From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerome Brunet Subject: Re: [PATCH 3/3] ARM64: dts: meson: fix clock source of the pclk for UART_AO Date: Tue, 27 Mar 2018 11:20:50 +0200 Message-ID: <1522142450.2632.41.camel@baylibre.com> References: <20180326081809.49493-1-yixun.lan@amlogic.com> <20180326081809.49493-4-yixun.lan@amlogic.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180326081809.49493-4-yixun.lan@amlogic.com> Sender: linux-kernel-owner@vger.kernel.org To: Yixun Lan , Neil Armstrong , Kevin Hilman , Carlo Caione Cc: Rob Herring , Michael Turquette , Stephen Boyd , Qiufang Dai , linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org On Mon, 2018-03-26 at 16:18 +0800, Yixun Lan wrote: > From the hardware perspective, the clk81 is the parent of > the UART_AO clocks. So it make more sense to mark > the CLKID_AO_UART1/2 as the pclk. > > Previous we had flag=CLK_IGNORE_UNUSED in AO clock driver. > This will make kernel leave clock as it is while bootloader > set the clock on. > Hi Yixun, I'm not sure I understand your description correctly so I'll phrase. Please tell me if I misunderstood something The actual pclk of the AO uarts is the corresponding clkc_ao uart gate, not the main clock controller clk81. This was not problem so far, because the uart_gate had the CLK_IGNORE_UNUSED flag, which kept the gate open. In another patch, you removed this flag, so you need to give the correct clock in DT to make things work again ? right ? If I got it correctly, please rephrase the description a bit. Also you need to be careful in which order patches get merged. 1. You need the clkc_ao in place, exporting CLKID_AO_UARTx with CLK_IGNORE_UNUSED. 2. This patch can be merged (still with CLK_IGNORE_UNUSED) 3. Once the DT patch have reached mainline, you should a patch to remove to CLK_IGNORE_UNUSED flag This way, we avoid breaking bisect, with revision where CLKID_AO_UARTx would get disabled by the CCF clk_disable_unused() mechanism while the UART driver does not claim the appropriate clock. > Signed-off-by: Yixun Lan > --- > arch/arm64/boot/dts/amlogic/meson-axg.dtsi | 4 ++-- > arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi | 4 ++-- > arch/arm64/boot/dts/amlogic/meson-gxl.dtsi | 4 ++-- > 3 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi > index 48584d5a329b..e538e2448bb5 100644 > --- a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi > +++ b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi > @@ -533,7 +533,7 @@ > compatible = "amlogic,meson-gx-uart", "amlogic,meson-ao-uart"; > reg = <0x0 0x3000 0x0 0x18>; > interrupts = ; > - clocks = <&xtal>, <&clkc CLKID_CLK81>, <&xtal>; > + clocks = <&xtal>, <&clkc_AO CLKID_AO_UART1>, <&xtal>; > clock-names = "xtal", "pclk", "baud"; > status = "disabled"; > }; > @@ -542,7 +542,7 @@ > compatible = "amlogic,meson-gx-uart", "amlogic,meson-ao-uart"; > reg = <0x0 0x4000 0x0 0x18>; > interrupts = ; > - clocks = <&xtal>, <&clkc CLKID_CLK81>, <&xtal>; > + clocks = <&xtal>, <&clkc_AO CLKID_AO_UART2>, <&xtal>; > clock-names = "xtal", "pclk", "baud"; > status = "disabled"; > }; > diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi > index 3290a4dc3522..a458ea50c2ef 100644 > --- a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi > +++ b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi > @@ -783,12 +783,12 @@ > }; > > &uart_AO { > - clocks = <&xtal>, <&clkc CLKID_CLK81>, <&xtal>; > + clocks = <&xtal>, <&clkc_AO CLKID_AO_UART1>, <&xtal>; > clock-names = "xtal", "pclk", "baud"; > }; > > &uart_AO_B { > - clocks = <&xtal>, <&clkc CLKID_CLK81>, <&xtal>; > + clocks = <&xtal>, <&clkc_AO CLKID_AO_UART2>, <&xtal>; > clock-names = "xtal", "pclk", "baud"; > }; > > diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi b/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi > index 4f355f17eed6..474f4f9630e4 100644 > --- a/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi > +++ b/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi > @@ -733,12 +733,12 @@ > }; > > &uart_AO { > - clocks = <&xtal>, <&clkc CLKID_CLK81>, <&xtal>; > + clocks = <&xtal>, <&clkc_AO CLKID_AO_UART1>, <&xtal>; > clock-names = "xtal", "pclk", "baud"; > }; > > &uart_AO_B { > - clocks = <&xtal>, <&clkc CLKID_CLK81>, <&xtal>; > + clocks = <&xtal>, <&clkc_AO CLKID_AO_UART2>, <&xtal>; > clock-names = "xtal", "pclk", "baud"; > }; >