linux-kernel - Re: [PATCH v2 00/16] gpio: Tight IRQ chip integration and banked infrastructure

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Date:   Mon, 2 Oct 2017 09:55:24 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Grygorii Strashko <grygorii.strashko@...com>,
        Andrew Bresticker <abrestic@...omium.org>,
        James Hogan <james.hogan@...tec.com>,
        Shawn Guo <shawn.guo@...aro.org>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 00/16] gpio: Tight IRQ chip integration and banked infrastructure

On Thu, Sep 28, 2017 at 4:22 PM, Grygorii Strashko
<grygorii.strashko@...com> wrote:

> Sry, but I do not agree with this series.
> - no prof that it can be re-used by other drivers than tegra
>  (at least I do not see reasons to re-use it for any TI drivers)

This is not necessarily a blocker if it can be shown that others than
TI/OMAP can reuse it.

I've looked at things like the imagination pistachio:

pinctrl@...01C00 {
        compatible = "img,pistachio-system-pinctrl";
        reg = <0x18101C00 0x400>;

        gpio0: gpio0 {
                interrupts = <GIC_SHARED 71 IRQ_TYPE_LEVEL_HIGH>;

                gpio-controller;
                #gpio-cells = <2>;

                interrupt-controller;
                #interrupt-cells = <2>;
        };

        ...

        gpio5: gpio5 {
                interrupts = <GIC_SHARED 76 IRQ_TYPE_LEVEL_HIGH>;

                gpio-controller;
                #gpio-cells = <2>;

                interrupt-controller;
                #interrupt-cells = <2>;
        };

This looks like a clear candidate.
CC: to  Andrew Bresticker, can you look into this?

Another example would be gpio-tz1090, notably with interrupt optional:

       gpios: gpio-controller@...05800 {
                #address-cells = <1>;
                #size-cells = <0>;
                compatible = "img,tz1090-gpio";
                reg = <0x02005800 0x90>;

                /* bank 0 with an interrupt */
                gpios0: bank@0 {
                        #gpio-cells = <2>;
                        #interrupt-cells = <2>;
                        reg = <0>;
                        interrupts = <13 IRQ_TYPE_LEVEL_HIGH>;
                        gpio-controller;
                        gpio-ranges = <&pinctrl 0 0 30>;
                        interrupt-controller;
                };

                /* bank 2 without interrupt */
                gpios2: bank@2 {
                        #gpio-cells = <2>;
                        reg = <2>;
                        gpio-controller;
                        gpio-ranges = <&pinctrl 0 60 30>;
                };
        };

CC to James Hogan to look at the series from this perspective.

A third is gpio-mxs.c:

pinctrl@...18000 {
        compatible = "fsl,imx28-pinctrl", "simple-bus";
        reg = <0x80018000 2000>;

        gpio0: gpio@0 {
                compatible = "fsl,imx28-gpio";
                interrupts = <127>;
                gpio-controller;
                #gpio-cells = <2>;
                interrupt-controller;
                #interrupt-cells = <2>;
        };

        gpio1: gpio@1 {
                compatible = "fsl,imx28-gpio";
                interrupts = <126>;
                gpio-controller;
                #gpio-cells = <2>;
                interrupt-controller;
                #interrupt-cells = <2>;
        };

        gpio2: gpio@2 {
                compatible = "fsl,imx28-gpio";
                interrupts = <125>;
                gpio-controller;
                #gpio-cells = <2>;
                interrupt-controller;
                #interrupt-cells = <2>;
        };
(...)

CC to Shawn Guo to look into this.

So in short I think there can be others that can make good use of this
infrastructure.

> - all GPIO IRQs mapped statically

This really needs to be fixed.

> - irq->map[offset + j] = irq->parents[parent]; holds IRQs for all pins
>   which is waste of memory
> - DT binding changes not documented and no DT examples
> - below is ugly ;)
> +       bank = (spec[0] >> gc->of_gpio_bank_mask) & gc->of_gpio_bank_shift;
> +       pin = (spec[0] >> gc->of_gpio_pin_mask) & gc->of_gpio_pin_shift;

These should be fixable quite easily I think. Thierry?

Yours,
Linus Walleij