Re: [PATCH V2 06/12] clk: tegra: add suspend resume support for DFLL clock

[Peter De Schrijver <pdeschrijver@xxxxxxxxxx>]

On Tue, May 28, 2019 at 04:08:50PM -0700, Sowjanya Komatineni wrote:
> This patch adds support for suspend and resume for DFLL clock.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> ---
>  drivers/clk/tegra/clk-dfll.c | 82 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/clk/tegra/clk-dfll.h |  2 ++
>  2 files changed, 84 insertions(+)
> 
> diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
> index 1fc71baae13b..d92a5a05fbbc 100644
> --- a/drivers/clk/tegra/clk-dfll.c
> +++ b/drivers/clk/tegra/clk-dfll.c
> @@ -286,6 +286,7 @@ struct tegra_dfll {
>  	unsigned long			dvco_rate_min;
>  
>  	enum dfll_ctrl_mode		mode;
> +	enum dfll_ctrl_mode		resume_mode;
>  	enum dfll_tune_range		tune_range;
>  	struct dentry			*debugfs_dir;
>  	struct clk_hw			dfll_clk_hw;
> @@ -1873,6 +1874,87 @@ static int dfll_fetch_common_params(struct tegra_dfll *td)
>  }
>  
>  /*
> + * tegra_dfll_suspend
> + * @pdev: DFLL instance
> + *
> + * dfll controls clock/voltage to other devices, including CPU. Therefore,
> + * dfll driver pm suspend callback does not stop cl-dvfs operations. It is
> + * only used to enforce cold voltage limit, since SoC may cool down during
> + * suspend without waking up. The correct temperature zone after suspend will
> + * be updated via dfll cooling device interface during resume of temperature
> + * sensor.

Temperature dependent cl-dvfs is not yet implemented in upstream, so
leave out the part about cold voltage limits and temperature zones.

Peter.