>-----Original Message----- >From: ext Kevin Hilman [mailto:khil...@deeprootsystems.com] >Sent: 12 November, 2009 01:30 >To: Kristo Tero (Nokia-D/Tampere) >Cc: linux-omap@vger.kernel.org >Subject: Re: [PATCH 08/11] OMAP3: PM: Disabled I2C4 repeated >start operation mode > >Tero Kristo <tero.kri...@nokia.com> writes: > >> From: Tero Kristo <tero.kri...@nokia.com> >> >> Repeated start forces I2C4 pads low during idle, which >increases power >> consumption through external pull-ups. On the other hand, this change >> increases I2C4 command latencies a bit. > >Could you give an idea about how much the latencies increased?
There is an additional master code (= 10 bits with start + ack) transmitted in the beginning of each I2C4 transmission. It is transmitted in fast/standard mode instead of high-speed, thus the duration of each I2C command is approximately doubled, from 25us to 50us. I'll update the patch description a bit and re-send. > >I'll apply this one but would like to update the changelog with some >more details if available. > >Kevin > >> Signed-off-by: Tero Kristo <tero.kri...@nokia.com> >> --- >> arch/arm/mach-omap2/pm34xx.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/arch/arm/mach-omap2/pm34xx.c >b/arch/arm/mach-omap2/pm34xx.c >> index fec9c38..154cd31 100644 >> --- a/arch/arm/mach-omap2/pm34xx.c >> +++ b/arch/arm/mach-omap2/pm34xx.c >> @@ -1219,7 +1219,7 @@ static void __init configure_vc(void) >> prm_write_mod_reg(OMAP3430_CMD1 | OMAP3430_RAV1, >OMAP3430_GR_MOD, >> OMAP3_PRM_VC_CH_CONF_OFFSET); >> >> - prm_write_mod_reg(OMAP3430_MCODE_SHIFT | OMAP3430_HSEN >| OMAP3430_SREN, >> + prm_write_mod_reg(OMAP3430_MCODE_SHIFT | OMAP3430_HSEN, >> OMAP3430_GR_MOD, >> OMAP3_PRM_VC_I2C_CFG_OFFSET); >> >> -- >> 1.5.4.3 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe >linux-omap" in >> the body of a message to majord...@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
