diff mbox series

[v1,02/14] serial: core: Add UPIO_UNSET constant for unset port type

Message ID 20240221183442.4124354-3-andriy.shevchenko@linux.intel.com
State New
Headers
Series serial: Add a helper to parse device properties and more |

Commit Message

Andy Shevchenko Feb. 21, 2024, 6:31 p.m. UTC 
  In some APIs we would like to assign the special value to iotype
and compare against it in another places. Introduce UPIO_UNSET
for this purpose.

Note, we can't use 0, because it's a valid value for IO port access.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/serial_core.h | 1 +
 1 file changed, 1 insertion(+)

Comments

Jiri Slaby Feb. 22, 2024, 6:58 a.m. UTC | #1 
On 21. 02. 24, 19:31, Andy Shevchenko wrote:
> In some APIs we would like to assign the special value to iotype
> and compare against it in another places. Introduce UPIO_UNSET
> for this purpose.
> 
> Note, we can't use 0, because it's a valid value for IO port access.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>   include/linux/serial_core.h | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 2d2ec99eca93..2b0526ae1fac 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -470,6 +470,7 @@ struct uart_port {
>   
>   	unsigned char		iotype;			/* io access style */
>   
> +#define UPIO_UNSET		((unsigned char)~0U)	/* UCHAR_MAX */

Perhaps making the var u8 and this U8_MAX then? It would make more sense 
to me.

>   #define UPIO_PORT		(SERIAL_IO_PORT)	/* 8b I/O port access */
>   #define UPIO_HUB6		(SERIAL_IO_HUB6)	/* Hub6 ISA card */
>   #define UPIO_MEM		(SERIAL_IO_MEM)		/* driver-specific */

thanks,
Andy Shevchenko Feb. 22, 2024, 1:21 p.m. UTC | #2 
On Thu, Feb 22, 2024 at 07:58:32AM +0100, Jiri Slaby wrote:
> On 21. 02. 24, 19:31, Andy Shevchenko wrote:

..

> >   	unsigned char		iotype;			/* io access style */
> > +#define UPIO_UNSET		((unsigned char)~0U)	/* UCHAR_MAX */
> 
> Perhaps making the var u8 and this U8_MAX then? It would make more sense to
> me.

WFM, should it be a separate change? Btw, how can I justify it?
Jiri Slaby Feb. 23, 2024, 5:42 a.m. UTC | #3 
On 22. 02. 24, 14:21, Andy Shevchenko wrote:
> On Thu, Feb 22, 2024 at 07:58:32AM +0100, Jiri Slaby wrote:
>> On 21. 02. 24, 19:31, Andy Shevchenko wrote:
> 
> ...
> 
>>>    	unsigned char		iotype;			/* io access style */
>>> +#define UPIO_UNSET		((unsigned char)~0U)	/* UCHAR_MAX */
>>
>> Perhaps making the var u8 and this U8_MAX then? It would make more sense to
>> me.
> 
> WFM, should it be a separate change?

Likely.

> Btw, how can I justify it?

Hmm, thinking about it, why is it not an enum?

But it could be also an u8 because you want it be exactly 8 bits as you 
want to be sure values up to 255 fit.

thanks,
Andy Shevchenko Feb. 23, 2024, 2:59 p.m. UTC | #4 
On Fri, Feb 23, 2024 at 06:42:15AM +0100, Jiri Slaby wrote:
> On 22. 02. 24, 14:21, Andy Shevchenko wrote:
> > On Thu, Feb 22, 2024 at 07:58:32AM +0100, Jiri Slaby wrote:
> > > On 21. 02. 24, 19:31, Andy Shevchenko wrote:

..

> > > >    	unsigned char		iotype;			/* io access style */
> > > > +#define UPIO_UNSET		((unsigned char)~0U)	/* UCHAR_MAX */
> > > 
> > > Perhaps making the var u8 and this U8_MAX then? It would make more sense to
> > > me.
> > 
> > WFM, should it be a separate change?
> 
> Likely.

Then I need a commit message, because I'm unable to justify this change myself.

> > Btw, how can I justify it?
> 
> Hmm, thinking about it, why is it not an enum?

Maybe, but it is a replica of UAPI definitions, do we want to see it as a enum?
To me it will be a bit ugly looking.

> But it could be also an u8 because you want it be exactly 8 bits as you want
> to be sure values up to 255 fit.

Depends on what we assume UAPI does with those flags. It maybe even less than
8 bits, or great than, currently 8 bits is enough...

TL;DR: I would rather take a patch from you and incorporate into the series
than trying hard to invent a justification and proper type.
Andy Shevchenko Feb. 26, 2024, 2:17 p.m. UTC | #5 
On Fri, Feb 23, 2024 at 04:59:25PM +0200, Andy Shevchenko wrote:
> On Fri, Feb 23, 2024 at 06:42:15AM +0100, Jiri Slaby wrote:
> > On 22. 02. 24, 14:21, Andy Shevchenko wrote:
> > > On Thu, Feb 22, 2024 at 07:58:32AM +0100, Jiri Slaby wrote:
> > > > On 21. 02. 24, 19:31, Andy Shevchenko wrote:

..

> > > > >    	unsigned char		iotype;			/* io access style */
> > > > > +#define UPIO_UNSET		((unsigned char)~0U)	/* UCHAR_MAX */
> > > > 
> > > > Perhaps making the var u8 and this U8_MAX then? It would make more sense to
> > > > me.
> > > 
> > > WFM, should it be a separate change?
> > 
> > Likely.
> 
> Then I need a commit message, because I'm unable to justify this change myself.
> 
> > > Btw, how can I justify it?
> > 
> > Hmm, thinking about it, why is it not an enum?
> 
> Maybe, but it is a replica of UAPI definitions, do we want to see it as a enum?
> To me it will be a bit ugly looking.
> 
> > But it could be also an u8 because you want it be exactly 8 bits as you want
> > to be sure values up to 255 fit.
> 
> Depends on what we assume UAPI does with those flags. It maybe even less than
> 8 bits, or great than, currently 8 bits is enough...
> 
> TL;DR: I would rather take a patch from you and incorporate into the series
> than trying hard to invent a justification and proper type.

Okay, I want to send a new version, for now I leave the type change for
the next time. It looks that quirks as well will benefit from type clarifying.
diff mbox series

Patch

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 2d2ec99eca93..2b0526ae1fac 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -470,6 +470,7 @@  struct uart_port {
 
 	unsigned char		iotype;			/* io access style */
 
+#define UPIO_UNSET		((unsigned char)~0U)	/* UCHAR_MAX */
 #define UPIO_PORT		(SERIAL_IO_PORT)	/* 8b I/O port access */
 #define UPIO_HUB6		(SERIAL_IO_HUB6)	/* Hub6 ISA card */
 #define UPIO_MEM		(SERIAL_IO_MEM)		/* driver-specific */