pinctrl: intel: Fix a glitch when updating IRQ flags on a preconfigured line

From: Andy Shevchenko <[email protected]>

The commit af7e3eeb84e2 ("pinctrl: intel: Disable input and output buffer when switching to GPIO") hadn't taken into account an update of the IRQ flags scenario.

When updating the IRQ flags on the preconfigured line the ->irq_set_type() is called again. In such case the sequential Rx buffer configuration changes may trigger a falling or rising edge interrupt that may lead, on some platforms, to an undesired event.

This may happen because each of intel_gpio_set_gpio_mode() and __intel_gpio_set_direction() updates the pad configuration with a different value of the GPIORXDIS bit. Notable, that the intel_gpio_set_gpio_mode() is called only for the pads that are configured as an input. Due to this fact, integrate the logic of __intel_gpio_set_direction() call into the intel_gpio_set_gpio_mode() so that the Rx buffer won't be disabled and immediately re-enabled.

---
 drivers/pinctrl/intel/pinctrl-intel.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

index 85750974d182..afd35e6999cc 100644
@@ -451,8 +451,8 @@ static void intel_gpio_set_gpio_mode(void __iomem *padcfg0)
 	value &= ~PADCFG0_PMODE_MASK;
 	value |= PADCFG0_PMODE_GPIO;
 
-	/* Disable input and output buffers */
-	value |= PADCFG0_GPIORXDIS;
+	/* Disable TX buffer and enable RX (this will be input) */
+	value &= ~PADCFG0_GPIORXDIS;
 	value |= PADCFG0_GPIOTXDIS;
 
 	/* Disable SCI/SMI/NMI generation */

@@ -497,9 +497,6 @@ static int intel_gpio_request_enable(struct pinctrl_dev *pctldev,
 
 	intel_gpio_set_gpio_mode(padcfg0);
 
-	/* Disable TX buffer and enable RX (this will be input) */
-	__intel_gpio_set_direction(padcfg0, true);
-
 	raw_spin_unlock_irqrestore(&pctrl->lock, flags);
 
 	return 0;

@@ -1115,9 +1112,6 @@ static int intel_gpio_irq_type(struct irq_data *d, unsigned int type)
 
 	intel_gpio_set_gpio_mode(reg);
 
-	/* Disable TX buffer and enable RX (this will be input) */
-	__intel_gpio_set_direction(reg, true);
-
 	value = readl(reg);
 
 	value &= ~(PADCFG0_RXEVCFG_MASK | PADCFG0_RXINV);

2.17.1

Thanks for testing. I will apply the tag to the original patch. The idea that you simply reply to the original message with the line above and that's it, no need to resend a full patch.

I see it comes from the internal tree.

With Best Regards,
Andy Shevchenko

Original patch with your tag has been pushed to my review and testing queue, thanks!

With Best Regards,
Andy Shevchenko