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

Pierre Yves MORDRET
2018-03-26T08:21:19Z

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
>>