Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tolunay Orkun]

I am not sure when to use the following RTC choices:

CONFIG_RTC (PC Architecture?)
CONFIG_GEN_RTC
CONFIG_PPC_RTC

I also saw references to CONFIG_GEN_RTC_X with Google searches...

I appreciate if someone explain me when to use each of these kernel config
options?

Best regards,
Tolunay


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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tom Rini]

On Tue, Apr 06, 2004 at 02:00:01PM -0500, Tolunay Orkun wrote:

>
> I am not sure when to use the following RTC choices:
>
> CONFIG_RTC (PC Architecture?)
> CONFIG_GEN_RTC
> CONFIG_PPC_RTC
>
> I also saw references to CONFIG_GEN_RTC_X with Google searches...
>
> I appreciate if someone explain me when to use each of these kernel config
> options?

In the context of 2.4 or 2.6?

--
Tom Rini
http://gate.crashing.org/~trini/

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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tolunay Orkun]

>> CONFIG_RTC (PC Architecture?)
>> CONFIG_GEN_RTC
>> CONFIG_PPC_RTC
>>
>> I also saw references to CONFIG_GEN_RTC_X with Google searches...
>>
>> I appreciate if someone explain me when to use each of these kernel
>> config
>> options?
>
> In the context of 2.4 or 2.6?

2.4


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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tom Rini]

On Tue, Apr 06, 2004 at 03:59:59PM -0500, Tolunay Orkun wrote:

> >> CONFIG_RTC (PC Architecture?)
> >> CONFIG_GEN_RTC
> >> CONFIG_PPC_RTC
> >>
> >> I also saw references to CONFIG_GEN_RTC_X with Google searches...
> >>
> >> I appreciate if someone explain me when to use each of these kernel
> >> config
> >> options?
> >
> > In the context of 2.4 or 2.6?
>
> 2.4

CONFIG_RTC is the "pc style" rtc driver, which works on a number of
arches, so long as they have a rtc chip found in PCs, and it can be
talked to as such.
GEN_RTC is a generic RTC driver, which offers hooks to the architectures
to do the hw-specific portions.  This _could_ be made to work with RTCs
over I2C, but at this time does not.
PPC_RTC is like the above, except it calls the PPC hooks directly, and
is obsolete (and gone in 2.6).

--
Tom Rini
http://gate.crashing.org/~trini/

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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tolunay Orkun]

> GEN_RTC is a generic RTC driver, which offers hooks to the architectures
> to do the hw-specific portions.  This _could_ be made to work with RTCs
> over I2C, but at this time does not.

Can you offer some info/pointers regarding what do I need to implement to
get the generic driver work with my board?

> PPC_RTC is like the above, except it calls the PPC hooks directly, and
> is obsolete (and gone in 2.6).

These hooks are ppc_md.get_rtc_time and ppc_md.set_rtc_time right? I was
thinking of providing these functions in arc/ppc/platforms/csb272.c but if
this driver is obsolete, I would rather use the generic interface above.

Best regards,
Tolunay

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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tom Rini]

On Tue, Apr 06, 2004 at 04:23:26PM -0500, Tolunay Orkun wrote:
> > GEN_RTC is a generic RTC driver, which offers hooks to the architectures
> > to do the hw-specific portions.  This _could_ be made to work with RTCs
> > over I2C, but at this time does not.
>
> Can you offer some info/pointers regarding what do I need to implement to
> get the generic driver work with my board?
>
> > PPC_RTC is like the above, except it calls the PPC hooks directly, and
> > is obsolete (and gone in 2.6).
>
> These hooks are ppc_md.get_rtc_time and ppc_md.set_rtc_time right? I was
> thinking of providing these functions in arc/ppc/platforms/csb272.c but if
> this driver is obsolete, I would rather use the generic interface above.

