# Re: \[PATCH v3\] clk: exynos7: Keep aclk\_fsys1\_200 enabled

- From: Sylwester Nawrocki \<snawrocki@kernel.org\>
- Date: 2021-02-01 15:24:44 
- List: linux-arm-kernel
- Page: https://ratatoskr.run/linux-arm-kernel/2021/02/6253862
- Thread: https://ratatoskr.run/linux-samsung-soc/2021/02/6253862/t.md

```text
On 1/31/21 18:04, Paweł Chmiel wrote:
> This clock must be always enabled to allow access to any registers in
> fsys1 CMU. Until proper solution based on runtime PM is applied
> (similar to what was done for Exynos5433), fix this by calling
> clk_prepare_enable() directly from clock provider driver.
>
> It was observed on Samsung Galaxy S6 device (based on Exynos7420), where
> UFS module is probed before pmic used to power that device.
> In this case defer probe was happening and that clock was disabled by
> UFS driver, causing whole boot to hang on next CMU access.
>
> Signed-off-by: Paweł Chmiel <redacted>
> ---
> Changes from v2:
>    - Avoid __clk_lookup() call when enabling clock
> Changes from v1:
>    - Instead of marking clock as critical, enable it manually in driver.

Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

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