Commit 02b7cd68 authored May 02, 2026 by Marek Vasut Committed by Wolfram Sang May 04, 2026

i2c: stm32f7: reinit_completion() per transfer not per msg



Currently, the driver may repeatedly call reinit_completion() during
transfer which contains multiple messages, while another thread is
waiting for the completion.

This happens during transfer with more than 1 message, invoked via
stm32f7_i2c_xfer_core() -> stm32f7_i2c_xfer_msg(). After invoking the
stm32f7_i2c_xfer_msg() to start transfer, stm32f7_i2c_xfer_core()
calls wait_for_completion_timeout() to wait for completion of the
transfer of all messages. When the first message transfer completes,
the hard IRQ handler triggers, and detects transfer completion, which
leads to stm32f7_i2c_isr_event_thread() IRQ thread being started. The
stm32f7_i2c_isr_event_thread() calls stm32f7_i2c_xfer_msg() in case
there are more messages.

Without this change, the second and later stm32f7_i2c_xfer_msg() would
call reinit_completion() on the completion which is still being waited
for in stm32f7_i2c_xfer_core(). Fix this by moving the reinit_completion()
into stm32f7_i2c_xfer_core(), together with wait_for_completion_timeout().

Since stm32f7_i2c_xfer_core() now waits for completion of the entire
transfer, increase the default timeout. This fixes sporadic transfer
timeouts on STM32MP25xx during kernel boot.

Fixes: aeb068c5 ("i2c: i2c-stm32f7: add driver")
Signed-off-by: Marek Vasut <marex@nabladev.com>
[wsa: reworded commit subject]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

parent 9a937ca2

drivers/i2c/busses/i2c-stm32f7.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -895,8 +895,6 @@ static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
		f7_msg->result = 0;
		f7_msg->stop = (i2c_dev->msg_id >= i2c_dev->msg_num - 1);

		reinit_completion(&i2c_dev->complete);

		cr1 = readl_relaxed(base + STM32F7_I2C_CR1);
		cr2 = readl_relaxed(base + STM32F7_I2C_CR2);

		@@ -1728,6 +1726,8 @@ static int stm32f7_i2c_xfer_core(struct i2c_adapter *i2c_adap,
		if (ret)
		goto pm_free;

		reinit_completion(&i2c_dev->complete);

		stm32f7_i2c_xfer_msg(i2c_dev, msgs);

		if (!i2c_dev->atomic)
		@@ -2253,7 +2253,7 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
		snprintf(adap->name, sizeof(adap->name), "STM32F7 I2C(%pa)",
		&res->start);
		adap->owner = THIS_MODULE;
		adap->timeout = 2 * HZ;
		adap->timeout = 8 * HZ;
		adap->retries = 3;
		adap->algo = &stm32f7_i2c_algo;
		adap->dev.parent = &pdev->dev;