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Subject: Re: [PATCH v3 2/2] rockchip: rk3399: Add support for FriendlyARM
 NanoPi R4S
To:     CN_SZTL <cnsztl@gmail.com>
Cc:     Rob Herring <robh+dt@kernel.org>, Heiko Stuebner <heiko@sntech.de>,
        Jagan Teki <jagan@amarulasolutions.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        David Bauer <mail@david-bauer.net>,
        =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <uwe@kleine-koenig.org>,
        Johan Jonker <jbx6244@gmail.com>,
        Michael Trimarchi <michael@amarulasolutions.com>,
        Marty Jones <mj8263788@gmail.com>,
        Jensen Huang <jensenhuang@friendlyarm.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
        kernel test robot <lkp@intel.com>
References: <20210313032515.12590-1-cnsztl@gmail.com>
 <20210313032515.12590-2-cnsztl@gmail.com>
 <1f7f1a11-0b9b-b2e4-efbc-193f61d62832@arm.com>
 <CAOP2_TgUQH9H9vuESek7KjStxu=idaBxX=S5Q7_=Mn=D_s-=JA@mail.gmail.com>
From:   Robin Murphy <robin.murphy@arm.com>
Message-ID: <67b314e7-92b9-8025-1a41-9b7da6ff2249@arm.com>
Date:   Mon, 15 Mar 2021 16:32:01 +0000
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On 2021-03-13 13:22, CN_SZTL wrote:
> Robin Murphy <robin.murphy@arm.com> 于2021年3月13日周六 下午7:55写道：
>>
>> On 2021-03-13 03:25, Tianling Shen wrote:
>>> This adds support for the NanoPi R4S from FriendlyArm.
>>>
>>> Rockchip RK3399 SoC
>>> 1GB DDR3 or 4GB LPDDR4 RAM
>>> Gigabit Ethernet (WAN)
>>> Gigabit Ethernet (PCIe) (LAN)
>>> USB 3.0 Port x 2
>>> MicroSD slot
>>> Reset button
>>> WAN - LAN - SYS LED
>>>
>>> [initial DTS file]
>>> Co-developed-by: Jensen Huang <jensenhuang@friendlyarm.com>
>>> Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com>
>>> [minor adjustments]
>>> Co-developed-by: Marty Jones <mj8263788@gmail.com>
>>> Signed-off-by: Marty Jones <mj8263788@gmail.com>
>>> [fixed format issues]
>>> Signed-off-by: Tianling Shen <cnsztl@gmail.com>
>>>
>>> Reported-by: kernel test robot <lkp@intel.com>
>>> ---
>>>    arch/arm64/boot/dts/rockchip/Makefile         |   1 +
>>>    .../boot/dts/rockchip/rk3399-nanopi-r4s.dts   | 179 ++++++++++++++++++
>>>    2 files changed, 180 insertions(+)
>>>    create mode 100644 arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
>>>
>>> diff --git a/arch/arm64/boot/dts/rockchip/Makefile b/arch/arm64/boot/dts/rockchip/Makefile
>>> index 62d3abc17a24..c3e00c0e2db7 100644
>>> --- a/arch/arm64/boot/dts/rockchip/Makefile
>>> +++ b/arch/arm64/boot/dts/rockchip/Makefile
>>> @@ -36,6 +36,7 @@ dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-nanopc-t4.dtb
>>>    dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-nanopi-m4.dtb
>>>    dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-nanopi-m4b.dtb
>>>    dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-nanopi-neo4.dtb
>>> +dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-nanopi-r4s.dtb
>>>    dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-orangepi.dtb
>>>    dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-pinebook-pro.dtb
>>>    dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-puma-haikou.dtb
>>> diff --git a/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts b/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
>>> new file mode 100644
>>> index 000000000000..41b3d5c5043c
>>> --- /dev/null
>>> +++ b/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
>>> @@ -0,0 +1,179 @@
>>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>>> +/*
>>> + * FriendlyElec NanoPC-T4 board device tree source
>>> + *
>>> + * Copyright (c) 2020 FriendlyElec Computer Tech. Co., Ltd.
>>> + * (http://www.friendlyarm.com)
>>> + *
>>> + * Copyright (c) 2018 Collabora Ltd.
>>> + *
>>> + * Copyright (c) 2020 Jensen Huang <jensenhuang@friendlyarm.com>
>>> + * Copyright (c) 2020 Marty Jones <mj8263788@gmail.com>
>>> + * Copyright (c) 2021 Tianling Shen <cnsztl@gmail.com>
>>> + */
>>> +
>>> +/dts-v1/;
>>> +#include "rk3399-nanopi4.dtsi"
>>> +
>>> +/ {
>>> +     model = "FriendlyElec NanoPi R4S";
>>> +     compatible = "friendlyarm,nanopi-r4s", "rockchip,rk3399";
>>> +
>>> +     /delete-node/ gpio-leds;
>>
>> Why? You could justify deleting &status_led, but redefining the whole
>> node from scratch seems unnecessary.
> 
> First of all, thank you for reviewing, and sorry for my poor English.
> 
> I need to redefine `pinctrl-0`, but if I use `/delete-property/
> pinctrl-0;`, it will throw an error,
> so maybe I made a mistake? And I will try again...

