linux-kernel - [PATCH 1/5] irqchip: vt8500: Split up ack/mask functions

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Message-Id: <20250424-vt8500-intc-updates-v1-1-4ab7397155b3@gmail.com>
Date: Thu, 24 Apr 2025 22:35:42 +0400
From: Alexey Charkov <alchark@...il.com>
To: Thomas Gleixner <tglx@...utronix.de>, 
 Krzysztof Kozlowski <krzk@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 Alexey Charkov <alchark@...il.com>
Subject: [PATCH 1/5] irqchip: vt8500: Split up ack/mask functions

Original vt8500_irq_mask function really did the ack for edge
triggered interrupts and the mask for level triggered interrupts.
Edge triggered interrupts never really got masked as a result,
and there was unnecessary reading of the status register before
the ack even though it's write-one-to-clear.

Split it up into a proper standalone vt8500_irq_ack and an
unconditional vt8500_irq_mask.

No Fixes tag added, as it has survived this way for 15 years and
nobody complained, so apparently nothing really used edge triggered
interrupts anyway.

Signed-off-by: Alexey Charkov <alchark@...il.com>
---
 drivers/irqchip/irq-vt8500.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/irqchip/irq-vt8500.c b/drivers/irqchip/irq-vt8500.c
index e17dd3a8c2d5a488fedfdea55de842177c314baa..d0580f6577c88ffd7e374d640418d1fc23db623e 100644
--- a/drivers/irqchip/irq-vt8500.c
+++ b/drivers/irqchip/irq-vt8500.c
@@ -67,25 +67,25 @@ struct vt8500_irq_data {
 static struct vt8500_irq_data intc[VT8500_INTC_MAX];
 static u32 active_cnt = 0;
 
-static void vt8500_irq_mask(struct irq_data *d)
+static void vt8500_irq_ack(struct irq_data *d)
 {
 	struct vt8500_irq_data *priv = d->domain->host_data;
 	void __iomem *base = priv->base;
 	void __iomem *stat_reg = base + VT8500_ICIS + (d->hwirq < 32 ? 0 : 4);
-	u8 edge, dctr;
-	u32 status;
-
-	edge = readb(base + VT8500_ICDC + d->hwirq) & VT8500_EDGE;
-	if (edge) {
-		status = readl(stat_reg);
-
-		status |= (1 << (d->hwirq & 0x1f));
-		writel(status, stat_reg);
-	} else {
-		dctr = readb(base + VT8500_ICDC + d->hwirq);
-		dctr &= ~VT8500_INT_ENABLE;
-		writeb(dctr, base + VT8500_ICDC + d->hwirq);
-	}
+	u32 status = (1 << (d->hwirq & 0x1f));
+
+	writel(status, stat_reg);
+}
+
+static void vt8500_irq_mask(struct irq_data *d)
+{
+	struct vt8500_irq_data *priv = d->domain->host_data;
+	void __iomem *base = priv->base;
+	u8 dctr;
+
+	dctr = readb(base + VT8500_ICDC + d->hwirq);
+	dctr &= ~VT8500_INT_ENABLE;
+	writeb(dctr, base + VT8500_ICDC + d->hwirq);
 }
 
 static void vt8500_irq_unmask(struct irq_data *d)
@@ -131,7 +131,7 @@ static int vt8500_irq_set_type(struct irq_data *d, unsigned int flow_type)
 
 static struct irq_chip vt8500_irq_chip = {
 	.name = "vt8500",
-	.irq_ack = vt8500_irq_mask,
+	.irq_ack = vt8500_irq_ack,
 	.irq_mask = vt8500_irq_mask,
 	.irq_unmask = vt8500_irq_unmask,
 	.irq_set_type = vt8500_irq_set_type,

-- 
2.49.0