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Commit 562de4ff authored by Pierre-Yves MORDRET's avatar Pierre-Yves MORDRET Committed by Wolfram Sang
Browse files

i2c: i2c-stm32f7: Implement I2C release mechanism 



Feature prevents I2C lock-ups. Mechanism resets I2C state machine
and releases SCL/SDA signals but preserves I2C registers.

Signed-off-by: default avatarPierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 7ecc8cfd

drivers/i2c/busses/i2c-stm32f7.c

+24 −3
Original line number Original line Diff line number Diff line
@@ -718,6 +718,20 @@ static void stm32f7_i2c_smbus_reload(struct stm32f7_i2c_dev *i2c_dev) 
	writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2);

	writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2);

}

}





static int stm32f7_i2c_release_bus(struct i2c_adapter *i2c_adap)

{

	struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);



	dev_info(i2c_dev->dev, "Trying to recover bus\n");



	stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1,

			     STM32F7_I2C_CR1_PE);



	stm32f7_i2c_hw_config(i2c_dev);



	return 0;

}



static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev)

static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev)

{

{

	u32 status;

	u32 status;
@@ -727,12 +741,18 @@ static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev) 
					 status,

					 status,

					 !(status & STM32F7_I2C_ISR_BUSY),

					 !(status & STM32F7_I2C_ISR_BUSY),

					 10, 1000);

					 10, 1000);

	if (!ret)

		return 0;



	dev_info(i2c_dev->dev, "bus busy\n");



	ret = stm32f7_i2c_release_bus(&i2c_dev->adap);

	if (ret) {

	if (ret) {

		dev_dbg(i2c_dev->dev, "bus busy\n");

		dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret);

		ret = -EBUSY;

		return ret;

	}

	}





	return ret;

	return -EBUSY;

}

}





static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,

static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
@@ -1474,6 +1494,7 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) 
	if (status & STM32F7_I2C_ISR_BERR) {

	if (status & STM32F7_I2C_ISR_BERR) {

		dev_err(dev, "<%s>: Bus error\n", __func__);

		dev_err(dev, "<%s>: Bus error\n", __func__);

		writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR);

		writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR);

		stm32f7_i2c_release_bus(&i2c_dev->adap);

		f7_msg->result = -EIO;

		f7_msg->result = -EIO;

	}

	}