Messages in this thread | | | Date | Mon, 6 Oct 2014 21:54:41 -0700 | Subject | Re: [PATCH] regulator: rk808: Fix min_uV for DCDC1 & DCDC2 | From | Doug Anderson <> |
| |
Chris and Mark,
On Mon, Oct 6, 2014 at 8:29 PM, Chris Zhong <zyw@rock-chips.com> wrote: > > On 10/01/2014 06:52 AM, Mark Brown wrote: >> >> On Tue, Sep 30, 2014 at 06:57:51PM +0200, Heiko Stübner wrote: >>> >>> Am Dienstag, 30. September 2014, 09:43:47 schrieb Doug Anderson: >>>> >>>> On Tue, Sep 30, 2014 at 2:44 AM, Chris Zhong <zyw@rock-chips.com> wrote: >>>>> >>>>> - REGULATOR_LINEAR_RANGE(700000, 0, 63, 12500), >>>>> + REGULATOR_LINEAR_RANGE(712500, 0, 63, 12500), >>>> >>>> I have no problem with this (and the current "dts" file I see don't go >>>> this low anyway), but it doesn't match the datasheet I have right now >>>> which says "0.700 V" is the min. >>> >>> Then it would be problem. >>> The original statement above says, that a register value of "0" equals >>> 700mV, >>> so changing this in this way would mean everything runs 12.5mV above the >>> target voltage. >>> And I can confirm, that the current datasheet lists 700mV as equallying >>> register value 0. >> >> Has anyone got a voltmeter? > > The latest datasheet has fixed this error. > The register value of "0" equals 712.5mV, so the max value can reach 1.5v > but not 1.4875v.
OK, that sounds like this is the right change, then.
To Mark's point, I measured voltage using the builtin voltage measurement feature this board (not 100% sure the accuracy / precision guarantees on them, but...):
Asked for 1.300 volts on vdd_arm (dcdc1). * Before: got 1.326 * After: got 1.310
Asked for 1.3 on vdd_gpu (dcdc2): * Before: 1.326 * After: got 1.314
Asked for 1.0 on vdd_gpu: * Before: 1.038 * After: got 1.026
Asked for .8 on vdd_gpu * Before:.836 * After: got .822
It almost sounds like we're still running a little too high for voltages, but this gets us in the right direction I guess.
-Doug -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |