[PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[Tzung-Bi Shih]

drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning
when using the randconfig in [1]:
>>> warning: unused variable 'keyboard_led_drvdata_ec_pwm'

The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set.
Reproduce:
- mkdir build_dir
- wget [1] -O build_dir/.config
- COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \
  O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/

Fix the warning by using __maybe_unused.  Also use IS_ENABLED() because
CROS_EC is a tristate.

[1]: https://download.01.org/0day-ci/archive/20220717/202207170538.MR39dw8m-lkp@intel.com/config

Fixes: 40f58143745e ("platform/chrome: cros_kbd_led_backlight: support EC PWM backend")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
Changes from v1 (https://patchwork.kernel.org/project/chrome-platform/patch/20220718061608.2303425-1-tzungbi@kernel.org/):
- Use __maybe_unused.

 drivers/platform/chrome/cros_kbd_led_backlight.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/chrome/cros_kbd_led_backlight.c b/drivers/platform/chrome/cros_kbd_led_backlight.c
index 5ad41c10412d..793fd3f1015d 100644
--- a/drivers/platform/chrome/cros_kbd_led_backlight.c
+++ b/drivers/platform/chrome/cros_kbd_led_backlight.c
@@ -119,7 +119,7 @@ static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
 
 #endif /* CONFIG_ACPI */
 
-#ifdef CONFIG_CROS_EC
+#if IS_ENABLED(CONFIG_CROS_EC)
 
 static int
 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
@@ -180,18 +180,18 @@ static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
 	return 0;
 }
 
-static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
+static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
 	.init = keyboard_led_init_ec_pwm,
 	.brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
 	.brightness_get = keyboard_led_get_brightness_ec_pwm,
 	.max_brightness = KEYBOARD_BACKLIGHT_MAX,
 };
 
-#else /* CONFIG_CROS_EC */
+#else /* IS_ENABLED(CONFIG_CROS_EC) */
 
-static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
+static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
 
-#endif /* CONFIG_CROS_EC */
+#endif /* IS_ENABLED(CONFIG_CROS_EC) */
 
 static int keyboard_led_probe(struct platform_device *pdev)
 {
-- 
2.37.0.170.g444d1eabd0-goog

Re: [PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[Guenter Roeck]

On Mon, Jul 18, 2022 at 3:51 AM Tzung-Bi Shih <tzungbi@kernel.org> wrote:
>
> drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning
> when using the randconfig in [1]:
> >>> warning: unused variable 'keyboard_led_drvdata_ec_pwm'
>
> The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set.
> Reproduce:
> - mkdir build_dir
> - wget [1] -O build_dir/.config
> - COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \
>   O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/
>
> Fix the warning by using __maybe_unused.  Also use IS_ENABLED() because
> CROS_EC is a tristate.

Is that sufficient ? What happens if CROS_KBD_LED_BACKLIGHT=y and
CROS_EC=m ? I suspect you might need IS_REACHABLE() instead of
IS_ENABLED().

Thanks,
Guenter

>
> [1]: https://download.01.org/0day-ci/archive/20220717/202207170538.MR39dw8m-lkp@intel.com/config
>
> Fixes: 40f58143745e ("platform/chrome: cros_kbd_led_backlight: support EC PWM backend")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
> ---
> Changes from v1 (https://patchwork.kernel.org/project/chrome-platform/patch/20220718061608.2303425-1-tzungbi@kernel.org/):
> - Use __maybe_unused.
>
>  drivers/platform/chrome/cros_kbd_led_backlight.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_kbd_led_backlight.c b/drivers/platform/chrome/cros_kbd_led_backlight.c
> index 5ad41c10412d..793fd3f1015d 100644
> --- a/drivers/platform/chrome/cros_kbd_led_backlight.c
> +++ b/drivers/platform/chrome/cros_kbd_led_backlight.c
> @@ -119,7 +119,7 @@ static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
>
>  #endif /* CONFIG_ACPI */
>
> -#ifdef CONFIG_CROS_EC
> +#if IS_ENABLED(CONFIG_CROS_EC)
>
>  static int
>  keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
> @@ -180,18 +180,18 @@ static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
>         return 0;
>  }
>
> -static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
> +static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
>         .init = keyboard_led_init_ec_pwm,
>         .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
>         .brightness_get = keyboard_led_get_brightness_ec_pwm,
>         .max_brightness = KEYBOARD_BACKLIGHT_MAX,
>  };
>
> -#else /* CONFIG_CROS_EC */
> +#else /* IS_ENABLED(CONFIG_CROS_EC) */
>
> -static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
> +static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
>
> -#endif /* CONFIG_CROS_EC */
> +#endif /* IS_ENABLED(CONFIG_CROS_EC) */
>
>  static int keyboard_led_probe(struct platform_device *pdev)
>  {
> --
> 2.37.0.170.g444d1eabd0-goog
>

Re: [PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[Tzung-Bi Shih]

On Mon, Jul 18, 2022 at 06:28:22AM -0700, Guenter Roeck wrote:
> On Mon, Jul 18, 2022 at 3:51 AM Tzung-Bi Shih <tzungbi@kernel.org> wrote:
> >
> > drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning
> > when using the randconfig in [1]:
> > >>> warning: unused variable 'keyboard_led_drvdata_ec_pwm'
> >
> > The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set.
> > Reproduce:
> > - mkdir build_dir
> > - wget [1] -O build_dir/.config
> > - COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \
> >   O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/
> >
> > Fix the warning by using __maybe_unused.  Also use IS_ENABLED() because
> > CROS_EC is a tristate.
> 
> Is that sufficient ? What happens if CROS_KBD_LED_BACKLIGHT=y and
> CROS_EC=m ? I suspect you might need IS_REACHABLE() instead of
> IS_ENABLED().

