[v2,6/6] i2c: i2c-stm32f7: Implement I2C recovery mechanism

Message ID 1521650940-11651-7-git-send-email-pierre-yves.mordret@st.com
State Under Review
Headers show
Series
  • Add different features for I2C
Related show

Commit Message

Pierre-Yves MORDRET March 21, 2018, 4:49 p.m.
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 <pierre-yves.mordret@st.com>
---
  Version history:
    v1:
       * Initial
    v2:
       * Don't use i2c engine recovery mechanism since driver
         procedure only recover master and not the slave.
---
---
 drivers/i2c/busses/i2c-stm32f7.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

Comments

Wolfram Sang March 24, 2018, 10:56 p.m. | #1
On Wed, Mar 21, 2018 at 05:49:00PM +0100, Pierre-Yves MORDRET wrote:
> 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 <pierre-yves.mordret@st.com>
> ---
>   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...

> ---
> ---
>  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
>
Pierre-Yves MORDRET March 26, 2018, 8:21 a.m. | #2
On 03/24/2018 11:56 PM, Wolfram Sang wrote:
> On Wed, Mar 21, 2018 at 05:49:00PM +0100, Pierre-Yves MORDRET wrote:
>> 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 <pierre-yves.mordret@st.com>
>> ---
>>   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 ?

>> ---
>> ---
>>  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
>>

Patch

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;
 	}