coccinelle: Add script to check for platform_get_irq() excessive prints

Add a coccinelle script to check for the usage of dev_err() after a call
to platform_get_irq{,_byname}() as it's redundant now that the function
already prints an error when it fails.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730053845.126834-4-swboyd@chromium.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/coccinelle/api/platform_get_irq.cocci

+// SPDX-License-Identifier: GPL-2.0
+/// Remove dev_err() messages after platform_get_irq*() failures
+//
+// Confidence: Medium
+// Options: --include-headers
+
+virtual patch
+virtual context
+virtual org
+virtual report
+
+@depends on context@
+expression ret;
+struct platform_device *E;
+@@
+
+ret =
+(
+platform_get_irq
+|
+platform_get_irq_byname
+)(E, ...);
+
+if ( ret \( < \| <= \) 0 )
+{
+(
+if (ret != -EPROBE_DEFER)
+{ ...
+*dev_err(...);
+... }
+|
+...
+*dev_err(...);
+)
+...
+}
+
+@depends on patch@
+expression ret;
+struct platform_device *E;
+@@
+
+ret =
+(
+platform_get_irq
+|
+platform_get_irq_byname
+)(E, ...);
+
+if ( ret \( < \| <= \) 0 )
+{
+(
+-if (ret != -EPROBE_DEFER)
+-{ ...
+-dev_err(...);
+-... }
+|
+...
+-dev_err(...);
+)
+...
+}
+
+@r depends on org || report@
+position p1;
+expression ret;
+struct platform_device *E;
+@@
+
+ret =
+(
+platform_get_irq
+|
+platform_get_irq_byname
+)(E, ...);
+
+if ( ret \( < \| <= \) 0 )
+{
+(
+if (ret != -EPROBE_DEFER)
+{ ...
+dev_err@p1(...);
+... }
+|
+...
+dev_err@p1(...);
+)
+...
+}
+
+@script:python depends on org@
+p1 << r.p1;
+@@
+
+cocci.print_main(p1)
+
+@script:python depends on report@
+p1 << r.p1;
+@@
+
+msg = "line %s is redundant because platform_get_irq() already prints an error" % (p1[0].line)
+coccilib.report.print_report(p1[0],msg)