Messages in this thread | | | Date | Wed, 17 Dec 2014 12:36:14 -0200 | Subject | Re: [PATCH 4/5] cpufreq: imx6q: add ldo-bypass support | From | Fabio Estevam <> |
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Hi Tim,
On Fri, Oct 31, 2014 at 2:27 AM, Tim Harvey <tharvey@gateworks.com> wrote: > When an external PMIC is used for VDD_SOC and VDD_ARM you can save power by > bypassing the internal LDO's provided by the anantop regulator as long as > you are running less than 1.2GHz. If running at 1.2GHz the IMX6 datasheets > state that you must use the internal LDO's to reduce ripple on the suplies. > > A failure to bypass the LDO's when using an external PMIC will result in an > extra voltage drop (~125mV) between VDD_ARM_IN and VDD_ARM and VDD_SOC_IN and > VDD_SOC which violates the voltages specificed by the datasheets. > > Cc: Philipp Zabel <p.zabel@pengutronix.de> > Cc: Shawn Guo <shawn.guo@freescale.com> > Signed-off-by: Tim Harvey <tharvey@gateworks.com> > --- > drivers/cpufreq/imx6q-cpufreq.c | 51 +++++++++++++++++++++++++++++++++++++++++
Shouldn't the LDO bypass support be added into the anatop regulator driver instead?
What if someone wants to use LDO bypass and not use the cpufreq driver?
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