[PATCH v2 0/4] Add max6639 regulator and devicetree support

[PATCH v2 0/4] Add max6639 regulator and devicetree support

[Marcello Sylvester Bauer]

these patches add devicetree support for the Maxim MAX6639.
In addition, it includes optional regulator support for the fan-supply and
updates the URL to the datasheet.

Changes in v2:
- dt: Rename polarity to pwm-polarity
- Remove unused platform_data header.
- Remove regulator enable/disable calls in pwm_store due to imbalance of
  calls.
- Move to strict per channel dt configuration without defaults.

Marcello Sylvester Bauer (4):
  hwmon: (max6639) Update Datasheet URL
  hwmon: (max6639) Add regulator support
  dt-bindings: hwmon: Add binding for max6639
  hwmon: (max6639) Change from pdata to dt configuration

 .../bindings/hwmon/maxim,max6639.yaml         | 112 +++++++++
 Documentation/hwmon/max6639.rst               |   2 +-
 drivers/hwmon/max6639.c                       | 235 ++++++++++++++----
 include/linux/platform_data/max6639.h         |  15 --
 4 files changed, 297 insertions(+), 67 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
 delete mode 100644 include/linux/platform_data/max6639.h

-- 
2.33.1

[PATCH v2 1/4] hwmon: (max6639) Update Datasheet URL

[Marcello Sylvester Bauer]

The old Datasheet does not exist anymore.

Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
---
 Documentation/hwmon/max6639.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/hwmon/max6639.rst b/Documentation/hwmon/max6639.rst
index 3da54225f83c..c85d285a3489 100644
--- a/Documentation/hwmon/max6639.rst
+++ b/Documentation/hwmon/max6639.rst
@@ -9,7 +9,7 @@ Supported chips:
 
     Addresses scanned: I2C 0x2c, 0x2e, 0x2f
 
-    Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6639.pdf
+    Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX6639-MAX6639F.pdf
 
 Authors:
     - He Changqing <hechangqing@semptian.com>
-- 
2.33.1

[PATCH v2 2/4] hwmon: (max6639) Add regulator support

[Marcello Sylvester Bauer]

Add regulator support for boards where the fan-supply have to be
powered up before it can be used.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
---
 drivers/hwmon/max6639.c | 64 +++++++++++++++++++++++++++++++++++------
 1 file changed, 56 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
index ccc0f047bd44..0b241f029229 100644
--- a/drivers/hwmon/max6639.c
+++ b/drivers/hwmon/max6639.c
@@ -87,6 +87,9 @@ struct max6639_data {
 	/* Register values initialized only once */
 	u8 ppr;			/* Pulses per rotation 0..3 for 1..4 ppr */
 	u8 rpm_range;		/* Index in above rpm_ranges table */
+
+	/* Optional regulator for FAN supply */
+	struct regulator *reg;
 };
 
 static struct max6639_data *max6639_update_device(struct device *dev)
@@ -516,6 +519,11 @@ static int max6639_detect(struct i2c_client *client,
 	return 0;
 }
 
+static void max6639_regulator_disable(void *data)
+{
+	regulator_disable(data);
+}
+
 static int max6639_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
@@ -528,6 +536,30 @@ static int max6639_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	data->client = client;
+
+	data->reg = devm_regulator_get_optional(dev, "fan");
+	if (IS_ERR(data->reg)) {
+		if (PTR_ERR(data->reg) != -ENODEV) {
+			err = (int)PTR_ERR(data->reg);
+			dev_warn(dev, "Failed looking up fan supply: %d\n", err);
+			return err;
+		}
+		data->reg = NULL;
+	} else {
+		/* Spin up fans */
+		err = regulator_enable(data->reg);
+		if (err) {
+			dev_err(dev, "Failed to enable fan supply: %d\n", err);
+			return err;
+		}
+		err = devm_add_action_or_reset(dev, max6639_regulator_disable,
+					       data->reg);
+		if (err) {
+			dev_err(dev, "Failed to register action: %d\n", err);
+			return err;
+		}
+	}
+
 	mutex_init(&data->update_lock);
 
