linux-kernel - Re: [PATCH 1/3] media: cx231xx: Convert enum into a define

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Message-ID: <c896221c-5ff2-4a2b-b431-7c7f805b4f68@xs4all.nl>
Date: Thu, 20 Feb 2025 14:55:42 +0100
From: Hans Verkuil <hverkuil@...all.nl>
To: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
 Ricardo Ribalda <ribalda@...omium.org>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
 Nathan Chancellor <nathan@...nel.org>,
 Nick Desaulniers <ndesaulniers@...gle.com>, Bill Wendling
 <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
 Hans de Goede <hdegoede@...hat.com>,
 Sakari Ailus <sakari.ailus@...ux.intel.com>,
 Andy Shevchenko <andy@...nel.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Tiffany Lin <tiffany.lin@...iatek.com>,
 Andrew-CT Chen <andrew-ct.chen@...iatek.com>,
 Yunfei Dong <yunfei.dong@...iatek.com>,
 Matthias Brugger <matthias.bgg@...il.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
 llvm@...ts.linux.dev, linux-staging@...ts.linux.dev,
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH 1/3] media: cx231xx: Convert enum into a define

On 12/3/24 09:31, Mauro Carvalho Chehab wrote:
> Em Mon, 02 Dec 2024 15:47:15 +0000
> Ricardo Ribalda <ribalda@...omium.org> escreveu:
> 
>> The code is running arithmentics with the enum, which when not done with
>> care makes the compiler a bit nervous.
>>
>> Because those enums are only used as defines (no argument or variable
>> from that enumeration type), convert it into a define and move on.
>>
>> It is required to build with llvm 9 without these warnings:
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:673:17: warning: bitwise operation between different enumeration types ('enum TS_PORT' and 'enum POWE_TYPE') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:680:21: warning: bitwise operation between different enumeration types ('enum AVDEC_STATUS' and 'enum POWE_TYPE') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:687:21: warning: bitwise operation between different enumeration types ('enum AVDEC_STATUS' and 'enum POWE_TYPE') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:702:17: warning: bitwise operation between different enumeration types ('enum TS_PORT' and 'enum POWE_TYPE') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:709:21: warning: bitwise operation between different enumeration types ('enum TS_PORT' and 'enum POWE_TYPE') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:718:21: warning: bitwise operation between different enumeration types ('enum AVDEC_STATUS' and 'enum POWE_TYPE') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:727:21: warning: bitwise operation between different enumeration types ('enum AVDEC_STATUS' and 'enum TS_PORT') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:737:21: warning: bitwise operation between different enumeration types ('enum AVDEC_STATUS' and 'enum TS_PORT') [-Wenum-enum-conversion]
>> drivers/media/usb/cx231xx/cx231xx-pcb-cfg.c:749:21: warning: bitwise operation between different enumeration types ('enum AVDEC_STATUS' and 'enum TS_PORT') [-Wenum-enum-conversion]
>>
>> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
>> ---
>>  drivers/media/usb/cx231xx/cx231xx-pcb-cfg.h | 18 +++++++-----------
>>  1 file changed, 7 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/media/usb/cx231xx/cx231xx-pcb-cfg.h b/drivers/media/usb/cx231xx/cx231xx-pcb-cfg.h
>> index 5bc44f194d0a..62ffa16bb82c 100644
>> --- a/drivers/media/usb/cx231xx/cx231xx-pcb-cfg.h
>> +++ b/drivers/media/usb/cx231xx/cx231xx-pcb-cfg.h
>> @@ -57,19 +57,17 @@ enum USB_SPEED{
>>  };
>>  
>>  #define TS_MASK         0x6
>> -enum TS_PORT{
>> -	NO_TS_PORT = 0x0,	/* 2'b00: Neither port used. PCB not a Hybrid,
>> +#define NO_TS_PORT	0x0	/* 2'b00: Neither port used. PCB not a Hybrid,
>>  				   only offers Analog TV or Video */
>> -	TS1_PORT = 0x4,		/* 2'b10: TS1 Input (Hybrid mode :
>> +#define TS1_PORT	0x4	/* 2'b10: TS1 Input (Hybrid mode :
>>  				Digital or External Analog/Compressed source) */
>> -	TS1_TS2_PORT = 0x6,	/* 2'b11: TS1 & TS2 Inputs
>> +#define TS1_TS2_PORT	0x6	/* 2'b11: TS1 & TS2 Inputs
>>  				(Dual inputs from Digital and/or
>>  				External Analog/Compressed sources) */
>> -	TS1_EXT_CLOCK = 0x6,	/* 2'b11: TS1 & TS2 as selector
>> +#define TS1_EXT_CLOCK	0x6	/* 2'b11: TS1 & TS2 as selector
>>  						to external clock */
>> -	TS1VIP_TS2_PORT = 0x2	/* 2'b01: TS1 used as 656/VIP Output,
>> +#define TS1VIP_TS2_PORT 0x2	/* 2'b01: TS1 used as 656/VIP Output,
>>  				   TS2 Input (from Compressor) */
>> -};
>>  
>>  #define EAVP_MASK       0x8
>>  enum EAV_PRESENT{
>> @@ -89,10 +87,8 @@ enum AT_MODE{
>>  };
>>  
>>  #define PWR_SEL_MASK    0x40
>> -enum POWE_TYPE{
>> -	SELF_POWER = 0x0,	/* 0: self power */
>> -	BUS_POWER = 0x40	/* 1: bus power */
>> -};
>> +#define SELF_POWER	0x0	/* 0: self power */
>> +#define BUS_POWER	0x40	/* 1: bus power */
>>  
>>  enum USB_POWE_TYPE{
>>  	USB_SELF_POWER = 0,
>>
> 
> IMO keeping them into enums are a lot better than defines.
> 
> Perhaps the right thing would be to join both enums here.

ORing enums is really not a good idea: you would normally never do that, and the
compiler warning is IMHO appropriate.

I think this is a good change and I plan to take this.

Regards,

	Hans

> 
> 
> Thanks,
> Mauro
>