| Message ID | 20250514082507.1983849-7-dario.binacchi@amarulasolutions.com |
|---|---|
| State | New |
| Headers | show |
| Series |
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| Related | show |
On 14/05/2025 11:25, Dario Binacchi wrote: > From: Wolfgang Birkner <wolfgang.birkner@bshg.com> > > Buck3 is called Buck5 in the BD71847 datasheet. This buck supports > 0.55...1.35V. Set the minimum allowed value. Setting this to PMIC's minimum value has little benefits because the voltage can't be set lower than it anyways. AFICS, the idea of the regulator-min-microvolt and the regulator-max-microvolt is to protect a system which can't tolerate lower/higher than NNN voltage. So, basically, these properties are meaningful when PMIC can go higher / lower than the system design tolerates. In these cases the constrains set in device tree should be strictier than the PMIC's range. The existing regulator-min-microvolt = <700000>; could have resulted from the knowledge that the minimum voltage devices connected to the BUCK3 (5 in data-sheet) can survive is 700 mV. Dropping this to 500mV just because PMIC can go there might be plain wrong, and in some case get the device(s) connected to BUCK3/5 upset.. So, please provide better (more) rationale for this change. > > Signed-off-by: Wolfgang Birkner <wolfgang.birkner@bshg.com> > Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com> > --- > > arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi b/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi > index fd12b97525d1..81fa0a8767e2 100644 > --- a/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi > +++ b/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi > @@ -135,7 +135,7 @@ buck2_reg: BUCK2 { > buck3_reg: BUCK3 { > /* PMIC_BUCK5 - VDD_DRAM_VPU_GPU */ > regulator-name = "buck3"; > - regulator-min-microvolt = <700000>; > + regulator-min-microvolt = <550000>; > regulator-max-microvolt = <1350000>; > regulator-boot-on; > regulator-always-on; Yours, -- Matti To unsubscribe from this group and stop receiving emails from it, send an email to linux-amarula+unsubscribe@amarulasolutions.com.
diff --git a/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi b/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi index fd12b97525d1..81fa0a8767e2 100644 --- a/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi +++ b/arch/arm64/boot/dts/freescale/imx8mn-bsh-smm-s2-common.dtsi @@ -135,7 +135,7 @@ buck2_reg: BUCK2 { buck3_reg: BUCK3 { /* PMIC_BUCK5 - VDD_DRAM_VPU_GPU */ regulator-name = "buck3"; - regulator-min-microvolt = <700000>; + regulator-min-microvolt = <550000>; regulator-max-microvolt = <1350000>; regulator-boot-on; regulator-always-on;