 	/* Initialize the max6639 chip */
@@ -545,23 +577,39 @@ static int max6639_probe(struct i2c_client *client)
 static int max6639_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
-	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
-	if (data < 0)
-		return data;
+	struct max6639_data *data = dev_get_drvdata(dev);
+	int ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
+
+	if (ret < 0)
+		return ret;
+
+	if (data->reg)
+		regulator_disable(data->reg);
 
 	return i2c_smbus_write_byte_data(client,
-			MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
+			MAX6639_REG_GCONFIG, ret | MAX6639_GCONFIG_STANDBY);
 }
 
 static int max6639_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
-	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
-	if (data < 0)
-		return data;
+	struct max6639_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	if (data->reg) {
+		ret = regulator_enable(data->reg);
+		if (ret) {
+			dev_err(dev, "Failed to enable fan supply: %d\n", ret);
+			return ret;
+		}
+	}
+
+	ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
+	if (ret < 0)
+		return ret;
 
 	return i2c_smbus_write_byte_data(client,
-			MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
+			MAX6639_REG_GCONFIG, ret & ~MAX6639_GCONFIG_STANDBY);
 }
 #endif /* CONFIG_PM_SLEEP */
 
-- 
2.33.1

[PATCH v2 3/4] dt-bindings: hwmon: Add binding for max6639

[Marcello Sylvester Bauer]

Add Devicetree binding documentation for Maxim MAX6639 temperature
monitor with PWM fan-speed controller.

The devicetree documentation for the SD3078 device tree.

Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
---
 .../bindings/hwmon/maxim,max6639.yaml         | 112 ++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml

diff --git a/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml b/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
new file mode 100644
index 000000000000..7093cbeba44b
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
@@ -0,0 +1,112 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/hwmon/maxim,max6639.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim max6639
+
+maintainers:
+  - Roland Stigge <stigge@antcom.de>
+
+description: |
+  The MAX6639 is a 2-channel temperature monitor with dual, automatic, PWM
+  fan-speed controller.  It monitors its own temperature and one external
+  diode-connected transistor or the temperatures of two external diode-connected
+  transistors, typically available in CPUs, FPGAs, or GPUs.
+
+  Datasheets:
+    https://datasheets.maximintegrated.com/en/ds/MAX6639-MAX6639F.pdf
+
+properties:
+  compatible:
+    enum:
+      - maxim,max6639
+
+  reg:
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - "channel@0"
+  - "channel@1"
+
+additionalProperties: false
+
+patternProperties:
+  "^channel@[0-1]$":
+    type: object
+    description: |
+      Represents the two fans and their specific configuration.
+
+    properties:
+      reg:
+        description: |
+          The fan number.
+        items:
+          minimum: 0
+          maximum: 1
+
+      pwm-polarity:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        enum: [0, 1]
+        description:
+          PWM output is low at 100% duty cycle when this bit is set to zero. PWM
+          output is high at 100% duty cycle when this bit is set to 1.
+
+      pulses-per-revolution:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        enum: [1, 2, 3, 4]
+        description:
+          Value specifying the number of pulses per revolution of the controlled
+          FAN.
+
+      rpm-range:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        enum: [2000, 4000, 8000, 16000]
+        description:
+          Scales the tachometer counter by setting the maximum (full-scale) value
+          of the RPM range.
+
+    required:
+      - reg
+      - pwm-polarity
+      - pulses-per-revolution
+      - rpm-range
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      max6639@10 {
+        compatible = "maxim,max6639";
+        reg = <0x10>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        channel@0 {
+          reg = <0x0>;
+          pwm-polarity = <1>;
+          pulses-per-revolution = <2>;
+          rpm-range = <4000>;
+        };
+
+        channel@1 {
+          reg = <0x1>;
+          pwm-polarity = <1>;
+          pulses-per-revolution = <2>;
+          rpm-range = <4000>;
+        };
+      };
+    };
+...
-- 
2.33.1

[PATCH v2 4/4] hwmon: (max6639) Change from pdata to dt configuration

[Marcello Sylvester Bauer]

max6639_platform_data is not used by any in-kernel driver and does not
address the MAX6639 channels separately. Move to a strict device tree
configuration with explicit properties to configure each channel.

Non-DT platform can still use this module with its default
configuration.

Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
---
 drivers/hwmon/max6639.c               | 171 +++++++++++++++++++-------
 include/linux/platform_data/max6639.h |  15 ---
 2 files changed, 128 insertions(+), 58 deletions(-)
 delete mode 100644 include/linux/platform_data/max6639.h

diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
index 0b241f029229..26772532bce4 100644
--- a/drivers/hwmon/max6639.c
+++ b/drivers/hwmon/max6639.c
@@ -19,7 +19,6 @@
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
-#include <linux/platform_data/max6639.h>
 
 /* Addresses to scan */
 static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
@@ -85,8 +84,9 @@ struct max6639_data {
 	u8 temp_ot[2];		/* OT Temperature, 0..255 C (->_emergency) */
 
 	/* Register values initialized only once */
-	u8 ppr;			/* Pulses per rotation 0..3 for 1..4 ppr */
-	u8 rpm_range;		/* Index in above rpm_ranges table */
+	u8 ppr[2];		/* Pulses per rotation 0..3 for 1..4 ppr */
+	u8 rpm_range[2];	/* Index in above rpm_ranges table */
+	u8 pwm_polarity[2];	/* Fans PWM polarity, 0..1 */
 
 	/* Optional regulator for FAN supply */
 	struct regulator *reg;
@@ -319,7 +319,7 @@ static ssize_t fan_input_show(struct device *dev,
 		return PTR_ERR(data);
 
 	return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
-		       data->rpm_range));
+		       data->rpm_range[attr->index]));
 }
 
 static ssize_t alarm_show(struct device *dev,
@@ -386,28 +386,26 @@ static struct attribute *max6639_attrs[] = {
 ATTRIBUTE_GROUPS(max6639);
 
 /*
- *  returns respective index in rpm_ranges table
- *  1 by default on invalid range
+ *  Get respective index in rpm_ranges table
  */
-static int rpm_range_to_reg(int range)
+static int rpm_range_to_index(u8 *index, int range)
 {
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
-		if (rpm_ranges[i] == range)
-			return i;
+		if (rpm_ranges[i] == range) {
+			*index = i;
+			return 0;
+		}
 	}
 
-	return 1; /* default: 4000 RPM */
+	return -EINVAL;
 }
 
 static int max6639_init_client(struct i2c_client *client,
 			       struct max6639_data *data)
 {
-	struct max6639_platform_data *max6639_info =
-		dev_get_platdata(&client->dev);
 	int i;
-	int rpm_range = 1; /* default: 4000 RPM */
 	int err;
 
 	/* Reset chip to default values, see below for GCONFIG setup */
@@ -416,43 +414,25 @@ static int max6639_init_client(struct i2c_client *client,
 	if (err)
 		goto exit;
 
-	/* Fans pulse per revolution is 2 by default */
-	if (max6639_info && max6639_info->ppr > 0 &&
-			max6639_info->ppr < 5)
-		data->ppr = max6639_info->ppr;
-	else
-		data->ppr = 2;
-	data->ppr -= 1;
-
-	if (max6639_info)
-		rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
-	data->rpm_range = rpm_range;
-
 	for (i = 0; i < 2; i++) {
 
 		/* Set Fan pulse per revolution */
 		err = i2c_smbus_write_byte_data(client,
 				MAX6639_REG_FAN_PPR(i),
-				data->ppr << 6);
+				data->ppr[i] << 6);
 		if (err)
 			goto exit;
 
 		/* Fans config PWM, RPM */
 		err = i2c_smbus_write_byte_data(client,
 			MAX6639_REG_FAN_CONFIG1(i),
-			MAX6639_FAN_CONFIG1_PWM | rpm_range);
+			MAX6639_FAN_CONFIG1_PWM | data->rpm_range[i]);
 		if (err)
 			goto exit;
 
-		/* Fans PWM polarity high by default */
-		if (max6639_info && max6639_info->pwm_polarity == 0)
-			err = i2c_smbus_write_byte_data(client,
-				MAX6639_REG_FAN_CONFIG2a(i), 0x00);
-		else
-			err = i2c_smbus_write_byte_data(client,
-				MAX6639_REG_FAN_CONFIG2a(i), 0x02);
-		if (err)
-			goto exit;
+		/* Fans PWM polarity */
+		err = i2c_smbus_write_byte_data(client,
+			MAX6639_REG_FAN_CONFIG2a(i), data->pwm_polarity[i] ? 0x00 : 0x02);
 
 		/*
 		 * /THERM full speed enable,
@@ -464,10 +444,6 @@ static int max6639_init_client(struct i2c_client *client,
 		if (err)
 			goto exit;
 
-		/* Max. temp. 80C/90C/100C */
-		data->temp_therm[i] = 80;
-		data->temp_alert[i] = 90;
-		data->temp_ot[i] = 100;
 		err = i2c_smbus_write_byte_data(client,
 				MAX6639_REG_THERM_LIMIT(i),
 				data->temp_therm[i]);
@@ -483,8 +459,6 @@ static int max6639_init_client(struct i2c_client *client,
 		if (err)
 			goto exit;
 
