On Thu, Jan 25, 2024 at 9:02 AM Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> wrote: > > On 24/01/2024 08:45, Krzysztof Kozlowski wrote: > > Devices sharing a reset GPIO could use the reset framework for > > coordinated handling of that shared GPIO line. We have several cases of > > such needs, at least for Devicetree-based platforms. > > > > If Devicetree-based device requests a reset line, while "resets" > > Devicetree property is missing but there is a "reset-gpios" one, > > instantiate a new "reset-gpio" platform device which will handle such > > reset line. This allows seamless handling of such shared reset-gpios > > without need of changing Devicetree binding [1]. > > > > To avoid creating multiple "reset-gpio" platform devices, store the > > Devicetree "reset-gpios" GPIO specifiers used for new devices on a > > linked list. Later such Devicetree GPIO specifier (phandle to GPIO > > controller, GPIO number and GPIO flags) is used to check if reset > > controller for given GPIO was already registered. > > > > If two devices have conflicting "reset-gpios" property, e.g. with > > different ACTIVE_xxx flags, this would allow to spawn two separate > > "reset-gpio" devices, where the second would fail probing on busy GPIO > > request. > > > > Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@xxxxxxxxxxxxxxxxxx/ [1] > > Cc: Bartosz Golaszewski <brgl@xxxxxxxx> > > Cc: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> > > Cc: Sean Anderson <sean.anderson@xxxxxxxx> > > Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> > > > > --- > > > > Depends on previous of change. > > --- > > drivers/reset/core.c | 215 +++++++++++++++++++++++++++++-- > > include/linux/reset-controller.h | 4 + > > 2 files changed, 206 insertions(+), 13 deletions(-) > > > > LKP reported issue when building !GPIOLIB: > https://lore.kernel.org/oe-kbuild-all/202401250958.YksQmnWj-lkp@xxxxxxxxx/ > > but I intend to solve it providing the stubs. Therefore this patch will > not change. > > Best regards, > Krzysztof > Ah, so this is why you sent the patches. I don't like stubs in gpio/driver.h but I get why they're needed here. Maybe we should consider adding gpio/misc.h for that kind of stuff. Bart
