[PATCH v2] driver: pwm: pwm-imx: fix probing on imx6

[Heiko Schocher]

Hello Tom,

On 13.08.24 18:16, Tom Rini wrote:
> On Tue, Aug 13, 2024 at 03:57:08PM +0200, Heiko Schocher wrote:
>> Hello Fabio, Tom,
>>
>> On 13.08.24 14:27, Fabio Estevam wrote:
>>> Hi Heiko,
>>>
>>> On Wed, Aug 7, 2024 at 12:53 PM Heiko Schocher <hs at denx.de> wrote:
>>>>
>>>> U-Boot 2024.07 drops on aristainetos2 board the following
>>>> warning:
>>>>
>>>>           Failed to enable per_clk
>>>>
>>>> and bootlogo is not seen on LVDS display.
>>>>
>>>> This patch uses old behaviour for systems without clock framework
>>>> if CONFIG_CLK is not enabled.
>>>>
>>>> Fixes: bfc778cb93a3 ("driver: pwm: pwm-imx: get and enable per/ipg clock using dm")
>>>>
>>>> Signed-off-by: Heiko Schocher <hs at denx.de>
>>>> ---
>>>>
>>>> Changes in v2:
>>>> use CONFIG_IS_ENABLED instead of IS_ENABLED
>>>> as Anatolij suggested.
>>>
>>> This causes build failures:
>>>
>>> https://source.denx.de/u-boot/custodians/u-boot-imx/-/jobs/887503
>>>
>>> Please fix and resend.
>>
>> Hmm... yes ... I work/worked on aristainetos2 board update for 2024.07
>> (or later)  ... and saw this
>>
>>    Failed to enable per_clk
>>
>> warning when 2024.07 boots ... and bootlogo did not work anymore, as
>> backlight is pwm driven on this hardware...
>>
>> I bet, for all the boards which fail in the azure run with this patch,
>> PWM do not work anymore... because CONFIG_CLK is not enabled for them!
>>
>> I am really unhappy, that I have no automated U-Boot runtime tests anymore
>> running on real hardware... setup with tbot was very easy, but had no
>> time for looking at the bugs poping up...
>>
>> Hmm... looking in git history, there comes this commit in my eyes:
>>
>> commit 4eea76574062e9079b6a267229962d6ec0be910a
>> Author: Tom Rini <trini at konsulko.com>
>> Date:   Sat Nov 19 18:45:18 2022 -0500
>>
>>      pwm: imx: Remove unused references to CONFIG_IMX6_PWM_PER_CLK
>>
>>      On platforms that use DM_PWM, we do not need to define this value
>>      anymore, so remove it from config files.
>>
>>      Signed-off-by: Tom Rini <trini at konsulko.com>
>>
>> which exactly removes for all breaking boards this define...
>>
>> Should we revert this patch?
>>
>> I just can say for the aristianetos2 board, that I readded exactly this
>> define in my work for the port to currentmainline ... and with my patch,
>> pwm and so bootlogo works again ...
> 
> We can't do a strict revert, no, the symbol is now CFG_IMX6_PWM_PER_CLK.
> But also, isn't this board using DM_PWM? And if so, that value isn't
> used?

Yes, of course, simple revert does not work.

Yes, the failing boards are converted to DM_PWM, but they do not work
anymore as bfc778cb93a3 intrdocued clk framework functions, and the
failing boards have no clk framwork enabled. So my patch simply
readded the define for DM_PWM case.

bye,
Heiko
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