linux-kernel - Re: [PATCH v3 05/14] [media] cxd2880: Add tuner part of the driver

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Message-ID: <22918ced-b130-abf6-847d-369b7a5c0ebf@sony.com>
Date:   Thu, 7 Sep 2017 19:12:57 +0900
From:   "Takiguchi, Yasunari" <Yasunari.Takiguchi@...y.com>
To:     Mauro Carvalho Chehab <mchehab@...pensource.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "tbird20d@...il.com" <tbird20d@...il.com>,
        "frowand.list@...il.com" <frowand.list@...il.com>,
        "Yamamoto, Masayuki" <Masayuki.Yamamoto@...y.com>,
        "Nozawa, Hideki (STWN)" <Hideki.Nozawa@...y.com>,
        "Yonezawa, Kota" <Kota.Yonezawa@...y.com>,
        "Matsumoto, Toshihiko" <Toshihiko.Matsumoto@...y.com>,
        "Watanabe, Satoshi (SSS)" <Satoshi.C.Watanabe@...y.com>,
        <yasunari.takiguchi@...y.com>
Subject: Re: [PATCH v3 05/14] [media] cxd2880: Add tuner part of the driver

Dear Mauro

Thanks for your review and reply.

We are going to discuss how to change our code with your comments internally.

I reply for your  2 comments,

>> [Change list]
>> Changes in V3
>>    drivers/media/dvb-frontends/cxd2880/cxd2880_dtv.h
>>       -removed code relevant to ISDB-T
> 
> Just curiosity here: why is it removed?
We decided to withhold the ISDB-T functionality as it contains some company proprietary code.


>> +	if (ret)
>> +		return ret;
>> +	if ((sys == CXD2880_DTV_SYS_DVBT2) && en_fef_intmtnt_ctrl) {
>> +		data[0] = 0x01;
>> +		data[1] = 0x01;
>> +		data[2] = 0x01;
>> +		data[3] = 0x01;
>> +		data[4] = 0x01;
>> +		data[5] = 0x01;
>> +	} else {
>> +		data[0] = 0x00;
>> +		data[1] = 0x00;
>> +		data[2] = 0x00;
>> +		data[3] = 0x00;
>> +		data[4] = 0x00;
>> +		data[5] = 0x00;
>> +	}
> 
> Instead, just do:
> 
> 	if ((sys == CXD2880_DTV_SYS_DVBT2) && en_fef_intmtnt_ctrl)
> 		memset(data, 0x01, sizeof(data));
> 	else
> 		memset(data, 0x00, sizeof(data));
> 
>> +	ret = tnr_dmd->io->write_regs(tnr_dmd->io,
>> +				      CXD2880_IO_TGT_SYS,
>> +				      0xef, data, 6);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = tnr_dmd->io->write_reg(tnr_dmd->io,
>> +				     CXD2880_IO_TGT_DMD,
>> +				     0x00, 0x2d);
>> +	if (ret)
>> +		return ret;
> 
>> +	if ((sys == CXD2880_DTV_SYS_DVBT2) && en_fef_intmtnt_ctrl)
>> +		data[0] = 0x00;
>> +	else
>> +		data[0] = 0x01;
> 
> Not actually needed, as the previous logic already set data[0]
> accordingly.
> 
>> +	ret = tnr_dmd->io->write_reg(tnr_dmd->io,
>> +				     CXD2880_IO_TGT_DMD,
>> +				     0xb1, data[0]);

In this case、logic of data[0]( logic of if() ) is different from that of previous one.
And with setting register for address 0xb1, a bug might occur in the future, 
if our software specification (sequence) is changed.
So we would like to keep setting value of data[0] for address 0xb1.

Thanks,
Takiguchi