RE: [PATCH 000/100] rtc: remove cargo culted code

[Steve Twiss]

On 02 March 2018 08:57, Alexandre Belloni wrote:

> To: Steve Twiss
> Cc: linux-kernel@vger.kernel.org; linux-...@vger.kernel.org
> Subject: Re: [PATCH 000/100] rtc: remove cargo culted code
> 
> On 02/03/2018 at 08:46:48 +, Steve Twiss wrote:
> > Hi Alexandre,
> >
> > Acked for:
> >   rtc: da9063: stop validating rtc_time in .read_time
> >   rtc: da9052: stop validating rtc_time in .read_time
> >   rtc: da9055: stop validating rtc_time in .read_time
> >
> > Acked-by: Steve Twiss <stwiss.opensou...@diasemi.com>
> >

[...]

> > But after some further looking, I have not got any explicit case of how the
> > time read directly from the DA9063
> > registers can be incorrectly represented. So there should be no need to
> > check this.
> 
> My point is that it is checked later in the core anyway so you end up
> doing:
> 
> da9063_rtc_read_time()
>   return rtc_valid_tm(tm);
> 
> __rtc_read_time()
>   if (err < 0)
>   return err;
>   err = rtc_valid_tm(tm);
> 
>   return err;
> 
> So the check in da9063_rtc_read_time is always pointless.

Ahh. I see. Thanks!
Regards,
Steve

RE: [PATCH 000/100] rtc: remove cargo culted code

[Steve Twiss]

On 02 March 2018 08:57, Alexandre Belloni wrote:

> To: Steve Twiss
> Cc: linux-kernel@vger.kernel.org; linux-...@vger.kernel.org
> Subject: Re: [PATCH 000/100] rtc: remove cargo culted code
> 
> On 02/03/2018 at 08:46:48 +, Steve Twiss wrote:
> > Hi Alexandre,
> >
> > Acked for:
> >   rtc: da9063: stop validating rtc_time in .read_time
> >   rtc: da9052: stop validating rtc_time in .read_time
> >   rtc: da9055: stop validating rtc_time in .read_time
> >
> > Acked-by: Steve Twiss 
> >

[...]

> > But after some further looking, I have not got any explicit case of how the
> > time read directly from the DA9063
> > registers can be incorrectly represented. So there should be no need to
> > check this.
> 
> My point is that it is checked later in the core anyway so you end up
> doing:
> 
> da9063_rtc_read_time()
>   return rtc_valid_tm(tm);
> 
> __rtc_read_time()
>   if (err < 0)
>   return err;
>   err = rtc_valid_tm(tm);
> 
>   return err;
> 
> So the check in da9063_rtc_read_time is always pointless.

Ahh. I see. Thanks!
Regards,
Steve

Re: [PATCH 000/100] rtc: remove cargo culted code

[Alexandre Belloni]

On 02/03/2018 at 08:46:48 +, Steve Twiss wrote:
> On Wed, Feb 21, 2018 at 8:54 PM, Alexandre Belloni wrote:
>  
> > subject:[PATCH 000/100] rtc: remove cargo culted code
> > mailing list:   linux-kernel@vger.kernel.org Filter messages from this 
> > mailing list
> >
> > Hello,
> >
> > This series:
> >  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
> >.set_alarm
> >  - removes code setting default values for RTCs (and lets the core
> >handle it)
> >  - removes useless "time is invalid" messages at probe time
> >  - removes useless indirect calls
> >
> > Those were mostly copy pasted from other drivers
> 
> Hi Alexandre,
> 
> Acked for:
>   rtc: da9063: stop validating rtc_time in .read_time
>   rtc: da9052: stop validating rtc_time in .read_time
>   rtc: da9055: stop validating rtc_time in .read_time
> 
> Acked-by: Steve Twiss 
> 
> Agreed -- rtc_valid_tm() call is cargo cult for the above.
> 
> (By definition) for DA9063 I was trying to be rigorous.
> The .read_time function is slightly different here because I can make a copy 
> the alarm time into the RTC time
> structure to solve an RTC synchronisation problem internally to the DA9063.
> https://elixir.bootlin.com/linux/v4.5.6/source/drivers/rtc/rtc-da9063.c#L253
> 
> But after some further looking, I have not got any explicit case of how the 
> time read directly from the DA9063
> registers can be incorrectly represented. So there should be no need to check 
> this.
> 

