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Date:   Tue, 16 Jun 2020 10:08:18 -0600
From:   Lina Iyer <ilina@codeaurora.org>
To:     Maulik Shah <mkshah@codeaurora.org>
Cc:     John Stultz <john.stultz@linaro.org>,
        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>,
        Saravana Kannan <saravanak@google.com>,
        Todd Kjos <tkjos@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-gpio@vger.kernel.org
Subject: Re: [RFC][PATCH 3/5] irqchip: Allow QCOM_PDC to be loadable as a
 perment module
Message-ID: <20200616160818.GD12942@codeaurora.org>
References: <20200616061338.109499-1-john.stultz@linaro.org>
 <20200616061338.109499-4-john.stultz@linaro.org>
 <55e5982a-1e73-7013-e02d-5d1d30815fba@codeaurora.org>
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On Tue, Jun 16 2020 at 05:30 -0600, Maulik Shah 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.
>
That is a good point. We probably should do that to RPMH RSC driver as well.

>Thanks,
>Maulik
>>+	},
>>+};
>>+module_platform_driver(qcom_pdc_driver);
>>+#else
>>  IRQCHIP_DECLARE(qcom_pdc, "qcom,pdc", qcom_pdc_init);
>>+#endif
>>+
>>+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Power Domain Controller");
>>+MODULE_LICENSE("GPL v2");
>
>-- 
>QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
>