irqchip/qcom-pdc: Switch to IRQCHIP_PLATFORM_DRIVER and allow as a module

This patch revives changes from Saravana Kannan to switch the
qcom-pdc driver to use IRQCHIP_PLATFORM_DRIVER helper macros,
and allows qcom-pdc driver to be loaded as a permanent module.

Earlier attempts at this ran into trouble with loading
dependencies, but with Saravana's fw_devlink=on set by default
now we should avoid those.

[jstultz: Folded in with my changes to allow the driver to be
 loadable as a permenent module]

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: Maulik Shah <mkshah@codeaurora.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: Saravana Kannan <saravanak@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210518211922.3474368-1-john.stultz@linaro.org

drivers/irqchip/Kconfig

@@ -415,7 +415,7 @@ 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

drivers/irqchip/qcom-pdc.c

@@ -11,9 +11,11 @@
 #include <linux/irqdomain.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/of_irq.h>
 #include <linux/soc/qcom/irq.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
@@ -459,4 +461,8 @@ fail:
 	return ret;
 }
 
-IRQCHIP_DECLARE(qcom_pdc, "qcom,pdc", qcom_pdc_init);
+IRQCHIP_PLATFORM_DRIVER_BEGIN(qcom_pdc)
+IRQCHIP_MATCH("qcom,pdc", qcom_pdc_init)
+IRQCHIP_PLATFORM_DRIVER_END(qcom_pdc)
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Power Domain Controller");
+MODULE_LICENSE("GPL v2");