert1
+      - const: alert2
+      - const: alert3
+      - const: alert4
 
   thermocouple-type:
     $ref: /schemas/types.yaml#/definitions/uint32
+    default: 3
     description:
       Type of thermocouple (THERMOCOUPLE_TYPE_K if omitted).
       Use defines in dt-bindings/iio/temperature/thermocouple.h.
@@ -44,6 +45,33 @@ properties:
 
   vdd-supply: true
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: microchip,mcp9601
+    then:
+      properties:
+        interrupts:
+          minItems: 1
+          maxItems: 6
+        interrupt-names:
+          items:
+            - const: alert1
+            - const: alert2
+            - const: alert3
+            - const: alert4
+            - const: open-circuit
+            - const: short-circuit
+        microchip,vsense:
+          default: false
+          description:
+            This flag indicates that the chip has been wired with VSENSE to
+            enable open and short circuit detect. By default, this is false,
+            since there's no way to detect that the chip is wired correctly.
+          type: boolean
+
 required:
   - compatible
   - reg
@@ -62,9 +90,24 @@ examples:
             compatible = "microchip,mcp9600";
             reg = <0x60>;
             interrupt-parent = <&gpio>;
-            interrupts = <25 IRQ_TYPE_EDGE_RISING>;
-            interrupt-names = "open-circuit";
+            interrupts = <25 IRQ_TYPE_EDGE_RISIN>;
+            interrupt-names = "alert1";
             thermocouple-type = <THERMOCOUPLE_TYPE_K>;
             vdd-supply = <&vdd>;
         };
     };
+  - |
+    #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,mcp9601", "microchip,mcp9600";
+            microchip,vsense;
+            reg = <0x62>;
+            interrupt-parent = <&gpio>;
+            vdd-supply = <&vdd>;
+        };
+    };
-- 
2.39.5

[PATCH v4 2/5] iio: mcp9600: White space and fixed width cleanup

[Ben Collins]

Make tabs consistent for register definitions and also fix width
to byte size.

Signed-off-by: Ben Collins <bcollins@watter.com>
---
 drivers/iio/temperature/mcp9600.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
index 6e9108d5cf75f..40906bb200ec9 100644
--- a/drivers/iio/temperature/mcp9600.c
+++ b/drivers/iio/temperature/mcp9600.c
@@ -23,25 +23,25 @@
 #include <linux/iio/iio.h>
 
 /* MCP9600 registers */
-#define MCP9600_HOT_JUNCTION 0x0
-#define MCP9600_COLD_JUNCTION 0x2
-#define MCP9600_STATUS			0x4
+#define MCP9600_HOT_JUNCTION		0x00
+#define MCP9600_COLD_JUNCTION		0x02
+#define MCP9600_STATUS			0x04
 #define MCP9600_STATUS_ALERT(x)		BIT(x)
-#define MCP9600_ALERT_CFG1		0x8
+#define MCP9600_ALERT_CFG1		0x08
 #define MCP9600_ALERT_CFG(x)		(MCP9600_ALERT_CFG1 + (x - 1))
 #define MCP9600_ALERT_CFG_ENABLE	BIT(0)
 #define MCP9600_ALERT_CFG_ACTIVE_HIGH	BIT(2)
 #define MCP9600_ALERT_CFG_FALLING	BIT(3)
 #define MCP9600_ALERT_CFG_COLD_JUNCTION	BIT(4)
-#define MCP9600_ALERT_HYSTERESIS1	0xc
+#define MCP9600_ALERT_HYSTERESIS1	0x0c
 #define MCP9600_ALERT_HYSTERESIS(x)	(MCP9600_ALERT_HYSTERESIS1 + (x - 1))
 #define MCP9600_ALERT_LIMIT1		0x10
 #define MCP9600_ALERT_LIMIT(x)		(MCP9600_ALERT_LIMIT1 + (x - 1))
 #define MCP9600_ALERT_LIMIT_MASK	GENMASK(15, 2)
-#define MCP9600_DEVICE_ID 0x20
+#define MCP9600_DEVICE_ID		0x20
 
 /* MCP9600 device id value */
-#define MCP9600_DEVICE_ID_MCP9600 0x40
+#define MCP9600_DEVICE_ID_MCP9600	0x40
 
 #define MCP9600_ALERT_COUNT		4
 
-- 
2.39.5

[PATCH v4 3/5] iio: mcp9600: Recognize chip id for mcp9601

[Ben Collins]

The current driver works with mcp9601, but emits a warning because it
does not recognize the chip id.