-		/* PWM 120/120 (i.e. 100%) */
-		data->pwm[i] = 120;
 		err = i2c_smbus_write_byte_data(client,
 				MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
 		if (err)
@@ -524,12 +498,96 @@ static void max6639_regulator_disable(void *data)
 	regulator_disable(data);
 }
 
+static int max6639_probe_child_from_dt(struct i2c_client *client,
+				      struct device_node *child,
+				      struct max6639_data *data)
+
+{
+	struct device *dev = &client->dev;
+	u32 i, val;
+	int err;
+
+	err = of_property_read_u32(child, "reg", &i);
+	if (err) {
+		dev_err(dev, "missing reg property of %pOFn\n", child);
+		return err;
+	}
+
+	if (i >= 2) {
+		dev_err(dev, "invalid reg %d of %pOFn\n", i, child);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32(child, "pulses-per-revolution", &val);
+	if (err) {
+		dev_err(dev, "missing pulses-per-revolution property of %pOFn\n", child);
+		return err;
+	}
+
+	if (val < 0 || val > 5) {
+		dev_err(dev, "invalid pulses-per-revolution %d of %pOFn\n", val, child);
+		return -EINVAL;
+	}
+	data->ppr[i] = val;
+
+	err = of_property_read_u32(child, "rpm-range", &val);
+	if (err) {
+		dev_err(dev, "missing rpm-range property of %pOFn\n", child);
+		return err;
+	}
+
+	err = rpm_range_to_index(&data->rpm_range[i], val);
+	if (err) {
+		dev_err(dev, "invalid rpm-range %d of %pOFn\n", val, child);
+		return err;
+	}
+
+	err = of_property_read_u32(child, "pwm-polarity", &val);
+	if (err) {
+		dev_err(dev, "missing pwm-polarity property of %pOFn\n", child);
+		return err;
+	}
+
+	if (val > 1) {
+		dev_err(dev, "invalid pwm-polarity %d of %pOFn\n", val, child);
+		return -EINVAL;
+	}
+	data->pwm_polarity[i] = val;
+
+	return 0;
+}
+
+static int max6639_probe_from_dt(struct i2c_client *client, struct max6639_data *data)
+{
+	struct device *dev = &client->dev;
+	const struct device_node *np = dev->of_node;
+	struct device_node *child;
+	int err;
+
+	/* Compatible with non-DT platforms */
+	if (!np)
+		return 0;
+
+	for_each_child_of_node(np, child) {
+		if (strcmp(child->name, "channel"))
+			continue;
+
+		err = max6639_probe_child_from_dt(client, child, data);
+		if (err) {
+			of_node_put(child);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static int max6639_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct max6639_data *data;
 	struct device *hwmon_dev;
-	int err;
+	int err, i;
 
 	data = devm_kzalloc(dev, sizeof(struct max6639_data), GFP_KERNEL);
 	if (!data)
@@ -562,6 +620,24 @@ static int max6639_probe(struct i2c_client *client)
 
 	mutex_init(&data->update_lock);
 
+	/* default values */
+	for (i = 0; i < 2; i++) {
+		/* 4000 RPM */
+		data->rpm_range[i] = 1;
+		data->ppr[i] = 2;
+		data->pwm_polarity[i] = 1;
+		/* Max. temp. 80C/90C/100C */
+		data->temp_therm[i] = 80;
+		data->temp_alert[i] = 90;
+		data->temp_ot[i] = 100;
+		/* PWM 120/120 (i.e. 100%) */
+		data->pwm[i] = 120;
+	}
+
+	err = max6639_probe_from_dt(client, data);
+	if (err)
+		return err;
+
 	/* Initialize the max6639 chip */
 	err = max6639_init_client(client, data);
 	if (err < 0)
@@ -620,6 +696,14 @@ static const struct i2c_device_id max6639_id[] = {
 
 MODULE_DEVICE_TABLE(i2c, max6639_id);
 
