linux-kernel - Re: [PATCH v2 3/4] i2c: imx: Simplify stopped state tracking

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Message-ID: <87k1ozzquk.fsf@gmail.com>
Date:   Thu, 09 Aug 2018 14:06:43 +0200
From:   Esben Haabendal <esben.haabendal@...il.com>
To:     Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc:     linux-i2c@...r.kernel.org,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Yuan Yao <yao.yuan@...escale.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Phil Reid <preid@...ctromag.com.au>,
        Lucas Stach <l.stach@...gutronix.de>,
        Clemens Gruber <clemens.gruber@...ruber.com>,
        Peter Rosin <peda@...ntia.se>,
        Fabio Estevam <fabio.estevam@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/4] i2c: imx: Simplify stopped state tracking

Uwe Kleine-König <u.kleine-koenig@...gutronix.de> writes:

> On Mon, Jul 09, 2018 at 11:43:03AM +0200, Esben Haabendal wrote:
>> From: Esben Haabendal <eha@...f.com>
>> 
>> Always update the stopped state when busy status have been checked.
>> This is identical to what was done before, with the exception of error
>> handling.
>> Without this change, some errors cause the stopped state to be left in
>> incorrect state in i2c_imx_stop(), i2c_imx_dma_read(), i2c_imx_read() and
>> i2c_imx_xfer().
>> 
>> Signed-off-by: Esben Haabendal <eha@...f.com>
>> ---
>>  drivers/i2c/busses/i2c-imx.c | 12 ++++++------
>>  1 file changed, 6 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
>> index d86f152176a4..1db8e6790afc 100644
>> --- a/drivers/i2c/busses/i2c-imx.c
>> +++ b/drivers/i2c/busses/i2c-imx.c
>> @@ -421,10 +421,14 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
>>  			return -EAGAIN;
>>  		}
>>  
>> -		if (for_busy && (temp & I2SR_IBB))
>> +		if (for_busy && (temp & I2SR_IBB)) {
>> +			i2c_imx->stopped = 0;
>>  			break;
>> -		if (!for_busy && !(temp & I2SR_IBB))
>> +		}
>> +		if (!for_busy && !(temp & I2SR_IBB)) {
>> +			i2c_imx->stopped = 1;
>>  			break;
>> +		}
>
> Would it make sense to assign to ->stopped independent of for_busy?

What do you mean?

Assigning to ->stopped on each check for I2SR_IBB in loop, independent
of the for_busy argument?  I don't think so.  The additional assignments
would be to the same value as it is set to already.

>>  		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
>>  			dev_dbg(&i2c_imx->adapter.dev,
>>  				"<%s> I2C bus is busy\n", __func__);
>> @@ -538,7 +542,6 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
>>  	result = i2c_imx_bus_busy(i2c_imx, 1);
>>  	if (result)
>>  		return result;
>> -	i2c_imx->stopped = 0;
>>  
>>  	temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
>>  	temp &= ~I2CR_DMAEN;
>> @@ -569,7 +572,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
>>  
>>  	if (!i2c_imx->stopped) {
>>  		i2c_imx_bus_busy(i2c_imx, 0);
>> -		i2c_imx->stopped = 1;
>>  	}
>
> The braces can go away here.

Will do.

/Esben