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From:   Sean Wang <sean.wang@kernel.org>
Date:   Fri, 4 Jan 2019 01:55:57 -0800
Message-ID: <CAGp9LzpNTKxgPyPOFQefJ1B_459dFtGUseW2sKHTiESDVLj9jw@mail.gmail.com>
Subject: Re: [PATCH v5 5/6] dt-bindings: pinctrl: mt8183: add binding document
To:     Zhiyong Tao <zhiyong.tao@mediatek.com>
Cc:     Rob Herring <robh@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Jason Cooper <jason@lakedaemon.net>,
        srv_heupstream <srv_heupstream@mediatek.com>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?B?RXJpbiBMbyAo576F6ZuF6b2hKQ==?= <erin.lo@mediatek.com>,
        Stephen Boyd <sboyd@codeaurora.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mediatek@lists.infradead.org" 
        <linux-mediatek@lists.infradead.org>,
        "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
        =?UTF-8?B?TWFycyBDaGVuZyAo6YSt5qOu5Y+LKQ==?= 
        <Mars.Cheng@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        =?UTF-8?B?WWluZ2pvZSBDaGVuICjpmbPoi7HmtLIp?= 
        <Yingjoe.Chen@mediatek.com>, Thomas Gleixner <tglx@linutronix.de>,
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On Fri, Jan 4, 2019 at 1:40 AM Zhiyong Tao <zhiyong.tao@mediatek.com> wrote:
>
> On Fri, 2019-01-04 at 01:14 -0800, Sean Wang wrote:
> > On Thu, Jan 3, 2019 at 11:09 PM Zhiyong Tao <zhiyong.tao@mediatek.com> wrote:
> > >
> > > On Sat, 2018-12-29 at 06:04 +0800, Rob Herring wrote:
> > > > On Fri, Dec 28, 2018 at 04:09:40PM +0800, Erin Lo wrote:
> > > > > From: Zhiyong Tao <zhiyong.tao@mediatek.com>
> > > > >
> > > > > The commit adds mt8183 compatible node in binding document.
> > > > >
> > > > > Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
> > > > > Signed-off-by: Erin Lo <erin.lo@mediatek.com>
> > > > > ---
> > > > >  .../devicetree/bindings/pinctrl/pinctrl-mt8183.txt | 110 +++++++++++++++++++++
> > > > >  1 file changed, 110 insertions(+)
> > > > >  create mode 100644 Documentation/devicetree/bindings/pinctrl/pinctrl-mt8183.txt
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8183.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8183.txt
> > > > > new file mode 100644
> > > > > index 0000000..7b5285e
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8183.txt
> > > > > @@ -0,0 +1,110 @@
> > > > > +* Mediatek MT8183 Pin Controller
> > > > > +
> > > > > +The Mediatek's Pin controller is used to control SoC pins.
> > > > > +
> > > > > +Required properties:
> > > > > +- compatible: value should be one of the following.
> > > > > +   "mediatek,mt8183-pinctrl", compatible with mt8183 pinctrl.
> > > > > +- gpio-controller : Marks the device node as a gpio controller.
> > > > > +- #gpio-cells: number of cells in GPIO specifier. Since the generic GPIO
> > > > > +  binding is used, the amount of cells must be specified as 2. See the below
> > > > > +  mentioned gpio binding representation for description of particular cells.
> > > > > +- gpio-ranges : gpio valid number range.
> > > > > +
> > > > > +   Eg: <&pio 6 0>
> > > > > +   <[phandle of the gpio controller node]
> > > > > +   [line number within the gpio controller]
> > > > > +   [flags]>
> > > > > +
> > > > > +   Values for gpio specifier:
> > > > > +   - Line number: is a value between 0 to 202.
> > > > > +   - Flags:  bit field of flags, as defined in <dt-bindings/gpio/gpio.h>.
> > > > > +            Only the following flags are supported:
> > > > > +            0 - GPIO_ACTIVE_HIGH
> > > > > +            1 - GPIO_ACTIVE_LOW
> > > > > +
> > > > > +Optional properties:
> > > > > +- reg: physicall address base for gpio base registers.
> > > >
> > > > s/physicall/physical/
> > > >
> > > > reg should never be optional.
> > > >
> > > > Need to say how many reg entries.
> > >
> > > ==> Thanks for your suggestion. We will change 'reg' to Required
> > > properties and add the reg entries in next version.
> > > >
> > > > > +- reg-names: gpio base registers name.
> > > >
> > > > Need to say what are the names. However, I don't find the names in the
> > > > example all that useful, so I'd just drop it.
> > >
> > > ==> we will add the reg-names in next version.
> > > They are used in the sample code, such as:
> > > > +             reg-names = "iocfg0", "iocfg1", "iocfg2",
> > > > > +                       "iocfg3", "iocfg4", "iocfg5",
> > > > > +                       "iocfg6", "iocfg7", "iocfg8";
> > >
> > > >
> > > > > +- interrupt-controller: Marks the device node as an interrupt controller
> > > > > +- #interrupt-cells: Should be two.
> > > > > +- interrupts : The interrupt outputs from the controller.