+#ifdef CONFIG_OF
+static const struct of_device_id maxim_of_platform_match[] = {
+	{.compatible = "maxim,max6639"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, maxim_of_platform_match);
+#endif
+
 static SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);
 
 static struct i2c_driver max6639_driver = {
@@ -627,6 +711,7 @@ static struct i2c_driver max6639_driver = {
 	.driver = {
 		   .name = "max6639",
 		   .pm = &max6639_pm_ops,
+		   .of_match_table = of_match_ptr(maxim_of_platform_match),
 		   },
 	.probe_new = max6639_probe,
 	.id_table = max6639_id,
diff --git a/include/linux/platform_data/max6639.h b/include/linux/platform_data/max6639.h
deleted file mode 100644
index 65bfdb4fdc15..000000000000
--- a/include/linux/platform_data/max6639.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_MAX6639_H
-#define _LINUX_MAX6639_H
-
-#include <linux/types.h>
-
-/* platform data for the MAX6639 temperature sensor and fan control */
-
-struct max6639_platform_data {
-	bool pwm_polarity;	/* Polarity low (0) or high (1, default) */
-	int ppr;		/* Pulses per rotation 1..4 (default == 2) */
-	int rpm_range;		/* 2000, 4000 (default), 8000 or 16000 */
-};
-
-#endif /* _LINUX_MAX6639_H */
-- 
2.33.1

Re: [PATCH v2 2/4] hwmon: (max6639) Add regulator support

[Guenter Roeck]

On Mon, Jan 17, 2022 at 11:40:24AM +0100, Marcello Sylvester Bauer wrote:
> Add regulator support for boards where the fan-supply have to be
> powered up before it can be used.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
> ---
>  drivers/hwmon/max6639.c | 64 +++++++++++++++++++++++++++++++++++------
>  1 file changed, 56 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
> index ccc0f047bd44..0b241f029229 100644
> --- a/drivers/hwmon/max6639.c
> +++ b/drivers/hwmon/max6639.c
> @@ -87,6 +87,9 @@ struct max6639_data {
>  	/* Register values initialized only once */
>  	u8 ppr;			/* Pulses per rotation 0..3 for 1..4 ppr */
>  	u8 rpm_range;		/* Index in above rpm_ranges table */
> +
> +	/* Optional regulator for FAN supply */
> +	struct regulator *reg;
>  };
>  
>  static struct max6639_data *max6639_update_device(struct device *dev)
> @@ -516,6 +519,11 @@ static int max6639_detect(struct i2c_client *client,
>  	return 0;
>  }
>  
> +static void max6639_regulator_disable(void *data)
> +{
> +	regulator_disable(data);
> +}
> +
>  static int max6639_probe(struct i2c_client *client)
>  {
>  	struct device *dev = &client->dev;
> @@ -528,6 +536,30 @@ static int max6639_probe(struct i2c_client *client)
>  		return -ENOMEM;
>  
>  	data->client = client;
> +
> +	data->reg = devm_regulator_get_optional(dev, "fan");
> +	if (IS_ERR(data->reg)) {
> +		if (PTR_ERR(data->reg) != -ENODEV) {
> +			err = (int)PTR_ERR(data->reg);
> +			dev_warn(dev, "Failed looking up fan supply: %d\n", err);

This could be -EPROBE_DEFER. I do not think that warrants
an error message.

> +			return err;
> +		}
> +		data->reg = NULL;
> +	} else {
> +		/* Spin up fans */
> +		err = regulator_enable(data->reg);
> +		if (err) {
> +			dev_err(dev, "Failed to enable fan supply: %d\n", err);
> +			return err;
> +		}
> +		err = devm_add_action_or_reset(dev, max6639_regulator_disable,
> +					       data->reg);
> +		if (err) {
> +			dev_err(dev, "Failed to register action: %d\n", err);
> +			return err;
> +		}
> +	}
> +
>  	mutex_init(&data->update_lock);
>  
>  	/* Initialize the max6639 chip */
> @@ -545,23 +577,39 @@ static int max6639_probe(struct i2c_client *client)
>  static int max6639_suspend(struct device *dev)
>  {
>  	struct i2c_client *client = to_i2c_client(dev);
> -	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> -	if (data < 0)
> -		return data;
> +	struct max6639_data *data = dev_get_drvdata(dev);
> +	int ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	if (data->reg)
> +		regulator_disable(data->reg);
>  
>  	return i2c_smbus_write_byte_data(client,
> -			MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
> +			MAX6639_REG_GCONFIG, ret | MAX6639_GCONFIG_STANDBY);
>  }
>  
>  static int max6639_resume(struct device *dev)
>  {
>  	struct i2c_client *client = to_i2c_client(dev);
> -	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> -	if (data < 0)
> -		return data;
> +	struct max6639_data *data = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (data->reg) {
> +		ret = regulator_enable(data->reg);
> +		if (ret) {
> +			dev_err(dev, "Failed to enable fan supply: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> +	if (ret < 0)
> +		return ret;
>  
>  	return i2c_smbus_write_byte_data(client,
> -			MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
> +			MAX6639_REG_GCONFIG, ret & ~MAX6639_GCONFIG_STANDBY);
>  }
>  #endif /* CONFIG_PM_SLEEP */
>  

