Re: [PATCH 16/17] OMAP3: PM: Write voltage and clock setup times dynamically in idle loop

[Kevin Hilman <khilman@deeprootsystems.com>]

Tero Kristo <tero.kristo@nokia.com> writes:

> From: Tero Kristo <tero.kristo@nokia.com>
>
> It is suggested by TI (SWPA152 February 2009) to write clksetup,
> voltsetup_time1, voltsetup_time2, voltsetup2 dynamically in idle loop.

Can you summarize the reasons why?

> Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
> ---
>  arch/arm/mach-omap2/pm34xx.c |   36 +++++++++++++++++++++++++-----------
>  1 files changed, 25 insertions(+), 11 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index f492142..ae83121 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -575,6 +575,30 @@ void omap_sram_idle(void)
>  	if (regset_save_on_suspend)
>  		pm_dbg_regset_save(1);
>  
> +	/* Write voltage setup times which are changed dynamically */

AFAICT, we only set these values at init time and they are never
changed.  Are there some forthcoming patches that change these
dynamically?

Kevin

> +	if (core_next_state == PWRDM_POWER_OFF) {
> +		prm_write_mod_reg(0, OMAP3430_GR_MOD,
> +				OMAP3_PRM_VOLTSETUP1_OFFSET);
> +		prm_write_mod_reg(prm_setup.voltsetup2, OMAP3430_GR_MOD,
> +				OMAP3_PRM_VOLTSETUP2_OFFSET);
> +		prm_write_mod_reg(prm_setup.clksetup, OMAP3430_GR_MOD,
> +				OMAP3_PRM_CLKSETUP_OFFSET);
> +	} else {
> +		prm_write_mod_reg((prm_setup.voltsetup_time2 <<
> +				OMAP3430_SETUP_TIME2_SHIFT) |
> +				(prm_setup.voltsetup_time1 <<
> +				OMAP3430_SETUP_TIME1_SHIFT),
> +				OMAP3430_GR_MOD, OMAP3_PRM_VOLTSETUP1_OFFSET);
> +		prm_write_mod_reg(0, OMAP3430_GR_MOD,
> +				OMAP3_PRM_VOLTSETUP2_OFFSET);
> +		/*
> +		 * Use static 1 as only HF_CLKOUT is turned off.
> +		 * Value taken from application note SWPA152
> +		 */
> +		prm_write_mod_reg(0x1, OMAP3430_GR_MOD,
> +				OMAP3_PRM_CLKSETUP_OFFSET);
> +	}
> +
>  	/*
>  	 * omap3_arm_context is the location where ARM registers
>  	 * get saved. The restore path then reads from this
> @@ -1379,19 +1403,9 @@ static void __init configure_vc(void)
>  			  OMAP3430_GR_MOD,
>  			  OMAP3_PRM_VC_I2C_CFG_OFFSET);
>  
> -	/* Write setup times */
> -	prm_write_mod_reg(prm_setup.clksetup, OMAP3430_GR_MOD,
> -			OMAP3_PRM_CLKSETUP_OFFSET);
> -	prm_write_mod_reg((prm_setup.voltsetup_time2 <<
> -			OMAP3430_SETUP_TIME2_SHIFT) |
> -			(prm_setup.voltsetup_time1 <<
> -			OMAP3430_SETUP_TIME1_SHIFT),
> -			OMAP3430_GR_MOD, OMAP3_PRM_VOLTSETUP1_OFFSET);
> -
> +	/* Write static setup times */
>  	prm_write_mod_reg(prm_setup.voltoffset, OMAP3430_GR_MOD,
>  			OMAP3_PRM_VOLTOFFSET_OFFSET);
> -	prm_write_mod_reg(prm_setup.voltsetup2, OMAP3430_GR_MOD,
> -			OMAP3_PRM_VOLTSETUP2_OFFSET);
>  
>  	pm_dbg_regset_init(1);
>  	pm_dbg_regset_init(2);
> -- 
> 1.5.4.3
>
> --
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