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

Kevin Hilman
2009-10-20T17:47:50Z

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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