MCP9601 is a superset of MCP9600. The drivers works without changes
on this chipset.

However, the 9601 chip supports open/closed-circuit detection if wired
properly, so we'll need to be able to differentiate between them.

Signed-off-by: Ben Collins <bcollins@watter.com>
---
 drivers/iio/temperature/Kconfig   |  8 +++--
 drivers/iio/temperature/mcp9600.c | 55 +++++++++++++++++++++++++------
 2 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index 1244d8e17d504..9328b2250aced 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -173,11 +173,13 @@ config MAX31865
 	  will be called max31865.
 
 config MCP9600
-	tristate "MCP9600 thermocouple EMF converter"
+	tristate "MCP9600 and similar thermocouple EMF converters"
 	depends on I2C
 	help
-	  If you say yes here you get support for MCP9600
-	  thermocouple EMF converter connected via I2C.
+	  If you say yes here you get support for...
+	  - MCP9600
+	  - MCP9601
+	  ...thermocouple EMF converters connected via I2C.
 
 	  This driver can also be built as a module. If so, the module
 	  will be called mcp9600.
diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
index 40906bb200ec9..54de38a39292e 100644
--- a/drivers/iio/temperature/mcp9600.c
+++ b/drivers/iio/temperature/mcp9600.c
@@ -42,6 +42,7 @@
 
 /* MCP9600 device id value */
 #define MCP9600_DEVICE_ID_MCP9600	0x40
+#define MCP9600_DEVICE_ID_MCP9601	0x41
 
 #define MCP9600_ALERT_COUNT		4
 
@@ -123,6 +124,11 @@ static const struct iio_chan_spec mcp9600_channels[][2] = {
 	MCP9600_CHANNELS(2, 0, 2, 0), /* Alerts: 1 2 3 4 */
 };
 
+struct mcp_chip_info {
+	u8 chip_id;
+	const char *chip_name;
+};
+
 struct mcp9600_data {
 	struct i2c_client *client;
 };
@@ -416,16 +422,33 @@ static int mcp9600_probe_alerts(struct iio_dev *indio_dev)
 
 static int mcp9600_probe(struct i2c_client *client)
 {
+	const struct mcp_chip_info *chip_info = i2c_get_match_data(client);
 	struct iio_dev *indio_dev;
 	struct mcp9600_data *data;
-	int ret, ch_sel;
+	int ch_sel, dev_id, ret;
+
+	if (chip_info == NULL)
+		return dev_err_probe(&client->dev, -EINVAL,
+                                     "No chip-info found for device\n");
+
+	dev_id = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);
+	if (dev_id < 0)
+		return dev_err_probe(&client->dev, dev_id,
+				     "Failed to read device ID\n");
+
+	switch (dev_id) {
+	case MCP9600_DEVICE_ID_MCP9600:
+	case MCP9600_DEVICE_ID_MCP9601:
+		if (dev_id != chip_info->chip_id)
+			dev_warn(&client->dev,
+				 "Expected id %02x, but device responded with %02x\n",
+				 chip_info->chip_id, dev_id);
+		break;
 
