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gpio: Update TODO to mention immutable irq_chip structures

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5 drivers are converted, a few hundred to go. Definitely worth of
a TODO entry, in the hope that someone will notice it and do
a bulk update.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220419141846.598305-10-maz@kernel.org
This commit is contained in:
Marc Zyngier 2022-04-19 15:18:45 +01:00
parent 6173e56f76
commit afefc32662
1 changed files with 19 additions and 0 deletions
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drivers/gpio/TODO
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@ -178,3 +178,22 @@ discussed but the idea is to provide a low-level access point
for debugging and hacking and to expose all lines without the
need of any exporting. Also provide ample ammunition to shoot
oneself in the foot, because this is debugfs after all.
Moving over to immutable irq_chip structures
Most of the gpio chips implementing interrupt support rely on gpiolib
intercepting some of the irq_chip callbacks, preventing the structures
from being made read-only and forcing duplication of structures that
should otherwise be unique.
The solution is to call into the gpiolib code when needed (resource
management, enable/disable or unmask/mask callbacks), and to let the
core code know about that by exposing a flag (IRQCHIP_IMMUTABLE) in
the irq_chip structure. The irq_chip structure can then be made unique
and const.
A small number of drivers have been converted (pl061, tegra186, msm,
amd, apple), and can be used as examples of how to proceed with this
conversion. Note that drivers using the generic irqchip framework
cannot be converted yet, but watch this space!