Re: [PATCH v2 1/2] dt-bindings: pinctrl: mediatek: add support for mt8196

["Cathy Xu (许华婷)" <ot_cathy.xu@mediatek.com>]

On Mon, 2025-01-13 at 14:20 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until
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> 
> 
> Il 11/01/25 10:41, Krzysztof Kozlowski ha scritto:
> > On Fri, Jan 10, 2025 at 06:42:28PM +0800, Cathy Xu wrote:
> > > 1.Add pinctrl file on MediaTek mt8196.
> > 
> > Where? What is pinctrl file?
> > 
> > > 2.Add the new binding document for pinctrl on MediaTek mt8196.
> > 
> > Look at git history how commit msgs are written for such changes.
> > 
> > > 
> > > Signed-off-by: Guodong Liu <guodong.liu@mediatek.com>
> > > Signed-off-by: Cathy Xu <ot_cathy.xu@mediatek.com>
> > > ---
> > >   .../pinctrl/mediatek,mt8196-pinctrl.yaml      |  266 +++
> > >   include/dt-bindings/pinctrl/mt8196-pinfunc.h  | 1572
> > > +++++++++++++++++
> > >   2 files changed, 1838 insertions(+)
> > >   create mode 100644
> > > Documentation/devicetree/bindings/pinctrl/mediatek,mt8196-
> > > pinctrl.yaml
> > >   create mode 100644 include/dt-bindings/pinctrl/mt8196-pinfunc.h
> > > 
> > > diff --git
> > > a/Documentation/devicetree/bindings/pinctrl/mediatek,mt8196-
> > > pinctrl.yaml
> > > b/Documentation/devicetree/bindings/pinctrl/mediatek,mt8196-
> > > pinctrl.yaml
> > > new file mode 100644
> > > index 000000000000..abeb0d942cc4
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/pinctrl/mediatek,mt8196-
> > > pinctrl.yaml
> > > @@ -0,0 +1,266 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: 
> > > https://urldefense.com/v3/__http://devicetree.org/schemas/pinctrl/mediatek,mt8196-pinctrl.yaml*__;Iw!!CTRNKA9wMg0ARbw!laNiB1eOycilYcAp5iBZ1fOGQrXEg2lr8Rkt727TE54e_9DlPoANkwssDGD16Q1Jif0EdQ8vaAVHNG1MMMi9U5rB9oYBgyMDZA$
> > > +$schema: 
> > > https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!laNiB1eOycilYcAp5iBZ1fOGQrXEg2lr8Rkt727TE54e_9DlPoANkwssDGD16Q1Jif0EdQ8vaAVHNG1MMMi9U5rB9oZoUiw09w$
> > > +
> > > +title: MediaTek MT8196 Pin Controller
> > > +
> > > +maintainers:
> > > +  - Lei Xue <lei.xue@mediatek.com>
> > > +  - Cathy Xu <ot_cathy.xu@mediatek.com>
> > > +
> > > +description:
> > > +  The MediaTek's MT8196 Pin controller is used to control SoC
> > > pins.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: mediatek,mt8196-pinctrl
> > > +
> > > +  gpio-controller: true
> > > +
> > > +  '#gpio-cells':
> > > +    description:
> > > +      Number of cells in GPIO specifier, should be two. The
> > > first cell is the
> > > +      pin number, the second cell is used to specify optional
> > > parameters which
> > > +      are defined in <dt-bindings/gpio/gpio.h>.
> > > +    const: 2
> > > +
> > > +  gpio-ranges:
> > > +    maxItems: 1
> > > +
> > > +  gpio-line-names: true
> > > +
> > > +  reg:
> > > +    items:
> > > +      - description: gpio registers base address
> > > +      - description: rt group io configuration registers base
> > > address
> > > +      - description: rm1 group io configuration registers base
> > > address
> > > +      - description: rm2 group io configuration registers base
> > > address
> > > +      - description: rb group io configuration registers base
> > > address
> > > +      - description: bm1 group io configuration registers base
> > > address
> > > +      - description: bm2 group io configuration registers base
> > > address
> > > +      - description: bm3 group io configuration registers base
> > > address
> > > +      - description: lt group io configuration registers base
> > > address
> > > +      - description: lm1 group io configuration registers base
> > > address
> > > +      - description: lm2 group io configuration registers base
> > > address
> > > +      - description: lb1 group io configuration registers base
> > > address
> > > +      - description: lb2 group io configuration registers base
> > > address
> > > +      - description: tm1 group io configuration registers base
> > > address
> > > +      - description: tm2 group io configuration registers base
> > > address
> > > +      - description: tm3 group io configuration registers base
> > > address
> > > +
> > > +  reg-names:
> > > +    items:
> > > +      - const: iocfg0
> > > +      - const: iocfg_rt
> > > +      - const: iocfg_rm1
> > > +      - const: iocfg_rm2
> > > +      - const: iocfg_rb
> > > +      - const: iocfg_bm1
> > > +      - const: iocfg_bm2
> > > +      - const: iocfg_bm3
> > > +      - const: iocfg_lt
> > > +      - const: iocfg_lm1
> > > +      - const: iocfg_lm2
> > > +      - const: iocfg_lb1
> > > +      - const: iocfg_lb2
> > > +      - const: iocfg_tm1
> > > +      - const: iocfg_tm2
> > > +      - const: iocfg_tm3
> > 
> > Are you sure these are separate address spaces?
> > 
> 
> Those are different partitions of the GPIO controller, of which, each
> one does
> provide full control and different functions that are partition-
> global and not
> controller-global.
> 
> So, I can confirm that these are indeed separate address spaces -
> this is right.
  Thank you for helping me respond!