-	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);
+	default:
+		dev_warn(&client->dev, "Unknown id %x, using %x\n", dev_id,
+			 chip_info->chip_id);
+	}
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
@@ -439,7 +462,7 @@ static int mcp9600_probe(struct i2c_client *client)
 		return ch_sel;
 
 	indio_dev->info = &mcp9600_info;
-	indio_dev->name = "mcp9600";
+	indio_dev->name = chip_info->chip_name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = mcp9600_channels[ch_sel];
 	indio_dev->num_channels = ARRAY_SIZE(mcp9600_channels[ch_sel]);
@@ -447,14 +470,26 @@ static int mcp9600_probe(struct i2c_client *client)
 	return devm_iio_device_register(&client->dev, indio_dev);
 }
 
+static const struct mcp_chip_info mcp9600_chip_info = {
+	.chip_id   = MCP9600_DEVICE_ID_MCP9600,
+	.chip_name = "mcp9600",
+};
+
+static const struct mcp_chip_info mcp9601_chip_info = {
+	.chip_id   = MCP9600_DEVICE_ID_MCP9601,
+	.chip_name = "mcp9601",
+};
+
 static const struct i2c_device_id mcp9600_id[] = {
-	{ "mcp9600" },
+	{ "mcp9600", .driver_data = (kernel_ulong_t)&mcp9600_chip_info },
+	{ "mcp9601", .driver_data = (kernel_ulong_t)&mcp9601_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mcp9600_id);
 
 static const struct of_device_id mcp9600_of_match[] = {
-	{ .compatible = "microchip,mcp9600" },
+	{ .compatible = "microchip,mcp9600", .data = &mcp9600_chip_info },
+	{ .compatible = "microchip,mcp9601", .data = &mcp9601_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, mcp9600_of_match);
-- 
2.39.5

[PATCH v4 4/5] iio: mcp9600: Add support for thermocouple-type

[Ben Collins]

dt-bindings documentation for this driver claims to support
thermocouple-type, but the driver does not actually make use of
the property.

Implement usage of the property to configure the chip for the
selected thermocouple-type.

Signed-off-by: Ben Collins <bcollins@watter.com>
---
 drivers/iio/temperature/mcp9600.c | 69 +++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
index 54de38a39292e..fa382a988a991 100644
--- a/drivers/iio/temperature/mcp9600.c
+++ b/drivers/iio/temperature/mcp9600.c
@@ -22,11 +22,15 @@
 #include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 
+#include <dt-bindings/iio/temperature/thermocouple.h>
+
 /* MCP9600 registers */
 #define MCP9600_HOT_JUNCTION		0x00
 #define MCP9600_COLD_JUNCTION		0x02
 #define MCP9600_STATUS			0x04
 #define MCP9600_STATUS_ALERT(x)		BIT(x)
+#define MCP9600_SENSOR_CFG		0x05
+#define MCP9600_SENSOR_TYPE_MASK	GENMASK(6, 4)
 #define MCP9600_ALERT_CFG1		0x08
 #define MCP9600_ALERT_CFG(x)		(MCP9600_ALERT_CFG1 + (x - 1))
 #define MCP9600_ALERT_CFG_ENABLE	BIT(0)
@@ -66,6 +70,30 @@ static const char * const mcp9600_alert_name[MCP9600_ALERT_COUNT] = {
 	[MCP9600_ALERT4] = "alert4",
 };
 
