| Message ID | 20230708173720.3548414-1-dmitry.baryshkov@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ARM: dts: nxp/imx: limit sk-imx53 supported frequencies | expand |
On Sat, Jul 8, 2023 at 2:37 PM Dmitry Baryshkov <dmitry.baryshkov@linaro.org> wrote: > > The SK-IMX53 board bearing i.MX536 CPU is not stable when running at 1.2 > GHz. Disable that frequency. > > Note, officially i.MX536 is rated up to 800 MHz, but running it at 1 GHz > proved to be stable. If the datasheet says the maximum operating frequency is 800 MHz, just adhere to it. Running at 1 GHz on an 800 MHz device is not guaranteed that it works on all the temperature range and across all devices. Better play safe here.
On Sun, 9 Jul 2023 at 15:25, Fabio Estevam <festevam@gmail.com> wrote: > > On Sat, Jul 8, 2023 at 2:37 PM Dmitry Baryshkov > <dmitry.baryshkov@linaro.org> wrote: > > > > The SK-IMX53 board bearing i.MX536 CPU is not stable when running at 1.2 > > GHz. Disable that frequency. > > > > Note, officially i.MX536 is rated up to 800 MHz, but running it at 1 GHz > > proved to be stable. > > If the datasheet says the maximum operating frequency is 800 MHz, just > adhere to it. > > Running at 1 GHz on an 800 MHz device is not guaranteed that it works > on all the temperature range and across all devices. I had to doublecheck this. Original board manufacturer (Starterkit) lists it as "FreeScale iMX536 (ARM Cortex-A8 1000MHz, ...". However I have verified that the board has MCIMX536AVV8C, SoC, which indeed is rated only up to 800 MHz. I'll send v2 using max 800 MHz for safety.
diff --git a/arch/arm/boot/dts/nxp/imx/imx53-sk-imx53.dts b/arch/arm/boot/dts/nxp/imx/imx53-sk-imx53.dts index 6ea103a49697..ccb993ddc445 100644 --- a/arch/arm/boot/dts/nxp/imx/imx53-sk-imx53.dts +++ b/arch/arm/boot/dts/nxp/imx/imx53-sk-imx53.dts @@ -77,6 +77,17 @@ &can1 { status = "okay"; }; +&cpu0 { + /* CPU rated to 800 MHz, not the default 1.2GHz. Keep 1.0 GHz as it seem stable too. */ + operating-points = < + /* kHz uV */ + 166666 850000 + 400000 900000 + 800000 1050000 + 1000000 1200000 + >; +}; + &ecspi1 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_ecspi1>;
The SK-IMX53 board bearing i.MX536 CPU is not stable when running at 1.2 GHz. Disable that frequency. Note, officially i.MX536 is rated up to 800 MHz, but running it at 1 GHz proved to be stable. Fixes: 0b8576d8440a ("ARM: dts: imx: Add support for SK-iMX53 board") Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> --- arch/arm/boot/dts/nxp/imx/imx53-sk-imx53.dts | 11 +++++++++++ 1 file changed, 11 insertions(+)