My point is that it is checked later in the core anyway so you end up
doing:

da9063_rtc_read_time()
return rtc_valid_tm(tm);

__rtc_read_time()
if (err < 0)
return err;
err = rtc_valid_tm(tm);

return err;

So the check in da9063_rtc_read_time is always pointless.


-- 
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH 000/100] rtc: remove cargo culted code

[Alexandre Belloni]

On 02/03/2018 at 08:46:48 +, Steve Twiss wrote:
> On Wed, Feb 21, 2018 at 8:54 PM, Alexandre Belloni wrote:
>  
> > subject:[PATCH 000/100] rtc: remove cargo culted code
> > mailing list:   linux-kernel@vger.kernel.org Filter messages from this 
> > mailing list
> >
> > Hello,
> >
> > This series:
> >  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
> >.set_alarm
> >  - removes code setting default values for RTCs (and lets the core
> >handle it)
> >  - removes useless "time is invalid" messages at probe time
> >  - removes useless indirect calls
> >
> > Those were mostly copy pasted from other drivers
> 
> Hi Alexandre,
> 
> Acked for:
>   rtc: da9063: stop validating rtc_time in .read_time
>   rtc: da9052: stop validating rtc_time in .read_time
>   rtc: da9055: stop validating rtc_time in .read_time
> 
> Acked-by: Steve Twiss 
> 
> Agreed -- rtc_valid_tm() call is cargo cult for the above.
> 
> (By definition) for DA9063 I was trying to be rigorous.
> The .read_time function is slightly different here because I can make a copy 
> the alarm time into the RTC time
> structure to solve an RTC synchronisation problem internally to the DA9063.
> https://elixir.bootlin.com/linux/v4.5.6/source/drivers/rtc/rtc-da9063.c#L253
> 
> But after some further looking, I have not got any explicit case of how the 
> time read directly from the DA9063
> registers can be incorrectly represented. So there should be no need to check 
> this.
> 

My point is that it is checked later in the core anyway so you end up
doing:

da9063_rtc_read_time()
return rtc_valid_tm(tm);

__rtc_read_time()
if (err < 0)
return err;
err = rtc_valid_tm(tm);

return err;

So the check in da9063_rtc_read_time is always pointless.


-- 
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

RE: [PATCH 000/100] rtc: remove cargo culted code

[Steve Twiss]

On Wed, Feb 21, 2018 at 8:54 PM, Alexandre Belloni wrote:
 
> subject:  [PATCH 000/100] rtc: remove cargo culted code
> mailing list: linux-kernel@vger.kernel.org Filter messages from this mailing 
> list
>
> Hello,
>
> This series:
>  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
>.set_alarm
>  - removes code setting default values for RTCs (and lets the core
>handle it)
>  - removes useless "time is invalid" messages at probe time
>  - removes useless indirect calls
>
> Those were mostly copy pasted from other drivers

Hi Alexandre,

Acked for:
  rtc: da9063: stop validating rtc_time in .read_time
  rtc: da9052: stop validating rtc_time in .read_time
  rtc: da9055: stop validating rtc_time in .read_time

Acked-by: Steve Twiss 

Agreed -- rtc_valid_tm() call is cargo cult for the above.

(By definition) for DA9063 I was trying to be rigorous.
The .read_time function is slightly different here because I can make a copy 
the alarm time into the RTC time
structure to solve an RTC synchronisation problem internally to the DA9063.
https://elixir.bootlin.com/linux/v4.5.6/source/drivers/rtc/rtc-da9063.c#L253

But after some further looking, I have not got any explicit case of how the 
time read directly from the DA9063
registers can be incorrectly represented. So there should be no need to check 
this.

