linux-kernel - [PATCH v3 5/9] i2c: stm32f7: perform I2C_ISR read once at beginning of event isr

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Date: Fri, 15 Dec 2023 18:06:09 +0100
From: Alain Volmat <alain.volmat@...s.st.com>
To: Andi Shyti <andi.shyti@...nel.org>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley
	<conor+dt@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre
 Torgue <alexandre.torgue@...s.st.com>,
        Pierre-Yves MORDRET
	<pierre-yves.mordret@...s.st.com>,
        Alain Volmat <alain.volmat@...s.st.com>
CC: Conor Dooley <conor@...nel.org>, <linux-i2c@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v3 5/9] i2c: stm32f7: perform I2C_ISR read once at beginning of event isr

Move readl_relaxed of I2C_ISR register at beginning of event isr
so that it done once for both master & slave handling.

Signed-off-by: Alain Volmat <alain.volmat@...s.st.com>
---
 drivers/i2c/busses/i2c-stm32f7.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 15100fed0a3f..f7abf6d3a7b9 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -1419,15 +1419,13 @@ static bool stm32f7_i2c_is_slave_busy(struct stm32f7_i2c_dev *i2c_dev)
 	return i == busy;
 }
 
-static irqreturn_t stm32f7_i2c_slave_isr_event(struct stm32f7_i2c_dev *i2c_dev)
+static irqreturn_t stm32f7_i2c_slave_isr_event(struct stm32f7_i2c_dev *i2c_dev, u32 status)
 {
 	void __iomem *base = i2c_dev->base;
-	u32 cr2, status, mask;
+	u32 cr2, mask;
 	u8 val;
 	int ret;
 
-	status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
-
 	/* Slave transmitter mode */
 	if (status & STM32F7_I2C_ISR_TXIS) {
 		i2c_slave_event(i2c_dev->slave_running,
@@ -1531,11 +1529,11 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
 	u32 status, mask;
 	int ret;
 
-	if (!i2c_dev->master_mode)
-		return stm32f7_i2c_slave_isr_event(i2c_dev);
-
 	status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
 
+	if (!i2c_dev->master_mode)
+		return stm32f7_i2c_slave_isr_event(i2c_dev, status);
+
 	/* NACK received */
 	if (status & STM32F7_I2C_ISR_NACKF) {
 		dev_dbg(i2c_dev->dev, "<%s>: Receive NACK (addr %x)\n",
-- 
2.25.1