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Date:   Thu, 12 Aug 2021 05:49:53 -0700
From:   Matthias Kaehlcke <mka@chromium.org>
To:     rajpat@codeaurora.org
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, rnayak@codeaurora.org,
        saiprakash.ranjan@codeaurora.org, msavaliy@qti.qualcomm.com,
        skakit@codeaurora.org
Subject: Re: [PATCH V4 2/4] arm64: dts: sc7280: Add QUPv3 wrapper_0 nodes
Message-ID: <YRUY8fpm2AuqNqN+@google.com>
References: <1627306847-25308-1-git-send-email-rajpat@codeaurora.org>
 <1627306847-25308-3-git-send-email-rajpat@codeaurora.org>
 <YP7cmkayoajJ+1yj@google.com>
 <bdfd39def9a11104c043090d920ef4df@codeaurora.org>
 <YRPkI8AQAjjFuXcf@google.com>
 <71fd47e7a83e2c56c96e2638004a7812@codeaurora.org>
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On Thu, Aug 12, 2021 at 12:43:11PM +0530, rajpat@codeaurora.org wrote:
> On 2021-08-11 20:22, Matthias Kaehlcke wrote:
> > On Wed, Aug 11, 2021 at 05:43:48PM +0530, rajpat@codeaurora.org wrote:
> > > On 2021-07-26 21:32, Matthias Kaehlcke wrote:
> > > > On Mon, Jul 26, 2021 at 07:10:45PM +0530, Rajesh Patil wrote:
> > > > > From: Roja Rani Yarubandi <rojay@codeaurora.org>
> > > > >
> > > > > Add QUPv3 wrapper_0 DT nodes for SC7280 SoC.
> > > > >
> > > > > Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> > > > > Signed-off-by: Rajesh Patil <rajpat@codeaurora.org>
> > > > > ---
> > > > > Changes in V4:
> > > > >  - As per Bjorn's comment, added QUP Wrapper_0 nodes
> > > > >    other than debug-uart node
> > > > >  - Dropped interconnect votes for wrapper_0 node
> > > > >
> > > > > Changes in V3:
> > > > >  - Broken the huge V2 patch into 3 smaller patches.
> > > > >    1. QSPI DT nodes
> > > > >    2. QUP wrapper_0 DT nodes
> > > > >    3. QUP wrapper_1 DT nodes
> > > > >
> > > > > Changes in V2:
> > > > >  - As per Doug's comments removed pinmux/pinconf subnodes.
> > > > >  - As per Doug's comments split of SPI, UART nodes has been done.
> > > > >  - Moved QSPI node before aps_smmu as per the order.
> > > > >
> > > > >  arch/arm64/boot/dts/qcom/sc7280-idp.dts |  84 ++++
> > > > >  arch/arm64/boot/dts/qcom/sc7280.dtsi    | 720
> > > > > ++++++++++++++++++++++++++++++++
> > > > >  2 files changed, 804 insertions(+)
> > > > >
> > > > > diff --git a/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > > > b/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > > > index b0bfd8e..f63cf51 100644
> > > > > --- a/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > > > +++ b/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > > > @@ -358,6 +358,16 @@
> > > > >  	vdda18-supply = <&vreg_l1c_1p8>;
> > > > >  };
> > > > >
> > > > > +&uart7 {
> > > > > +	status = "okay";
> > > > > +
> > > > > +	/delete-property/interrupts;
> > > > > +	interrupts-extended = <&intc GIC_SPI 608 IRQ_TYPE_LEVEL_HIGH>,
> > > > > +				<&tlmm 31 IRQ_TYPE_EDGE_FALLING>;
> > > > > +	pinctrl-names = "default", "sleep";
> > > > > +	pinctrl-1 = <&qup_uart7_sleep_cts>, <&qup_uart7_sleep_rts>,
> > > > > <&qup_uart7_sleep_tx>, <&qup_uart7_sleep_rx>;
> > > > > +};
> > > > > +
> > > > >  /* PINCTRL - additions to nodes defined in sc7280.dtsi */
> > > > >
> > > > >  &qspi_cs0 {
> > > > > @@ -428,3 +438,77 @@
> > > > >  		bias-pull-up;
> > > > >  	};
> > > > >  };
> > > > > +&qup_uart7_cts {
> > > > > +	/*
> > > > > +	 * Configure a pull-down on CTS to match the pull of
> > > > > +	 * the Bluetooth module.
> > > > > +	 */
> > > > > +	bias-pull-down;
> > > > > +};
> > > > > +
> > > > > +&qup_uart7_rts {
> > > > > +	/* We'll drive RTS, so no pull */
> > > > > +	drive-strength = <2>;
> > > > > +	bias-disable;
> > > > > +};
> > > > > +
> > > > > +&qup_uart7_tx {
> > > > > +	/* We'll drive TX, so no pull */
> > > > > +	drive-strength = <2>;
> > > > > +	bias-disable;
> > > > > +};
> > > > > +
> > > > > +&qup_uart7_rx {
> > > > > +	/*
> > > > > +	 * Configure a pull-up on RX. This is needed to avoid
> > > > > +	 * garbage data when the TX pin of the Bluetooth module is
> > > > > +	 * in tri-state (module powered off or not driving the
> > > > > +	 * signal yet).
> > > > > +	 */
> > > > > +	bias-pull-up;
> > > > > +};
> > > > > +
> > > > > +&tlmm {
> > > > > +	qup_uart7_sleep_cts: qup-uart7-sleep-cts {
> > > > > +		pins = "gpio28";
> > > > > +		function = "gpio";
> > > > > +		/*
> > > > > +		 * Configure a pull-down on CTS to match the pull of
> > > > > +		 * the Bluetooth module.
