Date:   Sat, 20 Jun 2020 00:10:04 +0200
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Dan Murphy <dmurphy@...com>, pavel@....cz, robh@...nel.org
Cc:     kbuild-all@...ts.01.org, devicetree@...r.kernel.org,
        linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH v27 11/15] leds: lp55xx: Add multicolor framework
 support to lp55xx

Dan,

On 6/19/20 6:35 PM, Dan Murphy wrote:
> Jacek
> 
> On 6/18/20 6:26 PM, Jacek Anaszewski wrote:
>> On 6/19/20 12:09 AM, Jacek Anaszewski wrote:
>>> Dan,
>>>
>>> On 6/18/20 11:44 PM, Dan Murphy wrote:
>>>> Jacek
>>>>
>>>> On 6/18/20 4:21 PM, Jacek Anaszewski wrote:
>>>>> Dan,
>>>>>
>>>>> On 6/18/20 12:33 AM, Dan Murphy wrote:
>>>>>> Jacek
>>>>>>
>>>>>> On 6/17/20 4:41 PM, Jacek Anaszewski wrote:
>>>>>>> Dan,
>>>>>>>
>>>>>>> On 6/17/20 9:22 PM, Dan Murphy wrote:
>>>>>>>> Pavel/Jacek
>>>>>>>>
>>>>>>>> On 6/17/20 11:28 AM, kernel test robot wrote:
>>>>>>>>> Hi Dan,
>>>>>>>>>
>>>>>>>>> I love your patch! Yet something to improve:
>>>>>>>>>
>>>>>>>>> [auto build test ERROR on pavel-linux-leds/for-next]
>>>>>>>>> [cannot apply to j.anaszewski-leds/for-next]
>>>>>>>>> [if your patch is applied to the wrong git tree, please drop us 
>>>>>>>>> a note to help
>>>>>>>>> improve the system. BTW, we also suggest to use '--base' option 
>>>>>>>>> to specify the
>>>>>>>>> base tree in git format-patch, please see 
>>>>>>>>> https://stackoverflow.com/a/37406982]
>>>>>>>>>
>>>>>>>>> url: 
>>>>>>>>> https://github.com/0day-ci/linux/commits/Dan-Murphy/Multicolor-Framework-v27/20200616-042217 
>>>>>>>>>
>>>>>>>>> base: 
>>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds.git 
>>>>>>>>> for-next
>>>>>>>>> config: ia64-randconfig-r015-20200617 (attached as .config)
>>>>>>>>> compiler: ia64-linux-gcc (GCC) 9.3.0
>>>>>>>>> reproduce (this is a W=1 build):
>>>>>>>>>          wget 
>>>>>>>>> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross 
>>>>>>>>> -O ~/bin/make.cross
>>>>>>>>>          chmod +x ~/bin/make.cross
>>>>>>>>>          # save the attached .config to linux build tree
>>>>>>>>>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 
>>>>>>>>> make.cross ARCH=ia64
>>>>>>>>>
>>>>>>>>> If you fix the issue, kindly add following tag as appropriate
>>>>>>>>> Reported-by: kernel test robot <lkp@...el.com>
>>>>>>>>>
>>>>>>>>> All errors (new ones prefixed by >>, old ones prefixed by <<):
>>>>>>>>>
>>>>>>>>> ia64-linux-ld: drivers/leds/leds-lp55xx-common.o: in function 
>>>>>>>>> `lp55xx_set_mc_brightness':
>>>>>>>>>>> drivers/leds/leds-lp55xx-common.c:146: undefined reference to 
>>>>>>>>>>> `led_mc_calc_color_components'
>>>>>>>>> ia64-linux-ld: drivers/leds/leds-lp55xx-common.o: in function 
>>>>>>>>> `devm_led_classdev_multicolor_register':
>>>>>>>>>>> include/linux/led-class-multicolor.h:74: undefined reference 
>>>>>>>>>>> to `devm_led_classdev_multicolor_register_ext'
>>>>>>>>> vim +146 drivers/leds/leds-lp55xx-common.c
>>>>>>>>>
>>>>>>>>>     138
>>>>>>>>>     139    static int lp55xx_set_mc_brightness(struct 
>>>>>>>>> led_classdev *cdev,
>>>>>>>>>     140                        enum led_brightness brightness)
>>>>>>>>>     141    {
>>>>>>>>>     142        struct led_classdev_mc *mc_dev = 
>>>>>>>>> lcdev_to_mccdev(cdev);
>>>>>>>>>     143        struct lp55xx_led *led = mcled_cdev_to_led(mc_dev);
>>>>>>>>>     144        struct lp55xx_device_config *cfg = led->chip->cfg;
>>>>>>>>>     145
>>>>>>>>>   > 146 led_mc_calc_color_components(&led->mc_cdev, brightness);
>>>>>>>>>     147        return cfg->multicolor_brightness_fn(led);
>>>>>>>>>     148
>>>>>>>>
>>>>>>>> Well this was a mess to figure out.
>>>>>>>>
>>>>>>>> The only fix I can figure out here is to remove the
>>>>>>>>
>>>>>>>>      depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR
>>>>>>>>
>>>>>>>> from each child device and add
>>>>>>>>
>>>>>>>>      select LEDS_CLASS_MULTI_COLOR
>>>>>>>>
>>>>>>>> to the LP55XX_COMMON
>>>>>>>>
>>>>>>>> This way the Multi color framework will inherit the symbol that 
>>>>>>>> was set by the COMMON flag which is inherited by majority from 
>>>>>>>> the child flags.
>>>>>>>
>>>>>>> Did you try this?
>>>>>>>
>>>>>>> --- a/drivers/leds/Kconfig
>>>>>>> +++ b/drivers/leds/Kconfig
>>>>>>> @@ -398,6 +398,7 @@ config LEDS_LP50XX
>>>>>>>  config LEDS_LP55XX_COMMON
>>>>>>>         tristate "Common Driver for TI/National 
>>>>>>> LP5521/5523/55231/5562/8501"
>>>>>>>         depends on LEDS_LP5521 || LEDS_LP5523 || LEDS_LP5562 || 
>>>>>>> LEDS_LP8501
>>>>>>> +       depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR
>>>>>>>         depends on OF
>>>>>>>         select FW_LOADER
>>>>>>>         select FW_LOADER_USER_HELPER
>>>>>>>
>>>>>>>
>>>>>> Yes I did
>>>>>>
>>>>>> That gave unmet dependencies.
>>>>>>
>>>>>> WARNING: unmet direct dependencies detected for LEDS_LP55XX_COMMON
>>>>>>    Depends on [m]: NEW_LEDS [=y] && (LEDS_LP5521 [=n] || 
>>>>>> LEDS_LP5523 [=m] || LEDS_LP5562 [=y] || LEDS_LP8501 [=y]) && 
>>>>>> (LEDS_CLASS_MULTI_COLOR [=m] || !LEDS_CLASS_MULTI_COLOR [=m]) && 
>>>>>> OF [=y]
>>>>>>    Selected by [y]:
>>>>>>    - LEDS_LP5562 [=y] && NEW_LEDS [=y] && LEDS_CLASS [=y] && I2C [=y]
>>>>>>    - LEDS_LP8501 [=y] && NEW_LEDS [=y] && LEDS_CLASS [=y] && I2C [=y]
>>>>>>    Selected by [m]:
>>>>>>    - LEDS_LP5523 [=m] && NEW_LEDS [=y] && LEDS_CLASS [=y] && I2C 
>>>>>> [=y] && (LEDS_CLASS_MULTI_COLOR [=m] || !LEDS_CLASS_MULTI_COLOR [=m])
>>>>>>
>>>>>
>>>>> When I was testing that yesterday I also had the same warning at some
>>>>> point of testing different Kconfig setups, but with what I showed 
>>>>> above
>>>>> it ceased to appear. Now every time I am doing "make oldconfig" the
>>>>> CONFIG_LEDS_LP55XX_COMMON=y entry gets changed to =m with the config
>>>>> from the test bot.
>>>>>
>>>> That is not what I saw in my testing especially after doing a distclean
>>>
>>> Could you please give your exact steps after "make distclean" and
>>> copying test bot config to the kernel root directory?
>>>
>>> Also, please share the toolchain you're using for tests.
>>
>> Actually at this stage the toolchain is of lesser relevance.
>>
>> I've tried once more and indeed the problem shows up.
>>
>> It is caused by the driver entries doing
>>
>> "select LEDS_LP55XX_COMMON".
>>
>> Select sets config to "y" so it conflicts with
>> "depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR"
>> in the "config LEDS_LP55XX_COMMON".
>>
>> Your proposed fix will block the possibility of building
>> LED_CLASS_MULTI_COLOR as a module when LP55XX drivers
>> are enabled so this is also not an option.
>>
>> Solving this riddle will require some more thinking.
>> I haven't analyzed it in detail but maybe "imply" statement from
>> kconfig-language.rst could help somehow here. 
> 
> The multicolor framework will build as a module if the LED_CLASS is 
> defined as a module.
> 
> See attached test_defconfig

