From: "Bogdan, Dragos" <Dragos.Bogdan@analog.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
CC: Lars-Peter Clausen <lars@metafoo.de>,
        "Hennerich, Michael" <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>, Hartmut Knaack <knaack.h@gmx.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] iio:ad7793: Fix the serial interface reset
Thread-Topic: [PATCH] iio:ad7793: Fix the serial interface reset
Thread-Index: AQHTJY6dMdVJ9ijKcUOAd6xVjREEAA==
Date: Mon, 4 Sep 2017 15:33:25 +0000
Message-ID: <6067964B99C6A049AA5840B6F7BB2D0ABDAD4161@NWD2MBX5.ad.analog.com>
References: <20170904150048.12420-1-dragos.bogdan@analog.com>
 <20170904162613.00003d47@huawei.com>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Sep 2017 15:33:26.2874
 (UTC)
X-MS-Exchange-CrossTenant-Id: eaa689b4-8f87-40e0-9c6f-7228de4d754a
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=eaa689b4-8f87-40e0-9c6f-7228de4d754a;Ip=[137.71.25.57];Helo=[nwd2mta4.analog.com]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN3PR03MB2355
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v84FXdmf020729
Content-Length: 1595
Lines: 56

On 09/04/2017 06:27 PM, Jonathan Cameron wrote:
> On Mon, 4 Sep 2017 18:00:48 +0300
> Dragos Bogdan <dragos.bogdan@analog.com> wrote:
>
>> The serial interface can be reset by writing 32 consecutive 1s to the device.
>> The value of 'ret' is overwritten when ad7793_check_platform_data() is called,
>> so it should be initialized to -1 only before doing the spi_write().
>>
>> Fixes: commit 2edb769d246e ("iio:ad7793: Add support for the ad7798 and ad7799")
>>
>> Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
> Hi Dragos,
>
> I'd prefer we introduced a separate variable.  Using ret for this
> is what got us into trouble in the first place.
>
> Would you mind respining with that change?
>
> Thanks,
>
> Jonathan

Hi Jonathan,

I agree with your suggestion. I'll change it accordingly in v2.

Thanks,
Dragos

>> ---
>>  drivers/iio/adc/ad7793.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
>> index e6706a09e100..8680abf72dd2 100644
>> --- a/drivers/iio/adc/ad7793.c
>> +++ b/drivers/iio/adc/ad7793.c
>> @@ -257,7 +257,7 @@ static int ad7793_setup(struct iio_dev *indio_dev,
>>  	unsigned int vref_mv)
>>  {
>>  	struct ad7793_state *st = iio_priv(indio_dev);
>> -	int i, ret = -1;
>> +	int i, ret;
>>  	unsigned long long scale_uv;
>>  	u32 id;
>>  
>> @@ -266,6 +266,7 @@ static int ad7793_setup(struct iio_dev *indio_dev,
>>  		return ret;
>>  
>>  	/* reset the serial interface */
>> +	ret = -1;
>>  	ret = spi_write(st->sd.spi, (u8 *)&ret, sizeof(ret));
>>  	if (ret < 0)
>>  		goto out;
>
>