The generic driver makes use of the ppc_md.*_rtc_time hooks, so that's
the right place to start.  See include/asm-ppc/genrtc.h for the
PPC-specific portions of the genrtc driver, and these bits are what have
to return the right values for your board/rtc chip.

--
Tom Rini
http://gate.crashing.org/~trini/

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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tolunay Orkun]

> On Tue, Apr 06, 2004 at 04:23:26PM -0500, Tolunay Orkun wrote:
>
> The generic driver makes use of the ppc_md.*_rtc_time hooks, so that's
> the right place to start.  See include/asm-ppc/genrtc.h for the
> PPC-specific portions of the genrtc driver, and these bits are what have
> to return the right values for your board/rtc chip.

Thanks. I will look to implement these functions.

Do you happen know what it would take to use the DS1307 driver from LM
Sensors package? Has anyone used LMSensors with PPC Linux?

Best regards,
Tolunay

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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tom Rini]

On Tue, Apr 06, 2004 at 04:51:03PM -0500, Tolunay Orkun wrote:

> > On Tue, Apr 06, 2004 at 04:23:26PM -0500, Tolunay Orkun wrote:
> >
> > The generic driver makes use of the ppc_md.*_rtc_time hooks, so that's
> > the right place to start.  See include/asm-ppc/genrtc.h for the
> > PPC-specific portions of the genrtc driver, and these bits are what have
> > to return the right values for your board/rtc chip.
>
> Thanks. I will look to implement these functions.
>
> Do you happen know what it would take to use the DS1307 driver from LM
> Sensors package? Has anyone used LMSensors with PPC Linux?

LM Sensors implies i2c, which means you'd have to use that, or add a few
more hooks to genrtc (a probe is required for i2c, but not others, maybe
others) to get it working w/ that driver.  But you'd still be using the
main i2c subsystem, which I think you've said is too heavy.

--
Tom Rini
http://gate.crashing.org/~trini/

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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tolunay Orkun]

>> Do you happen know what it would take to use the DS1307 driver from LM
>> Sensors package? Has anyone used LMSensors with PPC Linux?
>
> LM Sensors implies i2c, which means you'd have to use that, or add a few
> more hooks to genrtc (a probe is required for i2c, but not others, maybe
> others) to get it working w/ that driver.  But you'd still be using the
> main i2c subsystem, which I think you've said is too heavy.

No, I already use i2c on this board so i2c driver is included in kernel
configuration. We bring the i2c bus to a header for communication with
some external devices already.

My concern about bloat from rest of LM Sensors. I am not sure if I can
take ds1307 driver from sensors package and include in my build and if so
how/how much additional code to provide /dev/rtc support working.

I can also drop /dev/rtc completely and write a userland application
similar to hwclock and use it to do /dev/i2c I/O to RTC but would like to
standard scheme as much as possible.

Best regards,
Tolunay


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Re: Question on RTC options (CONFIG_RTC, CONFIG_GEN_RTC, CONFIG_PPC_RTC)

[Tom Rini]

On Tue, Apr 06, 2004 at 06:03:37PM -0500, Tolunay Orkun wrote:

> >> Do you happen know what it would take to use the DS1307 driver from LM
> >> Sensors package? Has anyone used LMSensors with PPC Linux?
> >
> > LM Sensors implies i2c, which means you'd have to use that, or add a few
> > more hooks to genrtc (a probe is required for i2c, but not others, maybe
> > others) to get it working w/ that driver.  But you'd still be using the
> > main i2c subsystem, which I think you've said is too heavy.
>
> No, I already use i2c on this board so i2c driver is included in kernel
> configuration. We bring the i2c bus to a header for communication with
> some external devices already.

Ah, OK.

> My concern about bloat from rest of LM Sensors. I am not sure if I can
> take ds1307 driver from sensors package and include in my build and if so
> how/how much additional code to provide /dev/rtc support working.

It should not be too hard, nor too bloaty.

--
Tom Rini
http://gate.crashing.org/~trini/

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