linux-kernel - Re: [PATCH] ARM: dts: rockchip: correct regular setting for act8846

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Date:   Wed, 24 May 2017 13:34:36 +0200
From:   Heiko Stuebner <heiko@...ech.de>
To:     Robin Murphy <robin.murphy@....com>
Cc:     Eddie Cai <eddie.cai.linux@...il.com>, mark.rutland@....com,
        devicetree@...r.kernel.org, linux@...linux.org.uk,
        linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
        robh+dt@...nel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM: dts: rockchip: correct regular setting for act8846

Am Mittwoch, 24. Mai 2017, 11:26:10 CEST schrieb Robin Murphy:
> On 24/05/17 09:17, Heiko Stuebner wrote:
> > Hi Eddie,
> > 
> > Am Mittwoch, 24. Mai 2017, 15:33:41 CEST schrieb Eddie Cai:
> >> the previous setting of act8846 is just copy from firefly board. but
> >> the reload board is a little different from firefly board. let's correct
> >> it.
> >>
> >> Signed-off-by: Eddie Cai <eddie.cai.linux@...il.com>
> >> ---
> >>  arch/arm/boot/dts/rk3288-firefly-reload-core.dtsi | 21 +++++++++++----------
> >>  1 file changed, 11 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/arch/arm/boot/dts/rk3288-firefly-reload-core.dtsi b/arch/arm/boot/dts/rk3288-firefly-reload-core.dtsi
> >> index 8134966..4cfa109 100644
> >> --- a/arch/arm/boot/dts/rk3288-firefly-reload-core.dtsi
> >> +++ b/arch/arm/boot/dts/rk3288-firefly-reload-core.dtsi
> >> @@ -179,6 +179,7 @@
> >>  				regulator-name = "vccio_sd";
> >>  				regulator-min-microvolt = <3300000>;
> >>  				regulator-max-microvolt = <3300000>;
> >> +				regulator-always-on;
> > 
> > the rest below looks pretty straight forward, but why does vccio_sd
> > need to be always on?
> > 
> > I've checked the reload's schematics but did not find any further users
> > of vccio_sd that may warant this attribute.
> 
> It looks like the card detect line is pulled up externally to vcc_sd,
> which isn't always-on either, so you probably do want this - on the
> (unrelated) rk3288 TV box I've been hacking on, I discovered that
> powering off the sdmmc-supply domain also kills the internal pull-up and
> leaves sdmmc_cd floating. The resulting stochastic card polling
> mechanism is amusing, but probably undesirable ;)

Hmm, are you mixing up vcc_sd and vccio_sd?

vccio_sd is the io supply (vqmmc in mmc-terms) to the mmc-host itself
while vcc_sd is the actual card supply (vmmc in mmc-terms).

After looking through some schematics, the pull-up to vcc_sd seems to be
the common pattern for rk3288 devices. So I guess this means the fixed
regulator vcc_sd should get an regulator-always-on instead to stabilize
the card-detect?

Heiko

> > 
> > 
> > Heiko
> > 
> > 
> >>  			};
> >>  
> >>  			vdd10_lcd: REG6 {
> >> @@ -187,24 +188,23 @@
> >>  				regulator-max-microvolt = <1000000>;
> >>  			};
> >>  
> >> -			vcca_18: REG7  {
> >> -				regulator-name = "vcca_18";
> >> -				regulator-min-microvolt = <1800000>;
> >> -				regulator-max-microvolt = <1800000>;
> >> -				regulator-always-on;
> >> +			vcca_33: REG7  {
> >> +				regulator-name = "vcca_33";
> >> +				regulator-min-microvolt = <3300000>;
> >> +				regulator-max-microvolt = <3300000>;
> >>  			};
> >>  
> >> -			vcca_33: REG8 {
> >> -				regulator-name = "vcca_33";
> >> +			vcc_lan: REG8 {
> >> +				regulator-name = "vcc_lan";
> >>  				regulator-min-microvolt = <3300000>;
> >>  				regulator-max-microvolt = <3300000>;
> >> -				regulator-always-on;
> >>  			};
> >>  
> >> -			vcc_lan: REG9 {
> >> -				regulator-name = "vcca_lan";
> >> +			vccio_pmu: REG9 {
> >> +				regulator-name = "vccio_pmu";
> >>  				regulator-min-microvolt = <3300000>;
> >>  				regulator-max-microvolt = <3300000>;
> >> +				regulator-always-on;
> >>  			};
> >>  
> >>  			vdd_10: REG10 {
> >> @@ -218,6 +218,7 @@
> >>  				regulator-name = "vcc_18";
> >>  				regulator-min-microvolt = <1800000>;
> >>  				regulator-max-microvolt = <1800000>;
> >> +				regulator-always-on;
> >>  			};
> >>  
> >>  			vcc18_lcd: REG12 {
> >>
> > 
> > 
> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@...ts.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> > 
> 
> 
> 

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