Hi Krzysztof, > Add startup time to LDO regulators of S2MPS11 PMIC on Odroid > XU3/XU4/HC1 family of boards to be sure the voltage is proper before > relying on the regulator. > > The datasheet for all the S2MPS1x family is inconsistent here and does > not specify unambiguously the value of ramp delay for LDO. It > mentions 30 mV/us in one timing diagram but then omits it completely > in LDO regulator characteristics table (it is specified for bucks). > > However the vendor kernels for Galaxy S5 and Odroid XU3 use values of > 12 mV/us or 24 mV/us. > > Without the ramp delay value the consumers do not wait for voltage > settle after changing it. Although the proper value of ramp delay for > LDOs is unknown, it seems safer to use at least some value from > reference kernel than to leave it unset. > > Signed-off-by: Krzysztof Kozlowski <k...@kernel.org>
Reviewed-by: Lukasz Majewski <lu...@denx.de> > --- > arch/arm/dts/exynos5422-odroidxu3.dts | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/arch/arm/dts/exynos5422-odroidxu3.dts > b/arch/arm/dts/exynos5422-odroidxu3.dts index > 9dfae90667cf..04ecc404f907 100644 --- > a/arch/arm/dts/exynos5422-odroidxu3.dts +++ > b/arch/arm/dts/exynos5422-odroidxu3.dts @@ -45,6 +45,7 @@ > regulator-name = "vdd_ldo1"; > regulator-min-microvolt = > <1000000>; regulator-max-microvolt = <1000000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -52,18 +53,21 @@ > regulator-name = "vddq_mmc0"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; }; > > ldo4_reg: LDO4 { > regulator-name = "vdd_adc"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; }; > > ldo5_reg: LDO5 { > regulator-name = "vdd_ldo5"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -71,6 +75,7 @@ > regulator-name = "vdd_ldo6"; > regulator-min-microvolt = > <1000000>; regulator-max-microvolt = <1000000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -78,6 +83,7 @@ > regulator-name = "vdd_ldo7"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -85,6 +91,7 @@ > regulator-name = "vdd_ldo8"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -92,6 +99,7 @@ > regulator-name = "vdd_ldo9"; > regulator-min-microvolt = > <3000000>; regulator-max-microvolt = <3000000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -99,6 +107,7 @@ > regulator-name = "vdd_ldo10"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -106,6 +115,7 @@ > regulator-name = "vdd_ldo11"; > regulator-min-microvolt = > <1000000>; regulator-max-microvolt = <1000000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -113,6 +123,7 @@ > regulator-name = "vdd_ldo12"; > regulator-min-microvolt = > <1800000>; regulator-max-microvolt = <1800000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -120,12 +131,14 @@ > regulator-name = "vddq_mmc2"; > regulator-min-microvolt = > <2800000>; regulator-max-microvolt = <2800000>; > + regulator-ramp-delay = > <12000>; }; > > ldo15_reg: LDO15 { > regulator-name = "vdd_ldo15"; > regulator-min-microvolt = > <3300000>; regulator-max-microvolt = <3300000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -133,6 +146,7 @@ > regulator-name = "vdd_ldo16"; > regulator-min-microvolt = > <2200000>; regulator-max-microvolt = <2200000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -140,6 +154,7 @@ > regulator-name = "vdd_ldo17"; > regulator-min-microvolt = > <3300000>; regulator-max-microvolt = <3300000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -147,18 +162,21 @@ > regulator-name = > "vdd_emmc_1V8"; regulator-min-microvolt = <1800000>; > regulator-max-microvolt = > <1800000>; > + regulator-ramp-delay = > <12000>; }; > > ldo19_reg: LDO19 { > regulator-name = "vdd_sd"; > regulator-min-microvolt = > <2800000>; regulator-max-microvolt = <2800000>; > + regulator-ramp-delay = > <12000>; }; > > ldo24_reg: LDO24 { > regulator-name = "tsp_io"; > regulator-min-microvolt = > <2800000>; regulator-max-microvolt = <2800000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > > @@ -166,6 +184,7 @@ > regulator-name = "vdd_ldo26"; > regulator-min-microvolt = > <3000000>; regulator-max-microvolt = <3000000>; > + regulator-ramp-delay = > <12000>; regulator-always-on; > }; > Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lu...@denx.de
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