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From:   Marcello Sylvester Bauer <sylv@sylv.io>
To:     linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Patrick Rudolph <patrick.rudolph@9elements.com>,
        Jean Delvare <jdelvare@suse.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>
Subject: [PATCH v2 2/4] hwmon: (max6639) Add regulator support
Date:   Mon, 17 Jan 2022 11:40:24 +0100
Message-Id: <4c644f279f6e205d3c9540a4ad35825e4d5f2da1.1642413668.git.sylv@sylv.io>
In-Reply-To: <cover.1642413668.git.sylv@sylv.io>
References: <cover.1642413668.git.sylv@sylv.io>
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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