Commit 1d6b6759 authored Sep 15, 2025 by Khaoula Bidani Committed by Henrik Brix Andersen Sep 17, 2025

drivers: i2c: stm32: Fix STM32 I2C hang on read



ensure LL_I2C_TransmitData8() is always called when
TXIS is set, even if read_processed() returns an error.
This prevents the peripheral from clock-stretching
indefinitely and blocking the I2C bus when the master
reads from the slave.

Signed-off-by: Khaoula Bidani <khaoula.bidani-ext@st.com>

parent 936876b5

drivers/i2c/i2c_ll_stm32_v2.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -343,13 +343,14 @@ static void i2c_stm32_slave_event(const struct device *dev)
		slave_cb = slave_cfg->callbacks;

		if (LL_I2C_IsActiveFlag_TXIS(i2c)) {
		uint8_t val;
		uint8_t val = 0x00;

		if (slave_cb->read_processed(slave_cfg, &val) < 0) {
		LOG_ERR("Error continuing reading");
		} else {
		LL_I2C_TransmitData8(i2c, val);
		}

		LL_I2C_TransmitData8(i2c, val);

		return;
		}

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