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From:   John Stultz <john.stultz@linaro.org>
Date:   Tue, 16 Jun 2020 14:21:55 -0700
Message-ID: <CALAqxLUvnhgL98T3LPaaCPq3w9b1notu=1a8ZhcRJNCkF3dXrQ@mail.gmail.com>
Subject: Re: [RFC][PATCH 3/5] irqchip: Allow QCOM_PDC to be loadable as a
 perment module
To:     Maulik Shah <mkshah@codeaurora.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <maz@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Lina Iyer <ilina@codeaurora.org>,
        Saravana Kannan <saravanak@google.com>,
        Todd Kjos <tkjos@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        iommu@lists.linux-foundation.org, linux-gpio@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org
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On Tue, Jun 16, 2020 at 4:30 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> Hi,
>
> On 6/16/2020 11:43 AM, John Stultz wrote:
> > Allows qcom-pdc driver to be loaded as a permenent module
>
> typo: permanent
>
> > Also, due to the fact that IRQCHIP_DECLARE becomes a no-op when
> > building as a module, we have to add the platform driver hooks
> > explicitly.
> >
> > Thanks to Saravana for his help on pointing out the
> > IRQCHIP_DECLARE issue and guidance on a solution.
> >
> > Cc: Andy Gross <agross@kernel.org>
> > Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> > Cc: Joerg Roedel <joro@8bytes.org>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Jason Cooper <jason@lakedaemon.net>
> > Cc: Marc Zyngier <maz@kernel.org>
> > Cc: Linus Walleij <linus.walleij@linaro.org>
> > Cc: Lina Iyer <ilina@codeaurora.org>
> > Cc: Saravana Kannan <saravanak@google.com>
> > Cc: Todd Kjos <tkjos@google.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: linux-arm-msm@vger.kernel.org
> > Cc: iommu@lists.linux-foundation.org
> > Cc: linux-gpio@vger.kernel.org
> > Signed-off-by: John Stultz <john.stultz@linaro.org>
> > ---
> >   drivers/irqchip/Kconfig    |  2 +-
> >   drivers/irqchip/qcom-pdc.c | 30 ++++++++++++++++++++++++++++++
> >   2 files changed, 31 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> > index 29fead208cad..12765bed08f9 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -425,7 +425,7 @@ config GOLDFISH_PIC
> >            for Goldfish based virtual platforms.
> >
> >   config QCOM_PDC
> > -     bool "QCOM PDC"
> > +     tristate "QCOM PDC"
> >       depends on ARCH_QCOM
> >       select IRQ_DOMAIN_HIERARCHY
> >       help
> > diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
> > index 6ae9e1f0819d..98d74160afcd 100644
> > --- a/drivers/irqchip/qcom-pdc.c
> > +++ b/drivers/irqchip/qcom-pdc.c
> > @@ -11,7 +11,9 @@
> >   #include <linux/irqdomain.h>
> >   #include <linux/io.h>
> >   #include <linux/kernel.h>
> > +#include <linux/module.h>
> >   #include <linux/of.h>
> > +#include <linux/of_irq.h>
> please move this include in order after of_device.h
> >   #include <linux/of_address.h>
> >   #include <linux/of_device.h>
> >   #include <linux/soc/qcom/irq.h>
> > @@ -430,4 +432,32 @@ static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
> >       return ret;
> >   }
> >
> > +#ifdef MODULE
> > +static int qcom_pdc_probe(struct platform_device *pdev)
> > +{
> > +     struct device_node *np = pdev->dev.of_node;
> > +     struct device_node *parent = of_irq_find_parent(np);
> > +
> > +     return qcom_pdc_init(np, parent);
> > +}
> > +
> > +static const struct of_device_id qcom_pdc_match_table[] = {
> > +     { .compatible = "qcom,pdc" },
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(of, qcom_pdc_match_table);
> > +
> > +static struct platform_driver qcom_pdc_driver = {
> > +     .probe = qcom_pdc_probe,
> > +     .driver = {
> > +             .name = "qcom-pdc",
> > +             .of_match_table = qcom_pdc_match_table,
>
> can you please set .suppress_bind_attrs = true,
>
> This is to prevent bind/unbind using sysfs. Once irqchip driver module
> is loaded, it shouldn't get unbind at runtime.

Thanks, I really appreciate the review! I've made these changes on my
side and they'll be included in v2.

thanks
-john