> > > > > +		 */
> > > > > +		bias-pull-down;
> > > > > +	};
> > > > > +
> > > > > +	qup_uart7_sleep_rts: qup-uart7-sleep-rts {
> > > > > +		pins = "gpio29";
> > > > > +		function = "gpio";
> > > > > +		/*
> > > > > +		 * Configure pull-down on RTS. As RTS is active low
> > > > > +		 * signal, pull it low to indicate the BT SoC that it
> > > > > +		 * can wakeup the system anytime from suspend state by
> > > > > +		 * pulling RX low (by sending wakeup bytes).
> > > > > +		 */
> > > > > +		bias-pull-down;
> > > > > +	};
> > > > > +
> > > > > +	qup_uart7_sleep_tx: qup-uart7-sleep-tx {
> > > > > +		pins = "gpio30";
> > > > > +		function = "gpio";
> > > > > +		/*
> > > > > +		 * Configure pull-up on TX when it isn't actively driven
> > > > > +		 * to prevent BT SoC from receiving garbage during sleep.
> > > > > +		 */
> > > > > +		bias-pull-up;
> > > > > +	};
> > > > >
> > > > > +	qup_uart7_sleep_rx: qup-uart7-sleep-rx {
> > > > > +		pins = "gpio31";
> > > > > +		function = "gpio";
> > > > > +		/*
> > > > > +		 * Configure a pull-up on RX. This is needed to avoid
> > > > > +		 * garbage data when the TX pin of the Bluetooth module
> > > > > +		 * is floating which may cause spurious wakeups.
> > > > > +		 */
> > > > > +		bias-pull-up;
> > > > > +	};
> > > > > +};
> > > >
> > > > How the patches of this series are split strikes me as a bit odd.
> > > > Supposedly
> > > > this patch adds the QUPv3 wrapper_0 DT nodes for the SC7280, however the
> > > > above is the pin configuration for the Bluetooth UART of the SC7280 IDP
> > > > board.
> > > > I don't see a good reason why that should be part of this patch. It
> > > > should be
> > > > a separate change whose subject indicates that it configures the
> > > > Bluetooth UART
> > > > of the SC7280 IDP.
> > > >
> > > 
> > > Okay will split this up.
> > > 
> > > > Without this conflation of SoC and board DT it would seem perfectly
> > > > reasonable
> > > > to squash this patch and '[4/4] arm64: dts: sc7280: Add QUPv3 wrapper_1
> > > > nodes'
> > > > into a single one, they are essentially doing the same thing, I see no
> > > > need to
> > > > have different patches for the wrapper 0 and 1 nodes.
> > > 
> > > Previously when QUP wrapper 0 and wrapper 1 nodes were added in single
> > > patch, we faced some git issues as the patch was huge. Hence we
> > > split it up.
> > > https://partnerissuetracker.corp.google.com/issues/177045897#comment12
> > 
> > That bug tracker entry isn't public, this is what the comment says:
> > 
> > > I suspect that diff is just having a hard time since your patch
> > > touches so
> > > much stuff. Presumably you could make it happier if you broke your
> > > patch
> > > into smaller changes. For instance:
> > > 
> > > One patch that adds the quad SPI. After all the quad SPI isn't really
> > > related to the other QUP stuff. One patch that fixes up the existing
> > > "uart5" and the QUP it's on to be how it's supposed to be. One patch
> > > that adds all the new stuff.
> > 
> > If I understand correctly the problem wasn't that the QUP wrappers are
> > added in a single patch (which should be pretty straightforward to
> > review), but that the previous patch(es) do too many things at once.
> > Adding both QUP wrappers is conceptionally a single thing, the problem
> > is intermingling that with adding board specific Bluetooth nodes, board
> > flash nodes, pinconf for UART, etc
> 
> Even after splitting the patches as suggested(i.e., additions and
> modifications separately), if I add qup wrapper0 and wrapper1 nodes in
> single patch the git diff is getting messed up. pasted the diff for
> reference
> 
> 
> +                       qup_spi14_cs_gpio: qup-spi14-cs_gpio {
> +                               pins = "gpio59";
> +                               function = "gpio";
> +                       };
> 
> -                       assigned-clocks = <&gcc
> GCC_USB30_PRIM_MOCK_UTMI_CLK>,
> -                                         <&gcc GCC_USB30_PRIM_MASTER_CLK>;
> -                       assigned-clock-rates = <19200000>, <200000000>;
> +                       qup_spi15_data_clk: qup-spi15-data-clk {
> +                               pins = "gpio60", "gpio61", "gpio62";
> +                               function = "qup17";
> +                       };
> 
> -                       interrupts-extended = <&intc GIC_SPI 131
> IRQ_TYPE_LEVEL_HIGH>,
> -                                             <&pdc 14 IRQ_TYPE_EDGE_BOTH>,
> -                                             <&pdc 15 IRQ_TYPE_EDGE_BOTH>,
> -                                             <&pdc 17 IRQ_TYPE_LEVEL_HIGH>;
> -                       interrupt-names = "hs_phy_irq", "dp_hs_phy_irq",
> -                                         "dm_hs_phy_irq", "ss_phy_irq";
> +                       qup_spi15_cs: qup-spi15-cs {
> +                               pins = "gpio63";
> +                               function = "qup17";
> +                       };
> 
> 
> -                       power-domains = <&gcc GCC_USB30_PRIM_GDSC>;
> +                       qup_spi15_cs_gpio: qup-spi15-cs_gpio {
> +                               pins = "gpio63";
> +                               function = "gpio";
> +                       };
> 

If the diffs actually end up more messy with a single patch in this case
then there is no point for it. Thanks for trying.