Re: [PATCH v2 7/9] clk: samsung: exynos850: Implement CMU_MFCMSCL domain

[Krzysztof Kozlowski]

On 09/08/2022 14:33, Sam Protsenko wrote:
> CMU_MFCMSCL clock domain provides clocks for MFC (Multi-Format Codec),
> JPEG Codec and Scaler IP-cores. According to Exynos850 TRM, CMU_MFCMSCL
> generates MFC, M2M, MCSC and JPEG clocks for BLK_MFCMSCL.
> 
> This patch adds next clocks:
>   - bus clocks in CMU_TOP for CMU_MFCMSCL
>   - all internal CMU_MFCMSCL clocks
>   - leaf clocks for MFCMSCL, TZPC (TrustZone Protection Controller),
>     JPEG codec, M2M (Memory-to-Memory), MCSC (Multi-Channel Scaler),
>     MFC (Multi-Format Codec), PPMU (Platform Performance Monitoring
>     Unit), SysMMU and SysReg
> 
> MFCMSCL related gate clocks in CMU_TOP were marked as CLK_IS_CRITICAL,
> because:
>   1. All of those have to be enabled in order to read
>      /sys/kernel/debug/clk/clk_summary file
>   2. When some user driver (e.g. exynos-sysmmu) disables some derived
>      leaf clock, it can lead to CMU_TOP clocks disable, which then makes
>      the system hang. To prevent that, the CLK_IS_CRITICAL flag is used,
>      as CLK_IGNORE_UNUSED is not enough.

No, same as with ISP these are not critical clocks.

Best regards,
Krzysztof