of: Make OF framebuffer device names unique

Since Linux 5.19 this error is observed:

sysfs: cannot create duplicate filename '/devices/platform/of-display'

This is because multiple devices with the same name 'of-display' are
created on the same bus. Update the code to create numbered device names
for the displays.

Also, fix a node refcounting issue when exiting the boot display loop.

cc: linuxppc-dev@lists.ozlabs.org
References: https://bugzilla.kernel.org/show_bug.cgi?id=216095
Fixes: 52b1b46c39ae ("of: Create platform devices for OF framebuffers")
Reported-by: Erhard F. <erhard_f@mailbox.org>
Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Link: https://lore.kernel.org/r/20230201162247.3575506-1-robh@kernel.org
[robh: Rework to avoid node refcount leaks]
Signed-off-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 81c8c227ab6bf259bab344b1cfea5e5d6024763f..b3878a98d27f75020a3966a9ccdcb76e20cae947 100644 (file)
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -525,6 +525,7 @@ static int __init of_platform_default_populate_init(void)
        if (IS_ENABLED(CONFIG_PPC)) {
                struct device_node *boot_display = NULL;
                struct platform_device *dev;
+               int display_number = 0;
                int ret;
 
                /* Check if we have a MacOS display without a node spec */
@@ -555,16 +556,23 @@ static int __init of_platform_default_populate_init(void)
                        if (!of_get_property(node, "linux,opened", NULL) ||
                            !of_get_property(node, "linux,boot-display", NULL))
                                continue;
-                       dev = of_platform_device_create(node, "of-display", NULL);
+                       dev = of_platform_device_create(node, "of-display.0", NULL);
+                       of_node_put(node);
                        if (WARN_ON(!dev))
                                return -ENOMEM;
                        boot_display = node;
+                       display_number++;
                        break;
                }
                for_each_node_by_type(node, "display") {
+                       char buf[14];
+                       const char *of_display_format = "of-display.%d";
+
                        if (!of_get_property(node, "linux,opened", NULL) || node == boot_display)
                                continue;
-                       of_platform_device_create(node, "of-display", NULL);
+                       ret = snprintf(buf, sizeof(buf), of_display_format, display_number++);
+                       if (ret < sizeof(buf))
+                               of_platform_device_create(node, buf, NULL);
                }
 
        } else {