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

PATCH In review Andy Shevchenko 2 participants 3 messages Jan 19, 2022 – Jan 24, 2022

Subsystems (3)
GPIO Pin control Pin controller - Intel
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Andy Shevchenko

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#0 lore raw

PATCH 1/1 pinctrl: intel: Fix a glitch when updating IRQ flags on a preconfigured line

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.

Fixes af7e3eeb84e2 ("pinctrl: intel: Disable input and output buffer when switching to GPIO")
Reported-by Kane Chen <[email protected]>
Signed-off-by Andy Shevchenko <[email protected]>
---
 drivers/pinctrl/intel/pinctrl-intel.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)
drivers/pinctrl/intel/pinctrl-intel.c +2 -8
index 7d8a7e7b0aef..4d718a928288 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);
Signature · 1 line
2.34.1
maintainer Acked-by on v1 1/1
#1 lore raw
Quoted 17 lines · Andy Shevchenko

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.

Quoted 3 lines
Fixes af7e3eeb84e2 ("pinctrl: intel: Disable input and output buffer when switching to GPIO")
Reported-by Kane Chen <[email protected]>
Signed-off-by Andy Shevchenko <[email protected]>
Acked-by Mika Westerberg <[email protected]>

Please mark this for stable too.

author
#2 lore raw
Quoted 18 lines · Mika Westerberg
Quoted 17 lines · Andy Shevchenko

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.

Quoted 7 lines
Quoted 3 lines
Fixes af7e3eeb84e2 ("pinctrl: intel: Disable input and output buffer when switching to GPIO")
Reported-by Kane Chen <[email protected]>
Signed-off-by Andy Shevchenko <[email protected]>
Acked-by Mika Westerberg <[email protected]>

Please mark this for stable too.

Pushed to my review and testing queue with the Grace Kao's tag, thanks!

Signature · 2 lines
With Best Regards,
Andy Shevchenko