+/* Map between dt-bindings enum and the chip's type value */
+static const unsigned int mcp9600_type_map[] = {
+	[THERMOCOUPLE_TYPE_K] = 0,
+	[THERMOCOUPLE_TYPE_J] = 1,
+	[THERMOCOUPLE_TYPE_T] = 2,
+	[THERMOCOUPLE_TYPE_N] = 3,
+	[THERMOCOUPLE_TYPE_S] = 4,
+	[THERMOCOUPLE_TYPE_E] = 5,
+	[THERMOCOUPLE_TYPE_B] = 6,
+	[THERMOCOUPLE_TYPE_R] = 7,
+};
+
+/* Map thermocouple type to a char for for iio info in sysfs */
+static const int mcp9600_tc_types[] = {
+	[THERMOCOUPLE_TYPE_K] = 'K',
+	[THERMOCOUPLE_TYPE_J] = 'J',
+	[THERMOCOUPLE_TYPE_T] = 'T',
+	[THERMOCOUPLE_TYPE_N] = 'N',
+	[THERMOCOUPLE_TYPE_S] = 'S',
+	[THERMOCOUPLE_TYPE_E] = 'E',
+	[THERMOCOUPLE_TYPE_B] = 'B',
+	[THERMOCOUPLE_TYPE_R] = 'R',
+};
+
 static const struct iio_event_spec mcp9600_events[] = {
 	{
 		.type = IIO_EV_TYPE_THRESH,
@@ -89,6 +117,7 @@ static const struct iio_event_spec mcp9600_events[] = {
 			.type = IIO_TEMP,				       \
 			.address = MCP9600_HOT_JUNCTION,		       \
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	       \
+					      BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE) | \
 					      BIT(IIO_CHAN_INFO_SCALE),	       \
 			.event_spec = &mcp9600_events[hj_ev_spec_off],	       \
 			.num_event_specs = hj_num_ev,			       \
@@ -131,6 +160,7 @@ struct mcp_chip_info {
 
 struct mcp9600_data {
 	struct i2c_client *client;
+	u32 thermocouple_type;
 };
 
 static int mcp9600_read(struct mcp9600_data *data,
@@ -165,11 +195,32 @@ static int mcp9600_read_raw(struct iio_dev *indio_dev,
 		*val = 62;
 		*val2 = 500000;
 		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
+		*val = mcp9600_tc_types[data->thermocouple_type];
+		return IIO_VAL_CHAR;
 	default:
 		return -EINVAL;
 	}
 }
 
+static int mcp9600_config(struct mcp9600_data *data)
+{
+	struct i2c_client *client = data->client;
+	int ret;
+	u8 cfg;
+
+	cfg  = FIELD_PREP(MCP9600_SENSOR_TYPE_MASK,
+			  mcp9600_type_map[data->thermocouple_type]);
+
+	ret = i2c_smbus_write_byte_data(client, MCP9600_SENSOR_CFG, cfg);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to set sensor configuration\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 static int mcp9600_get_alert_index(int channel2, enum iio_event_direction dir)
 {
 	if (channel2 == IIO_MOD_TEMP_AMBIENT) {
@@ -457,6 +508,24 @@ static int mcp9600_probe(struct i2c_client *client)
 	data = iio_priv(indio_dev);
 	data->client = client;
 
+	/* Accept type from dt with default of Type-K. */
+	data->thermocouple_type = THERMOCOUPLE_TYPE_K;
+	ret = device_property_read_u32(&client->dev, "thermocouple-type",
+				       &data->thermocouple_type);
+	if (ret < 0 && ret != -EINVAL)
+		return dev_err_probe(&client->dev, ret,
+				     "Error reading thermocouple-type property\n");
+
+	if (data->thermocouple_type >= ARRAY_SIZE(mcp9600_type_map))
+		return dev_err_probe(&client->dev, -EINVAL,
+				     "Invalid thermocouple-type property %u.\n",
+				     data->thermocouple_type);
+
+	/* Set initial config. */
+	ret = mcp9600_config(data);
+	if (ret < 0)
+		return ret;
+
 	ch_sel = mcp9600_probe_alerts(indio_dev);
 	if (ch_sel < 0)
 		return ch_sel;
-- 
2.39.5

[PATCH v4 5/5] iio: mcp9600: Add support for IIR filter

[Ben Collins]

MCP9600 supports an IIR filter with 7 levels. Add IIR attribute
to allow get/set of this value.

Use a filter_type[none, ema] for enabling the IIR filter.