For current code, it's impossible to set CROS_KBD_LED_BACKLIGHT=y and
CROS_EC=m without setting ACPI=y.  Given that the dependencies:
CHROME_PLATFORMS [=y] && LEDS_CLASS [=y] && (ACPI [=n] || CROS_EC [=m]).

$ ./scripts/kconfig/merge_config.sh -n <(cat <<EOF
CONFIG_MODULES=y

CONFIG_NEW_LEDS=y
CONFIG_LEDS_CLASS=y

CONFIG_CHROME_PLATFORMS=y
CONFIG_CROS_EC=m
CONFIG_CROS_KBD_LED_BACKLIGHT=y
EOF
)
[...]
Value requested for CONFIG_CROS_KBD_LED_BACKLIGHT not in final .config
Requested value:  CONFIG_CROS_KBD_LED_BACKLIGHT=y
Actual value:     CONFIG_CROS_KBD_LED_BACKLIGHT=m


However, when ACPI=y, `keyboard_led_drvdata_ec_pwm` is unused.  Instead, it
uses `keyboard_led_drvdata_acpi` for current code.

I guess IS_ENABLED() is sufficient.  Does it make sense?

Re: [PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[Guenter Roeck]

On Mon, Jul 18, 2022 at 9:54 PM Tzung-Bi Shih <tzungbi@kernel.org> wrote:
>
> On Mon, Jul 18, 2022 at 06:28:22AM -0700, Guenter Roeck wrote:
> > On Mon, Jul 18, 2022 at 3:51 AM Tzung-Bi Shih <tzungbi@kernel.org> wrote:
> > >
> > > drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning
> > > when using the randconfig in [1]:
> > > >>> warning: unused variable 'keyboard_led_drvdata_ec_pwm'
> > >
> > > The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set.
> > > Reproduce:
> > > - mkdir build_dir
> > > - wget [1] -O build_dir/.config
> > > - COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \
> > >   O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/
> > >
> > > Fix the warning by using __maybe_unused.  Also use IS_ENABLED() because
> > > CROS_EC is a tristate.
> >
> > Is that sufficient ? What happens if CROS_KBD_LED_BACKLIGHT=y and
> > CROS_EC=m ? I suspect you might need IS_REACHABLE() instead of
> > IS_ENABLED().
>
> For current code, it's impossible to set CROS_KBD_LED_BACKLIGHT=y and
> CROS_EC=m without setting ACPI=y.  Given that the dependencies:
> CHROME_PLATFORMS [=y] && LEDS_CLASS [=y] && (ACPI [=n] || CROS_EC [=m]).
>
> $ ./scripts/kconfig/merge_config.sh -n <(cat <<EOF
> CONFIG_MODULES=y
>
> CONFIG_NEW_LEDS=y
> CONFIG_LEDS_CLASS=y
>
> CONFIG_CHROME_PLATFORMS=y
> CONFIG_CROS_EC=m
> CONFIG_CROS_KBD_LED_BACKLIGHT=y
> EOF
> )
> [...]
> Value requested for CONFIG_CROS_KBD_LED_BACKLIGHT not in final .config
> Requested value:  CONFIG_CROS_KBD_LED_BACKLIGHT=y
> Actual value:     CONFIG_CROS_KBD_LED_BACKLIGHT=m
>

It is actually possible to configure CONFIG_CROS_KBD_LED_BACKLIGHT=y
with CONFIG_CROS_EC=m, by also setting CONFIG_LEDS_CLASS=y. However,
that doesn't seem to matter since the critical symbol is CROS_EC_PROTO
which is boolean.
Given that, IS_ENABLED should be fine.

Reviewed-by: Guenter Roeck <groeck@chromium.org>

Thanks,
Guenter

> However, when ACPI=y, `keyboard_led_drvdata_ec_pwm` is unused.  Instead, it
> uses `keyboard_led_drvdata_acpi` for current code.
>
> I guess IS_ENABLED() is sufficient.  Does it make sense?

Re: [PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[patchwork-bot+chrome-platform]

Hello:

This patch was applied to chrome-platform/linux.git (for-kernelci)
by Tzung-Bi Shih <tzungbi@kernel.org>:

On Mon, 18 Jul 2022 10:50:47 +0000 you wrote:
> drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning
> when using the randconfig in [1]:
> >>> warning: unused variable 'keyboard_led_drvdata_ec_pwm'
> 
> The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set.
> Reproduce:
> - mkdir build_dir
> - wget [1] -O build_dir/.config
> - COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \
>   O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/
> 
> [...]

Here is the summary with links:
  - [v2] platform/chrome: cros_kbd_led_backlight: fix build warning
    https://git.kernel.org/chrome-platform/c/7e76e4bc0099

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH v2] platform/chrome: cros_kbd_led_backlight: fix build warning

[patchwork-bot+chrome-platform]

Hello:

This patch was applied to chrome-platform/linux.git (for-next)
by Tzung-Bi Shih <tzungbi@kernel.org>:

On Mon, 18 Jul 2022 10:50:47 +0000 you wrote:
> drivers/platform/chrome/cros_kbd_led_backlight.c got a new build warning
> when using the randconfig in [1]:
> >>> warning: unused variable 'keyboard_led_drvdata_ec_pwm'
> 
> The warning happens when CONFIG_CROS_EC is set but CONFIG_OF is not set.
> Reproduce:
> - mkdir build_dir
> - wget [1] -O build_dir/.config
> - COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 \
>   O=build_dir ARCH=s390 SHELL=/bin/bash drivers/platform/chrome/
> 
> [...]

Here is the summary with links:
  - [v2] platform/chrome: cros_kbd_led_backlight: fix build warning
    https://git.kernel.org/chrome-platform/c/7e76e4bc0099

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html