From d6179f6c6204f9932aed3a7a2100b4a295dfed9d Mon Sep 17 00:00:00 2001 From: Mark Tomlinson Date: Thu, 6 Jun 2024 15:31:02 +1200 Subject: gpio: pca953x: Improve interrupt support 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: 44896beae605 ("gpio: pca953x: add PCAL9535 interrupt support for Galileo Gen2") Signed-off-by: Mark Tomlinson Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240606033102.2271916-1-mark.tomlinson@alliedtelesis.co.nz Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpio-pca953x.c | 19 ------------------- 1 file changed, 19 deletions(-) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index be4c9981ebc4..d63c1030e6ac 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -841,25 +841,6 @@ static bool pca953x_irq_pending(struct pca953x_chip *chip, unsigned long *pendin DECLARE_BITMAP(trigger, MAX_LINE); int ret; - if (chip->driver_data & PCA_PCAL) { - /* Read the current interrupt status from the device */ - ret = pca953x_read_regs(chip, PCAL953X_INT_STAT, trigger); - if (ret) - return false; - - /* Check latched inputs and clear interrupt status */ - ret = pca953x_read_regs(chip, chip->regs->input, cur_stat); - if (ret) - return false; - - /* Apply filter for rising/falling edge selection */ - bitmap_replace(new_stat, chip->irq_trig_fall, chip->irq_trig_raise, cur_stat, gc->ngpio); - - bitmap_and(pending, new_stat, trigger, gc->ngpio); - - return !bitmap_empty(pending, gc->ngpio); - } - ret = pca953x_read_regs(chip, chip->regs->input, cur_stat); if (ret) return false; -- cgit