RE: [PATCH 08/11] OMAP3: PM: Disabled I2C4 repeated start operation mode
-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
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? 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
[PATCH 08/11] OMAP3: PM: Disabled I2C4 repeated start operation mode
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. 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