Signed-off-by: Ben Collins <bcollins@watter.com>
---
 drivers/iio/temperature/mcp9600.c | 155 ++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)

diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
index fa382a988a991..32eddaea0239e 100644
--- a/drivers/iio/temperature/mcp9600.c
+++ b/drivers/iio/temperature/mcp9600.c
@@ -31,6 +31,7 @@
 #define MCP9600_STATUS_ALERT(x)		BIT(x)
 #define MCP9600_SENSOR_CFG		0x05
 #define MCP9600_SENSOR_TYPE_MASK	GENMASK(6, 4)
+#define MCP9600_FILTER_MASK		GENMASK(2, 0)
 #define MCP9600_ALERT_CFG1		0x08
 #define MCP9600_ALERT_CFG(x)		(MCP9600_ALERT_CFG1 + (x - 1))
 #define MCP9600_ALERT_CFG_ENABLE	BIT(0)
@@ -94,6 +95,27 @@ static const int mcp9600_tc_types[] = {
 	[THERMOCOUPLE_TYPE_R] = 'R',
 };
 
+enum mcp9600_filter {
+	MCP9600_FILTER_TYPE_NONE,
+	MCP9600_FILTER_TYPE_EMA,
+};
+
+static const char * const mcp9600_filter_type[] = {
+	[MCP9600_FILTER_TYPE_NONE] = "none",
+	[MCP9600_FILTER_TYPE_EMA] = "ema",
+};
+
+static const int mcp_iir_coefficients_avail[7][2] = {
+	/* Level 0 is no filter */
+	{ 0, 524549 },
+	{ 0, 243901 },
+	{ 0, 119994 },
+	{ 0,  59761 },
+	{ 0,  29851 },
+	{ 0,  14922 },
+	{ 0,   7461 },
+};
+
 static const struct iio_event_spec mcp9600_events[] = {
 	{
 		.type = IIO_EV_TYPE_THRESH,
@@ -118,7 +140,11 @@ static const struct iio_event_spec mcp9600_events[] = {
 			.address = MCP9600_HOT_JUNCTION,		       \
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	       \
 					      BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE) | \
+					      BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |  \
 					      BIT(IIO_CHAN_INFO_SCALE),	       \
+			.info_mask_separate_available =                        \
+					      BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
+			.ext_info = mcp9600_ext_filter,			       \
 			.event_spec = &mcp9600_events[hj_ev_spec_off],	       \
 			.num_event_specs = hj_num_ev,			       \
 		},							       \
@@ -134,6 +160,26 @@ static const struct iio_event_spec mcp9600_events[] = {
 		},							       \
 	}
 
+static int mcp9600_get_filter(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan);
+static int mcp9600_set_filter(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      unsigned int mode);
+
+static const struct iio_enum mcp9600_filter_enum = {
+	.items = mcp9600_filter_type,
+	.num_items = ARRAY_SIZE(mcp9600_filter_type),
+	.get = mcp9600_get_filter,
+	.set = mcp9600_set_filter,
+};
+
+static const struct iio_chan_spec_ext_info mcp9600_ext_filter[] = {
+	IIO_ENUM("filter_type", IIO_SHARED_BY_ALL, &mcp9600_filter_enum),
+	IIO_ENUM_AVAILABLE("filter_type", IIO_SHARED_BY_ALL,
+			   &mcp9600_filter_enum),
+	{ }
+};
+
 static const struct iio_chan_spec mcp9600_channels[][2] = {
 	MCP9600_CHANNELS(0, 0, 0, 0), /* Alerts: - - - - */
 	MCP9600_CHANNELS(1, 0, 0, 0), /* Alerts: 1 - - - */
@@ -161,6 +207,8 @@ struct mcp_chip_info {
 struct mcp9600_data {
 	struct i2c_client *client;
 	u32 thermocouple_type;
+	/* Filter enabled is 1-7, with 0 being off (filter_type none) */
+	u8 filter_level;
 };
 
