Re: [PATCH v5 5/6] dt-bindings: pinctrl: mt8183: add binding document

[Sean Wang <sean.wang@kernel.org>]

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.

> > > +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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