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ARM: dts: stm32: use usbphyc ck_usbo_48m as USBH OHCI clock on stm32m…
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…p151

Referring to the note under USBH reset and clocks chapter of RM0436,
"In order to access USBH_OHCI registers it is necessary to activate the USB
clocks by enabling the PLL controlled by USBPHYC" (ck_usbo_48m).

The point is, when USBPHYC PLL is not enabled, OHCI register access
freezes the resume from STANDBY. It is the case when dual USBH is enabled,
instead of OTG + single USBH.
When OTG is probed, as ck_usbo_48m is USBO clock parent, then USBPHYC PLL
is enabled and OHCI register access is OK.

This patch adds ck_usbo_48m (provided by USBPHYC PLL) as clock of USBH
OHCI, thus USBPHYC PLL will be enabled and OHCI register access will be OK.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
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Amelie Delaunay authored and Alexandre Torgue committed Oct 15, 2021
1 parent 1a9a9d2 commit db7be2c
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/arm/boot/dts/stm32mp151.dtsi
Original file line number Diff line number Diff line change
Expand Up @@ -1452,7 +1452,7 @@
usbh_ohci: usb@5800c000 {
compatible = "generic-ohci";
reg = <0x5800c000 0x1000>;
clocks = <&rcc USBH>;
clocks = <&rcc USBH>, <&usbphyc>;
resets = <&rcc USBH_R>;
interrupts = <GIC_SPI 74 IRQ_TYPE_LEVEL_HIGH>;
status = "disabled";
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