Re: [PATCH v2 2/4] hwmon: (max6639) Add regulator support

[sylv]

On Tue, 2022-01-18 at 08:11 -0800, Guenter Roeck wrote:
> On Mon, Jan 17, 2022 at 11:40:24AM +0100, Marcello Sylvester Bauer wrote:
> > Add regulator support for boards where the fan-supply have to be
> > powered up before it can be used.
> > 
> > Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> > Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
> > ---
> >  drivers/hwmon/max6639.c | 64 +++++++++++++++++++++++++++++++++++------
> >  1 file changed, 56 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
> > index ccc0f047bd44..0b241f029229 100644
> > --- a/drivers/hwmon/max6639.c
> > +++ b/drivers/hwmon/max6639.c
> > @@ -87,6 +87,9 @@ struct max6639_data {
> >  	/* Register values initialized only once */
> >  	u8 ppr;			/* Pulses per rotation 0..3 for 1..4 ppr */
> >  	u8 rpm_range;		/* Index in above rpm_ranges table */
> > +
> > +	/* Optional regulator for FAN supply */
> > +	struct regulator *reg;
> >  };
> >  
> >  static struct max6639_data *max6639_update_device(struct device *dev)
> > @@ -516,6 +519,11 @@ static int max6639_detect(struct i2c_client *client,
> >  	return 0;
> >  }
> >  
> > +static void max6639_regulator_disable(void *data)
> > +{
> > +	regulator_disable(data);
> > +}
> > +
> >  static int max6639_probe(struct i2c_client *client)
> >  {
> >  	struct device *dev = &client->dev;
> > @@ -528,6 +536,30 @@ static int max6639_probe(struct i2c_client *client)
> >  		return -ENOMEM;
> >  
> >  	data->client = client;
> > +
> > +	data->reg = devm_regulator_get_optional(dev, "fan");
> > +	if (IS_ERR(data->reg)) {
> > +		if (PTR_ERR(data->reg) != -ENODEV) {
> > +			err = (int)PTR_ERR(data->reg);
> > +			dev_warn(dev, "Failed looking up fan supply: %d\n", err);
> 
> This could be -EPROBE_DEFER. I do not think that warrants
> an error message.

I see. I'll adapt it analog to: drivers/hwmon/pwm-fan.c:323

> 
> > +			return err;
> > +		}
> > +		data->reg = NULL;
> > +	} else {
> > +		/* Spin up fans */
> > +		err = regulator_enable(data->reg);
> > +		if (err) {
> > +			dev_err(dev, "Failed to enable fan supply: %d\n", err);
> > +			return err;
> > +		}
> > +		err = devm_add_action_or_reset(dev, max6639_regulator_disable,
> > +					       data->reg);
> > +		if (err) {
> > +			dev_err(dev, "Failed to register action: %d\n", err);
> > +			return err;
> > +		}
> > +	}
> > +
> >  	mutex_init(&data->update_lock);
> >  
> >  	/* Initialize the max6639 chip */
> > @@ -545,23 +577,39 @@ static int max6639_probe(struct i2c_client *client)
> >  static int max6639_suspend(struct device *dev)
> >  {
> >  	struct i2c_client *client = to_i2c_client(dev);
> > -	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> > -	if (data < 0)
> > -		return data;
> > +	struct max6639_data *data = dev_get_drvdata(dev);
> > +	int ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> > +
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (data->reg)
> > +		regulator_disable(data->reg);
> >  
> >  	return i2c_smbus_write_byte_data(client,
> > -			MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
> > +			MAX6639_REG_GCONFIG, ret | MAX6639_GCONFIG_STANDBY);
> >  }
> >  
> >  static int max6639_resume(struct device *dev)
> >  {
> >  	struct i2c_client *client = to_i2c_client(dev);
> > -	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> > -	if (data < 0)
> > -		return data;
> > +	struct max6639_data *data = dev_get_drvdata(dev);
> > +	int ret;
> > +
> > +	if (data->reg) {
> > +		ret = regulator_enable(data->reg);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to enable fan supply: %d\n", ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> > +	if (ret < 0)
> > +		return ret;
> >  
> >  	return i2c_smbus_write_byte_data(client,
> > -			MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
> > +			MAX6639_REG_GCONFIG, ret & ~MAX6639_GCONFIG_STANDBY);
> >  }
> >  #endif /* CONFIG_PM_SLEEP */
> >