Shared GPIOs may be assigned to child nodes of device nodes which don't
themselves bind to any struct device. We need to pass the firmware node
that is the actual consumer to gpiolib-shared and compare against it
instead of unconditionally using the fwnode of the consumer device.
Fixes: a060b8c511 ("gpiolib: implement low-level, shared GPIO support")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/all/921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com/
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://patch.msgid.link/20260318-gpio-shared-xlate-v2-2-0ce34c707e81@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
OF-based GPIO controller drivers may provide a translation function that
calculates the real chip offset from whatever devicetree sources
provide. We need to take this into account in the shared GPIO management
and call of_xlate() if it's provided and adjust the entry->offset we
initially set when scanning the tree.
To that end: modify the shared GPIO API to take the GPIO chip as
argument on setup (to avoid having to rcu_dereference() it from the GPIO
device) and protect the access to entry->offset with the existing lock.
Fixes: a060b8c511 ("gpiolib: implement low-level, shared GPIO support")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/all/921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com/
Reviewed-by: Linus Walleij <linusw@kernel.org>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://patch.msgid.link/20260318-gpio-shared-xlate-v2-1-0ce34c707e81@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
When matching the firmware node with the potential consumer, we
currently omit the con_id string. This can lead to false positives in
the unlikely case of the consumer having been assigned more than one
shared GPIO. Check the connector ID before proceeding.
Fixes: a060b8c511 ("gpiolib: implement low-level, shared GPIO support")
Link: https://lore.kernel.org/r/20251222-gpio-shared-reset-gpio-proxy-v1-2-8d4bba7d8c14@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
This module scans the device tree (for now only OF nodes are supported
but care is taken to make other fwnode implementations easy to
integrate) and determines which GPIO lines are shared by multiple users.
It stores that information in memory. When the GPIO chip exposing shared
lines is registered, the shared GPIO descriptors it exposes are marked
as shared and virtual "proxy" devices that mediate access to the shared
lines are created. When a consumer of a shared GPIO looks it up, its
fwnode lookup is redirected to a just-in-time machine lookup that points
to this proxy device.
This code can be compiled out on platforms which don't use shared GPIOs.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-3-b51f97b1abd8@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
