Help: i.MX8MP AUDIOMIX BLK-CTRL CLK driver support

[Peng Fan]

Hi Marek,

On 9/26/2022 8:04 AM, Marek Vasut wrote:
> On 9/23/22 05:41, Peng Fan wrote:
>> Hi All,
> 
> Hi,
> 
>> I would start a discussion about the A/B B/A lock issue when make 
>> audiomix blk ctrl function as clk provider.
>>
>> I not have good idea on this, hope you have any suggestions.
>>
>> major issue is: the blk ctrl clk has a power domain supplier
>> The power domain supplier also use clk API to prepare_enable clks.
>> The blk ctrl clk driver has runtime pm enabled.
>>
>> The NXP downstream:
>> The dts:
>> https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8mp.dtsi#L1872
>>
>> The driver:
>> https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/drivers/clk/imx/clk-imx8mp.c
>> https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/drivers/clk/imx/clk-blk-ctrl.c
>>
>> Note: The following log was reproduced with NXP downstream. For upstream
>> I think we have similar issue if we still take audiomix blk ctrl as clk
>> driver. Because the gpcv2 also use clk prepare enable API.
>> 1. deadlock 1:
>> Callchain after enable some lock debug:
>> clk_ignore_unused will use lock seq: take prepare lock, take blk-ctrl 
>> parent power domain genpd lock
>> genpd_power_off_work_fun will use lock seq: take the power domain 
>> genpd lock, take prepare lock.
> 
> There is also this driver which does not suffer from the problem, at 
> least I didn't trigger it while using it for months:
> 
> https://patchwork.kernel.org/project/linux-clk/patch/20220625013235.710346-3-marex@denx.de/

yes, I see that, I thought Abel picked up, but seems still not land in.
I'll use your patches and need apply to nxp 5.15 tree for some test.

Thanks,
Peng.