linux-kernel - [PATCH] regulator: reorder initialization steps in regulator

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Date:	Tue, 12 Apr 2016 12:31:00 +0200
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>
Cc:	linux-kernel@...r.kernel.org, Caesar Wang <wxt@...k-chips.com>,
	Heiko Stübner <heiko@...ech.de>,
	Stephen Barber <smbarber@...omium.org>,
	Douglas Anderson <dianders@...omium.org>,
	Brian Norris <briannorris@...omium.org>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH] regulator: reorder initialization steps in regulator_register()

device_register() is calling ->get_voltage() as part of is sysfs attribute
initialization process, and this functions might need to know the regulator
constraints to return a valid value.
This is at least true for the pwm regulator driver (when operating in
continuous mode) which needs to know the minimum and maximum voltage values
to calculate the current voltage:

min_uV + (((max_uV - min_uV) * dutycycle) / 100);

Move device_register() after set_machine_constraints() to make sure those
constraints are correctly initialized when ->get_voltage() is called.

Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
Reported-by: Stephen Barber <smbarber@...omium.org>
---
 drivers/regulator/core.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index e0b7642..8258568 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3950,13 +3950,6 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	rdev->dev.parent = dev;
 	dev_set_name(&rdev->dev, "regulator.%lu",
 		    (unsigned long) atomic_inc_return(&regulator_no));
-	ret = device_register(&rdev->dev);
-	if (ret != 0) {
-		put_device(&rdev->dev);
-		goto wash;
-	}
-
-	dev_set_drvdata(&rdev->dev, rdev);
 
 	/* set regulator constraints */
 	if (init_data)
@@ -3964,7 +3957,15 @@ regulator_register(const struct regulator_desc *regulator_desc,
 
 	ret = set_machine_constraints(rdev, constraints);
 	if (ret < 0)
-		goto scrub;
+		goto wash;
+
+	ret = device_register(&rdev->dev);
+	if (ret != 0) {
+		put_device(&rdev->dev);
+		goto wash;
+	}
+
+	dev_set_drvdata(&rdev->dev, rdev);
 
 	if (init_data && init_data->supply_regulator)
 		rdev->supply_name = init_data->supply_regulator;
@@ -3993,8 +3994,6 @@ out:
 
 unset_supplies:
 	unset_regulator_supplies(rdev);
-
-scrub:
 	regulator_ena_gpio_free(rdev);
 	device_unregister(&rdev->dev);
 	/* device core frees rdev */
@@ -4002,6 +4001,7 @@ scrub:
 	goto out;
 
 wash:
+	kfree(rdev->constraints);
 	regulator_ena_gpio_free(rdev);
 clean:
 	kfree(rdev);
-- 
2.5.0