You don't need to delete the property itself though - simply specifying 
it replaces whatever previous value was inherited from the DTSI. Think 
about how all those "status = ..." lines work, for example.

Similarly, given that you're redefining the led-0 node anyway you 
wouldn't really *need* to delete that either; doing so just avoids the 
extra &status_led label hanging around if the DTB is built with symbols, 
and saves having to explicitly override/delete the default trigger 
property if necessary.

>>> +     gpio-leds {
>>> +             compatible = "gpio-leds";
>>> +             pinctrl-0 = <&lan_led_pin>, <&sys_led_pin>, <&wan_led_pin>;
>>> +             pinctrl-names = "default";
>>> +
>>> +             lan_led: led-0 {
>>> +                     gpios = <&gpio1 RK_PA1 GPIO_ACTIVE_HIGH>;
>>> +                     label = "nanopi-r4s:green:lan";
>>> +             };
>>> +
>>> +             sys_led: led-1 {
>>> +                     gpios = <&gpio0 RK_PB5 GPIO_ACTIVE_HIGH>;
>>> +                     label = "nanopi-r4s:red:sys";
>>> +                     default-state = "on";
>>> +             };
>>> +
>>> +             wan_led: led-2 {
>>> +                     gpios = <&gpio1 RK_PA0 GPIO_ACTIVE_HIGH>;
>>> +                     label = "nanopi-r4s:green:wan";
>>> +             };

Nit: (apologies for overlooking it before) there isn't an obvious 
definitive order for the LEDs, but the order here is certainly not 
consistent with anything. The most logical would probably be sys, wan, 
lan since that's both in order of GPIO number and how they are 
physically positioned relative to each other on the board/case (although 
you could also argue for wan, lan, sys in that regard, depending on how 
you look at it).

>>> +     };
>>> +
>>> +     /delete-node/ gpio-keys;
>>
>> Ditto - just removing the power key node itself should suffice.
> 
> Just like gpio-leds.
>>
>>> +     gpio-keys {
>>> +             compatible = "gpio-keys";
>>> +             pinctrl-names = "default";
>>> +             pinctrl-0 = <&reset_button_pin>;
>>> +
>>> +             reset {
>>> +                     debounce-interval = <50>;
>>> +                     gpios = <&gpio1 RK_PC6 GPIO_ACTIVE_LOW>;
>>> +                     label = "reset";
>>> +                     linux,code = <KEY_RESTART>;
>>> +             };
>>> +     };
>>> +
>>> +     vdd_5v: vdd-5v {
>>> +             compatible = "regulator-fixed";
>>> +             regulator-name = "vdd_5v";
>>> +             regulator-always-on;
>>> +             regulator-boot-on;
>>> +     };
>>> +
>>> +     fan: pwm-fan {
>>> +             compatible = "pwm-fan";
>>> +             /*
>>> +              * With 20KHz PWM and an EVERCOOL EC4007H12SA fan, these levels
>>> +              * work out to 0, ~1200, ~3000, and 5000RPM respectively.
>>> +              */
>>> +             cooling-levels = <0 12 18 255>;
>>
>> This is clearly not true - those numbers refer to a 12V fan on my
>> NanoPC-T4's 12V PWM circuit, while the output circuit here is 5V. If you
>> really want a placeholder here maybe just use <0 255>, or figure out
>> some empirical values with a suitable 5V fan that are actually meaningful.
> 
> Okay... I'll drop these as they're not really meaningful.
>>
>>> +             #cooling-cells = <2>;
>>> +             fan-supply = <&vdd_5v>;
>>> +             pwms = <&pwm1 0 50000 0>;
>>> +     };
>>> +};
>>> +
>>> +&cpu_thermal {
>>> +     trips {
>>> +             cpu_warm: cpu_warm {
>>> +                     temperature = <55000>;
>>> +                     hysteresis = <2000>;
>>> +                     type = "active";
>>> +             };
>>> +
>>> +             cpu_hot: cpu_hot {
>>> +                     temperature = <65000>;
>>> +                     hysteresis = <2000>;
>>> +                     type = "active";
>>> +             };
>>> +     };
>>> +
>>> +     cooling-maps {
>>> +             map2 {
>>> +                     trip = <&cpu_warm>;
>>> +                     cooling-device = <&fan THERMAL_NO_LIMIT 1>;
>>> +             };
>>> +
>>> +             map3 {
>>> +                     trip = <&cpu_hot>;
>>> +                     cooling-device = <&fan 2 THERMAL_NO_LIMIT>;
>>> +             };
>>> +     };
>>> +};
>>> +
>>> +&emmc_phy {
>>> +     status = "disabled";
>>> +};
>>> +
>>> +&fusb0 {
>>> +     status = "disabled";
>>
>> This can never be enabled since it doesn't exist in the design at all,
>> so it's one place where deletion *would* make good sense. AFAICS this
>> means you also don't need i2c4 enabled either.
> 
> Is it fine to disable i2c4 directly?