> 
> > > +
> > > +  interrupt-controller: true
> > > +
> > > +  '#interrupt-cells':
> > > +    const: 2
> > > +
> > > +  interrupts:
> > > +    description: The interrupt outputs to sysirq.
> > > +    maxItems: 1
> > > +
> > > +  mediatek,rsel-resistance-in-si-unit:
> > > +    type: boolean
> > > +    description:
> > > +      We provide two methods to select the resistance for I2C
> > > when pull up or
> > > +      pull down. The first is by RSEL definition value, another
> > > one is by
> > > +      resistance value(ohm). This flag is used to identify if
> > > the method is
> > > +      resistance(si unit) value.
> > 
> > What is the point of choosing it? This is one hardware, one SoC, so
> > how
> > different boards can have different units? No, just use Ohms
> > 
> 
> That's legacy from when the paris driver didn't specify the RSEL in
> ohms, and I
> agree about deprecating that property and making it a default.
> 
> Cathy, please add a `has_legacy_rsel` boolean in the platform data
> and assign that
> to true in *all* MediaTek pinctrl drivers that are not MT8196, then
> in
> pinctrl-paris:
> 
> if (hw->soc->has_legacy_rsel)
>         hw->rsel_si_unit = of_property_read_bool(....)
> else
>         hw->rsel_si_unit = true;
> 
> That way we can finally drop this property from drivers for new SoCs,
> including
> the one for MT8196.
  'mediatek,rsel-resistance-in-si-unit' won't be used now, and will
remove it in next version.

> 
> > > +
> > > +# PIN CONFIGURATION NODES
> > > +patternProperties:
> > > +  '-pins$':
> > > +    type: object
> > > +    additionalProperties: false
> > > +
> > > +    patternProperties:
> > > +      '^pins':
> > > +        type: object
> > > +        $ref: /schemas/pinctrl/pincfg-node.yaml
> > > +        additionalProperties: false
> > > +        description:
> > > +          A pinctrl node should contain at least one subnode
> > > 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.
> > > +
> > > +        properties:
> > > +          pinmux:
> > > +            description:
> > > +              Integer array, represents gpio pin number and mux
> > > setting.
> > > +              Supported pin number and mux varies for different
> > > SoCs, and are
> > > +              defined as macros in dt-bindings/pinctrl/mt8196-
> > > pinfunc.h
> > > +              directly, for this SoC.
> > > +
> > > +          drive-strength:
> > > +            enum: [2, 4, 6, 8, 10, 12, 14, 16]
> > > +
> > > +          drive-strength-microamp:
> > > +            enum: [125, 250, 500, 1000]
> > 
> > Why duplicating properties? No, use only one.
> > 
> 
> The problem here is not entirely about duplicating properties, and
> I'm not
> sure that the reason is actually acceptable (but being this a special
> case
> the `description` field would be mandatory to have IMO!!).
> 
> So, the reason for this separation is that the drive-strength-
> microamp does
> activate a special feature in the controller called "advanced drive
> strength
> mode", which is switching to different shunts that will decrease the
> power
> efficiency of the chip (by an ignorable amount, if that's one pin -
> but if
> that goes to something like 100 pins, it's not ignorable anymore).
> 
> I'd be happy if we could let them retain both properties after
> putting a
> clear description of what's happening and why there are two of them.
  drive-strength-microamp is for i2c special current, and drive-
strength is for other pins current.