> > > > > +
> > > > > +Please refer to pinctrl-bindings.txt in this directory for details of the
> > > > > +common pinctrl bindings used by client devices.
> > > > > +
> > > > > +Subnode format
> > > > > +A pinctrl node should contain at least one subnodes representing the
> > > > > +pinctrl groups available on the machine. Each subnode will list the
> > > > > +pins it needs, and how they should be configured, with regard to muxer
> > > > > +configuration, pullups, drive strength, input enable/disable and input schmitt.
> > > > > +
> > > > > +    node {
> > > > > +   pinmux = <PIN_NUMBER_PINMUX>;
> > > > > +   GENERIC_PINCONFIG;
> > > > > +    };
> > > > > +
> > > > > +Required properties:
> > > > > +- pinmux: integer array, represents gpio pin number and mux setting.
> > > > > +    Supported pin number and mux varies for different SoCs, and are defined
> > > > > +    as macros in boot/dts/<soc>-pinfunc.h directly.
> > > > > +
> > > > > +Optional properties:
> > > > > +- GENERIC_PINCONFIG: is the generic pinconfig options to use, bias-disable,
> > > > > +    bias-pull-down, bias-pull-up, input-enable, input-disable, output-low, output-high,
> > > > > +    input-schmitt-enable, input-schmitt-disable and drive-strength are valid.
> > > > > +
> > > > > +    Some special pins have extra pull up strength, there are R0 and R1 pull-up
> > > > > +    resistors available, but for user, it's only need to set R1R0 as 00, 01, 10 or 11.
> > > > > +    So when config mediatek,pull-up-adv or mediatek,pull-down-adv,
> > > > > +    it support arguments for those special pins.
> > > > > +
> > > > > +    When config drive-strength, it can support some arguments, such as
> > > > > +    MTK_DRIVE_4mA, MTK_DRIVE_6mA, etc. See dt-bindings/pinctrl/mt65xx.h.
> > > > > +
> >
> > One point we can fix more is the drive-strength already is supported
> > as the generic one, not need to depend on a dedicated header file.
>
> ==> We think that we use MTK_DRIVE_4mA to set as driving in dts. it it
> more clear in v2 common driver for single pin -> single group mode.
> How about the idea?
>

Sure, thank for post your idea and it sounds not bad to keep the
convention for the single pin -> single group mode binding.

> Thanks.
> >
> > > > > +Examples:
> > > > > +
> > > > > +#include "mt8183-pinfunc.h"
> > > > > +
> > > > > +...
> > > > > +{
> > > > > +   pio: pinctrl@10005000 {
> > > > > +           compatible = "mediatek,mt8183-pinctrl";
> > > > > +           reg = <0 0x10005000 0 0x1000>,
> > > > > +                 <0 0x11F20000 0 0x1000>,
> > > > > +                 <0 0x11E80000 0 0x1000>,
> > > > > +                 <0 0x11E70000 0 0x1000>,
> > > > > +                 <0 0x11E90000 0 0x1000>,
> > > > > +                 <0 0x11D30000 0 0x1000>,
> > > > > +                 <0 0x11D20000 0 0x1000>,
> > > > > +                 <0 0x11C50000 0 0x1000>,
> > > > > +                 <0 0x11F30000 0 0x1000>;
> > > > > +           reg-names = "iocfg0", "iocfg1", "iocfg2",
> > > > > +                       "iocfg3", "iocfg4", "iocfg5",
> > > > > +                       "iocfg6", "iocfg7", "iocfg8";
> > > > > +           gpio-controller;
> > > > > +           #gpio-cells = <2>;
> > > > > +           gpio-ranges = <&pio 0 0 192>;
> > > > > +           interrupt-controller;
> > > > > +           interrupts = <GIC_SPI 153 IRQ_TYPE_LEVEL_HIGH>;
> > > > > +           interrupt-parent = <&gic>;
> > > > > +           #interrupt-cells = <2>;
> > > > > +
> > > > > +           i2c0_pins_a: i2c0@0 {
> > > >
> > > > unit-address without reg property is not valid.
> > >
> > > ==> we will change "i2c0_pins_a: i2c0@0" to "i2c0_pins_a: i2c0" in the
> > > next version.
> > > >
> > > > > +                   pins1 {
> > > > > +                           pinmux = <PINMUX_GPIO48__FUNC_SCL5>,
> > > > > +                                    <PINMUX_GPIO49__FUNC_SDA5>;
> > > > > +                           mediatek,pull-up-adv = <11>;
> > > > > +                   };
> > > > > +           };
> > > > > +
> > > > > +           i2c1_pins_a: i2c1@0 {
> > > > > +                   pins {
> > > > > +                           pinmux = <PINMUX_GPIO50__FUNC_SCL3>,
> > > > > +                                    <PINMUX_GPIO51__FUNC_SDA3>;
> > > > > +                           mediatek,pull-down-adv = <10>;
> > > > > +                   };
> > > > > +           };
> > > > > +           ...
> > > > > +   };
> > > > > +};
> > > > > --
> > > > > 1.9.1
> > > > >
> > >
> > >
> > >
> > > _______________________________________________
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>
>