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Subject: Re: [PATCH 1/1] ARM: dts: stm32: use usbphyc ck_usbo_48m as USBH OHCI
 clock on stm32mp151
To:     Amelie Delaunay <amelie.delaunay@foss.st.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Rob Herring <robh+dt@kernel.org>
CC:     <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20211006095355.59078-1-amelie.delaunay@foss.st.com>
From:   Alexandre TORGUE <alexandre.torgue@foss.st.com>
Message-ID: <8bae8e79-97d4-f914-5adf-eee1b6526de6@foss.st.com>
Date:   Fri, 15 Oct 2021 15:31:51 +0200
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On 10/6/21 11:53 AM, Amelie Delaunay wrote:
> 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>
> ---
>   arch/arm/boot/dts/stm32mp151.dtsi | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/stm32mp151.dtsi b/arch/arm/boot/dts/stm32mp151.dtsi
> index bd289bf5d269..fe194c787e6c 100644
> --- a/arch/arm/boot/dts/stm32mp151.dtsi
> +++ b/arch/arm/boot/dts/stm32mp151.dtsi
> @@ -1452,7 +1452,7 @@ stmmac_axi_config_0: stmmac-axi-config {
>   		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";
> 

Applied on stm32-next

regards
Alex