"Rafael J. Wysocki" <raf...@kernel.org> writes: > On Wed, Feb 20, 2019 at 11:41 AM Måns Rullgård <m...@mansr.com> wrote: >> >> "Rafael J. Wysocki" <raf...@kernel.org> writes: >> >> > On Mon, Feb 18, 2019 at 12:10 PM Måns Rullgård <m...@mansr.com> wrote: >> >> >> >> "Rafael J. Wysocki" <raf...@kernel.org> writes: >> >> >> >> > On Sat, Feb 16, 2019 at 5:50 PM Mans Rullgard <m...@mansr.com> wrote: >> >> >> >> >> >> If the provided fwnode is an OF node, set dev.of_node as well. >> >> >> >> >> >> Signed-off-by: Mans Rullgard <m...@mansr.com> >> >> >> --- >> >> >> drivers/base/platform.c | 1 + >> >> >> 1 file changed, 1 insertion(+) >> >> >> >> >> >> diff --git a/drivers/base/platform.c b/drivers/base/platform.c >> >> >> index dff82a3c2caa..853a1d0e5845 100644 >> >> >> --- a/drivers/base/platform.c >> >> >> +++ b/drivers/base/platform.c >> >> >> @@ -512,6 +512,7 @@ struct platform_device >> >> >> *platform_device_register_full( >> >> >> >> >> >> pdev->dev.parent = pdevinfo->parent; >> >> >> pdev->dev.fwnode = pdevinfo->fwnode; >> >> >> + pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode)); >> >> > >> >> > of_node_get() generally does a kobject_get() on the node's kobject, so >> >> > when is that reference dropped? Or if it doesn't need to be dropped >> >> > at all, why is this the case? >> >> >> >> platform_device_release() calls of_device_node_put(). >> > >> > Yes, it does, but this is the reference that's already acquired for >> > devices added while parsing DT, isn't it? >> > >> > Your change adds an extra reference AFAICS. >> > >> > Also, why is this patch needed? >> >> Some drivers are just shims that create extra "glue" devices with the DT >> device as parent and have the real driver bind to these. In other >> cases, the same real driver matches the DT node directly. When a glue >> device is used, it needs to get a reference to the original DT node in >> order for the main driver to access properties and child nodes. >> >> Right now, my problem is that the suxi-musb driver creates such a glue >> device for the musb core driver to bind to without setting of_node. >> This means devices attached to this USB interface don't get associated >> with DT nodes, if present, the way they do with EHCI. > > You really should describe problems that you want to address in patch > changelogs. This helps a lot to understand the motivation for the > changes.
Do you want me to send a new patch with the above explanation in the commit message? >> The sunxi-musb driver uses platform_device_register_full(), so this >> seemed like the easiest way to let it set of_node of the new device. >> Since this creates a second reference to the same node, of_node_get() >> is required. > > But what about devices that already have of_node set at this point? > > Maybe check if of_node is NULL before trying to set it? It's a brand new device allocated a few lines above. of_node has to be null here. -- Måns Rullgård
