Hi Lee, On Tue, 3 Sep 2024 16:38:39 +0100 Lee Jones <lee@xxxxxxxxxx> wrote: > On Thu, 08 Aug 2024, Herve Codina wrote: > > > From: Clément Léger <clement.leger@xxxxxxxxxxx> > > > > Syscon releasing is not supported. > > Without release function, unbinding a driver that uses syscon whether > > explicitly or due to a module removal left the used syscon in a in-use > > state. > > > > For instance a syscon_node_to_regmap() call from a consumer retrieves a > > syscon regmap instance. Internally, syscon_node_to_regmap() can create > > syscon instance and add it to the existing syscon list. No API is > > available to release this syscon instance, remove it from the list and > > free it when it is not used anymore. > > > > Introduce reference counting in syscon in order to keep track of syscon > > usage using syscon_{get,put}() and add a device managed version of > > syscon_regmap_lookup_by_phandle(), to automatically release the syscon > > instance on the consumer removal. > > > > Signed-off-by: Clément Léger <clement.leger@xxxxxxxxxxx> > > Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx> > > --- > > drivers/mfd/syscon.c | 138 ++++++++++++++++++++++++++++++++++--- > > include/linux/mfd/syscon.h | 16 +++++ > > 2 files changed, 144 insertions(+), 10 deletions(-) > > This doesn't look very popular. > > What are the potential ramifications for existing users? > Existing user don't use devm_syscon_regmap_lookup_by_phandle() nor syscon_put_regmap(). So refcount is incremented but never decremented. syscon is never released. Exactly the same as current implementation. Nothing change for existing users. Best regards, Hervé