Date:   Mon, 22 Jun 2020 14:42:11 +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 6/21/20 10:24 PM, Jacek Anaszewski wrote:
> Dan,
> 
> On 6/21/20 4:12 PM, Dan Murphy wrote:
>> Jacek
>>
>> On 6/19/20 5:10 PM, Jacek Anaszewski wrote:
>>> 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.
>>>
>> I was not removing the dependency for the LP50xx only the LP55xx.
> 
> It was my typo, I meant LP55XX.
> 
>>
>>> This is actually why the above entry was needed.
>>>
>>> LP55XX drivers have to work also without multicolor class.
>>>
>> Well I am not sure how else to resolve this problem.  Because the 
>> LP55xx has multi level dependencies.
>>
>> Only the LP55xx_common has the dependency on the MC framework. The 
>> device drivers do not.
>>
>> The issue is the mixing and matching of the MC fw as a module vs the 
>> LP55XX_COMMON as a built-in.
> 
> The simplest solution is to avoid selecting LP55XX_COMMON in favor
> of making child drivers depending on it. Of course, maybe there exists
> some trickier option to keep the selection, but I would have to play
> a bit more with it to be sure.

Yep, this seems to be the only viable solution.

My proposed change to the Kconfig:

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index adfa762cb291..10de7d237ffd 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -397,10 +397,10 @@ 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 OF
         select FW_LOADER
         select FW_LOADER_USER_HELPER
+       depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR
         help
           This option supports common operations for 
LP5521/5523/55231/5562/8501
           devices.
@@ -408,8 +408,7 @@ config LEDS_LP55XX_COMMON
  config LEDS_LP5521
         tristate "LED Support for N.S. LP5521 LED driver chip"
         depends on LEDS_CLASS && I2C
-       depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR
-       select LEDS_LP55XX_COMMON
+       depends on LEDS_LP55XX_COMMON
         help
           If you say yes here you get support for the National 
Semiconductor
           LP5521 LED driver. It is 3 channel chip with programmable 
engines.
@@ -419,8 +418,7 @@ config LEDS_LP5521
  config LEDS_LP5523
         tristate "LED Support for TI/National LP5523/55231 LED driver chip"
         depends on LEDS_CLASS && I2C
-       depends on LEDS_CLASS_MULTI_COLOR || !LEDS_CLASS_MULTI_COLOR
-       select LEDS_LP55XX_COMMON
+       depends on LEDS_LP55XX_COMMON
         help
           If you say yes here you get support for TI/National Semiconductor
           LP5523/55231 LED driver.
@@ -431,7 +429,7 @@ config LEDS_LP5523
  config LEDS_LP5562
         tristate "LED Support for TI LP5562 LED driver chip"
         depends on LEDS_CLASS && I2C
-       select LEDS_LP55XX_COMMON
+       depends on LEDS_LP55XX_COMMON
         help
           If you say yes here you get support for TI LP5562 LED driver.
           It is 4 channels chip with programmable engines.
@@ -441,7 +439,7 @@ config LEDS_LP5562
  config LEDS_LP8501
         tristate "LED Support for TI LP8501 LED driver chip"
         depends on LEDS_CLASS && I2C
-       select LEDS_LP55XX_COMMON
+       depends on LEDS_LP55XX_COMMON
         help
           If you say yes here you get support for TI LP8501 LED driver.
           It is 9 channel chip with programmable engines.


-- 
Best regards,
Jacek Anaszewski

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