linux-kernel - [PATCH v2 2/3] hwmon: (amc6821) Move reading fan data from OF to a function

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Message-Id: <20250603-b4-amc6821-cooling-device-support-v2-2-74943c889a2d@toradex.com>
Date: Tue, 03 Jun 2025 08:44:55 -0300
From: João Paulo Gonçalves <jpaulo.silvagoncalves@...il.com>
To: Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Farouk Bouabid <farouk.bouabid@...rry.de>, 
 Quentin Schulz <quentin.schulz@...rry.de>
Cc: linux-hwmon@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 João Paulo Gonçalves <joao.goncalves@...adex.com>
Subject: [PATCH v2 2/3] hwmon: (amc6821) Move reading fan data from OF to a
 function

From: João Paulo Gonçalves <joao.goncalves@...adex.com>

Move fan property reading from OF to a separate function. This keeps OF
data handling separate from the code logic and makes it easier to add
features like cooling device support that use the same fan node.

Signed-off-by: João Paulo Gonçalves <joao.goncalves@...adex.com>
---
v2:
- Remove devm_action on release and call of_node_put() manually
- Change of_pwm_polarity to store resulting pwm polarity on driver private data
v1: https://lore.kernel.org/lkml/20250530-b4-v1-amc6821-cooling-device-support-b4-v1-0-7bb98496c969@toradex.com/
---
 drivers/hwmon/amc6821.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 13a789cc85d24da282430eb2d4edf0003617fe6b..850a42510649279fba23ed504826384e1d8e335c 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -126,6 +126,7 @@ module_param(init, int, 0444);
 struct amc6821_data {
 	struct regmap *regmap;
 	struct mutex update_lock;
+	enum pwm_polarity pwm_polarity;
 };
 
 /*
@@ -848,11 +849,11 @@ static int amc6821_detect(struct i2c_client *client, struct i2c_board_info *info
 	return 0;
 }
 
-static enum pwm_polarity amc6821_pwm_polarity(struct i2c_client *client)
+static enum pwm_polarity amc6821_pwm_polarity(struct i2c_client *client,
+					      struct device_node *fan_np)
 {
 	enum pwm_polarity polarity = PWM_POLARITY_NORMAL;
 	struct of_phandle_args args;
-	struct device_node *fan_np;
 
 	/*
 	 * For backward compatibility, the pwminv module parameter takes
@@ -863,10 +864,6 @@ static enum pwm_polarity amc6821_pwm_polarity(struct i2c_client *client)
 	if (pwminv > 0)
 		return PWM_POLARITY_INVERSED;
 
-	fan_np = of_get_child_by_name(client->dev.of_node, "fan");
-	if (!fan_np)
-		return PWM_POLARITY_NORMAL;
-
 	if (of_parse_phandle_with_args(fan_np, "pwms", "#pwm-cells", 0, &args))
 		goto out;
 	of_node_put(args.np);
@@ -877,10 +874,16 @@ static enum pwm_polarity amc6821_pwm_polarity(struct i2c_client *client)
 	if (args.args[1] & PWM_POLARITY_INVERTED)
 		polarity = PWM_POLARITY_INVERSED;
 out:
-	of_node_put(fan_np);
 	return polarity;
 }
 
+static void amc6821_of_fan_read_data(struct i2c_client *client,
+				     struct amc6821_data *data,
+				     struct device_node *fan_np)
+{
+	data->pwm_polarity = amc6821_pwm_polarity(client, fan_np);
+}
+
 static int amc6821_init_client(struct i2c_client *client, struct amc6821_data *data)
 {
 	struct regmap *regmap = data->regmap;
@@ -902,7 +905,7 @@ static int amc6821_init_client(struct i2c_client *client, struct amc6821_data *d
 			return err;
 
 		regval = AMC6821_CONF1_START;
-		if (amc6821_pwm_polarity(client) == PWM_POLARITY_INVERSED)
+		if (data->pwm_polarity == PWM_POLARITY_INVERSED)
 			regval |= AMC6821_CONF1_PWMINV;
 
 		err = regmap_update_bits(regmap, AMC6821_REG_CONF1,
@@ -944,6 +947,7 @@ static int amc6821_probe(struct i2c_client *client)
 	struct amc6821_data *data;
 	struct device *hwmon_dev;
 	struct regmap *regmap;
+	struct device_node *fan_np;
 	int err;
 
 	data = devm_kzalloc(dev, sizeof(struct amc6821_data), GFP_KERNEL);
@@ -956,6 +960,12 @@ static int amc6821_probe(struct i2c_client *client)
 				     "Failed to initialize regmap\n");
 	data->regmap = regmap;
 
+	fan_np = of_get_child_by_name(dev->of_node, "fan");
+	if (fan_np) {
+		amc6821_of_fan_read_data(client, data, fan_np);
+		of_node_put(fan_np);
+	}
+
 	err = amc6821_init_client(client, data);
 	if (err)
 		return err;

-- 
2.43.0