linux-kernel - [PATCH 5.15 078/177] pinctrl: stm32: Do not call stm32_gpio

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Message-Id: <20220504153100.054423299@linuxfoundation.org>
Date:   Wed,  4 May 2022 18:44:31 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Marek Vasut <marex@...x.de>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Fabien Dessenne <fabien.dessenne@...s.st.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Marc Zyngier <maz@...nel.org>,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 078/177] pinctrl: stm32: Do not call stm32_gpio_get() for edge triggered IRQs in EOI

From: Marek Vasut <marex@...x.de>

[ Upstream commit e74200ebf7c4f6a7a7d1be9f63833ddba251effa ]

The stm32_gpio_get() should only be called for LEVEL triggered interrupts,
skip calling it for EDGE triggered interrupts altogether to avoid wasting
CPU cycles in EOI handler. On this platform, EDGE triggered interrupts are
the majority and LEVEL triggered interrupts are the exception no less, and
the CPU cycles are not abundant.

Fixes: 47beed513a85b ("pinctrl: stm32: Add level interrupt support to gpio irq chip")
Signed-off-by: Marek Vasut <marex@...x.de>
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>
Cc: Fabien Dessenne <fabien.dessenne@...s.st.com>
Cc: Linus Walleij <linus.walleij@...aro.org>
Cc: Marc Zyngier <maz@...nel.org>
Cc: linux-stm32@...md-mailman.stormreply.com
Cc: linux-arm-kernel@...ts.infradead.org
To: linux-gpio@...r.kernel.org
Link: https://lore.kernel.org/r/20220415215410.498349-1-marex@denx.de
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pinctrl/stm32/pinctrl-stm32.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c b/drivers/pinctrl/stm32/pinctrl-stm32.c
index 8934b4878fa8..2c78af0aac57 100644
--- a/drivers/pinctrl/stm32/pinctrl-stm32.c
+++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
@@ -311,6 +311,10 @@ static void stm32_gpio_irq_trigger(struct irq_data *d)
 	struct stm32_gpio_bank *bank = d->domain->host_data;
 	int level;
 
+	/* Do not access the GPIO if this is not LEVEL triggered IRQ. */
+	if (!(bank->irq_type[d->hwirq] & IRQ_TYPE_LEVEL_MASK))
+		return;
+
 	/* If level interrupt type then retrig */
 	level = stm32_gpio_get(&bank->gpio_chip, d->hwirq);
 	if ((level == 0 && bank->irq_type[d->hwirq] == IRQ_TYPE_LEVEL_LOW) ||
-- 
2.35.1