linux-kernel - Re: [PATCH] [v2] i2c: stm32f7: Fix runtime PM imbalance on error

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Message-ID: <22cad188-c13c-207d-ad8e-fac9d7277346@st.com>
Date:   Fri, 13 Nov 2020 09:27:47 +0100
From:   Pierre Yves MORDRET <pierre-yves.mordret@...com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>,
        "kjlu@....edu" <kjlu@....edu>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [v2] i2c: stm32f7: Fix runtime PM imbalance on error

Hello

Looks good to me

Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@...com>

Thx
Regards


On 6/1/20 7:56 AM, Alain Volmat wrote:
> Hi,
> 
> Reviewed-by: Alain Volmat <alain.volmat@...com>
> 
> Thanks,
> Alain
> 
> On Wed, May 27, 2020 at 01:38:53AM +0000, Dinghao Liu wrote:
>> pm_runtime_get_sync() increments the runtime PM usage counter even
>> the call returns an error code. Thus a pairing decrement is needed
>> on the error handling path to keep the counter balanced.
>>
>> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
>> ---
>>
>> Changelog:
>>
>> v2: - Use pm_runtime_put_noidle() instead of
>>       pm_runtime_put_autosuspend(). Fix 5 more
>>       similar cases within this dirver.
>> ---
>>  drivers/i2c/busses/i2c-stm32f7.c | 24 ++++++++++++++++++------
>>  1 file changed, 18 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
>> index 330ffed011e0..822fd1f5b5ae 100644
>> --- a/drivers/i2c/busses/i2c-stm32f7.c
>> +++ b/drivers/i2c/busses/i2c-stm32f7.c
>> @@ -1620,8 +1620,10 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
>>  	f7_msg->smbus = false;
>>  
>>  	ret = pm_runtime_get_sync(i2c_dev->dev);
>> -	if (ret < 0)
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(i2c_dev->dev);
>>  		return ret;
>> +	}
>>  
>>  	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
>>  	if (ret)
>> @@ -1666,8 +1668,10 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
>>  	f7_msg->smbus = true;
>>  
>>  	ret = pm_runtime_get_sync(dev);
>> -	if (ret < 0)
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(dev);
>>  		return ret;
>> +	}
>>  
>>  	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
>>  	if (ret)
>> @@ -1767,8 +1771,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
>>  		return ret;
>>  
>>  	ret = pm_runtime_get_sync(dev);
>> -	if (ret < 0)
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(dev);
>>  		return ret;
>> +	}
>>  
>>  	if (!stm32f7_i2c_is_slave_registered(i2c_dev))
>>  		stm32f7_i2c_enable_wakeup(i2c_dev, true);
>> @@ -1837,8 +1843,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
>>  	WARN_ON(!i2c_dev->slave[id]);
>>  
>>  	ret = pm_runtime_get_sync(i2c_dev->dev);
>> -	if (ret < 0)
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(i2c_dev->dev);
>>  		return ret;
>> +	}
>>  
>>  	if (id == 0) {
>>  		mask = STM32F7_I2C_OAR1_OA1EN;
>> @@ -2182,8 +2190,10 @@ static int stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
>>  	struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
>>  
>>  	ret = pm_runtime_get_sync(i2c_dev->dev);
>> -	if (ret < 0)
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(i2c_dev->dev);
>>  		return ret;
>> +	}
>>  
>>  	backup_regs->cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
>>  	backup_regs->cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
>> @@ -2204,8 +2214,10 @@ static int stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
>>  	struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
>>  
>>  	ret = pm_runtime_get_sync(i2c_dev->dev);
>> -	if (ret < 0)
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(i2c_dev->dev);
>>  		return ret;
>> +	}
>>  
>>  	cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
>>  	if (cr1 & STM32F7_I2C_CR1_PE)
>> -- 
>> 2.17.1
>>