Hi Lee, Arnd, On Tue, 3 Sep 2024 18:01:16 +0200 Herve Codina <herve.codina@xxxxxxxxxxx> wrote: > 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 I hope I answered to Lee's question related to possible impacts on existing drivers. Is there anything else that blocks this patch from being applied ? Best regards, Hervé