> 
> > > +
> > > +          bias-pull-down:
> > > +            oneOf:
> > > +              - type: boolean
> > > +              - enum: [100, 101, 102, 103]
> > > +                description: mt8196 pull down PUPD/R0/R1 type
> > > define value.
> > > +              - enum: [200, 201, 202, 203, 204, 205, 206, 207]
> > > +                description: mt8196 pull down RSEL type define
> > > value.
> 
> These two must go away, RSEL shall be defined in Ohms unit in
> DTs/bindings.
  It will be removed in next version.

> 
> > > +              - enum: [75000, 5000]
> > > +                description: mt8196 pull down RSEL type si unit
> > > value(ohm).
> > > +            description: |
> > > +              For pull down type is normal, it doesn't need add
> > > RSEL & R1R0
> > > +              define and resistance value.
> > > +              For pull down type is PUPD/R0/R1 type, it can add
> > > R1R0 define to
> > > +              set different resistance. It can support
> > > "MTK_PUPD_SET_R1R0_00" &
> > > +              "MTK_PUPD_SET_R1R0_01" & "MTK_PUPD_SET_R1R0_10" &
> > > +              "MTK_PUPD_SET_R1R0_11" define in mt8196.
> > > +              For pull down type is RSEL, it can add RSEL define
> > > & resistance
> > > +              value(ohm) to set different resistance by
> > > identifying property
> > > +              "mediatek,rsel-resistance-in-si-unit". It can
> > > support
> > > +              "MTK_PULL_SET_RSEL_000" & "MTK_PULL_SET_RSEL_001"
> > > &
> > > +              "MTK_PULL_SET_RSEL_010" & "MTK_PULL_SET_RSEL_011"
> > > &
> > > +              "MTK_PULL_SET_RSEL_100" & "MTK_PULL_SET_RSEL_101"
> > > &
> > > +              "MTK_PULL_SET_RSEL_110" & "MTK_PULL_SET_RSEL_111"
> > > define in
> > > +              mt8196. It can also support resistance value(ohm)
> > > "75000" & "5000"
> > > +              in mt8196.
> > > +
> > > +          bias-pull-up:
> > > +            oneOf:
> > > +              - type: boolean
> > > +              - enum: [100, 101, 102, 103]
> > > +                description: mt8196 pull up PUPD/R0/R1 type
> > > define value.
> > > +              - enum: [200, 201, 202, 203, 204, 205, 206, 207]
> > > +                description: mt8196 pull up RSEL type define
> > > value.
> > > +              - enum: [1000, 1500, 2000, 3000, 4000, 5000,
> > > 10000, 75000]
> > > +                description: mt8196 pull up RSEL type si unit
> > > value(ohm).
> > 
> > Same problems.
> > 
> > > +++ b/include/dt-bindings/pinctrl/mt8196-pinfunc.h
> > > @@ -0,0 +1,1572 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> > > +/*
> > > + * Copyright (C) 2025 Mediatek Inc.
> > > + * Author: Guodong Liu <Guodong.Liu@mediatek.com>
> > > + */
> > > +
> > > +#ifndef __MT8196_PINFUNC_H
> > > +#define __MT8196_PINFUNC_H
> > > +
> > > +#include <dt-bindings/pinctrl/mt65xx.h>
> > > +
> > > +#define PINMUX_GPIO0__FUNC_GPIO0 (MTK_PIN_NO(0) | 0)
> > > +#define PINMUX_GPIO0__FUNC_DMIC1_CLK (MTK_PIN_NO(0) | 1)
> > > +#define PINMUX_GPIO0__FUNC_SPI3_A_MO (MTK_PIN_NO(0) | 3)
> > > +#define PINMUX_GPIO0__FUNC_FMI2S_B_LRCK (MTK_PIN_NO(0) | 4)
> > > +#define PINMUX_GPIO0__FUNC_SCP_DMIC1_CLK (MTK_PIN_NO(0) | 5)
> > > +#define PINMUX_GPIO0__FUNC_TP_GPIO14_AO (MTK_PIN_NO(0) | 6)
> > 
> > You got comment, so respond to it. Sending the same and expecting
> > different results is fast way to get a grumpy response.
> > 
> 
> ...and I agree about every other comment from Krzysztof.
  Ok, thank you for your review.

> 
> Cheers,
> Angelo