 static int mcp9600_read(struct mcp9600_data *data,
@@ -191,13 +239,43 @@ static int mcp9600_read_raw(struct iio_dev *indio_dev,
 		if (ret)
 			return ret;
 		return IIO_VAL_INT;
+
 	case IIO_CHAN_INFO_SCALE:
 		*val = 62;
 		*val2 = 500000;
 		return IIO_VAL_INT_PLUS_MICRO;
+
 	case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
 		*val = mcp9600_tc_types[data->thermocouple_type];
 		return IIO_VAL_CHAR;
+
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		if (data->filter_level == 0)
+			return -EINVAL;
+
+		*val = mcp_iir_coefficients_avail[data->filter_level - 1][0];
+		*val2 = mcp_iir_coefficients_avail[data->filter_level - 1][1];
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mcp9600_read_avail(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      const int **vals, int *type, int *length,
+			      long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		if (data->filter_level == 0)
+			return -EINVAL;
+
+		*vals = (int *)mcp_iir_coefficients_avail;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*length = 2 * ARRAY_SIZE(mcp_iir_coefficients_avail);
+		return IIO_AVAIL_LIST;
 	default:
 		return -EINVAL;
 	}
@@ -211,6 +289,7 @@ static int mcp9600_config(struct mcp9600_data *data)
 
 	cfg  = FIELD_PREP(MCP9600_SENSOR_TYPE_MASK,
 			  mcp9600_type_map[data->thermocouple_type]);
+	FIELD_MODIFY(MCP9600_FILTER_MASK, &cfg, data->filter_level);
 
 	ret = i2c_smbus_write_byte_data(client, MCP9600_SENSOR_CFG, cfg);
 	if (ret < 0) {
@@ -221,6 +300,79 @@ static int mcp9600_config(struct mcp9600_data *data)
 	return 0;
 }
 
+static int mcp9600_write_raw_get_fmt(struct iio_dev *indio_dev,
+				     struct iio_chan_spec const *chan,
+				     long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mcp9600_write_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 i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		for (i = 0; i < ARRAY_SIZE(mcp_iir_coefficients_avail); i++) {
+			if (mcp_iir_coefficients_avail[i][0] == val &&
+			    mcp_iir_coefficients_avail[i][1] == val2)
+				break;
+		}
+
+		if (i == ARRAY_SIZE(mcp_iir_coefficients_avail))
+			return -EINVAL;
+
+		data->filter_level = i + 1;
+		return mcp9600_config(data);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mcp9600_get_filter(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan)
+{
+	struct mcp9600_data *data = iio_priv(indio_dev);
+
+	if (data->filter_level == 0)
+		return MCP9600_FILTER_TYPE_NONE;
+
+	return MCP9600_FILTER_TYPE_EMA;
+}
+
+static int mcp9600_set_filter(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      unsigned int mode)
+{
+	struct mcp9600_data *data = iio_priv(indio_dev);
+
+	switch (mode) {
+	case MCP9600_FILTER_TYPE_NONE:
+		data->filter_level = 0;
+		return mcp9600_config(data);
+
+	case MCP9600_FILTER_TYPE_EMA:
+		if (data->filter_level == 0) {
+			/* Minimum filter by default */
+			data->filter_level = 1;
+			return mcp9600_config(data);
+		}
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
 static int mcp9600_get_alert_index(int channel2, enum iio_event_direction dir)
 {
 	if (channel2 == IIO_MOD_TEMP_AMBIENT) {
@@ -358,6 +510,9 @@ static int mcp9600_write_thresh(struct iio_dev *indio_dev,
 
 static const struct iio_info mcp9600_info = {
 	.read_raw = mcp9600_read_raw,
+	.read_avail = mcp9600_read_avail,
+	.write_raw = mcp9600_write_raw,
+	.write_raw_get_fmt = mcp9600_write_raw_get_fmt,
 	.read_event_config = mcp9600_read_event_config,
 	.write_event_config = mcp9600_write_event_config,
 	.read_event_value = mcp9600_read_thresh,
-- 
2.39.5

Re: [PATCH v4 2/5] iio: mcp9600: White space and fixed width cleanup

[Andy Shevchenko]

On Sun, Aug 17, 2025 at 11:50:50PM -0400, Ben Collins wrote:
> Make tabs consistent for register definitions and also fix width
> to byte size.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 3/5] iio: mcp9600: Recognize chip id for mcp9601

[Andy Shevchenko]

On Sun, Aug 17, 2025 at 11:50:51PM -0400, Ben Collins wrote:
> The current driver works with mcp9601, but emits a warning because it
> does not recognize the chip id.
> 
> MCP9601 is a superset of MCP9600. The drivers works without changes
> on this chipset.
> 
> However, the 9601 chip supports open/closed-circuit detection if wired
> properly, so we'll need to be able to differentiate between them.