Regards,
Steve

RE: [PATCH 000/100] rtc: remove cargo culted code

[Steve Twiss]

On Wed, Feb 21, 2018 at 8:54 PM, Alexandre Belloni wrote:
 
> subject:  [PATCH 000/100] rtc: remove cargo culted code
> mailing list: linux-kernel@vger.kernel.org Filter messages from this mailing 
> list
>
> Hello,
>
> This series:
>  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
>.set_alarm
>  - removes code setting default values for RTCs (and lets the core
>handle it)
>  - removes useless "time is invalid" messages at probe time
>  - removes useless indirect calls
>
> Those were mostly copy pasted from other drivers

Hi Alexandre,

Acked for:
  rtc: da9063: stop validating rtc_time in .read_time
  rtc: da9052: stop validating rtc_time in .read_time
  rtc: da9055: stop validating rtc_time in .read_time

Acked-by: Steve Twiss 

Agreed -- rtc_valid_tm() call is cargo cult for the above.

(By definition) for DA9063 I was trying to be rigorous.
The .read_time function is slightly different here because I can make a copy 
the alarm time into the RTC time
structure to solve an RTC synchronisation problem internally to the DA9063.
https://elixir.bootlin.com/linux/v4.5.6/source/drivers/rtc/rtc-da9063.c#L253

But after some further looking, I have not got any explicit case of how the 
time read directly from the DA9063
registers can be incorrectly represented. So there should be no need to check 
this.

Regards,
Steve

Re: [PATCH 000/100] rtc: remove cargo culted code

[Alexandre Belloni]

On 22/02/2018 at 07:48:03 -0800, Christoph Hellwig wrote:
> On Wed, Feb 21, 2018 at 09:54:55PM +0100, Alexandre Belloni wrote:
> > Hello,
> > 
> > This series:
> >  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
> >.set_alarm
> >  - removes code setting default values for RTCs (and lets the core
> >handle it)
> >  - removes useless "time is invalid" messages at probe time
> >  - removes useless indirect calls
> 
> Seems like this could be just one patch for each of the issues..

I'll probably squash the simpler ones before sending to Linus.

-- 
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH 000/100] rtc: remove cargo culted code

[Alexandre Belloni]

On 22/02/2018 at 07:48:03 -0800, Christoph Hellwig wrote:
> On Wed, Feb 21, 2018 at 09:54:55PM +0100, Alexandre Belloni wrote:
> > Hello,
> > 
> > This series:
> >  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
> >.set_alarm
> >  - removes code setting default values for RTCs (and lets the core
> >handle it)
> >  - removes useless "time is invalid" messages at probe time
> >  - removes useless indirect calls
> 
> Seems like this could be just one patch for each of the issues..

I'll probably squash the simpler ones before sending to Linus.

-- 
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH 000/100] rtc: remove cargo culted code

[Christoph Hellwig]

On Wed, Feb 21, 2018 at 09:54:55PM +0100, Alexandre Belloni wrote:
> Hello,
> 
> This series:
>  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
>.set_alarm
>  - removes code setting default values for RTCs (and lets the core
>handle it)
>  - removes useless "time is invalid" messages at probe time
>  - removes useless indirect calls

Seems like this could be just one patch for each of the issues..

Re: [PATCH 000/100] rtc: remove cargo culted code

[Christoph Hellwig]

On Wed, Feb 21, 2018 at 09:54:55PM +0100, Alexandre Belloni wrote:
> Hello,
> 
> This series:
>  - removes useless calls to rtc_valid_tm in .read_time, .set_time and
>.set_alarm
>  - removes code setting default values for RTCs (and lets the core
>handle it)
>  - removes useless "time is invalid" messages at probe time
>  - removes useless indirect calls

Seems like this could be just one patch for each of the issues..