On 03/24/2018 11:56 PM, Wolfram Sang wrote:

On Wed, Mar 21, 2018 at 05:49:00PM +0100, Pierre-Yves MORDRET wrote:

quoted

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

Signed-off-by: Pierre-Yves MORDRET <redacted>
---
  Version history:
    v1:
       * Initial
    v2:
       * Don't use i2c engine recovery mechanism since driver
         procedure only recover master and not the slave.

s/recovery/release/ throughout the patch, please. Recovery is really
something else. Also, I think the dev_info's are too noisy in the log
files. I'd think the whole driver could be lifted from quite some
logging...

ok. will do.
Do you have example of info's that we should get rid of ?

quoted

---
---
 drivers/i2c/busses/i2c-stm32f7.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 91f73e0..9a9c469 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c

@@ -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);
 }
 
+static int stm32f7_i2c_recover_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)
 {
 	u32 status;

@@ -727,12 +741,18 @@ static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev)
 					 status,
 					 !(status & STM32F7_I2C_ISR_BUSY),
 					 10, 1000);
+	if (!ret)
+		return 0;
+
+	dev_info(i2c_dev->dev, "bus busy\n");
+
+	ret = stm32f7_i2c_recover_bus(&i2c_dev->adap);
 	if (ret) {
-		dev_dbg(i2c_dev->dev, "bus busy\n");
-		ret = -EBUSY;
+		dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret);
+		return ret;
 	}
 
-	return ret;
+	return -EBUSY;
 }
 
 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) {
 		dev_err(dev, "<%s>: Bus error\n", __func__);
 		writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR);
+		stm32f7_i2c_recover_bus(&i2c_dev->adap);
 		f7_msg->result = -EIO;
 	}
 

-- 
2.7.4