...

>  static int mcp9600_probe(struct i2c_client *client)
>  {
> +	const struct mcp_chip_info *chip_info = i2c_get_match_data(client);

I believe I have commented on this already, please, split assignment...

>  	struct iio_dev *indio_dev;
>  	struct mcp9600_data *data;
> -	int ret, ch_sel;
> +	int ch_sel, dev_id, ret;

...and put it here.

> +	if (chip_info == NULL)
> +		return dev_err_probe(&client->dev, -EINVAL,
> +                                     "No chip-info found for device\n");

Wrong indentation.

Besides that I have commented as well on

	struct device *dev = &client->dev;

at the top that helps to make the code neater.

...

Since it seems the comments were ignored, I stopped here. Please, find previous
emails, take your time and fine grain the result for the next version.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 3/5] iio: mcp9600: Recognize chip id for mcp9601

[Ben Collins]

On Thu, Aug 21, 2025 at 12:33:19PM -0500, Andy Shevchenko wrote:
> On Sun, Aug 17, 2025 at 11:50:51PM -0400, Ben Collins wrote:
> > The current driver works with mcp9601, but emits a warning because it
> > does not recognize the chip id.
> > 
> > MCP9601 is a superset of MCP9600. The drivers works without changes
> > on this chipset.
> > 
> > However, the 9601 chip supports open/closed-circuit detection if wired
> > properly, so we'll need to be able to differentiate between them.
> 
> ...
> 
> >  static int mcp9600_probe(struct i2c_client *client)
> >  {
> > +	const struct mcp_chip_info *chip_info = i2c_get_match_data(client);
> 
> I believe I have commented on this already, please, split assignment...
> 
> >  	struct iio_dev *indio_dev;
> >  	struct mcp9600_data *data;
> > -	int ret, ch_sel;
> > +	int ch_sel, dev_id, ret;
> 
> ...and put it here.
> 
> > +	if (chip_info == NULL)
> > +		return dev_err_probe(&client->dev, -EINVAL,
> > +                                     "No chip-info found for device\n");
> 
> Wrong indentation.
> 
> Besides that I have commented as well on
> 
> 	struct device *dev = &client->dev;
> 
> at the top that helps to make the code neater.
> 
> ...
> 
> Since it seems the comments were ignored, I stopped here. Please, find previous
> emails, take your time and fine grain the result for the next version.

You're looking at v4. The latest is v7.

-- 
 Ben Collins
 https://libjwt.io
 https://github.com/benmcollins
 --
 3EC9 7598 1672 961A 1139  173A 5D5A 57C7 242B 22CF

Re: [PATCH v4 3/5] iio: mcp9600: Recognize chip id for mcp9601

[Andy Shevchenko]

On Thu, Aug 21, 2025 at 07:14:21AM -0400, Ben Collins wrote:
> On Thu, Aug 21, 2025 at 12:33:19PM -0500, Andy Shevchenko wrote:
> > On Sun, Aug 17, 2025 at 11:50:51PM -0400, Ben Collins wrote:

...

> > Since it seems the comments were ignored, I stopped here. Please, find previous
> > emails, take your time and fine grain the result for the next version.
> 
> You're looking at v4. The latest is v7.

Nice, please make sure you are not so quick with new versions.
Can you Cc me for v8? Or at least give a pointer to v7?

-- 
With Best Regards,
Andy Shevchenko