I think it would make sense, since it's not physically available short 
of trying to solder on to the 0201 pull-up resistors.

>>
>>> +};
>>
>> It might be nice to disable HDMI and all the other display pieces given
>> that the board is physically headless.
> 
> Fine, I will delete `display-subsystem` node.
>>
>>> +
>>> +&pcie0 {
>>> +     max-link-speed = <1>;
>>> +     num-lanes = <1>;
>>> +     vpcie3v3-supply = <&vcc3v3_sys>;
>>> +
>>> +     pcie@0 {
>>> +             reg = <0x00000000 0 0 0 0>;
>>> +             #address-cells = <3>;
>>> +             #size-cells = <2>;
>>> +     };
>>
>> What's this for?
> 
> This is for the on-board PCIe ethernet adapter (RTL8111h).

OK, but *how* exactly does the ethernet adapter need an empty DT node 
describing the root port?

>>
>>> +};
>>> +
>>> +&pinctrl {
>>> +     /delete-node/ gpio-leds;
>>
>> Again, at most you'd only need to delete &status_led_pin.
> 
> Yes, I will do it.
>>
>>> +     gpio-leds {
>>> +             lan_led_pin: lan-led-pin {
>>> +                     rockchip,pins = <1 RK_PA1 RK_FUNC_GPIO &pcfg_pull_none>;
>>> +             };
>>> +
>>> +             sys_led_pin: sys-led-pin {
>>> +                     rockchip,pins = <0 RK_PB5 RK_FUNC_GPIO &pcfg_pull_none>;
>>> +             };
>>> +
>>> +             wan_led_pin: wan-led-pin {
>>> +                     rockchip,pins = <1 RK_PA0 RK_FUNC_GPIO &pcfg_pull_none>;
>>> +             };
>>> +     };
>>> +
>>> +     /delete-node/ rockchip-key;
>>
>> Ditto for &power_key.
> 
> Yes.
>>
>>> +     rockchip-key {
>>> +             reset_button_pin: reset-button-pin {
>>> +                     rockchip,pins = <1 RK_PC6 RK_FUNC_GPIO &pcfg_pull_up>;
>>> +             };
>>> +     };
>>> +};
>>> +
>>> +&sdhci {
>>> +     status = "disabled";
>>> +};
>>> +
>>> +&sdio0 {
>>> +     status = "disabled";
>>> +};
>>> +
>>> +&sdmmc {
>>> +     sd-uhs-sdr12;
>>> +     sd-uhs-sdr25;
>>> +     sd-uhs-sdr50;
>>
>> Are those modes unique to this particular board?
> 
> These seem not right and I will drop them.

I mean that if the other boards already support SDR104, they can 
presumably support slower modes as well, so if these are worth having at 
all then they could probably go in the common DTSI.

>>
>>> +};
>>> +
>>
>> What about the Bluetooth stuff on uart0?
> 
> R4S doesn't have it, so I guess I should disable uart0, like i2c4.

Yes, the UART itself isn't available on the board, and either way you 
certainly don't want the kernel wasting time and possibly throwing 
errors trying to probe a non-existent device through it.

Thanks,
Robin.