Re: [PATCH 2/2] clk: qcom: dispcc-sdm845: park disp_cc_mdss_mdp_clk_src

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Tue 07 Dec 18:22 PST 2021, Dmitry Baryshkov wrote:

> To stop disp_cc_mdss_mdp_clk_src from getting stuck during boot if it
> was enabled by the bootloader, part it to the TCXO clock source.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  drivers/clk/qcom/dispcc-sdm845.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/clk/qcom/dispcc-sdm845.c b/drivers/clk/qcom/dispcc-sdm845.c
> index 735adfefc379..f2afbba7bc72 100644
> --- a/drivers/clk/qcom/dispcc-sdm845.c
> +++ b/drivers/clk/qcom/dispcc-sdm845.c
> @@ -858,6 +858,9 @@ static int disp_cc_sdm845_probe(struct platform_device *pdev)
>  
>  	clk_fabia_pll_configure(&disp_cc_pll0, regmap, &disp_cc_pll0_config);
>  
> +	/* Park disp_cc_mdss_mdp_clk_src */
> +	clk_rcg2_park_safely(regmap, 0x2088, 0);

Today booting the system with "clk_ignore_unused" will give you a
working efifb up until the point where the display driver kicks in and
reinitializes the hardware state - which during development might be
indefinite.

If we blindly cut the mdp_clk_src here that will no longer be possible.

Regards,
Bjorn

> +
>  	/* Enable hardware clock gating for DSI and MDP clocks */
>  	regmap_update_bits(regmap, 0x8000, 0x7f0, 0x7f0);
>  
> -- 
> 2.33.0
>