Mark Tomlinson
2d1637afc4
[ Upstream commitd6179f6c62] The GPIO drivers with latch interrupt support (typically types starting with PCAL) have interrupt status registers to determine which particular inputs have caused an interrupt. Unfortunately there is no atomic operation to read these registers and clear the interrupt. Clearing the interrupt is done by reading the input registers. The code was reading the interrupt status registers, and then reading the input registers. If an input changed between these two events it was lost. The solution in this patch is to revert to the non-latch version of code, i.e. remembering the previous input status, and looking for the changes. This system results in no more I2C transfers, so is no slower. The latch property of the device still means interrupts will still be noticed if the input changes back to its initial state. Fixes:44896beae6("gpio: pca953x: add PCAL9535 interrupt support for Galileo Gen2") Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20240606033102.2271916-1-mark.tomlinson@alliedtelesis.co.nz Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>