Re: [PATCH] OMAP3: PM: Adding T2 enabling of smartreflex

Gulati, Shweta
2011-01-20T13:14:07Z

On Wed, Jan 19, 2011 at 5:54 PM, Nishanth Menon <nm@ti.com> wrote:
> Gulati, Shweta wrote, on 01/19/2011 02:10 PM:
>>
>>     >I cant see how disable_sr is usable, further as discussed in
>>    http://marc.info/?l=linux->omap&m=129424774929498&w=2
>>    <http://marc.info/?l=linux-omap&m=129424774929498&w=2> we decided to
>>    introduce api *if needed*. does any one need it?
>>
>>    There might be some OMAP3xxx chips where for DVFS VMODE or VSEL
>>    method is used, for those boards this disable API could be called
>>    from Board File,  to make sure the sequence of execution  of
>>
>>     late_init_call of twl_init from omap2_common_pm_late_init does not
>> hamper clearing of this bit I would add a global variable to keep track
>> if Resetting is required or not, will submit V2 with changes.
>
> Apologies, but a Dumb question:
>
> late_initcall(omap2_common_pm_late_init)
> board files(arch/arm/include/asm/mach/arch.h machine_desc) tend to have the
> following hooks:
>
> void                    (*fixup)(struct machine_desc *,
>                                 struct tag *, char **,
>                                 struct meminfo *);
> void                    (*reserve)(void);/* reserve mem blocks  */
> void                    (*map_io)(void);/* IO mapping function  */
> void                    (*init_early)(void);
> void                    (*init_irq)(void);
> struct sys_timer        *timer;         /* system tick timer    */
> void                    (*init_machine (void);
> void                    (*handle_irq)(struct pt_regs *);
>
> So if i wanted to disable the SR setting, where should I do it?
>
> --
> Regards,
> Nishanth Menon

Nishanth,

I think i could not make my point clear in my previous reply.

There are two APIs added 'omap3_twl_disable_sr' and
'omap3_twl_enable_sr'. omap3_twl_enable_sr sets SR bit in TWL4030
registers to make sure VPforceupdate method of voltage scaling works
properly but there could be some OMAP3xxx chips where VMODE or VSEL
method of voltage scaling is used (though today these voltage scaling
methods are not recommended by HW folks). For the boards where
Vpforceupdate method is used this 'omap3_twl_disable_sr' would not be
called. For possible case of platforms where VMODE or VSEL methods
are used the API 'omap3_twl_disable_sr' will reset this bit.
The API 'omap3_twl_disable_sr' can be called from board file, to make
sure the resetting of this bit is not
overwritten in late_init call of omap3_twl_init(where
'omap3_twl_enable_sr' is called) I suggested adding a
global flag which will keep track whether this bit is cleared from
board file or not.
Would make these changes in V2.

Regards,
Shweta
> PS: could you please fix your mailer when replying on l-o for netetiquette
> reasons?
>

--
Thanks,
Regards,
Shweta
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