linux-kernel - Re: [PATCH v3] gpio: dwapb: Add support for 1 interrupt per port A GPIO

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Date:   Wed, 18 Apr 2018 00:02:31 -0700
From:   Hoan Tran <hotran@....com>
To:     Phil Edworthy <phil.edworthy@...esas.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Lee Jones <lee.jones@...aro.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Michel Pollet <michel.pollet@...renesas.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        Devicetree List <devicetree@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] gpio: dwapb: Add support for 1 interrupt per port A GPIO

Hi Phil,

On Fri, Apr 13, 2018 at 9:47 AM, Phil Edworthy
<phil.edworthy@...esas.com> wrote:
> Hi Hoan,
>
> On 13 April 2018 17:37 Hoan Tran wrote:
>> On Fri, Apr 13, 2018 at 1:51 AM, Phil Edworthy wrote:
>> > The DesignWare GPIO IP can be configured for either 1 interrupt or 1
>> > per GPIO in port A, but the driver currently only supports 1 interrupt.
>> > See the DesignWare DW_apb_gpio Databook description of the
>> > 'GPIO_INTR_IO' parameter.
>> >
>> > This change allows the driver to work with up to 32 interrupts, it
>> > will get as many interrupts as specified in the DT 'interrupts' property.
>> > It doesn't do anything clever with the different interrupts, it just
>> > calls the same handler used for single interrupt hardware.
>> >
>> > Signed-off-by: Phil Edworthy <phil.edworthy@...esas.com>
>> > ---
>> > One point to mention is that I have made it possible for users to have
>> > unconncted interrupts by specifying holes in the list of interrupts.
>> > This is done by supporting the interrupts-extended DT prop.
>> > However, I have no use for this and had to hack some test case for this.
>> > Perhaps the driver should support 1 interrupt or all GPIOa as interrupts?
>> >
>> > v3:
>> >  - Rolled mfd: intel_quark_i2c_gpio fix into this patch to avoid
>> > bisect problems
>> > v2:
>> >  - Replaced interrupt-mask DT prop with support for the interrupts-
>> extended
>> >    prop. This means replacing the call to irq_of_parse_and_map() with calls
>> >    to of_irq_parse_one() and irq_create_of_mapping().
>> >
>> > Note: There are a few *code* lines over 80 chars, but this is just guidance,
>> >    right? Especially as there are already some lines over 80 chars.
>> > ---
> [snip]
>
>> > -               if (has_acpi_companion(dev) && pp->idx == 0)
>> > -                       pp->irq = platform_get_irq(to_platform_device(dev), 0);
>> > +               if (has_acpi_companion(dev) && pp->idx == 0) {
>> > +                       pp->irq[0] = platform_get_irq(to_platform_device(dev), 0);
>> > +                       if (pp->irq[0])
>> > +                               pp->has_irq = true;
>> > +               }
>>
>> It doesn't work for ACPI. Could you do the same logic for ACPI?
> I don’t have access to any device that was baked (i.e. fabbed) with multiple
> output interrupts from the Synopsys GPIO blocks and use ACPI. I don't
> know if any such device exists.

Below code is tested on X-Gene system which supports 1 interrupt per
GPIO on Port A. You can update it into your patch.

-               if (has_acpi_companion(dev) && pp->idx == 0)
-                       pp->irq = platform_get_irq(to_platform_device(dev), 0);
+               if (has_acpi_companion(dev) && pp->idx == 0) {
+                       unsigned int j;
+                       for (j = 0; j < pp->ngpio; j++) {
+                               pp->irq[j] =
platform_get_irq(to_platform_device(dev), j);
+                               if (pp->irq[j])
+                                       pp->has_irq = true;
+                       }
+               }

Thanks
Hoan

>
> I would prefer not writing code that can be tested easily. I cannot even
> test the current, albeit small, changes to the Intel Quark MFD.
>
> Regards
> Phil
>
>> Thanks
>> Hoan
>>
>> >
>> >                 pp->irq_shared  = false;
>> >                 pp->gpio_base   = -1;
>> > diff --git a/drivers/mfd/intel_quark_i2c_gpio.c
>> > b/drivers/mfd/intel_quark_i2c_gpio.c
>> > index 90e35de..5bddb84 100644
>> > --- a/drivers/mfd/intel_quark_i2c_gpio.c
>> > +++ b/drivers/mfd/intel_quark_i2c_gpio.c
>> > @@ -233,7 +233,8 @@ static int intel_quark_gpio_setup(struct pci_dev
>> *pdev, struct mfd_cell *cell)
>> >         pdata->properties->idx          = 0;
>> >         pdata->properties->ngpio        = INTEL_QUARK_MFD_NGPIO;
>> >         pdata->properties->gpio_base    = INTEL_QUARK_MFD_GPIO_BASE;
>> > -       pdata->properties->irq          = pdev->irq;
>> > +       pdata->properties->irq[0]       = pdev->irq;
>> > +       pdata->properties->has_irq      = true;
>> >         pdata->properties->irq_shared   = true;
>> >
>> >         cell->platform_data = pdata;
>> > diff --git a/include/linux/platform_data/gpio-dwapb.h
>> > b/include/linux/platform_data/gpio-dwapb.h
>> > index 2dc7f4a..5a52d69 100644
>> > --- a/include/linux/platform_data/gpio-dwapb.h
>> > +++ b/include/linux/platform_data/gpio-dwapb.h
>> > @@ -19,7 +19,8 @@ struct dwapb_port_property {
>> >         unsigned int    idx;
>> >         unsigned int    ngpio;
>> >         unsigned int    gpio_base;
>> > -       unsigned int    irq;
>> > +       unsigned int    irq[32];
>> > +       bool            has_irq;
>> >         bool            irq_shared;
>> >  };
>> >
>> > --
>> > 2.7.4
>> >