Date:   Sat, 18 Feb 2023 00:32:49 -0800
In-Reply-To: <20230218083252.2044423-1-saravanak@google.com>
Message-Id: <20230218083252.2044423-3-saravanak@google.com>
Mime-Version: 1.0
References: <20230218083252.2044423-1-saravanak@google.com>
Subject: [RFC v1 2/4] regulator: core: Add sysfs class backward compatibility
From:   Saravana Kannan <saravanak@google.com>
To:     Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>
Cc:     Saravana Kannan <saravanak@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Tony Lindgren <tony@atomide.com>,
        Doug Anderson <dianders@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Luca Weiss <luca.weiss@fairphone.com>, kernel-team@android.com,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

A regulator device's sysfs directory used to be created under
/sys/class/regulator when it is added to a class. Since the device is
now moved to be under a bus, add symlinks from /sys/class/regulator to
the real device sysfs directory.

Signed-off-by: Saravana Kannan <saravanak@google.com>
---
 drivers/regulator/core.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 1a212edcf216..b6700d50d230 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -43,6 +43,7 @@ static LIST_HEAD(regulator_coupler_list);
 static bool has_full_constraints;
 
 static struct dentry *debugfs_root;
+static struct class_compat *regulator_compat_class;
 
 /*
  * struct regulator_map
@@ -5636,6 +5637,11 @@ regulator_register(struct device *dev,
 	if (ret != 0)
 		goto unset_supplies;
 
+	if (class_compat_create_link(regulator_compat_class, &rdev->dev,
+				     rdev->dev.parent))
+		dev_warn(&rdev->dev,
+			 "Failed to create compatibility class link\n");
+
 	rdev_init_debugfs(rdev);
 
 	/* try to resolve regulators coupling since a new one was registered */
@@ -5702,6 +5708,8 @@ void regulator_unregister(struct regulator_dev *rdev)
 	unset_regulator_supplies(rdev);
 	list_del(&rdev->list);
 	regulator_ena_gpio_free(rdev);
+	class_compat_remove_link(regulator_compat_class, &rdev->dev,
+				 rdev->dev.parent);
 	device_unregister(&rdev->dev);
 
 	mutex_unlock(&regulator_list_mutex);
@@ -6107,7 +6115,13 @@ static int __init regulator_init(void)
 {
 	int ret;
 
+	regulator_compat_class = class_compat_register("regulator");
+	if (!regulator_compat_class)
+		return -ENOMEM;
+
 	ret = bus_register(&regulator_bus);
+	if (ret)
+		goto unreg_compat;
 
 	debugfs_root = debugfs_create_dir("regulator", NULL);
 	if (!debugfs_root)
@@ -6120,11 +6134,16 @@ static int __init regulator_init(void)
 	debugfs_create_file("regulator_summary", 0444, debugfs_root,
 			    NULL, &regulator_summary_fops);
 #endif
+
 	regulator_dummy_init();
 
 	regulator_coupler_register(&generic_regulator_coupler);
 
 	return ret;
+
+unreg_compat:
+	class_compat_unregister(regulator_compat_class);
+	return ret;
 }
 
 /* init early to allow our consumers to complete system booting */
-- 
2.39.2.637.g21b0678d19-goog