linux-kernel - Re: [PATCH 1/2] of: unittest: add overlay gpio test to catch gpio hog problem

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Message-ID: <20200219215656.GA15842@bogus>
Date:   Wed, 19 Feb 2020 15:56:56 -0600
From:   Rob Herring <robh@...nel.org>
To:     frowand.list@...il.com
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        pantelis.antoniou@...sulko.com, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Alan Tull <atull@...nel.org>
Subject: Re: [PATCH 1/2] of: unittest: add overlay gpio test to catch gpio
 hog problem

On Tue, Jan 28, 2020 at 11:46:04PM -0600, frowand.list@...il.com wrote:
> From: Frank Rowand <frank.rowand@...y.com>
> 
> Geert reports that gpio hog nodes are not properly processed when
> the gpio hog node is added via an overlay reply and provides an
> RFC patch to fix the problem [1].
> 
> Add a unittest that shows the problem.  Unittest will report "1 failed"
> test before applying Geert's RFC patch and "0 failed" after applying
> Geert's RFC patch.

What's the status of that? I don't want to leave the tests failing at 
least outside of a kernel release.

> 
> [1] https://lore.kernel.org/linux-devicetree/20191230133852.5890-1-geert+renesas@glider.be/
> 
> Signed-off-by: Frank Rowand <frank.rowand@...y.com>
> ---
> 
> There are checkpatch warnings.
>   - New files are in a directory already covered by MAINTAINERS
>   - The undocumented compatibles are restricted to use by unittest
>     and should not be documented under Documentation
>   - The printk() KERN_<LEVEL> warnings are false positives.  The level
>     is supplied by a define parameter instead of a hard coded constant
>   - The lines over 80 characters are consistent with unittest.c style
> 
> This unittest was also valuable in that it allowed me to explore
> possible issues related to the proposed solution to the gpio hog
> problem.
> 
> changes since RFC:
>   - fixed node names in overlays
>   - removed unused fields from struct unittest_gpio_dev
>   - of_unittest_overlay_gpio() cleaned up comments
>   - of_unittest_overlay_gpio() moved saving global values into
>     probe_pass_count and chip_request_count more tightly around
>     test code expected to trigger changes in the global values
> 
>  drivers/of/unittest-data/Makefile             |   8 +-
>  drivers/of/unittest-data/overlay_gpio_01.dts  |  23 +++
>  drivers/of/unittest-data/overlay_gpio_02a.dts |  16 ++
>  drivers/of/unittest-data/overlay_gpio_02b.dts |  16 ++
>  drivers/of/unittest-data/overlay_gpio_03.dts  |  23 +++
>  drivers/of/unittest-data/overlay_gpio_04a.dts |  16 ++
>  drivers/of/unittest-data/overlay_gpio_04b.dts |  16 ++
>  drivers/of/unittest.c                         | 255 ++++++++++++++++++++++++++
>  8 files changed, 372 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_01.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_02a.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_02b.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_03.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_04a.dts
>  create mode 100644 drivers/of/unittest-data/overlay_gpio_04b.dts
> 
> diff --git a/drivers/of/unittest-data/Makefile b/drivers/of/unittest-data/Makefile
> index 9b6807065827..009f4045c8e4 100644
> --- a/drivers/of/unittest-data/Makefile
> +++ b/drivers/of/unittest-data/Makefile
> @@ -21,7 +21,13 @@ obj-$(CONFIG_OF_OVERLAY) += overlay.dtb.o \
>  			    overlay_bad_add_dup_prop.dtb.o \
>  			    overlay_bad_phandle.dtb.o \
>  			    overlay_bad_symbol.dtb.o \
> -			    overlay_base.dtb.o
> +			    overlay_base.dtb.o \
> +			    overlay_gpio_01.dtb.o \
> +			    overlay_gpio_02a.dtb.o \
> +			    overlay_gpio_02b.dtb.o \
> +			    overlay_gpio_03.dtb.o \
> +			    overlay_gpio_04a.dtb.o \
> +			    overlay_gpio_04b.dtb.o
>  
>  # enable creation of __symbols__ node
>  DTC_FLAGS_overlay += -@
> diff --git a/drivers/of/unittest-data/overlay_gpio_01.dts b/drivers/of/unittest-data/overlay_gpio_01.dts
> new file mode 100644
> index 000000000000..f039e8bce3b6
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_01.dts
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	gpio_01 {

Missing unit address:

gpio@0


> +		compatible = "unittest-gpio";
> +		reg = <0>;
> +		gpio-controller;
> +		#gpio-cells = <2>;
> +		ngpios = <2>;
> +		gpio-line-names = "line-A", "line-B";
> +
> +		line_b {

Don't use '_'.

line-b

> +			gpio-hog;
> +			gpios = <2 0>;
> +			input;
> +			line-name = "line-B-input";
> +		};
> +	};
> +};
> diff --git a/drivers/of/unittest-data/overlay_gpio_02a.dts b/drivers/of/unittest-data/overlay_gpio_02a.dts
> new file mode 100644
> index 000000000000..cdafab604793
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_02a.dts
> @@ -0,0 +1,16 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	gpio_02 {

gpio@1

...and a few more.

> +		compatible = "unittest-gpio";
> +		reg = <1>;
> +		gpio-controller;
> +		#gpio-cells = <2>;
> +		ngpios = <2>;
> +		gpio-line-names = "line-A", "line-B";
> +	};
> +};