But it will be impossible to enable CONFIG_LEDS_LP50XX without
CONFIG_LEDS_CLASS_MULTI_COLOR if you will remove

depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR.

This is actually why the above entry was needed.

LP55XX drivers have to work also without multicolor class.

> 
> defconfig contents
> 
> CONFIG_NEW_LEDS=y
> CONFIG_LEDS_CLASS=y
> CONFIG_LEDS_CLASS_MULTI_COLOR=m
> CONFIG_LEDS_LP50XX=m
> CONFIG_LEDS_LP55XX_COMMON=y
> CONFIG_LEDS_LP5523=m
> CONFIG_LEDS_LP5562=m
> CONFIG_LEDS_LP8501=m
> 
> Output is
> 
> CONFIG_NEW_LEDS=y
> CONFIG_LEDS_CLASS=y
> CONFIG_LEDS_CLASS_MULTI_COLOR=m
> CONFIG_LEDS_LP50XX=m
> CONFIG_LEDS_LP55XX_COMMON=m
> CONFIG_LEDS_LP5523=m
> CONFIG_LEDS_LP5562=m
> CONFIG_LEDS_LP8501=m
> 
> If any of the children are built in then the MC framework must be built 
> in as well.
> 
> Dan
> 
> 

-- 
Best regards,
Jacek Anaszewski

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